The Development of the Rhine
Author(s): E. M. Yates
Source: Transactions and Papers (Institute of British Geographers), No. 32 (Jun., 1963), pp. 6581
Published by: Blackwell Publishing on behalf of The Royal Geographical Society (with the Institute of
British Geographers)
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THE DEVELOPMENT OF THE RHINE
E. M. YATES, M.SC., PH.D.
(Lecturerin Geography,Universityof LondonKing's College)
Trieb nieder und nieder,
Du herrlicher Rhein!
Du kommst mir ja wieder,
Lasst nie mich allein.
C. BRENTANO
DERRHEINstimulates the imagination: the Vandal horde crossing the river on
the last day of 406; Charlemagne'scampaigns; the long strugglebetween France
and Germany.The riverhas indeed played an importantrole in both the political
and the economic history of western Europe, because it joins and provides a
route between three major relief units: the Alps; the Hercynian uplands; and
the north European plain (Fig. 1). Yet this link has only recently been achieved
(in the geological sense). The Rhine is not an example of a superimposedriver,
but it is a remarkablefusion of originally distinct drainageelements. The fusion
has taken place during the course of Tertiaryand Quaternarytime.
The Rhine Valley in OligoceneTimes
The period was marked by a widespread marine transgression, generally
reaching its maximum in mid-Oligocene (Stampian) times. The sea reached the
northernedge of the Rhenish Uplands, enteredthe Cologne Bay and penetrated
the Hessian Corridorto the Rhine Rift Valley.l The latter had been drowned in
the lower Oligocene from the Swiss Foreland as far as the present Neckar
confluence. In the mid-Oligocene,however, the southern sea reachedforwardto
the Mainz Basin, joined the sea occupying the Hessian Corridor,and thus completed a link between the North Sea and Tethys across the presentRhine course.
Another strait, close to the route now followed by the Rhine-Marnecanal, may
have linkedthe Rift Valleywith the ParisBasin.2Fromthe SwissForelanda further
arm of the sea, probably quite narrow, extended along the northern Alps into
Bavaria. In both the Swiss Forelandand the Rhine Rift Valley very considerable
deposition took place. The Oligocene beds of the Rift Valley reach a thicknessof
1500 metres, and contain important reserves of salt and potash, and some
oil. The 'Untere Meeresmolasse'(Stampian)of the Forelandis up to 1000metres
thick. In upper Oligocene times (Chattian) the marine deposits of the Foreland
were succeeded by fresh water deposits, the 'Untere Siisswassermolasse'.The
forerunnersof the present Alpine headstreamsof the Rhine, stimulated by the
tectogenesis, contributed to this sedimentation by building great rock deltas,
which now form the conglomerate 'Nagelfluh' and give rise to mountains in
the Foreland such as Rigi and Speer (Fig. 1). This sedimentation blocked
temporarilyin upper Oligocene times (Chattian)the southern exit from the Rift
65
66
THE DEVELOPMENT OF THE RHINE
0
!
I
*
.
Ki!ometres
100
.
.
I,
1
,
N
0
FIGURE1-The Rhine: key to places named in text.
I
.
I
.
200
i
THE DEVELOPMENT OF THE RHINE
67
Valley. Subsequentdeposition in the Rift Valley took place under fresh water or
brackish conditions, leaving marls distinguished by the presence of the mussel
Cyrena convexa, the 'Cyrenenmergel',and fresh water limestone distinguished
by the presence of the snail Helix ramondi.In the Bavarian Strait east of the
Lech some marine deposition took place in the upper Oligocene, as is
demonstratedby the PrombergerBeds, but these are underlainand overlain by
Cyrenenmergeland show a fluctuatingmargin to the sea that extendedfrom the
Hungarian Basin. Marine molasse is now exposed in Bavaria along a narrowfaulted zone that marks in a tectonic sense the northernboundary of the Alps.3
In these narrow seas the Rhenish Uplands formed a broad peninsula
(Fig. 2a). These Uplands are of course a remnant of the Hercynianmountains,
composed of a great series of Devonian sediments, lying in a number of complicated folds. By the beginning of the Tertiary epoch the mountains had been
largely reducedto a plain with rounded residualhills, the latter formed along the
quartzite outcrops and giving a relief of some 200 metres. A long period of
tropical or sub-tropical weathering had led to a deep decomposition of the
shales, and, where this material was washed into hollows, the formation of
early Tertiaryclays, which are of some importance in the ceramic industry. On
the plains flourished luxuriant forests, from which are derived the lignite
reserves of the Rhinelands. The drainage differed considerably from that of
today. The Oligocene streams have left the gravels known as the Vallendar
Schotter, and from these gravels the pattern of drainage can be reconstructed
(Fig. 2a). The river aligned along the present courses of the Mosel and Lahn
flowed, in the reversedirection to the modern Lahn, into the Hessian Corridor.4
A distributaryof this riverfollowed the same directionas the present Rhine into
the Cologne Bay.
The Vallendar Schotter rise to an altitude of 480 metres, but they are well
developed upon an important 400-metre surface within the uplands, into which
the Rhine, Mosel and Lahn are incised. This surface, occasionally reaching a
width of 30 kilometres, is the 'Trog' of A. Philippson.5 Stratigraphicallyabove
the Vallendar Schotter, and apparently laid down under brackish conditions,
are sediments derived from the products of the Tertiaryweathering, the Arenberger Beds. The late Oligocene and early Miocene appearsindeed to have been
a period of great sedimentationin which the old Vallendardrainagedivideswere
buried and the streams graduallyreplaced by strings of salty pools. The formation of the Trog has been attributedby H. Louis to the lateral planation of the
debris-laden streams responsible for the sedimentation.6This is, however, far
from being the only explanation for the formation of the Trog. Above the Trog
are two further surfaces at 500 and 600 metres, the Rumpfflachen,designated
respectively Rl and R2. Above these high surfaces there are residual hills, in
which traces of a third surface have been distinguishedat 740 to 800 metres, the
R3. The higher surfaces R1, R2, R3 and the Trog have been regardedalternatively as derivedfrom one original surface, buckled during uplift from Miocene
times.7 This is supported by the presence on the Trog, in situ, of older Tertiary
G
FIGURE 2a (left)-The Rhine valley in Oligocene times (Stampian); 2b (middle)-The Rhine valley in Miocene time
The Rhine valley in Pliocene times (Astian).
