Clay Minerals (1984) 19, 681-707
THE
S O I L C L A Y S OF G R E A T B R I T A I N :
I. E N G L A N D
AND WALES
P. J. L O V E L A N D
Sail Survey of England and Wales, Rothamsted Experimental Station, Harpenden, Hertfordshire AL5 2JQ
(Received 12 March 1984; revised 17 May 1984)
A B S T R A C T : The mineralogy of the clay fractions (<2 ~tm)of the major soils of England and
Wales is reviewed, and the data presented in terms of the 1:250 000 National Soil Map. Most
soils developed in pre-Rhaetic sediments are dominated by mica with lesser amounts of chlorite
and kaolin. Exceptions are soils developed in calcareous Coal Measure shales which have
significant smectite contents, and freely drained soils in Keuper Marl which contain swelling
chlorite, sepiolite and palygorskite. Soils developed in post-Triassic sediments are dominated
generally by expansible minerals, except for those developed in Lower Lias and Estuarine Series
rocks (Jurassic) which are dominated by mica and kaolin respectively. The presence of loess in
soils seems to be associated with the occurrence of a complex interstratified mineral with X-ray
diffraction properties akin to vermiculite. Weathering of soil clays is most marked in the wetter
uplands, but over most of lowland England is detectable only by slight changes in
non-exchangeable potassium content and cation exchange capacity towards the soil surface.
Applications of soil clay mineralogy in the fields of plant nutrition and soil mechanics are
discussed, in particular the production of maps showing mineralogical provinces.
A s early as 1911, Hall & Russell pointed out that soil clays were of more than one 'type'.
The work on soil clays or soil-clay-related phenomena in the first decades of this century
concentrated on either adsorptive processes (water sorption, cation exchange), or major
element chemistry (particularly the ratios between A120 3, SiO2 and F e 2 0 3 ) - - s e e , for
example, Prescott (1916) and Crowther (1930) for respective reviews. Mineralogical
studies o f soil clays per se grew out o f the application o f X - r a y diffraction techniques by
Nagelschmidt, working at R o t h a m s t e d Experimental Station (1939, 1944). Schofield
(1940) reiterated the importance of the clay fraction for understanding the chemical and
physical properties o f the soil.
These ideas, coupled with post-war development of X - r a y techniques and allied
chemistry, led to considerable investigation of the soil clays of England and Wales. By the
late 1960s it was believed that a knowledge of such mineralogy would provide basic
information related to m a n y soil properties, and would be a useful adjunct in soil
classification (B. W. Avery, pets. c o m m . ) - - m u c h as has now happened in the United States
(Soil Survey Staff, 1975). To this end the Soil Survey of England and Wales ( S S E W ) has
determined the mineralogy o f the < 2 r
fractions o f many o f the more extensive soils.
Some of the earlier work was reviewed b y A v e r y & Bullock (1977), who showed that there
were significant and consistent differences in the clay mineralogy of the soils of England
and Wales. M o s t of the information is, however, unpublished. This paper aims both to
extend the work of A v e r y & Bullock (1977) and to incorporate earlier work by giving a
general overview of the subject as it stands at present. The d a t a are presented in terms o f
9 1984 The Mineralogical Society
682
P. J. Loveland
soil series which in turn are related to the soil associations shown on the recently published
1 : 250 000 soil map of England and Wales (Soil Survey of England and Wales, 1983). It is
believed that this map is currently the most useful vehicle by which general information of
this kind can be conveyed.
SOURCES
AND
METHODS
The SSEW has clay mineral data for (largely) the B, BC and C horizons of some 680 soil
profiles, determined by methods given in Bullock & Loveland (1974), in the form of:
(i) semi-quantitative estimates of phyllosilicate species derived from X R D line profiles;
(ii) cation-exchange capacity;
(iii) non-exchangeable potassium content (as % KzO).
These data are used to assign the clay to a mineral class--smectitic, vermiculitic,
micaceous, chloritic, kaolinitic, or mixed (Avery & Bullock, 1977). Fig. 1 shows the
present class boundaries and the relationships between the chemical parameters and the
dominant mineralogy derived from X R D data alone. 'Dominant' means that the content of
I00'
e-Expansible
o- M i c a c e o u s
9 Chloritic/Mixed
0 0
80"
-'~ - K a o l i n i t i c
9
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.-.
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o
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o o
~
odd
0
9
CM
~l~'l
0
0
CI~
0
K
I0
~K20
FIG. 1. Relationships between non-exchangeable KzO content, cation exchange capacity,
mineralogy determined by XRD and clay mineral class boundaries. SV = smectitic/vermiculitic
('expansible');Mi = micaceous; CM = chloritic/mixed; K = kaolinitic.
Soil clays of England and Wales
683
the relevant species (mica, chlorite etc.) exceeds that of any other by 25% or more. Given
the approximations involved, the agreement between class boundaries and chemical data
as shown in Fig. 1 is not unreasonable, although it is clear that the 'mixed' class represents
a considerable problem 9 The micaceous class boundary is altered from that of Avery &
Bullock (1977) to a K 2 0 value of 3% instead of 3.5%. There is some suggestion that the
boundary between the smectitic/vermiculitic classes and the other classes might be drawn
better at 50 m E q / 1 0 0 g, but this awaits further consideration although it does accord with
earlier proposals (B. W. Avery, pers. comm.). There are very few soil clay fractions
dominated, on X-ray evidence, by chlorite or kaolin, and none dominated by vermiculite.
The latter finding suggests that for practical purposes the smectitic/vermiculitic classes
may be best considered as one class of 'expansible' mineralogy.
9
~
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:~
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FIG. 2. Locations of soil sampling points.
~ Ibl.~.j.
9
684
P..1. Loveland
A literature search yielded data for a further 80 or so profiles which could be recast
reliably in the terms outlined above. All the sites are plotted in Fig. 2. Other reports giving
X-ray data only were utilized with caution, but often provided confirmation of
extrapolations made from the more complete data.
Finally, it should be noted that this paper deals almost exclusively with the mineralogy
of the <2 am separates from soils. Extrapolation from geological reports to soils is fraught
with difficulties, given, for example, the variable nature of glacial and periglacial
modification to the soil cover in England and Wales (Catt, 1979), and whilst such
extrapolations have been made in this paper they represent an approximation of uncertain
and varying magnitude.
TERMINOLOGY
Given the difficulty of precise identification of soil clay minerals, certain generalizations
have been necessary. The general term smectite has been preferred to the mineral name
montmorillonite. Minerals with a glycollated (001) reflection ~>17 /k (Mg 2+- or Ca 2+saturated) and an associated rational series of 00l reflections have not been reported from
our soils, although Weir & Catt (1965) suggested that the absence of rational reflections
may result from poor crystallinity/sample orientation. However, most reports of smectite
minerals in the soils of Britain have been of randomly interstratified dioctahedral species
with mica as the commonest co-mineral. Mica seems to have been used synonymously
with 'illite' in the British soil-clay literature to describe a K-depleted, hydrous, dioctahedral
phyllosilicate with d(00/) near to 10 A and a rational series of 001 reflections, and is the
term used in this paper so as to conform with the class name usage given earlier. With the
exception of glauconite, specific identification of other mica-group minerals, e.g.
muscovite, biotite etc., in the soil clays of England and Wales seems to have been
attempted only rarely.
Whilst an attempt has been made to name randomly interstratified minerals
systematically by both relevant species name and by giving the minor component(s) first,
the information to do this has not always been available. In many cases, the minerals are
very poorly defined in XRD terms and some simplification has been inevitable (Weir et al.,
1969). This has been particularly true of the term 'vermiculite', used extensively in the
earlier literature but which modern instrumentation shows to be generally a complex
interstratification.
RESULTS
AND
DISCUSSION
Note: (i) For brevity, the unpublished work of the SSEW is referred to throughout as
'unpublished'. (ii) The geographical context is England and Wales unless specifically stated
to be otherwise. (iii) Many soil clays are now known to be complex, often random
interstratifications, and the names applied to such minerals, particularly in early work, are
inadequate descriptors. This has necessitated some judicious interpretations when
comparing sets of data obtained many years apart. (iv) The data are presented in terms of
most important or 'lead' series of the soil associations shown on the 1: 250 000 soil map of
England and Wales (Soil Survey of England and Wales, 1983), grouped in terms of major
rock type and arranged within each group in order of geological age of known or inferred
parent material. The soils within an association are not, however, defined in terms of
geological age of parent material, but by lithology (effectively particle-size distribution)
Soil clays of England and Wales
685
and soil-profile morphology. It is possible therefore to have the same soil type developed on
rocks of very different geological ages and mineralogy. The word 'association' as used in
England and Wales has thus very different connotations to the usage in Scotland
(Glentworth & Dion, 1949).
Soils derived from igneous and metamorphic rocks
Stephen (1951, 1952a,b) reported vermiculite, chlorite and interstratified chloritevermiculite in soils developed from basic igneous rocks of the Malvern Hills in central
England. In contrast, he found the principal clay minerals of a granite-derived soil in the
same area to be mica and kaolin. The complex of both soil types is now mapped as the
Malvern Association. The findings for the granite soil are similar to those of Clayden
(1964), and Loveland & Bullock (1975, 1976) for the Moretonhampstead series developed
in the granite of south-west England, although Clayden (1964) also reported significant
amounts of vermiculite and interstratified species formed by weathering (see below). Such
soils are usually developed in locally-derived head of relatively uniform mineralogy
(Waters, 1964; Clayden, 1971; Findlay et al., 1984). It is thus likely that the clay
mineralogy of extensive areas of granite-derived soils is similar, namely those mapped as
the Earle, Hexworthy, Laployd, Moor Gate, Moretonhampstead and Princetown
Associations. The possible exceptions are areas affected by loess in East Devon (Harrod
et al., 1973), West Cornwall and the Scilly Isles (Catt & Staines, 1982), albeit the data
presented by the latter suggest the most abundant clay mineral in the loess to be
muscovite, which is already widespread in the granite.
Soils of the Arvon, Bangor, Deiniol and Eivion series included in the Bangor and Wick
Associations contain appreciable amounts of acid igneous rocks derived from the Mona
complex of Anglesey (Precambrian) and the North Wales volcanics (Lower Palaeozoic).
The clay mineralogy of these soils is dominated by a vermiculite-like mineral with lesser
and rather variable amounts of mica and kaolin (Roberts, 1958; Ball, 1963). The latter
author noted the existence of bands of material dominated by chlorite and mica within the
Bangor soils and suggested these could be differentiated on mineralogical grounds. Ball
(1966) and Bastow (1968) reported the presence of very large amounts of chlorite in soils
(Bangor Association) derived from pumice-tuffs of Ordovician age in Snowdonia.
Hornung & Hatton (1974) and Hatton (1978) reported on the mineralogy of the altered
dolerite of the Wbin Sill (intruded during the Hercynian orogeny) and of soils developed in
the drift from the altered rock at Holwick, Co. Durham. The soils are mapped as part of
the Ellerbeck Association. The principal mineral in the clay fractions is a vermiculite or
possibly a very poorly ordered chlorite, with traces of mica and kaolin.
Soils of the Croft Pascoe Association developed from serpentine on the Lizard (Staines,
1984) are unusual in containing a trioctahedral smectite (Coombe et al., 1956;
unpublished) presumed to derive from the weathering of olivine. Again, such soils are
affected to a varying degree by additions of loess similar to those found on the granite
(Coombe et al., 1956; Cart & Staines, 1982).
