EAGE
Basin Research (2014) 1–18, doi: 10.1111/bre.12095
Multicyclic sediment transfer along and across
convergent plate boundaries (Barbados, Lesser
Antilles)
,* Maria Boni† and
Mara Limonta,* Eduardo Garzanti,* Alberto Resentini,* Sergio And o
€ dt‡,§
Thilo Bechst a
*Laboratory for Provenance Studies, Department of Earth and Environmental Sciences, Universita di MilanoBicocca, Milano, Italy
†Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse, Universita Federico II di Napoli, Napoli,
Italy
‡GeoResources STC, Heidelberg, Germany
§Institute of Geological Sciences, Jagiellonian University, Krakow, Poland
ABSTRACT
The main source of siliciclastic sediment in the Barbados accretionary prism is off-scraped quartzose
to feldspatho-litho-quartzose metasedimentaclastic turbidites, ultimately supplied from South
America chiefly via the Orinoco fluvio-deltaic system. Modern sand on Barbados island is either
quartzose with depleted heavy-mineral suites recycled from Cenozoic turbidites and including epidote, zircon, tourmaline, andalusite, garnet, staurolite and chloritoid, or calcareous and derived from
Pleistocene coral reefs. The ubiquitous occurrence of clinopyroxene and hypersthene, associated
with green-brown kaersutitic hornblende in the north or olivine in the south, points to reworking of
ash-fall tephra erupted from andesitic (St Lucia) and basaltic (St Vincent) volcanic centres in the
Lesser Antilles arc. Modern sediments on Barbados island and those shed by larger accretionary
prisms such as the Indo-Burman Ranges and Andaman-Nicobar Ridge define the distinctive mineralogical signature of Subduction Complex Provenance, which is invariably composite. Detritus recycled from accreted turbidites and oceanic mudrocks is mixed in various proportions with detritus
from the adjacent volcanic arc or carbonate reefs widely developed at tropical latitudes. Ophiolitic
detritus, locally prominent on the Andaman Islands, is absent on Barbados, where the prism formed
above a westward subduction zone with a shallow decollement plane. The four-dimensional complexities inherent with multicyclic sediment dispersal along and across convergent plate boundaries
require quantitative provenance analysis as a basic tool in paleogeographic reconstructions. Such
analysis provides the link between faraway factories of detritus and depositional sinks, as well as clues
on subduction geometry and the nature of associated growing orogenic belts, and even information
on climate, atmospheric circulation and weathering intensity in source regions.
The beasts that talk, The streams that stand,
The stones that walk, The singing sand. . .
Josephine Tey, Singing sands
INTRODUCTION
Sediments sourced in large orogenic belts generated by
oceanic or continental subduction are conveyed longdistance by major river systems across foreland basins,
and eventually supplied to continental margins at specific deltaic or estuarine entry points (Potter, 1978;
Correspondence: Eduardo Garzanti, Laboratory for Provenance
Studies, Department of Earth and Environmental Sciences,
Universita di Milano-Bicocca, 20126 Milano, Italy. E-mail:
[email protected]
Dickinson, 1988; Hinderer, 2012). Sediment dispersal
continues via turbidity currents for hundreds to thousands of kilometers beyond the river mouth, and huge
masses of sediment are thus transferred from the continent to the deep ocean (Ingersoll et al., 2003). This typically occurs along the trend of major Himalayan-type
continent–continent collision zones, where huge turbiditic successions accumulate on remnant-ocean floors
destined to be subsequently subducted, while the clastic
cover is detached and progressively accreted at the front
of a growing fold-thrust belt (Fig. 1a; Morley et al.,
2011). Geologically and geometrically distinct is the case
of the Caribbean accretionary prism (Fig. 1b). Here,
detritus generated in the Andean Cordillera and carried
along the retro-belt basin by the Orinoco River finally
reaches the Atlantic Ocean, and is deposited by turbidity
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
1
M. Limonta et al.
(b)
(a)
Fig. 1. The two conceptual diagrams illustrate opposite cases of long-distance multistep sediment transport and final incorporation
of orogenic turbidites at convergent plate margins. (a) Himalayan case: detritus is transferred from the Gangetic pro-belt basin to the
Bengal remnant-ocean basin, both lying on the northeastward-subducting Indian lower plate (Ingersoll et al., 2003). (b) Andean case:
Orinoco sediments carried along the retro-belt basin resting on the upper plate feed ocean floors on the westward-subducting Atlantic
Plate (Velbel, 1985).
currents on sea-floors actively subducting westwards
beneath the Caribbean plate (Velbel, 1985). Diverse
multistep trajectories in space and time are thus followed during sediment transport along and across convergent plate boundaries (Zuffa, 1987; Zuffa et al.,
2000). Only by thoroughly studying modern environments, where such source-to-sink complexities can be
physically traced and understood, can we acquire the
necessary experience and sharpen our conceptual tools
to solve the provenance conundrums posed by ancient
clastic successions, where the original geometry of
converging plates has been obscured by the subsequent
geological evolution.