THE DEVELOPMENT OF THE RHINE
69
weathered complexes. Evidence for buckling of the surfaces above the Trog
comes from the courses of tributariesof the Mosel, such as the Kyll, which are,
or appear to be, antecedent to buckling. They cross remnants of the R2 surface
in their middle courses, flowing from R1 across R2 to the Trog. These interpretations suggest either an Oligocene or a Miocene age for the Trog and this
latter date receives confirmationfrom the Westerwaldwhere the surfaceis cut in
basalt of lower Miocene age. Because of the presence upon it of flints the R3
surface has also been considered as Eocene or even Senonian. In general it may
be said that the conflict of views on the age of the upper surfacesof the Rhenish
Uplands is similar to that associated with the Welsh Uplands. A similar conflict
of opinion applies to the Belgian part of the massif, the Ardennes. Both eustatic
change and crustal warping have been argued as explanations for the various
surfaces, including that at 400 metres. Some of the various interpretationsare
given by A. Godard, and in table form by J. F. Gellert.8
The coastline of the peninsula on which these developments took place
fluctuated considerably during the Oligocene. In the upper Oligocene the sea
withdrew from the northern shores and the swamp forests extended into the
Cologne Bay. The subsidence of the latter led to the accumulationthere of up to
200 metres of lignite, the brown coalfield of Cologne. On the southern shores
a transgression of short duration linked the northern end of the Rhine valley
with the Neuwied Basin,as shown by the presencewithin the Basin of the Cyrenenmergel. This linkage, through the Bingen Gate, foreshadowed a later development of the Rhine and presumably led to changes in the already disrupted
Vallendar drainage pattern. The major changes came, however, with the uplift
in Miocene times and the accompanying faulting and vulcanism.
The Rhine Valley in Miocene Times
Vulcanismin the Rhenish Uplands began with the formationof the andesites
and trachytesof the Siebengebirgeand the Westerwald,and was followed in the
Miocene by the basalt flows of the latter. The Siebengebirge,Oligocene in age,
are situated at the southern apex of the Cologne Bay and are associated with its
downfaulting. The massif as a whole, however, did not lift either uniformly or
as an entity. The greatestuplift occurredin the south: in the Neuwied Basin, and
possibly along the line of the gorge, movement was much less. The masking of
the old divides by the Arenberger Beds, together with disruption associated
with differential faulting, led to important changes in the drainage pattern.
The reversed Lahn, the Mosel and the Rhine gathered in the Neuwied Basin
and flowed northward. As well as being disrupted by the earth movements,
these streams, in particular the Mosel, became superimposed, since they
developed on the upper surface of the ArenbergerBeds. This superimposition
makes intelligibleboth the curious course of the Mosel, where it is incised in the
Devonian outcrops on the south side of the depression of the Wittlich Sink, and
its spectacular incised meanders. The Wittlich Sink had been filled by the
Tertiary weathered complexes, and has subsequently been re-excavated. The
70
THE DEVELOPMENT OF THE RHINE
very curious course of the Wiipper is partly explained by the adjustmentof the
lower stream to an infilled Oligocene valley.
The new drainage system was initially contained within the massif. The
Mosel appears to have extended rapidly its course in the Mesozoic outcrops of
the Trier bay, but its culminating capture of the upper Meuse in the Val de
l'Asne did not occur until Pleistocene times.9
In the Alpine Foreland the Miocene was a period of great disturbance.
The Alps and the Jura were elevated and the Foreland between was deepened.
The movement must have begun in the upper Oligocene when a considerable
deposition of molasse took place under fresh water or brackish conditions.
These beds were followed by Miocene marine molasse, the 'Oberemeeresmolasse' (Burdigalian and Helvetian) as the deepening continued, and the
Rhone valley and Vienna Basin were rejoined by an arm of the sea 100 kilometres wide and 600 kilometres long. The extent of the transgressionis shown
by an old cliff on the dip-slopes of the SwabianJura.Continuous deposition and
further movement was followed by the withdrawalof the sea in the middle and
upper Miocene. The withdrawal was most rapid from Swabia. The Swiss
Foreland remainedoccupied by an arm of the Mediterranean,and into this arm
of the sea discharged the Alpine torrents, like their predecessorsin Oligocene
times. They laid down the coarse debris that now forms the Nagelfluh masses of
Hornli and Napf. The molasse (Oligocene and Miocene) reaches a thickness of
3000 metres and varies in facies from the coarse conglomeratesnear to the Alps
to finer material farther north. On the northern side of the Foreland, coarser
material derived from the Jura is again present, the Juranagelfluh.Also, on
the northernside of the Foreland, near the site of Schaffhausen,entereda major
stream, known from its sands as the 'Graupensande-Strom'.10This flowed
south parallel to the Franconian Jura, and thence westward in the Swabian
Foreland. The northern part of the course of the Graupensande-Stromis now
that of the Main above Bamberg;the southernhalf is that of the Danube above
Ingoldstadt. In both instances the flow was in a direction the reverse of that of
today (Fig. 2b).
The lower Main probably dischargedinto the Mainz Basin, but the earliest
Main gravels are of Pliocene age.1 The Mainz Basin was reached by an arm of
the sea or a lagoon during the marine reoccupation of the Alpine Foreland
(Aquitanian). In this sea were laid down considerablethicknesses of limestones
and marls, the Cerithia Beds and the Corbicula Beds, which now form the hill
country south-east of Bingen. Both formations have littoral facies in the northeast, showing that the Hessian corridor was no longer an arm of the sea. This
former exit was furtherblocked in the upper Miocene and Pliocene by the basalts
of Vogelsberg, the biggest basalt mass in mainland Europe, with an area of
2500 square kilometres. Farther to the east is the similar but smaller mass
forming the highest point of the Rhongebirge. At the southern end of the Rift
Valley the Miocene disturbances,which produced the Jura and re-elevatedthe
Alps, had been accompanied by the vulcanicity of the Kaiserstuhl.