Soils derived from carbonate sediments
This group of soils encompasses those derived from, or containing considerable
amounts of, the 'hard' calcian and magnesian limestones of Devonian (ORS),
686
P.J. Loveland
Carboniferous and Permian age, Carboniferous Limestone Shales, the 'hard' and otlitic
limestones of Jurassic age, the Cretaceous Chalk, and the chalky tills derived in part from
the latter (principally the Chalky Boulder Clay of pre-Devensian age).
Soil clays of the Malham, Nordrach, Lulsgate and Priddy series typical of the Crwbin,
East Keswick 3, Malham, Waltham and Wetton Associations in Carboniferous Limestone
have been investigated by Khan (1957), Babiker (1960), Bullock (1964), Findlay (1965)
and Crampton (1972). Majumdar (1963) gave data for unnamed series both in the
Carboniferous Limestone (probably mainly Malham Association) and Magnesian
(Permian) Limestone (probably Aberford Association), and there are data for a soil of the
Torbryan series in Devonian Limestone (unpublished). Piggott (1962) and Bullock (1964)
showed the Carboniferous Limestone to be extremely pure, and both authors as well as
Findlay (1965) point to an aeolian component in many Carboniferous Limestone soils.
The clay mineral suite is essentially similar in the soils on limestone formations of both
eras. The dominant mineral is mica with lesser amounts of an expansible mineral identified
as vermiculite, and traces of kaolin, although Piggott (1962) gave one instance near
Buxton (Derbyshire) where the sole clay mineral appeared to be kaolin.
It is worth noting, however, that the CEC and K20 values given by Majumdar (1963)
are almost all >45 mEq/100 g and <2% respectively, suggesting that mica may be less
abundant than Majumdar proposed. In this context, Avery & Bullock (1977) reported
mica-smectite to be the major component of the clay fraction of a Windley soil developed
in Carboniferous Limestone Shales, with lesser amounts of mica and no kaolin, indicating
perhaps a connection between the presence of carbonates and a larger content of
expansible minerals.
Findlay (1965) found soil clays of the Ston Easton Association developed in Lower Lias
limestones to be dominated by mica with variable amounts of a vermiculite-like mineral
and traces of mica-chlorite and kaolin, i.e. an assemblage not unlike that reported for the
soils derived from the Carboniferous and Permian limestones. Soils of the Sherborne series
characteristic of the Elmton and Sherborne Associations developed in otlitic limestones of
Lower Jurassic age have been investigated by Pahm (1967). He found the clay fractions to
be dominated by kaolin, with subordinate mica and an expansible mineral, tentatively
identified as mica-smectite or mica-vermiculite, roughly in equal proportions. Confirmation
and cause of the differences in mineralogy between the two kinds of Jurassic limestones
await further investigation.
The extensive areas of shallow soils (Rendzinas) mapped on the Chalk are grouped as
Andover, Icknield and Upton Associations, the deeper soils being mapped as Blewbury,
Charity 2, Frilsham, Landbeach, Moulton, Newmarket, Panholes, Ruskington and
Wantage Associations. There is a considerable literature on the clay mineralogy of the
divisions of the Chalk. The general conclusions are that the Lower Chalk is very variable,
with the rocks underlying East Anglia and the northern Weald (east of Farnham)
containing a clay assemblage dominated by mica, kaolin, chlorite, vermiculite and
mica-smectite (Perrin, 1956, 1964; Jeans, 1968), whilst the rocks to the west of Farnham,
the southern Weald and to the north of the Wash contain mica and mica-smectite in much
greater proportions (Jeans, 1968). The latter assemblage is very similar to that found in the
Upper and Middle Chalk (Khan, 1957; Weir & Catt, 1965; Young, 1965; Morgan-Jones,
1977; Pitman, 1978).
There are relatively few reports of soil clay mineralogy for Chalk soils. Perrin (1956)
Soil clays of England and Wales
687
gave the mineralogy of soils derived from (?Upper) Chalk as 'mica plus dioctahedral
montmoriUonoid'. Khan (1957) gave the mineralogy of soils from Upper Chalk in
Buckinghamshire (Andover Association) as smectite and kaolin with lesser amounts of
mica, whilst the soils on the Middle Chalk (Andover Association) and Lower Chalk
(Wantage Association) were dominated by smectite with subsidiary mica and very little
kaolin. These results contrast with the findings of Jeans (1968) and Pitman (1978) for the
parent rocks. Majumdar (1963) gave the clay mineralogy of an Andover soil (Panholes
Association) on Chalk in South Yorkshire as dominantly micaceous with subsidiary
amounts of vermiculite and a little kaolin which, from the findings of Jeans (1968),
suggests the Lower Chalk. Avery (1964) and Pahm (1967) gave the clay mineralogy of
Icknield soils (locality and geology unknown in the case of the latter author) as dominantly
mica-smectite with lesser but approximately equal amounts of mica and kaolin, which is
similar to that of a soil developed in Chalk head at Pitstone, Buckinghamshire described by
Valentine (1973). The mineralogy suggests that in both cases the Middle or Upper Chalk is
the parent rock.
A major problem with extrapolating these data to other areas of Chalk soils is the
variable presence of additions of loessial material. Perrin (1956), Avery et al. (1959)
and Weir & Catt (1965) have shown the Chalk to be a very pure limestone, and
that likely dissolution rates are inadequate to account for the amount of soil material
existing at present, as soil formation probably began only in late glacial times (late or
post-Devensian?) (Kerney 1963). Cope (1976) has shown the composition of the clay
fractions of soils in Upper and Middle Chalk in Wiltshire to be similar to that of the
clay fractions of the upper horizons of soils on Clay-with-Flints, suggesting that these
Chalk soils have received substantial additions of loess.
Both Cope (1976) and Catt (1977) consider the distribution of loess to be essentially
ubiquitous over at least the Middle and Upper Chalk, the latter author suggesting
a maximum thickness of 0.3 m, i.e. effectively influencing the soils of the Andover and
Icknield Associations. Cope (1976; also pers. comm.) regards the Lower Chalk as relatively
free of loessial additions, at least at the western end of its outcrop, and that the shallower
soils thereon (Upton Association) more truly reflect derivation from the parent rock.
The clay mineralogy of soils developed in colluvium derived in large part from the Chalk
is barely known. Avery et al. (1959) and Avery (1964) showed that the upper parts of
Charity soils typical of 'Coombe deposits' in the Chilterns (mapped as Charity 2
Association) contained a vermiculite-like mineral, kaolin and mica, all of which decreased
with depth as smectite increased. There is, however, a major contribution from loess in
these soils. It is clear, therefore, that considerably more work needs to be done before the
distribution is known of clay minerals in soils related to the outcrop of the Chalk and
associated superficial or derived deposits.
The Chalky Boulder Clay of East Anglia and the south-east Midlands gives rise to a
number of soil associations--Burlingham, Beccles, Cannamore, Hanslope, Hornbeam 3,
Melford, Oak 2, Ragdale, Stretham. However, the same problem arises in these soils as
with the Chalk proper, namely the till is covered or admixed to a variable degree with loess
(Perrin et al., 1974; Catt, 1977). Despite this, it is fairly clear that the clay mineralogy of
soils developed in the Chalky Boulder Clay is similar, the principal components being mica
and mica-smectite, with subordinate amounts of kaolin and chlorite (Hodge & Scale,
1966; Perry, 1971; Sturdy et al., 1979; unpublished).
688
P. J. Loveland
Soils derivedfrom non-carbonate sediments
This group comprises all other soils, most of which are non-calcareous, and all contain
much less carbonate than those reviewed in the previous section. The soils are discussed in
the order of age of their known or inferred parent materials, although in some cases the
same soil type may be found in parent materials of different geological ages.
Lower Palaeozoic sediments. The most extensive areas of Lower Palaeozoic rocks are
in Wales and consist largely of fine-grained mudstones and shales with occasional
sandstones. Jones & Pugh (1935) showed that much of Wales is covered by periglacial
'head' very similar in composition to the country rocks--a point confirmed by extensive
soil mapping (Rudeforth et al., 1984).
The clay mineralogy of Brickfield, Cegin, Clwyd, Conway, Denbigh, Hiraethog, Manod,
Sannan and Ynys series characteristic of the Brickfield, Cegin, Conway, Denbigh, and
Manod Associations developed in----or from--these fine-grained rocks has been reported
by Luna (1959), All (1964), Livesey (1969), Abdulla (1966), Bower (1970), Rudeforth
(1970), Adams et al. (1971), Evans (1972, 1973), Adams (1974, 1976), Evans & Adams
(1975a,b), Loveland & Bullock (1975, 1976), Avery & Bullock (1977), Adams & Kassim
(1983) and in unpublished work. Bower (1970) gave the clay mineralogy of an Hiraethog
soil in Silurian grit as kaolin with subsidiary mica. On the finer-grained rocks the other
authors report the soil clays as having mica as the main component, with about half as
much chlorite and variable amounts of vermiculite. K20 contents are typically ~>3% and
CEC values <30 mEq/100 g, i.e. the soils are classed as micaceous. These findings refer to
an area stretching from Aberystwyth to Bangor and give further weight to the concept of
relatively uniform parent materials for these soils. Rudeforth (1970) reported kaolin to be a
significant component of the soil clays in North Cardiganshire (mainly Silurian rocks), but
Evans & Adams (1975b) suggested that the relevant X-ray reflections were those of
chlorite (002). Loveland & Bullock (1976) found traces of kaolin in a Manod soil, and
unpublished work utilizing intercalation tests suggests that the mineral may be a
widespread but very minor component of these soils, but clearly further work is required.
Soils developed on these rocks have been subject to weathering to a varying degree and
this is discussed later. Because of the relative uniformity of these Lower Palaeozoic parent
materials it is reasonable to suggest that soil associations for which clay mineralogical data
are absent are likely to have similar mineralogy. Such associations are Skiddaw, Powys,
Rivington 2, Munslow, Barton, Rheidol, Wharfe, Teme, Alun, Yeld, Rowton, Withnell 1,
Parc, Hafren, Stanway, Pinder, Hallsworth 1, Wilcocks, Yeolland Park, Nercwys and
Sportsmans.
Devonian~Old Red Sandstone (ORS) sediments. Lithologically the rocks of the
Devonian/ORS of Central England are essentially similar to those of the Lower
Palaeozoic of Wales (Mackney & Burnham, 1966). This is reflected in the clay mineralogy
of the soils of the Bromyard, Netchwood and Vernolds series developed in ORS marls and
characteristic of the Bromyard, Escrick i, Fforest, Middleton and Milford Associations.
The dominant species is mica with lesser amounts of chlorite, rather variable amounts of
an interstratified species (poorly defined mica-smectite or 'chloritized' vermiculite) and
traces of kaolin. This is reflected in the non-exchangeable K20 contents (3.5-4.2%) and
CEC values (29--49 mEq/100 g), placing most soils in the micaceous class, with just one
sample being in the smectitic class (Avery & Bullock, 1977; unpublished).
K20 and CEC values are similar for clays of Eardiston soils of the similarly named
Association found in coarse sandstones, but the mineral assemblage contains significantly
Soil clays of England and Wales
689
more chlorite. Soils of the Hollington and Lugwardine series developed in riverine alluvium
derived from ORS rocks and representative of Associations of the same names, closely
resemble the soils on ORS marls in clay mineralogy (unpublished). It seems reasonable on
the basis of the data given here to regard the soils developed in ORS sediments of Central
England as part of the same clay mineralogical province as the soils developed in Lower
Palaeozoic rocks, emphasizing further the similarities in the lithology of the parent
materials.
Soils of the Dartington, Highweek and Pulsford series, characteristic of soils developed
in Devonian slate in south-west England and mapped as Denbigh Association, were
examined by Loveland & Bullock (1975) and Avery & Bullock (1977). The mineral suite
is again similar to that of the soils developed in rocks of similar age in central England, the
soils containing considerable amounts of mica with small amounts of chlorite, kaolin and
interstratified mica-chlorite and mica-vermiculite. This is reflected in K20 values >5% and
CEC values ~<25 mEq/100 g, i.e. the soils are placed in the micaceous class.