In this article, we present a regional provenance study
of the compositional variability and long-distance multicyclic transport of terrigenous sediments along the convergent and transform plate boundaries of Central
America, from the northern termination of the Andes to
the Lesser Antilles arc-trench system (Fig. 2). We specifically focus on the petrographic composition and heavymineral assemblages characterizing modern beach and fluvial sediments as well as Cenozoic sandstones of Barbados
island, one of the places in the world where an active
accretionary prism is subaerially exposed (Speed, 1994;
Speed et al., 2012). This study extends the regional database on the petrology of modern sands across the South
American and Caribbean regions (e.g. Johnsson et al.,
1991; Morton & Johnsson, 1993; Potter, 1994), and represents a complement of the thorough investigation carried
out with the same methods, rationale and goals on sediments produced and recycled along the Himalayan collision system, from the Bengal Basin to the Indo-Burman
Ranges and the Andaman and Nicobar ridge (Garzanti
et al., 2013a).
2
BARBADOS ISLAND AND ADJACENT
SEDIMENT SOURCES
Barbados lies 150 km east of the active magmatic arc of
the Lesser Antilles, at a latitude of ca. 13° N in the
western Atlantic Ocean outside of the principal hurricane
strike zone. Climate is warm tropical of the ‘trade-wind
littoral’ type, with mean annual temperatures of 24–28°C
relatively constant throughout the year. Annual precipitation, increasing with elevation, ranges from 1.1 m at sea
level to 2.1 m in the Scotland District (Fig. 3), and is
mostly concentrated in the wet season between June and
December. The dry season lasts from January to May.
The trade winds blow from the northeast at altitudes
between 1.5 and 4 km, and are responsible for long-range
transport of Saharan dust across the Atlantic (particles < 20 lm in diameter, 30–50% clay; Muhs et al.,
2007). The year-round dominance of northeast trade
winds in this region prevents ash transport from the Lesser Antilles volcanoes except during breaks in the flow,
and the dominant role in eastward ash dispersal is played
by westerly anti-trade winds in the upper troposphere (6–
18 km; Carey & Sigurdsson, 1978). Soil composition on
Barbados testifies to the importance of trade winds in the
dispersal of Saharan dust out of northern Africa or loess
from the Mississippi Valley of North America, and of
anti-trade winds in ash-fall transport across the Caribbean
(Muhs, 2001).
Geology of Barbados
Accretionary prisms display a great range in width,
depending on their stage of development and sedimentary
influx, which may be derived from fluvio-deltaic
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
Fig. 2. Tectonic framework of the Caribbean plate and location of Barbados island (DEM modified from www.geomapapp.org).
Sampling sites for South American rivers are indicated.
sediments delivered directly to the upper plate or from
deep-water sediments scraped off the lower plate and
accreted to the upper plate. The northern Barbados Ridge
has an east–west cross-sectional area of only 100 km2,
whereas the frontal 50 km of the Italian Apennines display an average cross-sectional area of 500 km2. Such a
large variation in volume and elevation is the result of a
shallower detachment plane beneath Barbados than
beneath the Apennines (Bigi et al., 2003). Emergent subduction complexes formed on the trend of major plateconvergence zones and fed by large volumes of orogenic
sand, such as the offshore island of Barbados and the
Myanmar-Andaman-Nicobar ridge, display signs of
hydrocarbon generation with oil and gas seeps from deepwater sediments, often from mud volcanoes (Hill &
Schenk, 2005). Since 1896, Barbados has had a small
hydrocarbon production, much less important than in the
transpressional setting of Trinidad to the south (Speed
et al., 1991; Boettcher et al., 2003; Vincent et al., 2014).