THE DEVELOPMENT OF THE RHINE
71
On the north side of the Rhenish uplands the Rhine mouth must have been
in the Cologne bay, for the mid-Miocene was a period of marine transgression,
the last to reach the borders of the massif.l2 In mid-Miocene times the Rhine
thus remained a Hercynian stream.
The Rhine Valley in Pliocene Times
The date of the linkage of the Hercynian Rhine with the drainage of
the Rhine Rift Valley is establishedas Pliocene (Pontian) by the presence on the
massif of the Kieseloolith Beds. A Pliocene date is ascribedto the Kieseloolith
Beds because of their stratigraphical relationships in the lower Rhinelands,
where they rest upon the Miocene Fischbach Beds and are in turn followed by
clays containing traces of a mid-Pliocene (Astian and Piacentin) flora. The
Kieseloolith Beds are pebble beds, distinguishedby the very high percentage of
gangue quartz and quartzite (reaching on average 98 per cent), and by the
absence of pebbles derived from the rocks of the massif, for examplegreywacke,
slate or sandstone.13The source of the pebbles was the Triassic outcrops of the
south German scarplandsand of Lorraine (Lotharingia).Their presence within
the massif must be associated with the southward extension of the Rhine
catchment. This extension took place, in the opposite sense, along the route
followed by the Oligocene transgression into the Neuwied Basin as already
described, and the headward erosion presumablyresponsible for the extension
was probably facilitated by the presence of Tertiary rocks. Within the massif
the Kieseloolith Beds are associated with the Higher Terraces, the first true
terracesof the Rhine. They are incised below the level of the Trog, and fall from
320 metres near Bingen to about 150 metres near the Ruhr. This fall is of course
much steeper than that of the present Rhine, and is due to the continued uplift
of the massif. Northward into the Netherlands the Kieseloolith Beds pass into
littoral and marine facies. Owing to the subsidence of the western Netherlands
the surface of the marine Pliocene reaches a depth of 600 metres whilst in the
central Netherlands, Pleistocene faulting has lowered the littoral facies to
depths of 300 metres.14Even within the massif the Kieseloolith Beds have been
affected by fault movements as well as uplift. In the Neuwied Basin the Higher
Terraces are down-faulted some 80 metres.15Such fault movements have also
led to considerablediscussion as to whether the Higher Terracesdo consist of a
number of distinct erosional stages or are the faulted remnantsof one surface.16
The considerablechanges in the north were paralleledby major changes in
the south of the Rhine basin. The molasse sedimentation, which had infilled
the Alpine Foreland by the end of the Miocene, together with uplift of the Jura
at the western end of the Foreland, destroyed the former drainage pattern. On
the northward-slopingmolasse surface such Danubian headstreams as the Ill,
Lech and Inn developed. The Danube was a much more powerful stream than
it is today. It receivedthe presentAlpine headstreamsof the Rhine, the drainage
of the southernRift Valleyvia an eastward-extendingAare, and possiblythe upper
72
THE DEVELOPMENT OF THE RHINE
Rhone.17This former relationshipof Aare and Danube is shown by the presence
in Danube terracegravels of pebbles derivedfrom the Aare massif. The Danube
tributary coming from the southern end of the rift valley left sheets of gravels
derived from the Vosges. Significantly, however, in the upper Pliocene the
Vosges material was overlain by debris from the Alps.18 A great reversal of
drainagehad taken place. The Danube had lost its upper headstreamsfrom the
Swiss Alps, and they formed a majorstreamthat flowed throughthe Burgundian
gate, between the Vosges and Jura, into the Rhone-Saone corridor (Fig. 2c).
During the same interval the Rhine extendedits catchmentarea in the Rift
Valley and in the south German scarplandswith the aid of the Main and Neckar.
Both of these tributarieshad to contend with considerabletectonic movement
along their courses. Uplift took place along the axis Rhon-Spessart-Odenwald,
amounting to 200 metres where the axis is crossed by the Neckar.19 Consequently both rivers have become deeply incised and the destruction of the
upwarped Mesozoic rocks was intensified. The Muschelkalk,which has a considerableoutcrop south of the axis, exists north of the axis only where preserved
by the basalt of Rhin. In the Odenwald even the Bunter and the thin Permian
cover have been removedto expose the underlyinggranitesand quartzporphyry.
The erosion surfaces cut in the granite outcrops have been variously interpreted
as exhumed surfaces of Permian age, and as piedmont surfaces (Piedmontflachen) formed as the Mesozoic rocks were removed. South-east of the Spessart
axis a 300-metresurface is present, best preservedin the Muschelkalk outcrops,
the 'Gauflache', and with Pliocene clays occasionally presentupon it.20Farther
south and east the highest levels of the Franconian Jura appear to be of older
Tertiaryage and are associated with a gravel, the 'Hochflachenschotter',which
contains materials derived from the Frankenwald. The distribution of these
gravels indicates an earlier drainage directed southward (Fig. 2b). These
southward-flowingstreams, captured during the Pliocene, now constitute the
upper Main. The latter is indeed a most complex tributaryof the Rhine, for its
lower course is also composite. Below Miltenburg it may be considered consequent, but the sector from Gemiinden to Miltenburg is subsequent, and
adjusted closely to the outcrop of the Rot (the clayey sand formation at the top
of the Bunter).
This is the orthodox explanation of the development of the Main. An
alternative 'Klimamorphological' interpretation has been put forward by J.