Carboniferous sediments. Clays from Brickfield, Halstow, Neath and Tedburn soils
derived from Culm Chales (Lower Carboniferous) of south-west England and characteristic of the Halstow and Hallsworth Associations fall into the micaceous class. They are
dominated by large amounts of mica with much smaller amounts of kaolin and a
vermiculite-like mineral. The content of the latter differs from soil to soil but it is nowhere a
major component. Traces of chlorite are found occasionally. These findings are reflected
in non-exchangeable K20 contents rarely <4% and CEC values <30 mEq/100 g, often
much smaller (Avery & Bullock, 1977; unpublished). Such soils resemble closely, in terms
of clay mineralogy, those developed in Devonian slates reviewed in the previous section.
A single example of the Hazlewood series in Millstone Grit, now mapped as part of the
Dale Association, has been examined. The clay fraction has a K20 content of 1.8%, a
CEC of 38 mEq/100 g and is classed as mixed. X-ray data show there to be large amounts
of kaolin with lesser amounts of mica-smectite and minor amounts of chlorite and mica
(Avery & Bullock, 1977). The kaolin may be inherited from the parent material, being
common in Carboniferous rocks, or it may be a weathering product of the felspar which is
ubiquitous in sandstones of this age (Carrol et al., 1979). Babiker (1960) and Hornung
(1968) found considerable variations in the mineralogy of soils developed in Carboniferous
sandstones of the northern Pennines, some being dominated by kaolin, others by mica.
Bardsey, Coalpit Heath and Dale soils developed in Coal Measure rocks (Upper
Carboniferous) of northern England are characteristic of the Dale Association. They have
K20 contents >3% (commonly >4%) and CEC values of 20-40 mEq/100 g; they are thus
of the micaceous mineral class. As expected, the mineral suite is dominated by mica, and
there are lesser amounts of kaolin and chlorite plus traces of ill-defined expansible phases
though to be mica-chlorite or mica-smectite.
Amounts of the latter are significant in three profiles developed in 'clay shales' of the
Lower Coal Measures of the Bristol Coalfield (Coalpit Heath Series-2 profiles) and the
Warwickshire Coalfield (Bardsey Series) (Findlay, 1976; Avery & Bullock, 1977;
Whitfield & Beard, 1980; unpublished). Expansible minerals--mica-smeetite and
smectite--are major components also of two profiles representative of the Onecote
Association developed in similar kinds of rocks in North Staffordshire (Hollis, 1975;
unpublished), and of a profile of the Windley series in the Limestone Shales in Derbyshire
(Avery & Bullock, 1977). The clay fractions have K20 contents <3% and CEC values
>45 mEq/100 g thereby falling into the smectite class. Subsidiary minerals are mica and
690
P. J. Loveland
kaolin with traces of chlorite. It is thus interesting to note that there may be a relationship
between the kind of rock type in these Lower Coal Measure 'clay shales' and 'Limestone
Shales' and soil clay mineralogy in that they all contain, or tend to contain, larger amounts
of expansible minerals than other soils characteristic of the rocks of the higher parts of the
fine-grained Coal Measure succession.
Expansible minerals are also a feature of soils developed in tills derived from Coal
Measure rocks (Brickfield, Dunkeswick and Hallsworth soils representative of similarly
named Associations). K20 contents are <2.5% and often <2% with CEC values >35
mEq/100 g and usually >45 mEq/100 g. The clay mineral suite is not dissimilar to the
Dale Association soils although there tends to be more mica-chlorite in it. Amounts of the
other non-expansible phases are much reduced, and mica-smectite becomes an important
component. The soil clays thus fall mainly into the smectitic class, others being of mixed
mineralogy. However, unlike the Dale Association soils, the clay mineralogy of the soils
developed in the tills is quite variable both within and between profiles. This undoubtedly
reflects the mixed nature of the till (Searl, 1968; Avery & Bullock, 1977; unpublished).
The soils of the Baxterley, Dodmoor and Brockhurst series developed on the
finer-grained members of the reddish beds at the top of the Coal Measure succession
(Keele Beds) are representative of part of the Brockhurst Association, whilst soils of the
Shifnal series on the coarser sandstones of similar age are representative of part of the
Bromsgrove Association. The clay mineral suite in these soils is like that of the majority of
the Dale Association soils, namely mica, kaolin and chlorite, although an expansible phase
is identified as mica-vermiculite rather than mica-smectite. The proportions of these
minerals vary and this is reflected in the chemistry. Non-exchangeable K20 contents are
typically >3% and CEC values <35 mEq/100 g, although the upper parts of the Baxterley
and Shifnal profiles have K20 contents of ~2.5% and CEC values of 35-40 mEq/100 g.
The mineralogical class of these soils is therefore usually micaceous but some, all or in
part, are of mixed mineralogy.
Permian sediments. Despite the name, the Permian Marl has been shown during soil
mapping to be decalcified to at least 1 m or more where exposed at the surface (Bridges,
1966; Crompton & Matthews, 1970; Clayden, 1971). Therefore the formation is
considered to be non-calcareous in the context of this paper. The Marl is a silty clay and
the clay mineral assemblage is said to be dominantly mica, with moderate amounts of
smectite and traces of kaolin (Crompton & Matthews, 1970). The principal soils are of the
Micklefield, Watnall and Whimple series, mapped now as part of the Worcester,
Brockhurst I, Hodnet, Whimple 1 and Dunnington Heath Associations. The clay
mineralogy of representative soils is given by Avery & Bullock (1977). All except one (a
Watnall soil from North Yorkshire) are distinctly micaceous and reflect the mineralogy of
the parent material. The exception contains large amounts of a regularly interstratified
chlorite-smectite and is classed as chloritic.
The clay mineralogy of a Bridgnorth series soil in Penrith Sandstone (Eardiston
Association) is quite different. The principal components are a mica-smectite with lesser
amounts of mica and chlorite. K20 contents are <2% and CEC values >45 mEq/100 g;
the soil is therefore classed as smectitic (unpublished). Whether this one profile is truly
representative and the Penrith Sandstone as a whole does have a clay mineralogy which
differs from other rocks of Permian age is a subject requiring further work.
Triassic rocks. These soils cover extensive areas of Central England, both in Triassic
rocks in situ and in tills and drifts derived from them (Ragg et al., 1984).
Soil clays of England and Wales
691
Soil clays of the Bromsgrove and Bridgnorth Series developed in the Bunter and Keuper
sandstones (Bromsgrove Association) have K20 contents >/3.5% and CEC values <40
mEq/100 g. The mineral assemblage is dominated by mica with very small amounts of
kaolin and chlorite, traces of mica-chlorite and a poorly defined expansible phase-possibly chlorite-smectite. The clays are therefore classed as micaceous. A soil of the
Newport series (Newport Association) in colluvium derived from Bunter and Keuper
Sandstones has a very similar mineralogy to these soils.
Worcester and Spetchley soils developed in Keuper Marl are included in Worcester and
Brockhurst 2 Associations. The Worcester soils generally have K20 contents >4% and
CEC values ~<40mEq/100 g. The clay mineral suite contains swelling chlorite, corrensite(?),
sepiolite and palygorskite in variable amounts although mica dominates. The
soils are thus classed as micaceous, except for occasional samples with smaller K20
contents which are classed as chloritic (Bajwa, 1971; Avery & Bullock, 1977;
unpublished). In this respect the majority of the samples reflect the mineralogy of the
parent material, although the distribution of sepiolite and palygorskite, in particular, is
known to be erratic (Dumbleton & West, 1966).
In contrast, the Spetchley soils have slightly smaller K20 contents (<4%) and greater
CEC values (40-50 mEq/100 g). The mineral suite contains significant amounts of
mica-smectite with lesser amounts of mica and chlorite, and traces of interstratified
mica-chlorite. There is no swelling chlorite, sepiolite or palygorskite (Ahmad, 1957; Avery
& Bullock, 1977; unpublished). The soils are classed mostly as smectitic, but one example
from the Midlands is micaceous.
Zelazny & Calhoun (1977) have pointed out that sepiolite and palygorskite are stable
only in dry environments rich in Mg, and decompose rapidly in wetter environments to
give smectite minerals. The Spetchley soils are all strongly gleyed, i.e. of poor drainage
status, the Worcester soils only slightly gleyed, i.e. moderately to well-drained. It is thus
clear that the clay mineralogy of these soils relates at least in part to their moisture regime.
The soils of the Brockhurst, Clifton, Compton, Crewe, Flint, Rufford, Salop and
Salwick series are developed in tills and alluvial deposits derived in large part from Triassic
rocks, and are dominant soils in similarly-named associations and also included in the Oak
1 and Newbiggin Associations. The clay mineralogy of the Flint soils is very similar to that
of the Worcester soils described above. That of the other soils is more variable, but is
distinctive in this context by the absence of swelling chlorite, sepiolite and palygorskite. In
almost all cases the clay mineralogy of these till/alluvial soils is dominated by mica and
chlorite in very approximately equal amounts, with lesser amounts of kaolin and
subsidiary amounts of ill-defined interstratified species tentatively identified as micachlorite, mica-vermiculite and mica-smectite (Bajwa, 1971; Avery & Bullock, 1977;
Conway, 1980; unpublished). Non-exchangeable K20 contents are generally >3% and
CEC values are in the range 25-45 mEq/100 g, although there are a few examples with
K20 contents <3% and CEC values >45 mEq/100 g (mainly in the Compton soils which
are developed in alluvial deposits). These soils tend to be the most difficult to classify in
terms of clay mineralogy. On chemical grounds most should be regarded as of micaceous
mineralogy and a few as of smectitic or mixed mineralogy. However, the mineral suite is
very complex and many components are poorly defined. They tend therefore to be classed
as being of mixed mineralogy.
Rhaetic sediments. Although of very limited areal extent the lithological variation of
Rhaetic sediments and hence of soils derived from them is great. Soils of the Ashley,
692
P. J. Loveland
Charlton Bank, Denchworth, Evesham, Marchington and Wedmore series have all been
described on such rocks (Findlay, 1965; Crampton, 1972; unpublished).
Mineralogically the soils fall into two groups, those dominated by micaceous minerals
with K20 contents <3% and CEC values >40 mEq/100 g, and those with considerably
greater amounts of mica-smectite and correspondingly larger CEC values, i.e. smectitic
class (Avery & Bullock, 1977; unpublished). The former are mapped as Dale association,
the latter as Wickham 2 association. Although one assumes that the differences in
mineralogy are stratigraphic in origin, the data are insufficient to show the exact nature of
this.