Biidel, an interpretationhaving much in common with the ideas of Louis on
the formation of the Trog.21Biidel suggests that both the present Main course
and the Gauflacheare best understood as the products of the tropical climates of
Pliocene times. Under such climates, with associated rapid chemicalweathering,
streamslack the angularrock waste they requireto incise. As a resultthe streams
are wide and shallow, and experience in time of flood many major changes of
course. By such changes and the abstraction of the formerly southward-flowing
streams, the present Main was formed. With the onset of colder conditions in
the Pleistocene, mechanical weathering became more important than chemical
THE DEVELOPMENT OF THE RHINE
73
weathering.The Main, now carryingangularrock fragments,was able to incise,
forming the present steep-sided valley.
Similarlythe course of the Neckar has been variously explained. It has been
considered a successful pirate stream which beheaded a series of streams
formerly flowing south-east across the Alb to the Danube. The north-eastflowing section of the Neckar near Stuttgart is a reversed section of one such
stream.22The section of the Neckar above Tiibingen may be regarded as a
strike stream, similar to the Main between Gemiinden and Miltenburg but
adjusted to the outcrop of the Gipskeuper and Lettenkohle. Alternatively the
Neckar has been considered largely the result of the tectonics that flexured
the south German scarplands.The Spessart axis is paralleled to the south by a
further axis extending east-north-eastfrom the Black Forest. On the northern
slopes of this southern axis developed the Neckar, turning into the basin
between the two axes at Eberbach.23
This emphasis upon tectonic effects and the various references to antecedence may appear strange to English geographers; but it is important to note
that such uplifts as that of the Black Forest and the consequent warping of the
south German scarplands continued in Pleistocene and in Holocene times.
The recent nature of the movements is shown by the various levels at which
cirques of Wiirm age are now to be found in the Black Forest. Obviously the
drainage must have been either antecedent to or deflected by the movement.
The tectonic explanationof the Neckar course is similar to that made originally
by W. Penck.24He considered that the Neckar occupied a depression between
two separateareas of uplift, the Alb or Swabian Jura, and the Black Forest. The
present headstreamswere antecedentto the later more pronounced uplift of the
southern Alb.
The success of both the Neckar and the Main in capturing the streams
flowing towards the Swabian Foreland is due of course to the rejuvenation
consequent upon the lowering of their base-level with the continued downfaultingof the Rift Valley.This movementcontinuedin the Pliocene,and some 150
metres of Pliocene deposits are present in the Mainz Basin, but the most rapid
period of movement appears to have come at the end of Pliocene times.25
Not only the Rhine Rift Valley was affected. The northernend of the Rhine Rift
Valley, the Mainz Basin, is paralleledto the east by the AschaffenburgBasin,from
which it is separatedby the FrankfurtHorst. The AschaffenburgBasin developed
in the Pliocene, and its movements diverted the lower Main northwards.
The Rhine Valley in Pleistocene Times
the
By
beginning of the Quaternaryera only the Alpine part of the present
Rhine drainage remained unconnected with the major stream. The structural
elements already connected by the Rhine at the end of the Tertiaryera were the
Lower Rhinelands, the Rhenish Uplands and the Rhine Rift Valley. The first
and the third of these elementswereaffectedby downwardmovementthroughout
74
THE DEVELOPMENT OF THE RHINE
the Pleistocene whilst the elevation of the Rhenish Uplands continued contemporaneously.
Across the rising massif the Rhine has cut its gorge, but the downcutting
has been spasmodic. Beneath the Higher Terraces, with their Kieseloolith
gravels, is present a great suite of terraces: the High Terrace; the Middle
Terrace; the Low Terrace. Each of these terraces is in fact composite and
consists of some two or three distinct stages. There are, for example, Upper,
Middle and Lower Middle Terraces. Furthermore the terraces have been
warpedand faulted, especiallyin the vicinityof the Neuwied Basinwherevolcanic
activity occurredin the late Pleistocene and in Holocene times. Consequentlythe
terrace sequence is extraordinarilycomplicated, and there exists a considerable
differenceof opinion on the identificationof the various terracelevels.26
The lifting of the massif has given the upper terraces a much steeper fall
northwardthan the present Rhine, and the older the terracethe greaterthe fall.
The Middle High Terrace is at an altitude of 220 metres at Rochusberg immediately south of the massif. It rises to 265 metres at Trechlinghausenwithin
the gorge, and then falls northward.27Within the Neuwied Basin it is probably
below 100 metresand is thickly coveredwith loess and tuff. At Andernachit is at
220 metres; at Linz 210 metres; at Duisburg 100 metres. In contrast the Low
Terraceis at 60 metres at Andernachand at 30 metres at Krefeld. This is a much
gentler fall northward and as a result the terraces cross in the vicinity of
Nijmegen, the High Terrace gravels descending beneath those of the Low
Terrace.28
In the lower Rhinelands the oldest of the High Terracegravels, also known
as the 'Alteste Diluvialschotter', are followed stratigraphicallyby the Tegelian
Beds and their marine equivalents, part of the Icenian Beds. The latter reach a
thickness of 200 metres and are evidence of a continued subsidence.This downward movement was not uniform, however. The underlying Mesozoic and
Paleozoic rocks are much faulted in a north-north-west to south-south-east
direction and form, beneath the Rhine gravels, a series of horsts and graben.
Movement along some of these fault lines took place during the Pleistocene.
The High Terracein the Cologne Bay is faulted and presents to the east a steep
fault scarp, the Ville Ridge. This faulting is of considerableimportanceto the
brown coal industryof the Bay since it is in such horsts that the ligniteapproaches
close to the surface. Similarlythe relative uplift of the Peel Horst in the Netherlands brings the Carboniferousrocks closer to the surface, and is of importance
in the hard coal industry. The Tegelian Beds, famous for their rich fauna,
probably belong to an early interglacial,and this introduces the vexed problem
of chronology.
The problem is a difficultone because three theories have been advancedof
the formation of the terraces: tectonic; glacial-eustatic; and climatic. The
tectonic theory was developed by H. Quiring who saw the faulting of the lower
Rhinelands as the major cause of the terraceformation.29The climatic theory,
derived initially from the work of A. Penck and E. Brucknerin the Alps,30 is
THE DEVELOPMENT OF THE RHINE
75
dependent upon the view that in glacial times the great quantity of weathered
material that becomes available is in excess of the transportativepower of the
streams. The surplus material is spread in aggradational terraces. Applied to
the lower Rhine terraces this theory, sometimes in a modified form, has had a
number of exponents.31The glacial-eustatic interpretation of the lower Rhine
terraceswas first put forward by R. Grahmann,and was stimulatedby work on
the terracesystems of the Somme and Thames.32Recently, however, the gravels
of the terraces below and including the High Terrace have been distinguished
from the Kieseloolith gravels, and dated as glacial,33on the following grounds:
lack of leaching; presence of cryoturbations;presence of large boulders, which
it is consideredmust have been transportedby ice floes; presenceof uncemented
sand blocks which must have been transportedin a frozen state; and the degreeof
'rounding' of the individual pebbles.34Some furtherevidence of the glacial date
of the terracesis to be seen in the relationshipbetween the terracesof the Rhine
and the Ruhr, and the moraine of the Saale ice. This was the only ice advance to
reach the Lower Rhinelands (and the Rhine must then have had a regimelike
one of the present Siberianrivers).The ice overranthe Rhine terracesand pushed
up a remarkable morainic wall, the 'Stauchmorine', which extends from
Krefeld via Apeldoorn to the Zuider Zee and forms part of the Amersfoorter
stadium.35This featureis built largely of Rhine gravelsbut contains also a small
quantity of material derived from the north.36 In places outwash sand and
ground moraine associated with the Saale advance rest on the Middle Terrace,
and on the Ruhr small quantitiesof northernmaterialhave been incorporatedin
the Lower Middle Terracegravels.37It would appear, therefore,that the terrace
formation and the ice advance were contemporaneous. The Lower Middle
Terrace is considered to be of Saale age (Riss) and the Upper Low Terrace
Weichsel (Wiirm). Some furtherevidence for the Saale age of the Lower Middle
Terrace comes from the Krefeld area. There substantial fragments of this
Terrace remain on the western side of the push moraine. They were formed by
the Rhine after it had been deflected westward by the ice, and before it broke
back through the moraine to its present position. Beneath the Terrace is a
buried 'Rinne' (meander)of the Rhine, the floor of which descends to sea-level.
The Rinne is infilled with gravel, but in places on the gravel is a peat which
pollen analysis has shown to be of Holstein age (Elster-Saaleinterglacial).This
again suggests a Saale age for the Middle Terrace. The Rinne itself may be of
Elster age and its depth is interpretedas an eustatic effect.
The presence of the Holstein pollen is crucial to the dating of the Rinne
near Krefeld, for deep Rinnen are also present in the Dutch Rhinelands,
reachingdepths of 40 metres below sea-level in the Gelder valley and 100 metres
below sea-level in the Ijssel valley. These Rinnen are considered to have been
formed by glacial erosion and not to be due to a rejuvenation of the Rhine
following eustatic change for the following reasons:
(1) The Rinnen did not guide the ice lobes and therefore could not have
existed before the arrival of the ice.
76
THE DEVELOPMENT OF THE RHINE
(2) They descend to different depths.
(3) The fall in sea-level in glacial times would have been accompanied by a
great extension of the river. In Weichsel times, for example, the sea-level
fell by 86 metresbut the Rhine coursewas extendedby 700-800 kilometres.
Only on steep coasts would eustatic effects cause incision by the streams,
and the course of the Low Terrace shows that this did not take place
along the Rhine.38
In view of these contrastingexplanationsthe problem of eustatic effects on
the Rhine remains extremelypuzzling. Studies of the gravelsand of the Stauchmorane provide evidence of a glacial rather than inter-glacial age for the
terraces, but do not prove that the terraces owe their origin solely to the
degeneration of the climate and to the lack of vegetation which might prevent
weathering:in otherwords,to glacial aggradation.It would appearreasonableto
assume that all the various causal factors considered contributed to the formation of the terraces. H. W. Quitzow, who adopts broadly the tectonic view for
the incision, accepts a climatic explanation for the terrace development.39
K. Kaiser, although he does not accept the tectonic interpretation, briefly
discusses possible isostatic compensation beyond the ice rim. This would
mean a contemporaneity of tectonic and climatic effects. A comparison with
the Danube is of value. The number of terraces present in the Hungarian
Middle Mountains (Bakony Wald) exceedsthat downstreamin the Great Alfold.
This would appear to be due to crustal movement. Furthermoreit is difficultto
see any climatic explanation for the presence of Danube terracesat 200 metres
in the Middle Mountains when, in the Little Alfold and the Great Alfold,
Danube gravels descend to below 100 metres beneath sea-level.40 Similar
crustal movements, continuing until well into the Pleistocene, are clearly in
evidence in the Rhenish Uplands and Cologne Bay.41The conclusion seems inescapable, therefore, that tectonic forces have been of major importancein the
development of the Rhine terraces. Indeed, in view of Kaiser's careful study of
the High Terracegravels and of Louis's work on the Trog, it would appear that
terraces have been formed under a variety of climatic conditions. In general it
may be said that climate (in the sense described), tectonic forces, and glacialeustatic change have all contributed to the formation of the Rhine terraces,
but the role played by the crustal movements was a major one. In view of the
excessive claims made by some 'Klimamorphologists' O. Maull's comment is
readily understandable.When discussing the relative contribution of tectonic
forces and 'climate'to the relief of the Rhenish uplands and the Alps he observes
'Obwohl die verschiedensten Klimate an ihnen geformt haben, wenn auch
ungleich intensiver,der Art nach doch nur so wie das Klima an den Formen des
Kolner Doms'. ('Therefore different climates have fashioned them, if with
unequal intensity, only as much as climate contributes to the form of Cologne
Cathedral'.) On the other hand Biidel, as an exponent of Klimamorphologie,
writes 'Alterbtetektonische Strukturen,die an der Oberflachedurch die Auslese
THE DEVELOPMENT OF THE RHINE
77
harter und weicher Schichten "petrographische"sichtbar werden, oder jung
tektonische Vorgange, die die Erdkruste zerrechen, zerreissen oder sonst
deformieren, sind in diesem gesetzmassig an die Klimazonen geknupften Bild
nur Stirungen Arabesken und-wenn auch oft sehr auffallige-Ausnahmen'.