Mesozoic sediments. This section deals with soils developed in the Jurassic and
Cretaceous clays, shales and sands. Avery (1964) and Avery & Bullock (1977) gave
details of the clay mineralogy of many soils developed in the deposits of the Lower, Middle
and Upper Lias, Fuller's Earth, Great Oolite, Forest Marble, Oxford and Kimmeridge
Clays (Jurassic) and the Gault Clay (Cretaceous). The soils belong to the Dale,
Denchworth and Evesham series (which now include soils formerly classed as Charlton
Bank, Long Load and Wicken series) and are currently included as components of the
Dale, Denchworth, Evesham, and Wickham Associations. Further work (unpublished) has
confirmed the findings of Avery (1964) and Avery & Bullock (1977) that, with certain
exceptions detailed below, the clay mineralogy of most of the soils developed on the clayey
sediments of the Mesozoic is very similar. The Denchworth and Evesham soils have a
mineralogy dominated by mica-smectite with much smaller amounts of kaolin and,
occasionally, chlorite. The mica-smectite is randomly interstratified with between 50 and
70% smectite layers (Weir & Rayner, 1974; Jones & Greenland, 1980; unpublished). K20
contents are generally <2.5% and CEC values >50 mEq/100 g, i.e. the soil clays are
classed as smectitic. Soils of different mineralogy formerly mapped as Long Load series
and now mapped as Dale series (Dale Association) are associated principally with Middle
and Upper Lias sediments. These soils have CEC values <45 mEq/100 g (often <40
mEq/100 g) although K20 contents are similar to those of the Denchworth and Evesham
soils. XRD shows kaolin and mica to be present in significantly larger amounts in these
soils than in the latter soils, hence Dale soils are classed as being of mixed mineralogy
(Coulthard, 1975; Avery & Bullock, 1977). Unpublished work has shown that many soils
identified as Denchworth series on morphological/textural grounds on the Middle Jurassic
'Deltaic' sediments in Yorkshire have CEC values <30 mEq/100 g, and contain larger
amounts of kaolin and mica than the soils in Middle and Upper Lias in southern Britain
(see below).
Storrier (1958) and Storrier & Muir (1962) investigated the clay mineralogy of the
Banbury series developed in the Jurassic ironstones of south Oxfordshire. They found the
principal mineral in the clay fraction to be goethite with lesser amounts of kaolin,
vermiculite and mica, the layer-silicates being in the proportions 3 : 2:1 respectively. It is
reasonable to suppose that soils of the Tadmarton and Irondown series on the same parent
material have similar clay mineralogy. All three series are now included in the Banbury
Association.
Soils of the Harwell series developed in the Malmstone (Albian stage of the Cretaceous)
have been examined by Avery (1964), Brown et al. (1969), Talibudeen & Weir (1972) and
Loveland (1978). The principal clay mineral is a randomly interstratified mica-smectite
with ~70% smectitic layers, with discrete mica as a less important component. There are
traces of kaolin and of glauconite. The kaolin is probably pedogenic in origin (Loveland,
Soil clays of England and Wales
693
1978). KzO contents are 2.5-3% and CEC values >50 mEq/100 g and the soil clays are
classed therefore as smectitic. An unusual feature of the Malmstone and the soils derived
from it is the presence of a zeolite of the clinoptilolite-heulandite series (Brown et al.,
1969). The Harwell Association contains soils other than the Harwell series, i.e. Selborne,
Hendred, Buriton and Newtondale series. On the grounds of lithology, inferred parent
material and recent soil mapping (Jarvis et al., 1984) these other soils are clearly closely
associated with the Malmstone, and their clay mineralogy is likely to be similar to that of
the Harwell series.
The markedly glauconitic soils of the Lower and Upper Greensands have been
examined by McRae (1971) and Loveland (1978, 1981), and Loveland & Findlay (1982),
respectively, whilst McRae & Lambert (1968) examined mineral glauconite from a range
of soil-forming materials. The principal soils are of the Barming and Ditton series (Fyfield
1 and 2 Associations) in Lower Greensand sediments, and Ardington, Urchfont, Coate
and Pewsey series (Ardington Association) in Upper Greensand sediments. The major
component of the soil clays is a glauconite with about 20% smectite layers, with lesser
amounts of a randomly interstratified (ferruginous) mica-smectite with about 50% smectite
layers, and traces of pedogenic kaolin. K20 contents of the clays are generally >4% and
CEC values >45 mEq/100 g--often >50 mEq/100 g. The soils are thus classed as
smectitic.
Post-Mesozoic sediments. The more clayey parts of the Reading Beds of Palaeocene age
give rise to soils of the Denchworth series (originally mapped as Swanmore series) now
included in the Wickham 4 Association. These soils have clay fractions dominated by a
randomly interstratified mica-smectite with a variable smectite layer content (<50 to
>70%), lesser quantities of discrete mica and minor amounts of kaolin. K20 contents are
0-9-3.8% and CEC values 45-65 mEq/100 g (Avery & Bullock, 1977; unpublished).
These soil clays are classed as smectitic but are clearly rather variable in composition.
In the London Basin, soils derived from the London Clay (Middle Eocene)--Wickham,
Windsor and Woolhampton series--are mapped as the Wickham 4 and Windsor
Associations. Their clay mineralogy is very similar to that of soils on Reading Beds (Avery
& Bullock, 1977; unpublished), and reflects that of the London Clay itself (Weir & Catt,
1969), although the soil clay data are too sparse to say whether the soils reflect the known
regional mineralogical variation of the parent sediment (Burnett & Fookes, 1974).
Clay mineral information for the coarser Eocene sediments (Thanet, Woolwich,
Oldhaven, Claygate and Bagshot Beds) of north-east Kent is given by Weir & Catt (1969).
The major component is a 'montmorillonite', with rather small (<25%) amounts of mica.
Kaolin is said to be absent, and clinoptilolite and glauconite are given as minor
components. Such a mineralogy is not unlike that of the Malmstone discussed earlier,
although complicated by additions of loess. Soils in these sediments in north-west Kent
(relatively little loess) are mainly mapped as Fyfield 4 Association, whilst those in
north-east Kent (thicker loess) are mapped largely as Hamble 1 Association. However,
given the variability of the parent materials and the discontinuous nature of the loessial
additions, the extrapolation of parent material mineralogical information to the soils is
more than usually difficult.
Gilkes (1968) showed that the Tertiary sediments of the Hampshire Basin are generally
of either a mica-kaolin mineralogy with little or no smectite and chlorite in the west, and of
smectite-mica mineralogy with lesser amounts of kaolin and traces of chlorite in the east.
Again, extrapolation of this information to the soils (Windsor Association on the London
694
P.J. L o v e l a n d
Clay; Wiekham 3 Association on much of the other sediments) can only be tentative due
to lack of data. The position is further complicated by coverings of pebbly drift in parts of
the basin for which clay mineralogical data are absent.
Teigngrace and Knighton soils are restricted to the outcrop of the kaolinitic Oligocene
sediments of the Bovey Basin. They were described by Clayden (1971) and are now
included in the Wickham 2 Association (Findlay et al. 1984). They have, however, a very
different clay mineralogy to the bulk of the soils in this Association in south-west England.
The clay mineral suite is dominated by kaolin with minor amounts of mica, and this is
reflected in K20 contents 42% and CEC of 20 mEq/100 g or less.
Extensive Quaternary deposits ('Plateau Drift', 'Clay-with-Flints', Pleistocene 'till' etc.)
are important soil-forming materials in southern and eastern England, and their geology
has been reviewed by Catt (1979). The distinction between 'Plateau Drift' and 'Clay-withFlints' is inexact and for soil mapping purposes the two are generally considered together
(Soil Survey of England and Wales, 1983). In addition, loess is a widespread component of
these soil-forming materials, and a complicating factor in understanding their development,
distribution and mineralogy.
The clay mineralogy of soils developed in Plateau Drift/Clay-with-Flints (CWF) has
been reported for profiles in: (i) the Chilterns by Loveday (1958, 1962), Avery et al.
(1959), Avery (1964), Catt (1969), Weir et al. (1969), Bajwa (1971), Avery et al. (1972),
Rowell & Dillon (1972) and Akamigbo (1976); (ii) the South Downs by Sabine et al.
(1963) and Hodgson et al. (1967). In both areas soils studied belonged to the Batcombe,
Charity or Winchester series (now mapped as Batcombe, Charity and Hornbeam 2
Associations respectively), and additionally in the Chilterns to the Sonning series (Sonning
1 Association). The m i n o r components of the clay fractions of these soils consist of
roughly equal proportions of mica and kaolin with occasional traces of chlorite. There is
considerable variation between profiles in the amounts of expansible minerals reported.
Loveday (1958, 1962), Avery et al. (1959), Avery (1964) and Akamigbo (1976) give
vermiculite as the predominant clay mineral in the upper parts of their profiles and show it
to decrease with depth as smectite increases. Sabine et al. (1963) and Hodgson et al.
(1967) gave a smectite as the major component in the clay fractions of their soils, whilst
Rowell & Dillon (1972) presented evidence of considerable variation in the clay
mineralogy of their Sonning soil depending on which size fraction was taken, although this
cannot be confirmed or denied by the data of Akamigbo (1976). This apparent conflict of
evidence may be resolved partly by reference to Weir et al. (1969) and Avery et al. (1972),
who point out that the 'expansible' species in these CWF soils are extremely complex with
evidence for three-component interstratifications--thus the earlier terminology may
represent an oversimplification of a very complex situation. Additionally it is known that
the soils have suffered by weathering and cryoturbation to varying degrees. Soil mapping
has shown the soils of the Carstens, Dunkeswell, Essendon, Marlow and Sonning 2
Associations to be developed in very similar parent materials to the CWF and it is thought
that their clay mineralogy is unlikely to be substantially different from that of the profiles
actually studied.
Weir et al. (1971) have shown that the phyllosilicate suite of loess typical of southern
and south-east England can contain small amounts of muscovite and glauconite in the
coarse silt (50-20 /~m), mica, vermiculite, chlorite, kaolin and randomly-interstratified
mica-chlorite, vermiculite-chlorite and vermiculite-smectite in the fine silt (20-2/.tm), and
mica, vermiculite-mica and vermiculite-smectite in the clay fraction (<2 ~m). They noted
Soil clays of England and Wales
695
quite a degree of variation in the expansion of the interstratified species in the different size
fractions, and also suggested that these clay-size species were part of the original
loess--possibly as aggregates and/or particle coatings. Such expansible minerals in
particular are common in CWF both with and without addition of loess, and some at least
is thought to derive from weathered Reading Beds (Loveday, 1958, 1962; Avery et al.,
1959, 1972, 1982; Avery, 1964; Weir et al., 1969). The CWF proper is thought to contain
more kaolin and smaller amounts of expanding minerals than the loess (Weir et al., 1969).
The position is rather similar in the soils developed in the thin coverloams and
coversands of East Anglia. Particle-size distribution data suggest that the coverloam is
only ~0.4 m thick in places. The clay mineral suite may contain approximately equal
amounts of kaolin, mica and chlorite in some sites, but smectite, vermiculite and
interstratified smectite-vermiculite also occur, the relative proportions of all being quite
variable (Hodge & Seale, 1966; Catt et at., 1971; Hamblin, 1977). How much of this
variability is due to weathering and incorporation of underlying material by cryoturbation, and how much to inherent differences in the loess is not known. These coverloam
soils are currently mapped in the Wick 2 and 3, Worlington and Methwold Associations. It
is clear, however, that whilst one might associate the presence of a complex
'vermiculite-like' species with the presence of loess, much more work needs to be done to
clarify the influence of the latter on soil clay mineralogy in southern and eastern England.
Madgett (1974) and Madgett & C att (1978) examined the mineralogy of the Pleistocene
(Devensian) tills of the Holderness area (East Yorkshire and Lincolnshire), and of a soil
typical of the Burlingham 2 Association developed therein. They quantified the soil clay
minerals which were vermiculite, smectite, kaolin, mica and chlorite, there being only
traces of the latter. However, many of the clay mineral species are present as complex
interstratifications which were deliberately simplified for the purpose of quantification.
Mica and smectite increased with depth in the profile whilst kaolin decreased. The
mineralogical data for the tills themselves are very similar to that of the soil and it is
reasonable to suppose that extensive tracts of soils developed on these Holderness tills, i.e.
Burlingham 2, Flint and Holderness Associations, will be of similar clay mineralogy.