('Ancient structures that become visible on the surface owing to differential
erosion of beds of varying resistance,or recent tectonic events that break, tear or
deform the earth's crust, are to the morphology associated with climatic zones
only disturbances, arabesques and, even if very striking, exceptions.')42
To return to the chronology of the terraces, it is to be noted that an
accurate date can be given to the Lower Low Terrace.It contains pumice from
the late Pleistocene vulcanism of the Neuwied Basin and has therefore been
formed subsequent to the Allerod period, that is subsequent to about 11,000
B.C. In other words it is of Holocene age, the latest of the long series of
terraces and surfaceswithin the Rhenish Uplands which extend in age from the
Oligocene to the Holocene.
The occupation by the ice of the Amersfoorter stadium must have
deflected the Rhine mouths westward. The distribution of Eemian deposits
(Saale-Weichsel interglacial)suggests that after the deflection the exits were the
Ijssel and Geld valleys. In the Weichsel glaciation the northern North Sea was
again occupied by ice. Before the ice-sheet was complete the fall of sea-level
would have led to an extension of the Rhine. Eventually, however, the ice
extended from north-east England to Denmark. Thames and Rhine water was
ponded up by the ice and escaped south via the Straits of Dover.43Such ponding
probably also took place in the Saale glaciation when the ice reached further
south, and this may have been responsible for the initial formation of the
Straits.44An older extension of the Rhine across the floor of the present North
Sea may be shown by the Chillesford Crag of East Anglia. The crag contains
mica, the source region of which is believed to be the Ardennes.45
The formation of the straits of Dover has much changed tidal conditions,
and under the influence of the tides the more south-westerly distributaries of
the Rhine have experienced stronger scour than those of the north-east. The
greater part of the Rhine discharge has been diverted further south-west in
historical times, the deflection of the Waal above Dordrecht occurring on the
18 November 1421.46Factors contributory to the decline of the north-eastern
distributariesmay be the rise in sea-level, and local alluviation.47
Within the Rhine Rift Valley considerabledownwardmovement continued
during the Pleistocene. The Quaternary gravels reach great thicknesses: 397
metres has been recorded in a bore at Heidelberg.48This has had a profound
effect on the terrace formation. Whereas in the Rhenish Uplands the oldest
terraces are the highest, in the Rift Valley the floor is occupied by the Low
Terraceand the flood-plain, and their gravels lie above those of the buried older
terraces.49Older terrace remnants are found above the Low Terrace only on
the sides of the Rift Valley and on the Hessian Hills. Even so the height of these
remnants varies considerably according to the extent of the downward move-
78
THE DEVELOPMENT OF THE RHINE
ment. Old terracegravels (of the Higher Terrace)lie at 35-40 metres above the
present stream at Biebrich north of Mainz. In the Rhein-Hesse Hills they are at
140 metres above the Rhine.50The terraces,as in the Rhenish Uplands, are considered to be of glacial ratherthan interglacialdate, formed by the aggradation
of the Rhine when it was heavily laden with glacial debris. The Low Terraceis
considered to be of Wiirm age and the Middle Terrace of Riss age. The Rhine
terracesthus provide a link between the Saale glaciation of the North German
Plain and the Riss glaciation of the Alps. The presence of lakes in the Alpine
Foreland during interglacial periods is thought to be additional evidence of a
glacial rather than interglacial date, since lakes reduce the volume of material
entering the Rift Valley and inhibit the development of aggradational terraces.
The Low Terrace has a considerable slope from 148 metres at Strasbourg to
86 metres at Mainz. At Schaffhausenthe Upper Low Terraceis at 385 metres.
The steep slope of the terrace northward is partly due to the sorting of the
gravels since the finer material has been carried farther downstream. Near
Frankfurtthere is a considerabledevelopment of blown sand, whilst the gravels
in the Sundgau at the southern end of the Rift Valley contain large cobbles. As
well as descending steeply northwardsthe Low Terracealso descends relative to
the Rhine. It is 20 metres above the river at Basle, and 5 metres at Mainz.51In
Switzerlandthe relationship of the terrace with the moraines shows it to be of
Wiirm age. But the Upper Low Terrace does not correspond with the Young
Moraine. It must ratherbe dated as Friihwiirm.Any associated moraine would
lie nearer to the Alps than the Young Moraine (which is of Hochwiirm age)
and has yet to be identified.52Leeman, however, came to the conclusion that
near Schaffhausenthe Upper Low Terraceis aggradationalwhilstthe LowerLow
Terrace is erosional. This is at variance with the sequence in the Rhenish
uplands, and may mean that the correlation of fragments of terraces, even
over a short stretch of the stream as near Schaffhausen, is impossible because
many separate causes have led to the formation of terraces, and these causes
have been independently operative.53
The movements in the Rift Valley also contributed to the most marked
change of all. In Pliocene times, as noted, the Alpine Rhine flowed through the
Belfort Gap. In that gap and in the Sundgauis present a great sheet of gravels,
20 kilometres or more wide and 15 to 20 metres thick.54These gravels were laid
down by the Alpine Rhine (they are rich in rocks from the Aare massif) and the
width of the deposit shows the gradual deflection of this stream northwardsas
the Rift Valley subsided. This subsidence,coupled with the headwarderosion of
the Rift Valley Rhine, brought about the linkage of the Alpine part of the Rhine
with the main stream. The link was completed at the beginning of the Pleistocene. The Vorder Rhine, however, was not then one of the headstreamsof the
Rhine, but flowed to the Danube. The westwardturn of the Vorder Rhine into
the Boden Sea, which contrasts sharplywith the simpler courses of the Ill, Lech
and Inn, was due to the Pliocene-Pleistocene faulting in the molasse, for the
lake occupies a minor graben.55The change in direction of the Vorder Rhine,
THE DEVELOPMENT OF THE RHINE
79
that is its junction with the main Rhine rather than the Danube, came in the
Riss-Wiirm interglacial. The advance of the ice into the Alpine Foreland
caused a further notable change. The post-Wiirm Rhine has not succeeded in
re-occupying its old course at Schaffhausen. The new course descends over an
outcrop of Jurassic limestone in the spectacular Rhine fall.56
Also in the Wiirm occurredone of the most spectacularcapturesassociated
with the Rhine-Danube struggle-that of the Wutach at Blomberg. In midPliocene times the Aare, as already described,was a headstreamof the Danube,
and followed a course in the direction of the lower Wutach, receiving the upper
Wutach near Blomberg as a tributary. This old course of the Aare can be
traced by means of gravels near Blomberg containing rocks of Alpine origin. In
the upper Pliocene the Aare was lost by the Danube and the present lower
Wutach began as a small reversed stream in the abandoned section of the Aare
valley. By headward erosion this small stream cut back and beheaded the
Danube. From the elbow of capture the Wutach falls to the Rhine in 38 kilometres making its confluenceat an altitude of 313 metres. The beheadedDanube
flows 370 kilometres before reaching the same altitude.57Even this does not
complete the tally of the losses of the Danube to the Rhine. From the Danube
valley near Tuttlingen a considerable volume of water is lost into the Jurassic
limestones, and this reappearsin the great spring at Aach, from whence it flows
into the Boden Sea and the Rhine.