Chartres (1975) examined the clay mineralogy of a sequence of Quaternary river
terrace soils in the valley of the River Kennet near Reading. As with so many superficial
deposits in southern England these terrace deposits contain loess. The principal clay
minerals were given as a smectite--usually interstratified with mica, but in some of the
clay-rich B horizons it was regarded as 'pure'. Above these clay-rich horizons a
vermiculite-like mineral occurs and was thought by Chartres to be associated with the
presence of loess. Lesser amounts of kaolin and mica occur in all the soils but differ in
proportion both within and between profiles. The soils examined are now included in the
Hucklesbrook, Hornbeam 2, Southampton, Sonning 2 and Wickham 3 Associations.
Recent alluvium is differentiated during soil mapping into riverine, estuarine and marine
essentially on physiographic grounds (Clayden & Hollis, 1984). Soils developed in riverine
alluvium reflect largely the mineralogy of their parent rocks and several examples are given
earlier in this paper. Clay mineralogical data for soils in estuarine sediments are lacking.
Those for soils developed in marine alluvium are restricted to a few profiles around the
Wash (Agney, Downholland and Newchurch series), a profile from north Kent (Wallasea
series), and a profile from Romney Marsh (Kent) (Newchurch series)---all of similarly
named Associations. Despite the wide geographical spread of the sites, most of the soils
have a similar clay mineral assemblage--mica and mica-smectite are the most abundant
696
P. J. Loveland
minerals being in roughly equal proportion, with lesser but again fairly equal amounts of
kaolin and chlorite (Hamblin, 1977; unpublished). K20 contents are generally between 3
and 4% and CEC values 35-45 mEq/100 g, i.e. the soils are of the micaceous class. The
exception is the Romney Marsh soil which has CEC values mostly between 45 and 50
mEq/100 g and K20 contents <3%, and is classed as smectitic. This similarity of
mineralogy presumably indicates some commonality of parent material source rocks-most probably reworked post-Paleozoic sediments from southern and eastern England
and the north-west continent.
Accessory minerals
This section mentions briefly the non-phyllosilicate species which have been noted in the
clay fractions of soils of England and Wales. Quartz is ubiquitous and is invariably of the
g-form, whilst poorly-structured cristobalite-tridymite occurs in the soils derived from
Upper Greensand rocks (Loveland, 1978). K-felspars are almost as common as quartz in
soil clay fractions and both are present in amounts <5% by weight (Weir et al., 1969;
Madgett, 1974; unpublished). Iron oxides are also widespread, although their presence is
controlled strongly by soil conditions. Goethite is the commonest form in freely drained
soils, lepidocrocite in the less well-drained soils (Brown, 1953). In very poorly drained soils
iron oxides are often completely absent. It is possible that haematite may be a component of
the 'red' soils of south-west England, but clay mineral studies have so far failed to reveal it
(unpublished). Amounts of iron oxides range from <1%, to as much as 60% of the clay
fraction in soils developed in Jurassic ironstones (Storrier & Muir, 1962). Halloysite has
been tentatively identified in clays from soils developed in both granitic materials in
south-west England and in Lower Palaeozoic sediments in Wales, on the basis of unusual
broadening of the 7 A reflection usually attributed to kaolin and of electron microscope
studies (unpublished). However, further work is required to substantiate this. Finally,
traces of gibbsite (<5%?) have been detected in soils derived from granitic rocks in
south-west England (unpublished), and Hodge & Scale (1966) reported traces of boehmite
in Chalk soils (Icknield and Newmarket series).
Within-series variation
This paper has been concerned so far with differences between named soil profile classes
(soil series) and, by implication, differences between soil associations of which these series
are characteristic to a greater or lesser extent. In this context it is important to know
whether the differences between series are greater than those within series. Tables 1 and 2
set out data for two soil series of contrasting mineralogy for which a reasonable amount of
data is available, i.e. Denchworth soils with a clay mineral suite in which expansible phases
are dominant (or thought to be), and Dale soils in which mica minerals are expected to be
dominant. For most soils, however, there are not enough data to carry out this kind of
exercise.
Despite the gaps in the data it is clear that there is considerable variation in the
mineralogy of Denchworth soils identified on the basis of lithology and profile
morphology. CEC and K20 values range from 25-71 mEq/100 g and 1.5-4.4%
respectively. Nineteen profiles are classed as smectitic, and seven each as micaceous or
mixed, and reflect differences in the proportions of kaolin, mica and mica-smectite, which
Soil clays of England and Wales
69 7
TABLE 1. Non-exchangeable K20 content, cation exchange capacity and estimated amounts of major
layer-silicate species in B horizons of Denchworth Series.
Layer-silicate species*
Site (UK
GridRef.)
ST427498
ST696782
ST731752
S0926589
SO994541
SP360571
SP381542
SK108226
SE392958
SK788333
TL045992
TF093030
TF033483
SE509807
SE776920
SE794941
TF037000
TF049466
ST836815
ST849806
TF119011
ST935661
SU241963
SP608103
SP612116
SP703221
SP706236
SU273896
TL548761
SE725843
SU310110
SU334895
SU319903
Parent material
K20
(%)
CEC
(mEq/100g)
Rhaetic Shales
Rhaetic Shales
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Lower Lias Clay
Upper Estuarine Series
Upper Estuarine Series
Upper Estuarine Series
Upper Estuarine Series
Upper Estuarine Series
Upper Estuarine Series
Great Oolite Clay
Great Oolite Clay
Forest Marble Clay
Forest Marble Clay
Kellaways Clay
Oxford Clay
Oxford Clay
Oxford Clay
Oxford Clay
Oxford Clay
Oxford Clay
Kimmeridge Clay
Kimmeridge Clay
Kimmeridge Clay
Gault Clay
Gault Clay
Gault Clay
3.8
2.8
2-5
4.4
3.2
2.4
2.4
3.4
2.6
2-4
3.1
4.1
2.6
1.5
3-5
4.1
2.7
2.4
3.5
2-5
1.3
3-3
2.4
2.7
2.1
3.0
2.9
3.2
2.5
2,7
2.7
2.3
2.4
60
64
52
44
48
59
45
50
42
53
43
37
53
30
25
31
54
58
49
71
43
44
68
65
70
38
48
42
64
39
64
54
42
Ka
Mi
Mi-Sm Mi-Chl Chl
t
3
6
1
3
2
5
t
3
2
2
1
1
5
2
1
t
1
1
1
3
4
2
5
5
4
2
5
5
2
3
3
2
2
3
5
1
4
3
1
1
1
4
4
5
6
3
1
1
1
t
1
2
2
8
7
2
3
5
1
3
2
2
7
4
1
1
3
3
6
5
1
1
1
2
2
3
1
1
1
1
1
1
1
1
2
t
t
t
t
1
Clay mineral
class
Smectitic
Smectitic
Smectitic
Micaceous
Smectitic
Smectitic
Smectitic
Smectitic
Mixed
Mixed
Micaceous
Micaceous
Smectitic
Mixed
Micaceous
Micaceous
Smectitic
Smectitic
Smectitic
Smectitic
Mixed
Micaceous
Smectitic
Smectitic
Smectitic
Mixed
Smectitic
Micaceous
Smectitic
Mixed
Smectitic
Mixed
Mixed
* Estimated from XRD traces to nearest part in 10 (t = < 1); Ka = kaolin, Mi = mica, Sm
Chl = chlorite.
smectite,
r e l a t e c l e a r l y to s t r a t i g r a p h y . T h e soils d e v e l o p e d in U p p e r E s t u a r i n e Series s e d i m e n t s t e n d
t o c o n t a i n a m u c h g r e a t e r p r o p o r t i o n o f n o n - e x p a n s i b l e m i n e r a l s t h a n t h e i r fellows, a n d
also s h o w c o n s i d e r a b l e v a r i a b i l i t y .
T a b l e 2 s h o w s t h a t D a l e series soils d o n o t o c c u r o v e r s u c h a wide s p e c t r u m o f p a r e n t
m a t e r i a l s as D e n c h w o r t h soils, all b u t o n e o c c u r r i n g o n C o a l M e a s u r e s r o c k s . H o w e v e r ,
t h e r e is c l e a r l y still a r a n g e in m i n e r a l o g y . T h e M i l l s t o n e G r i t soil is m u c h m o r e k a o l i n i t i c
t h a n the o t h e r s , a n d t h e t w o soils d e r i v e d f r o m L i m e s t o n e S h a l e r o c k s c o n t a i n l a r g e
a m o u n t s o f m i c a - s m e c t i t e . A s m e n t i o n e d earlier in t h e p a p e r , this m a y i n d i c a t e a
P. J. Loveland
698
TABLE 2. Non-exchangeable KzO content, cation exchange capacity and estimated amounts of major
layer-silicate species in B horizons of Dale Series.
Site (UK
GridRef.)
SK068549
SK304452
SK326465
ST629585
ST667806
ST688802
SP283981
SK375208
SK405459
SK409425
SE024618
SE359238
SE389334
SP261977
ST168690
Parent material
Carboniferous
Limestone Shale
Carboniferous
Limestone Shale
Millstone Grit
Coal Measure Shale
CoalMeasure Shale
CoalMeasure Shale
Coal Measure Shale
Coat Measure Shale
CoalMeasure Shale
CoalMeasure Shale
CoalMeasure Shale
CoalMeasure Shale
CoalMeasure Shale
UpperCoalMeasures
Rhaetic Shales
Layer-silicate species*
K20
CEC
Clay mineral
(%) (mEq/100 g) Ka Mi Mi Sm Mi-Chl Chl-Sm Chl class
2.0
43
2
2
6
Mixed
3.3
52
1
3
6
Smectitic
1.8
3.0
4.5
3.1
2.6
4.1
3.9
3.4
2.6
3.5
4.6
3.3
5.9
38
38
35
36
30
26
33
31
43
31
22
20
38
5
1
2
6
3
3
2
3
3
3
5
6
4
4
2
2
2
1
5
6
6
8
1
1
t
1
1
t
3
2
1 Mixed
1 Micaceous
1 Micaceous
Micaceous
Mixed
1 Micaceous
1 Micaceous
1 Micaceous
Mixed
2 Micaceous
2 Micaceous
1 Micaceous
t Micaceous
* As for Table 1.
relationship between the presence o f carbonates and the occurrence of smectite. M o s t of
the soils are, however, dominated by non-expansible minerals.
A v e r y & Bullock (1977) pointed to great mineralogical differences between apparently
similar soils, and the d a t a in Tables 1 and 2 confirm this. F o r the two soils under
discussion it can be seen that the differences in clay mineralogy relate in a b r o a d w a y to
the differences in parent material. However, the latter relationship is not simple in that even
within one stratigraphic unit, e.g. the U p p e r Estuarine Series, considerable mineralogical
variation can occur. So, although it is possible to group soils into very b r o a d mineralogical
c l a s s e s - - i . e , most D e n c h w o r t h soils will be smectitic and most Dale soils will be
micaceous---it is known that this will not always be so and stratigraphy (in the sense o f
known soil parent material) m a y sometimes help in qualifying these judgements, but again
this is subject to error. If the point of clay mineralogy is to make useful statements about
soil behaviour then further qualification becomes necessary as, for example, soil structural
properties are only partially related to this p a r a m e t e r (see below). W i t h limited resources it
m a y be better therefore to measure the property o f particular interest.
Weathering
Post-glacial weathering o f soil clays in England and Wales is most m a r k e d in the higher,
wetter parts o f the country where soil conditions tend to be more acid reflecting the more
intense leaching. The principal processes of clay mineral alteration can be summarized as:
Oxidation. This is regarded as the chief requirement in the alteration of chlorite in
Soil clays of England and Wales
699
Lower Palaeozoic sediments to give vermiculite or other, more complex interstratified
minerals (Adams, 1974, 1976; Evans & Adams, 1975b; Adams & Kassim, 1983). It may
also apply to the breakdown of biotite in basic igneous rocks (Stephen, 1951, 1952a).
Oxidation is also important for the formation of the various hydrous oxides from iron
released during clay mineral alteration.
Loss of interlayer potassium. This has long been regarded as the classic mechanism for
the alteration of soil mica to produce expansible species--albeit these are often
interstratified, e.g. mica-vermiculite. Such a mechanism has been proposed for mica in
Lower Palaeozoic rocks (Loveland & Bullock, 1975, 1976), Evans and Adams (1975a)
and Adams & Kassim (1983), for acid igneous rocks (Roberts, 1958; Ball, 1963; Clayden,
1964; Loveland & Bullock, 1975, 1976), for glauconitic rocks (Loveland, 1978), for
Lower Lias clays (Coulthard, 1975) and for Pleistocene tills (Madgett & Catt, 1978).
Interestingly, however, Adams & Kassim (1983) have suggested that vermiculite in Lower
Palaeozoic rocks in Wales is more likely to be an alteration product of chlorite than of
illite. These authors do not dispute that K-removal from the latter can give rise to
vermiculite, but point out that the transformation is very difficult to achieve even using
fairly drastic procedures in the laboratory.
In contrast, Luna (1959), Livesey (1964) and Q ureshi (1969) found little evidence of the
expected decrease in mica content towards the soil surface in some soils developed in
Lower Palaeozoic rocks in North Wales that such a mechanism should bring about. Ali
(1964) and Bower (1970) working on similar soils found the reverse to happen, and the
former author suggested the increase in mica towards the soil surface to be a cryoturbation
(permafrost) effect.
Generally, however, over the country as a whole K20 contents in the upper parts of soil
profiles are smaller than in the lower parts, whilst the converse is true for CEC values.
Respective mean values for the peroxidized <2/~m fractions at 530 sites are:
B horizons: K20 3.9%; CEC 45 mEq/100 g
BC horizons: K20 3.4; CEC 40 mEq/100 g
indicating that mica does decrease towards the soil surface whilst expansible phases
increase albeit only slightly. For the great majority of lowland soils the chemical changes
are the only evidence of weathering, XRD patterns often offering little evidence beyond
slight peak broadening (unpublished).
Sorption of aluminium. It is well known that soil clays can sorb A1 released during
weathering into the interlayer space if the soil pH is in the range 4-5.5. This mechanism
has been invoked to explain the presence of 'chloritized' vermiculite in the upper part of a
number of soil profiles on a range of parent materials (see, for example, Loveland &
Bullock, 1975, 1976).
These processes can be superimposed on material weathered (perhaps by the same
process) during previous climatic periods. Such situations are thought to have arisen, for
example, in soils developed in Plateau Drift/Clay-with-Flints which contain complex
interstratified 'vermiculite-like' species (see above), where much of the parent material is
thought to derive from Reading Beds already weathered during the Tertiary (Avery et al.,
1959, 1982), and in palaeosols developed in Chalky Boulder Clay in Essex where there is
evidence of pre-Devensian weathering (Sturdy et al., 1979).
700
P. J. Loveland
Applications
Much of the early interest in soil clay minerals was generated by the belief that they
were a major source of nutrient cations, particularly potassium. Arnold & Close (1961)
found that the release of K from soils during pot experiments differed markedly from one
soil to another. The most important controlling factor was the amount and K-content of
the fine clay fraction (<0.1 am), and there was little direct correlation with clay
mineralogy as determined by XRD. Other studies in relation to soil-K release and clay
mineralogy are those of Luna (1959), Davies (1963) and Livesey (1964) for soils
developed in Lower Palaeozoic sediments in Mid- and North Wales, Avery (1964) for the
area around Aylesbury and Hemel Hempstead, Crompton (1966) for an area of
mid-Lancashire, Chaudry (1967) & Searl (1968) for soils developed in Northumbrian
boulder clays, McRae (1971, 1975a,b) for glauconitic soils in Kent, and Talibudeen &
Weir (1972) for a Harwell soil developed in Malmstone. The latter authors found that the
unusually great K-supplying power of the Harwell soil was due to the presence of a zeolite
of the clinoptilolite-heulandite series. The other workers did indeed find great differences in
the amount of K released from the soil, but found only a very general relationship between
the presence and amount of K-mica in the soil clays (and sometimes silts) and the
potassium-supplying power of the soil. None were successful in using clay mineralogy as a
reasonably exact predictive tool for this property.
More recently Goulding (1981) has reviewed the relationship between soil-K released to
Ca-saturated resin and K-sites in 2:1 layer-silicates, which sheds some light on ways in
which soil clays may release K to growing crops. However, the Ca-resin technique is very
slow, and recent experiments have shown no useful correlation between amounts of K
released from soil to Ca-resin and proportions of clay minerals derived from X R D
(Goulding & Loveland, unpublished data). There appears to be almost no work on
K-fixation by clays of British soils with the exception of that of Chaudry (1967), whilst
other nutrient cations, e.g. Mg and Na, seem to have been ignored in relation to soil clay
mineralogy.
The other area of interest has been soil physical properties, particularly those relating to
consistence and structure. Bryan (1971) suggested that clay mineralogy was an important
factor in explaining differences in water-stable aggregate formation in some silty soils from
Derbyshire. This was confirmed indirectly by Page (1979) who found that clay mineral
type had a strong influence on the response of soils to poly-(vinyl alcohol) during a study
of soil crusting. The poorest response was from soils with chlorite as a major component,
the better response being in soils in which chlorite was absent or present as a minor
component. It was suggested that these differences could be explained by the blocking of
adsorptive siloxane sites in the chlorite structure by brucite/gibbsite sheets which then
would present only non-adsorptive aluminol surfaces. Against this, however, is the
statement by Greenland (1977) that 'most of those [soils] with chloritic clays ... have a
high stability li.e. aggregate coherencel', which suggests other factors are at w o r k - possibly iron oxides. Greene-Kelly (1974) found a strong correlation between the
expansible mineral content and soil shrinkage over the pF range 4-6 in 63 soils, whilst
Rimmer & Greenland (1976) showed that the shrinkage behaviour of clayey soils is
greatly affected by the presence of calcium carbonate, partly because of electrical
double-layer suppression and partly because of cementation effects. Avery & Bullock
(1977) suggested that clayey soils could be separated into strongly-swelling and
Soil clays of England and Wales
701
weakly-swelling groups on the basis of the CEC of the peroxidized clay fraction
recalculated to a <2 mm soil basis, and thought a value of 25 mEq/100 g to be a suitable
class boundary. Reeve et al. (1980) found a close correlation between this parameter and
both the shrinkage of natural clods and the proportion of mica-smectite of a range of
JOBASS,C
L,MESTONE~
M/;'
MESOZOIC~
CLAYS ~
M/S,
K, C
CaCOs
CHALK~ M / S , M,K, M/V,
.....
CaCO=
~M/V,
M,K,
WITH
FLINTS
cLAY
M/S,M,
CHALKY
BOULDER
CLAY
0
I
K,C,
CaCO3
km
100
I
FIG. 3. Simplified sketch map showing grouping of soils in terms of mineralogy and calcium
carbonate content in south-east England. K = kaolin; M - mica; S = smectite; V = vermiculite;
C = chlorite; heavy type denotes major component; lighter face denotes minor component.
702
P. J. Loveland
clayey soils. However, the correlation of shrinkage measurement was much better with the
CEC values than with the mineralogy, suggesting that the former may be the more fruitful
line of enquiry. Spoor et al. (1982) suggested that soils rich in smectitic clays have better
properties for moling than soils rich in micaceous clays. Newman (1983) reported an
extremely strong correlation between the specific surface area of 62 clayey subsoils
measured by water sorption at r.h. = 47% and the CEC of the <2 mm soils, particularly
for those soils with a large smectite content.
From the foregoing it is apparent that whilst the outcome of the nutrient supply
investigations is not all that had been hoped for, there could be useful input from clay
mineralogy into the area of soil physical properties. In this context it is interesting to note
the recent review by Driscoll (1983) of the relationship between soil mineralogy and the
swelling and shrinking of clayey soils under the influence of vegetation. It is apparent from
his review that this subject is of great importance in relation to structures with shallow
foundations, and that there is a lack of data on the relevant properties of the soils of Great
Britain. In spite of the obvious limitations of the data presented in this paper, the portrayal
of soils in broad mineralogical provinces is a useful contribution in a national context to
the problem outlined by Driscoll (1983). Such a 'mineralogical province' map for
south-east England is given in Fig. 3. The soils have been placed in broad groups in terms
of clay mineralogy, presence of substantial amounts of calcium carbonate and depth of soil
material. The two latter points are not, admittedly, strictly clay mineralogical but could be
of considerable importance for both agricultural and geotechnical users of such a map.
CONCLUSIONS
A general review has been presented of the clay mineralogy of many of the more extensive
soils in England and Wales, the data being given in terms of the 1 : 250 000 National Soil
Map. The review is based on data from ~750 sites. Some conclusions are:
1. It is possible to give the clay mineralogy of most of the soils of England and Wales in
general terms.
2. The database is inadequate to give information for all soils, or to give detailed
information of the variation in clay mineralogy for many of the soils.
3. Most soils developed on pre-Rhaetic sediments are dominated by mica with lesser
amounts of chlorite and kaolin. Exceptions are certain calcareous soils developed in Coal
Measure shales which have a significant smectite content, and freely drained soils in
Keuper Marl which contain swelling chlorite, sepiolite and palygorskite.
4. Soils developed in post-Triassic sediments are dominated generally by expansible
minerals, exceptions being those soils developed in Lower Lias rocks which are often
micaceous, and soils developed in sediments of the Estuarine Series which are often
kaolinitic.
5. The presence of loess in soils in southern and eastern England seems to be associated
with a complex interstratified mineral with properties akin to vermiculite.
6. Weathering of clay minerals is most marked in the wetter upland areas and is
reflected in an increase in expansible minerals towards the soil surface. Evidence for clay
mineral weathering in lowland England hinges on changes in non-exchangeable K20
contents and CEC values towards the soil surface.
7. Clay mineralogy is not well related to the K-supplying power of soils, but shows
better relationships with geotechnical properties.
S o i l clays o f E n g l a n d a n d W a l e s
703
8. It is p o s s i b l e to g r o u p soils i n t o b r o a d c a t e g o r i e s b a s e d o n clay m i n e r a l o g y a n d o t h e r
properties to produce 'mineralogical province' maps.
ACKNOWLEDGMENTS
I am indebted to many members of the Soil Survey of England and Wales for discussions during the preparation
of this paper--particularly J. M. Hollis and Dr P. Bullock; to Mrs S. Harrop and D. Bamford for help with the
figures; to Miss L. Parry (Soils and Plant Nutrition Department, Rothamsted) for the computer production of
Fig. 2; to Mrs J. Palmer and Mrs J. Johnson of the Rothamsted Library for their outstanding assistance with
the bibliography; and to Mrs B. Cain for preparing the typescript.
REFERENCES
(Note: It is unlikely that this bibliography is complete--particularly for earlier work. The author would be
grateful if omissions were drawn to his attention.)
ABDULLA H.H. (1966) A study of the development of podzol profiles in the Dovey Forest. PhD thesis, Univ.
Wales (Aberystwyth), UK.
ADAMS W.A. (1974) Pedogenesis of soils derived from Lower Palaeozoic sediments in mid-Wales. Reports of
the Welsh Soils" Discussion Group 15, 61-69.
ADAMS W.A. (1976) Experimental evidence on the origin of vermiculite in soils on Lower Palaeozoic
sediments. Soil Sci. Soc. Am. J. 40, 793-796.