Thus was formed the Rhine. Of all the rivers of western Europe it is the
only one to join the Alps with HercynianEurope and the North European Plain,
but its importancedoes not rest solely there. The combination of these relief and
structural elements, with their differing hydrological regimes, has given the
river an unusually regularflow. The river crosses one of the major coalfields of
Europe, and its delta has an unmatched centrality for the nation states of
western Europe. The geological events described have fashioned both a river
and an artery of trade endowed with unparalleledadvantages.
ACKNOWLEDGMENT
The author gratefully acknowledges the grant made by his college, King's College, London,
towards the cost of the illustrations.
NOTES
1 R. HUNGER,Brockhaus Taschenbuch der Geologie (Berlin,
1955), 336-50.
2 C.
MORDZIOL,Der geologische Werdegang des Mittelrheintales. (Wittlich, 1951), 14; M.
GIGNOUX,Geologie stratigraphique (Paris, 1926), 413.
3 C. TROLL,'Der Diluviale Inn-Chiemsee-Gletscher', Forschungen zur deutschen Landeskunde, 23
(1924), 1-121.
4 W. KLUPFEL,'Zur Entstehung des Rheinsystems', Zeitschrift der deutschen
Geologischen Gesellschaft, 83 (1931), 597-611.
5 A.
PHILIPPSON, 'Entwicklunggeschichte des Rheinischen Schiefergebirge', Sitzung Berichte der
Niederrheinische Gesellschaft fur Natur- und Heimatkunde, 1899A (1899), 48-50.
80
THE DEVELOPMENT
OF THE RHINE
6
H. Louis, 'Ober die altere Formenentwicklung
im RheinischenSchiefergebirge,
inbesondereim
Moselgebiet', Munchner Geographische Hefte, 2 (1953), 1-97.
7 C.
op. cit., 52.
MORDZIOL,
8 J. F. GELLERT,Grundziige der physischen Geographie von Deutschland (Berlin, 1958), 84; A.
GODARD,'Morphologie des socles et des massifs anciens', Revue Geographiquede l'Est, 1 (1962), 79-96.
9 P. GEORGE
and J. TRICART,
L'Europe Centrale, vol. 1. (Paris, 1954), 52-65.
10 E. HENNIG,'Entwicklung des Schweizer Flussnetzes', Geographica Helvetica, 4 (1949), 11-16.
11 H. SCHREPFER,
'Das Maintal zwischen Spessart und Odenwald', Forschungen zur deutschen
Landeskunde, 23 (1924), 191-224.
12 P. KUKUK,Geologie des Niederrheinisch Westfalischen Steinkohlengebietes (Berlin, 1938), 477;
A. J. PANNAKOEK,
Geological history of the Netherlands (The Hague, 1956), 65.
13 K. KAISER, 'Geologischen Untersuchungen iuber die Hauptterrasse in der Niederrheinischen
Bucht', Sonderveriffentlichungen des Geologischen Institutes der Universitdt Koln, 1 (1956), 1-68.
14 A. J.
PANNAKOEK, op. cit., 69; P. WOLDSTEDT, Das Eiszeitalter, 2 (1958), 59.
15 M.
and J. FRECHEN,
Die Vulcanische Eifel (Wittlich, 1951), 23.
HOPMANN,G. KNETSCH
16 H.
BREDDIN,'Die Hohenterrassen von Rhein und Ruhr am Rande des Bergischen Landes',
Jahrbuch der preussischen Geologischen Landesanstalt, 49 (1928), 501-50; K. KAISER,op. cit.
17 W.
STAUB, Pliozine Verebnungen und Flusslaufe in den Schweizerischen Zentralalpen',
Erdkunde, 11 (1957), 124-8.
18 E. HENNIG, op. cit.
19 H. SCHNEIDER,
'Morphologie des Buntsandsteinodenenwaldes', Frankfurter Geographische
Hefte, 6 (1932), 1-76.
20 H. SCHREPFER,
op. cit.
21 J. BUDEL, 'Grunzuge der Klimamorphologischen Entwicklung Frankens', Wurzburger
Geographische Arbeiten, 4 (1957), 5-46.
22 W. STROEBEL,
Erlauterung zur Geologischen Karte von Stuttgart und Umgebung (1959),
chapter 4, 'Landschaftgeschichte'.
23 A. ZIENERT,
'Die Grossformen des Schwarzwaldes', Forschungen zur deutschen Landeskinde,
128 (1961), 1-108.