ADAMS W.A. & KASSlM J.K. (1983) The origin of vermiculite in soils developed from Lower Palaeozoic
sedimentary rocks in mid-Wales. Soil Sci. Soc. Am. J. 47, 316-320.
ADAMS W.A., EVANS L.J. & ABDULLA H. (1971) Quantitative pedological studies on soils derived from
silurian mudstones, III: Laboratory and in situ weathering in chlorite. J. Soil Sci. 22, 158-165.
AHMAD N. (1957) A pedological study of the soils of the University farm with reference to the development of
morphological features associated with impeded drainage. PhD thesis, Univ. Nottingham, UK.
AKAMIGBO F.O.R. (1976) Lessivage: the identification and laboratory simulation of the results of clay
translocation in the B horizons of soils in the Reading area. PhD thesis, Univ. Reading, UK.
ALI M.A. (1964) A comparative study of arable, permanent grass and associated forest, slope soils on
Ordovician and Silurian parent materials in mid-Wales, with special reference to soil moisture
relationships and gley-phenomena. MSc thesis, Univ. Wales (Bangor), UK.
AaNOLD P.W. & CLOSE B.M. (1961) Release of non-exchangeable potassium from some British soils cropped
in the glasshouse. J. Agrie. Sci. 57, 295-304.
AVERY B.W. (1964) The soils and land use of the district around Aylesbury and Hemel Hempstead. Memoir of
the Soil Survey of Great Britain, Harpenden, UK.
AVERY B.W. (1980) Soil Classification in England and Wales: Higher Categories. Technical Monograph of
the Soil Survey No. 14, Harpenden, UK.
AVERY B.W. & BULLOCK P. (1977) Mineralogy of clayey soils in relation to soil classification. Soil Survey
Technical Monograph 10, pp. 64, Harpenden, UK.
AVERY B.W., STEPHEN I., BROWN G. & YAALOND.H. (1959) The origin and development of Brown Earths on
Clay-with-Flints and Coombe deposits. J. Soil Sci. 10, 177-195.
AVERY B.W., BULLOCK P., CATT J.A., RAYNER J.H. & WEre A.H. (1982) Composition and origin of some
Brickearths on the Chiltern Hills, England. Catena 9, 153-174.
AVERY B.W., BULLOCK P., CAT'r J.A., NEWMAN A.C.D., RAYNER J.H. & WEIR A.H. (1972) The soil of
Barnfield. Pp. 5-37 in: R othamsted Experimental Station, Report for 1971, part 2. Harpenden, UK.
BARmER l.A. (1960) Studies on some profiles on Millstone Grit and Limestone till soils. MSc thesis,
Nottingham, UK.
BAJWA M.I. (1971) Investigation of clay minerals in relation to soil micromorphology. MSc thesis, Univ.
Wales (Bangor), UK.
BALL D.F. (1963) The soils and land use of the district around Bangor and Beaumaris. Memoir of the Soil
Survey of Great Britain, Harpenden, UK.
BALL D.F. (1966) Chlorite clay minerals in pumice-tuff and derived soils in Snowdonia. Clay Miner. 6,
195-210.
704
P. J. L o v e l a n d
BASTOW A.D. (1968) Chlorite clay minerals in some Snowdonian soils. MSc thesis, Univ. Wales (Bangor),
UK.
BOWER R.P. (1970) Trace elements and pedogenesis of podzols in North Wales: detailed studies o f three
seleetedprofiles. PhD thesis, Univ. Wales (Bangor), UK.
BmDGES E.M. (1966) The soils and land use of the district north of Derby. Memoir of the Soil Survey of Great
Britain, Harpenden, UK.
BROWN G. (1953) The occurrence of lepidocrocite in some British soils. J. Soil Sci. 4, 220-228.
BRown G., CATT J.A. & WEre A.H. (1969) Zeolites of the clinoptilolite-heulandite type in sediments of
south-east England. Mineral. Mag. 37, 480-488.
BRYAN R.B. (1971) The efficiency of aggregation indices in the comparison of some English and Canadian
soils. J. Soil Sci. 22, 166-178.
BULLOCK P. (1964) A study of the origin and development o f soils over Carboniferous Limestone in the
Malham district of Yorkshire. MSc thesis, Univ. Leeds, UK.
BULLOCK P. & LOVELANBP.J. (1974) Mineralogical Analysis. Pp. 57-69 in: Soil Survey Laboratory Methods
(B.W. Avery & C.L. Bascomb, editors). Soil Survey Technical Monograph No. 6, Harpenden, UK.
BURNETT A.D. & FOOKES P.G. (1974) A regional engineering geological study of the London Clay in the
London and Hampshire Basins. Q. J. Engng. Geol. 7, 257-295.
CARROLL D., HARTNUP R. & JARVIS R.A. (1979) Soils o f South and West Yorkshire. Bulletin of the Soil
Survey of Great Britain No. 7, Harpenden, UK.
CATT J.A. (1969) The origin and development of the [Broadbalk] soils. Pp. 89-93 in: Rothamsted
Experimental Station, Report for 1968, part 2. Harpenden, UK.
CATT J.A. (1977) Loess and Coversands. Pp. 221-229 in: British Quaternary Studies (F. W. Shotton, editor).
Oxford University Press, Oxford, UK.
CATT J.A. (1979). Soils and Quaternary geology in Britain. J. Soil Sci. 30, 607-642.
CATT J.A. & STAINES S.J. (1982) Loess in Cornwall, Proe. Ussher Soc. 5, 368-375.
CATT J.A., CORBETT W.M., HODGE C.A.H., MADGETT P.A., TAXLER W. & WEIR A.H. (1971) Loess in the
soils of north Norfolk. J. Soil Sci. 22, 444~,52.
CHARTRES C.J. (1975) Soil development on the terraees o f the River Kennett. PhD thesis, Univ. Reading, UK.
CHAUDRY M.S. (1967) The potassium fixing and releasing powers of the clay and siltfractions in some British
and Pakistani soils. PhD thesis, Univ. Newcastle, UK.
CLAYDEN B. (1964) Soils of the Middle Teign Valley district of Devon. Bulletin of the Soil Survey of Great
Britain No. 1, Harpenden, UK.
CLAYOEN D. (1971) Soils o f the Exeter District. Memoir of the Soil Survey of Great Britain, Harpenden, UK.
CLAYDEN B. & HOLLIS J.M. (1984) Criteria for differentiating soil series. Soil Survey Technical Monograph
No. 17, Harpenden, UK.
CONWAY J.S. (1980) The nature of void surfaces in soils of the Salop and related series. PhD. thesis, Univ.
Wales (Bangor), UK.
COOMBE D.E., FROST L.C., LE BAS M. & WATTERS W. (1956) The nature and origin of the soils over the
Cornish serpentine. J. Ecol. 44, 605-615.
COPE D.W. (1976) Soils in Wiltshire I: Sheet SU03 (Wilton). Soil Survey Record No. 32, pp. 166-174,
Harpenden, UK.
COULTHARD J.M. (1975) Petrology o f weathered Lower Lias clays. PhD thesis, Univ. Aston, UK.
CRAMPTON C.B. (1972) Soils o f the Vale of Glamorgan. Memoir of the Soil Survey of Great Britain,
Harpenden, UK.
CROMPTON E. (1966) The soils of the Preston district of Lancashire. Memoir of the Soil Survey of Great
Britain, Harpenden, UK.
CROMPTON A. & MATTHEWS B. (1970) Soils of the Leeds district. Memoir of the Soil Survey of Great Britain,
Harpenden, UK.
CROWTHER E.M. (1930) The relationship of climatic and geological factors to the composition of soil clay and
distribution of soil types. Proc. Roy. Soc. (Ser. B) 197, 1-30.
DAWES B.E. (1963) Soils developed on Silurian Shales and leys on them, with special reference to potassium,
magnesium, and trace elements. PhD thesis, Univ. Wales (Bangor), UK.
DRiSCOLL R. (1983) The influence of vegetation on the swelling and shrinking of clay soils in Britain.
Geoteehnique 32t, 93-106.
DUMBLETON M.J. & WEST G. (1966) Studies of the Keuper Marl: Mineralogy. Road Research Laboratory
Report No. 40, Ministry of Transport, Crowthorne, UK.
Soil clays of England and Wales
705
EVANS L.J. (1972) Mineralogical changes in Lower Palaeozoic mudstones during pedogenesis in mid-Wales.
Reports o f the Welsh Soils Discussion Group 13, 91-105.
EVANS L.J. (1973) Clay mineral alteration and elemental redistribution during pedogenesis in mid-Wales.
PhD thesis, Univ. Wales (Aberystwyth), UK.
EVANS L.J. & ADAMS W.A. (1975a) Quantitative pedological studies on soils derived from Silurian mudstones,
V: Redistribution and loss of mobilized constituents. J. Soil Sei. 26, 327-335.
EVANS L.J. & ADAMS W.A. (1975b) Chlorite and illlite in some lower Palaeozoic mudstones in mid-Wales.
Clay Miner. 10, 387-398.
FINDLAV D.C. (1965) The soils of the Mendip district of Somerset. Memoir of the Soil Survey of Great Britain,
Harpenden, UK.
FINDLAV D.C. (1976) Soils of the southern Cotswolds. Memoir of the Soil Survey of Great Britain, Harpenden,
UK.
F1NDLAY D.C., COLBORNE G.J.W. COPE D.W., HARROD T.R., HOGAN D.V. & STAINES S.J. (1984) Soils and
their use in South-West England. Bulletin of the Soil Survey of Great Britain No. 14, Harpenden, UK.
GILKES R.J. (1968) Clay mineral provinces in the Tertiary sediments of the Hampshire Basin. Clay Miner. 7,
351-362.
GLENTWORTH R. & DION H.G. (1949) The association or hydrologic sequence in certain soils of the podzolic
zone of North-East Scotland. J. Soil Sci. 1, 35-49.
GOULDING K.W.T. (1981) Potassium retention and release in Rothamsted and Saxmundham soils. J. Sci.
Food Agric. 32, 667-670.
GREENE-KELLY R. (1974) Shrinkage of clay soils: a statistical correlation with other soil properties.
Geoderma. 11, 243-257.
GREENLAND D.J. (1977) Soil damage by intensive arable cultivation: temporary or permanent? Phil. Trans. R.
Soe. Lond. B 281, 193-208.
HALL A.D. & RUSSELL E.J. (1911) Soil surveys and soil analyses. J. Agric. Sei. 4, 182-223.
HAMBLIN A.P. (1977) Factors determining the structural stability o f East Anglian soils of high silt content.
PhD thesis, Univ. Reading, UK.
HARROD T.R., CATT J.A. & WEIR A.H. (1973) Loess in Devon. Proc. Ussher Soc. 2, 554-564.
HATTO~ A.A. (1978) Deep alteration in the Whin Sill, northern England. MSc thesis, Univ. Wales (Bangor),
UK.
HODGE C.A.H. & SEALE R.A. (1966) The soils of the district around Cambridge. Memoir of the Soil Survey
of Great Britain, Harpenden, UK.
HODGSON J.M., CATr J.A. & WEIR A.H. (1967) The origin and development of clay-with-flints and associated
soil horizons on the South Downs. J. Soil Sei. 18, 85-102.
HOLLIS J.M. (1975) Soils in Staffordshire 1: Sheet SK05 (Onecote). Soil Survey Record No. 29, Harpenden,
UK.
HORNUNG M. (1968) The morphology, mineralogy and genesis of soils on the Moor House national nature
reserve. PhD. thesis, Univ. Durham, UK.
HORNUNG M. & HATTON A.A. (1974) Deep weathering in the Great Whin Sill, northern England. Proc. Yorks.