24 W. PENCK,'Die Piedmontflachen des Sudlichen Schwarzwaldes', Zeitschrift der Gesellschaft
fur Erdkunde zu Berlin, 3 (1925), 81-108.
25 J. P. BAKKER,'Einage Probleme der Morpholdgie und der jiingsten geologischen Geschichte
des Mainzer Becken und seiner Umgebung', Geographische en Geologische Mededeelingen, 3 (1930),
1-112.
26 G. SITTIG,'Le probleme des "terrasses fluviales" a propos d'une vallee du Masif Schisteux
Rhenan', Annales de Geographie, 45 (1936), 136-49.
27 D. GURLITT,
'Das Mittelrheintal: Formen und Gestalt', Forschungen zur deutschen Landeskunde,
46 (1949), 1-159.
28 P. WOLDSTEDT,
op. cit.
29 H.
QUIRING,Ober die tektonischen Grundlagen der Flussterrassenbildung', Zeitschrift der
deutschen Geologischen Gesellschaft, 78 (1926), 156-63.
30 A. PENCKand E. BRUCKNER, Die Alpen im Eiszeitalter (1909).
31 W. SOERGEL, 'Das Diluviale System, Die geologische Grundlage der Vollgleiderung des
Eiszeitalters', Forschritte der Geologie und Palaeontologie, 12 (1939), 155-283; K. TROLL,'Tiefenerosion, Seitenerosion und Akkumulation der Fliisse im fluvioglazialen und periglazialen Bereich',
Geomorphologischen Studien (1959), 213-27.
32 R. GRAHMANN, Zur Gliederung des Quartars am Mittel- und Niederrhein Zeitschrift der
deutschen Geologischen Gesellschaft, 96 (1944), 149-55.
33 K. KAISER,op. cit.
34 The use of the degree of 'roundness' in pebbles in the analysis of gravels has been developed
'L'indice d'emousse des
by A. Cailleux and is clearly described by J. TRICARTand R. SCHAEFFER
galets:moyen d'etudedes systemesd'6rosion',Rdvuede Geomorphologie
Dynamique,4 (1950), 151-79.
35 P. WOLDSTEDT, op. cit., A. J. PANNAKOEK, op. cit.
36 A. GUILCHER and A. CAILLEUX,
'Reliefs et Formations Quarternaires du Centre-est des PaysBas', Revue de Gdomorphologie Dynamique, 3 (1950), 128-43.
37 K. KAISER,'Die Hohenterrassen der Bergischen Randh6hen und die Eisrandbildungen an der
Ruhr', Sonderveroffentlichungen des Geologischen Institutes der Universitdt Koln, 2 (1957).
38 K. N. THOME,
'Eisvorstoss und Flussregime an Niederrhein und Zuider Zee in Jung-Pleistozan',
in Pliozdn and Pleistozdn am Mittel und Nierderrhein (Krefeld, 1959), 197-246.
THE DEVELOPMENT OF THE RHINE
39
81
H. W. QUITZOW,
'Die Terrassengliederungim NiederrheinischenTieflands.' Geologie en
Mijnbouw, 18, New Series (1956), 357-73.
40 M. PECSI,
'Das Ausmass der quartairentektonischenBewegungenim
ungarischenAbschnitt
des Donautales', Petermann's Geographischen Mitteilungen, 102 (1958) 274-80.
41 J. FRECHEN
and C. MORDZIOL,
Der Rheinische Bimsstein (1953), 14.
42 0. MAULL,Handbuch der Geomorphologie, 2nd edition (Vienna, 1958), 27; J. BijDEL, op.
cit., 7.
43 H. VALENTIN,'Glazialmorphologische Untersuchungen in
Ostengland', Abhandlungen des
Geographischen Instituts der Freien Universitit Berlin, 4 (1957), 1-86.
44 L. D. STAMP,'The geographical evolution of the North Sea
Basin', Journal du Conseil Internationalpour l'exploration de la mer, 11 (1936), 135-63.
45 F. W. HARMER, 'The Pliocene deposits of the eastern counties of
England', Jubilee volume of the
Geological Association (1909), 88-102.
46 K. N. THOME,op. cit.
47 A. J. PANNAKOEK,
op. cit., 119.
48 J. P. BAKKER,op. cit.
49 F. KLUTEand W. WILL, 'Terrassenbildung und Erosion des mittleren Rheingebeits in ihrer
Abhangigkeit von Tektonik und Klima des Diluviums', Petermann's Geographischen Mitteilungen, 80
(1934), 144-7.
50 0. SCHMIDTGEN
and W. WAGNER,'Bericht iiber die Begehungen der Hauptversammlung in
Mainz', Zeitschrift der deutschen Geologischen Gesellschaft, 83 (1931), 671-94.
51 E. JUILLERT,'Une carte des formes du relief dans la plaine d'Alsace-Bade', L'information
geographique, 13 (1949), 116-20.
52 0. WITTMAN,'Die Niederterrassenfelder im Umkreis von Basel und ihre Kartographische
Darstellung', Regio Basiliensis, 3 (1961), 1-46.
53 A. LEEMAN, 'Revision der Wiirmterrassen im Rheintal zwischen Diessenhofen und Koblenz',
Geographica Helvetica 13 (1958), 89-173 (note that the Koblenz to which reference is made in the
title is in Switzerland).
54 I. SCHAEFFER,
'Geomorphologische Analyse des Elsiissischen Sundgaus', Geomorphologischen
Studien (1957), 157-83.
55 J. F. GELLERT,
op. cit., 181.
56 H. HUBER,'Ablagerungen aus der Wiirmzeit im Rheintal zwischen Bondensee und
Aare',
Vierteljahrschriftder Naturforschenden Gessellschaft in Zurich, 1 (1956), 1-92; G. WAGNER,Einfuhrung
in die Erd- und Landschaftgeschichte, 3rd edition (1960), 74.
57 R. METZ and G. REIN, 'Erlauterung zur
geologisch-petrographischen Ubersichts Karte des
Sudschwarzwaldes (Lahr, 1958).