Geol. Soc. 40, 105-114.
JARVIS M.G., ALLEN R.H., FORDHAM S.J., HAZELDEN J., MOFFATT A.L & STURDY R. (1984) Soils and their
use in South East England. Bulletin of the Soil Survey of Great Britain 15, Harpenden, UK.
JEANS C.V. (1968) The origin of the montmorillonite of the European Chalk with special reference to the
Lower Chalk of England. Clay Miner. 7, 311-330.
JONES A.A. & GREENLAND D.J. (1980) Quantitative determination of the interlamellar volume in an
interstratified mica-smectite soil clay. Clay Miner. 15, 175-191.
JONES O.T. & PUGH W.J. (1935) The geology of the districts around Machynlleth and Aberystwyth. Proc.
Geol. Assoc. 46, 247-300.
KERNEY M.P. (1963) Late glacial deposits on the Chalk of south-east England. Phil. Trans. Roy. Soc. B 246,
203-254.
KhAN D.H. (1957) A pedological study of some red and brown soils on limestone. PhD thesis, Univ. London,
UK.
LlVESEY N.T. (1964) The physical and chemical behaviour of clay in some North Wales soils, especially in
relation to potassium. PhD thesis, Univ. Wales (Bangor), UK.
LOVEDAY J. (1958) A study of the soils and their relation to landscape form in the southern Chilterns. PhD
thesis, Univ. London, UK.
706
P. J. L o v e l a n d
LOVEDAYJ. (I 962) Plateau deposits of the southern Chiltern Hills. Proc. Geol. Assoe. 73, 83-102.
LOVELAND P.J. (1978) An investigation into the nature and genesis o f some glaueonitie soils in central
southern England. PhD thesis, Univ. London, UK.
LOVELAND P.J. (1981) Weathering of a soil glauconite in southern England. Geoderma 25, 35-54.
LOVELAND P.J. & BULLOCKP. (1975) Crystalline and amorphous components of the clay fractions in brown
podzolic soils. Clay Miner. 10, 451-469.
LOVELAND P.J. & BULLOCK P. (1976) Chemical and mineralogical properties of brown podzolic soils in
comparison with soils of other groups. J. Soil Sci. 27, 523-540.
LOVELAND P.J. & FINDLAY D.C. (1982) Composition and development of some soils on glauconitic
Cretaceous (Upper Greensand) rocks in southern England. J. Soil Sci. 33, 279-294.
LUNA C.Z. (1959) Fertility of upland soils in relation to mineralogy and nutrient status. MSc thesis. Univ.
Wales (Bangor), UK.
MACKNEY D. & BURNHAMC.P. (1966) The soils of the Church Stretton district of Shropshire. Memoir of the
Soil Survey of Great Britain, Harpenden, UK.
MADGETT P.A. (1974) The mineralogy and weathering o f Devensian tills in eastern England. PhD thesis,
Univ. London, UK.
MADGETT P.A. & CATT J.A. (1978) Petrography, stratigraphy and weathering of Late Pleistocene tills in East
Yorkshire, Lincolnshire and north Norfolk. Proc. Yorks. Geol. Soc. 42, 55-108.
MAJUMDAR N.N. (1963) A study of the pedological processes involved in the development of soils from
dolomitie limestones and their relation to those of calcie limestones. PhD thesis, Univ. Leeds, UK.
MCRAE S.G. (1971) Some studies on glauconite in soils with special reference to selected soils in south east
England. PhD thesis, Univ. London, UK.
MCRAE S.G. (1975a) The presence of indigenous glauconite in soils and its effect on soil fertility I. Soils
developed on sandy drift (Barming series). J. Agric. Sci. 84, 137-141.
McRAE S.G. (1975b) The presence of indigenous glauconite in soils and its effect on soil fertility II. Soils
developed on Gault Clay (Denchworth series). J. Agric. Sci. 84, 143-147.
MCRAE S.G. & LAMBERT J.L.M. (1968) A study of some glauconites from Cretaceous and Tertiary
formations in south-east England. Clay Miner. 7, 431-440.
MORGAN-JoNES M. (1977) Mineralogy of the non-carbonate material from the Chalk of Berkshire and
Oxfordshire. Clay Miner. 12, 331-344.
NAGELSCHMIDT G. (1939) The identification of minerals in soil colloids. J. Agric. Sci. 29, 477-501.
NAGELSCrIMIDT G. (1944) The mineralogy of soil colloids. Imperial Bureau of Soil Science, Technical
Communication No. 42, Harpenden, UK.
NEWMAN A.C.D. (1983) The specific surface of soils determined by water sorption. J. Soil Sci. 34, 23-32.
PAHM K.E. (1967) Studies of the potassium Status of some limestone and Chalk soils. MSc thesis, Univ.
Nottingham, UK.
PAGE E.R. (1979) The effect of poly (vinyl alcohol) on the crust strength of silty soils. J. Soil Sci. 30, 643651.
PERRIN R.M.S. (1956) The clay mineralogy of some tills in the Cambridge district. Clay Miner. 3, 193-205.
PERRIN R.M,S. (1964) Analysis of calcareous materials. Pp. 208-221 in: Society for the Chemical Industry,
Monograph 18. London, UK.
PERRIN R.M.S., DAVIES H. & Fvsn M.D. (1974) Distribution of Late Pleistocene aeolian deposits in eastern
and southern England. Nature 248, 320-3.
PERRY R. (1971) Caesium adsorption studies on the clay fraction of a Suffolk soil. PhD thesis, Univ.
Manchester, UK.
PIGGOTT C.D. (1962) The phenomenon of adsorption in its relation to soils, J. Agric. Sei. 8, 111-130.
PITMAN J.l. (1978) Chemistry and mineralogy of some Lower and Middle Chalks from Givendale, East
Yorkshire. Clay Miner. 13, 93-100.
PRESCOTT J.A. (1916) The phenomenon of adsorption in its relation to soils. J. Agric. Sci. 8, 111-130.
QURESHI R.H. (1969) The distribution of some nutrient elements within soil fabric. PhD thesis, Univ. Wales
(Bangor), UK.
RAGG J.M., BEARD G.R., GEORGE H., HEAVEN F.W., HOLL1S J.M., JONES R.J.A., PALMER R.C., REEVE M.J.,
ROBSON J.D. (~ WHITEIELD W.A.D. (1984) Soils and their use in Midland and Western England.
Bulletin of the Soil Survey of Great Britain No. 12, Harpenden, UK.
REEVE M.J., HALL D.G.M. & BULLOCKP. (1980) The effect of soil composition and environmental factors on
the shrinkage of some clayey British soils. ,/. Soil Sci. 31,429-442.
Soil clays of England and Wales
707
R1MMERD.L. & GREENLANDD.J. (1976) Effects of calcium carbonate on the swelling behaviour of a soil clay.
J. Soil Sci. 27, 129-139.
ROBERTS E. (1958) The county of Anglesey: soils and agriculture. Memoir of the Soil Survey of Great Britain,
Harpenden, UK.
ROWELL D.L. & DILLON P.J. (1972) Migration and aggregation of Na and Ca clays by the freezing of
dispersed and flocculated suspensions. J. Soil Sci. 23, 442-447.
RUDEFORTH C.C. (1970) Soils of north Cardiganshire. Memoir of the Soil Survey of Great Britain,
Harpenden, UK.
RUDEFORTH C.C., HARTNUPR., LEA J.W., THOMPSONT.R.E. & WRIGHT P.S. (1984) Soils in Wales and their
use. Bulletin of the Soil Survey of Great Britain No. 11, Harpenden, UK.
SABINE P.A., YOUNG B.R. & DANGERFIELDJ. (1963) Brickearth and Clay-with-Flints from Kent. Clay Miner.
5,248-253.
SCHOFIELD R.K. (1940) Clay mineral structures and their physical significance. Trans. Brit. Ceram. Soc. 39,
147-161.
SEARL P.L. (1968) A study of some Northumbrian boulder clays and their associated soils. PhD thesis, Univ.
Newcastle, UK.
SOIL SURVEY OF ENGLAND AND WALES (1983) Soil Map of England and Wales, Scale 1:250000.
Harpenden, UK.
SPOOR G., LEEDS-HARRISONP.B. & GODWIN R.J. (1982) Potential role of soil density and clay mineralogy in
assessing the suitability of soils for mole drainage. J. Soil Sci. 33, 427-441.
STAINES S.J. (1984) Soils in Cornwall 111: Sheets S W 61, 62, 71 and 72 (The Lizard). Soil Survey Record
No. 79, Harpenden, UK.
STEPHEN I. (1951) A study of rock weathering with reference to the soils of the Malvern Hills. PhD thesis,
Univ. London, UK.
STEPHEN I. (1952a) A study of rock weathering with reference to the soils of the Malvern Hills. Part 1:
Weathering of biotitite and granite. J. Soil Sci. 3, 20-33.
STEPHEN I. (1952b) A study of rock weathering with reference to the soils of the Malvern Hills lI. Weathering
of appinite and 'ivy scar' rock. J. Soil Sci. 2, 219-237.
STORRIER R.R. (1958) An investigation into the Ironstone and related soils in the Banbury district,
Oxfordshire. PhD thesis, Univ. London, UK.
STORRIER R.R. & MUIR A. (1962) The characteristics and genesis of a ferritic brown earth. J. Soil Sci. 13,
259-270.
STURDY R.G., ALLEN R.H., BULLOCK P., CATT J.A. & GREENFIELD S. (1979) Palaeosols developed on
Chalky Boulder Clay in Essex. J. Soil Sci. 30, 117-137.
TAL1BUDEEN O. & WEIR A.H. (1972) Potassium reserves in a 'Harwell' Series soil. J. Soil Sci. 23, 456-474.
VALENTINE K.W.G. (1973) The identification, lateral variation and chronology of three buried palaeocatenas
in Lowland England. PhD thesis, Univ. Reading, UK.
WATERS R.S. (1964) The Pleistocene legacy to the geomorphology of Dartmoor. In: Dartmoor Essays. Devon
Association for the Advancement of Science.
WEIR A.H. & CATT J.A. (1965) The mineralogy of some Upper Chalk samples from the Arundel area, Sussex.
Clay Miner. 6, 97 110.
WEIR A.H. & CATT J.A. (1969) The mineralogy of the Palaeogene sediments in northeast Kent. Sediment.
Geol. 3, 17-23.
WEIR A.H. & RAVNERJ.H. (1974) An interstratified illite smectite from Denchworth Series soil in weathered
Oxford Clay. ClayMiner. 10, 173-187.
WEIR A.H., CATT J.A. & ORMEROD E.C. (1969) The mineralogy of Broadbalk soils. Pp. 81-89 in:
Rothamsted Experimental Station, Report for 1968, part 2, H arpenden, U.K.
WEIR A.J., CATT J.A. & MADGETT P. (1971) Postglacial soil formation in the loess of Pegwell Bay, Kent
(England). Geoderma, 5, 131-149.
WHITFmLD W.A.D. & BEARDG.R. (1980) Soils in Warwickshire IV: Sheet SP29/39 (Nuneaton). Soil Survey
Record No. 32, Harpenden, UK.
YOUNG B.R. (1965) X ray examination of insoluble residues from the Chalk of the Leatherhead (Fetcham
Mill) Borehole. Bull. Geol. SurE. G.B. 23, 110.
ZELAZNY L.W. & CALHOUNF.G. (1977) Palygorskite (Attapulgite), Sepiolite, Talc, Pyrophyllite and Zeolites.
Pp. 435 470 in: Minerals in Soil Environments (J. B. Dixon & S. B. Weed, editors). Soil Science Society
of America, Madison, Wisconsin, USA.