Barbados island is the emerged part of a large subduction
complex, narrowing from 250 km in the south to 100 km
in the north (Fig. 2). The marked change in thickness of
Cenozoic sediments, decreasing northwards from >6 km
on the Venezuelan passive margin to 0.5 km on the Tiburon Ridge that constitutes a topographic barrier for turbidites, reflects dominant supply from the Orinoco Delta
(Faugeres et al., 1993). Turbiditic sandstone and mudrock, more abundant during the middle Eocene to late
Oligocene but continuing throughout the Neogene, are
being deposited on the floor of piggyback basins bounded
by anticlinal ridges, and are fed by erosional canyons cutting across the tectonic structures (Beck et al., 1990; Mascle et al., 1990; Faugeres et al., 1991). Sediment
entering the subduction zone includes calcareous mud
overlying pillow basalt, Eocene-Oligocene quartz-turbidite and interbedded mud, Lower Miocene radiolarianbearing ooze, and Middle Miocene to Pleistocene calcareous mud and volcanic ash (Underwood, 2007).
The Barbados accretionary prism, passing laterally to
the transpressional setting of Trinidad in the south and to
the northern Caribbean strike-slip margin in the north
(Fig. 2; Pindell & Kennan, 2007; Vincent et al., 2014),
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
3
M. Limonta et al.
(b)
(c)
(a)
Fig. 3. Geological sketch map (a), topography (b) and stratigraphy (c) of Barbados island (after Pudsey & Reading, 1982; Donovan,
2005). Sampling sites are indicated.
has been developing in the frontal part of the Lesser
Antilles arc-trench system since the middle Eocene, during westward subduction of the Atlantic plate beneath the
Caribbean plate (Weber et al., 2001). With the exception
of minor ash-fall tephra, the rock succession in Barbados
is entirely sedimentary, demonstrating its geological independence from the volcanic arc of the Lesser Antilles.
Exposed in an erosional window of ca. 40 km2 in the
Scotland District of north-eastern Barbados are deformed
deep-sea turbidite, radiolarite and hemipelagite of Cenozoic age, representing ca. 15% of total outcrops (Fig. 3a;
Donovan, 2005). Two tectono-stratigraphic levels can be
identified: (1) the Basal Complex and its cover strata; and
(2) the overlying allochthonous oceanic units (Speed &
Larue, 1982). The unconformably overlying Pleistocene
and Holocene limestone cap represents the remaining
85%.
The Basal Complex, a stack of fault-bounded packets
≥4.5-km thick, includes hemipelagic radiolarian-rich clay,
quartzose turbiditic sandstone and mudrock of the Scotland Formation, and the Joes River Melange (Senn,
1940). These rocks, originally deposited in deep-sea-fan
and trench settings and subsequently off-scraped to form
the accretionary prism around the end of the Eocene, have
4
undergone modest tectonic deformation since then
(Speed et al., 1991). The ca. 1700 m-thick Scotland
Formation was deposited during the Paleocene to
early?-middle Eocene (Jones, 2009). The Lower Scotland
Formation includes: (1) sandstone and mudrock of the
Walkers Member; (2) mudrock of the Morgan Lewis
Member, containing intercalated sandstone. The Upper
Scotland Formation includes: (3) Murphys Member, an
upward thickening and coarsening sequence including
slumped beds; (4) pebbly sandstone of the Chalky Mount
Member, containing large slide blocks and minor interbedded mud; (5) sandstone and mudrock of the Mount
All Member (Fig. 3c; Senn, 1940; Pudsey & Reading,
1982). Petrographic studies have long documented the
quartzose to litho-quartzose composition of Scotland Formation turbidites (Velbel, 1980). This signature, anomalous for an arc-trench system, is similar to that of Orinoco
sand (Johnsson et al., 1988, 1991), suggesting provenance
and long-distance turbiditic transport from northern
South America (Velbel, 1985). Heavy-mineral assemblages in these rocks include zircon, tourmaline, rutile,
epidote, clinozoisite, apatite, garnet, chloritoid, kyanite,
staurolite, andalusite, sillimanite and titanite (Senn, 1940;
Pindell et al., 2009; Vincent et al., 2014). The Joes River
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
Melange contains blocks dominantly from the Scotland
Formation, embedded in a foliated organic-rich sandstone/mudstone matrix with fossils of Paleocene to middle Eocene age. The melange cuts bedding and is
interpreted as formed by diapiric processes (Poole & Barker, 1983; Torrini et al., 1985; Babaie et al., 1992). After
accretion, the Basal Complex was unconformably overlain
by a trench-slope apron of Oligocene to Neogene hemipelagic mudrock interbedded with turbiditic sandstone
and debris flow (Speed et al., 1991). These deposits are
structurally intercalated with the Basal Complex to a
depth of 3 km (Torrini & Speed, 1989).
The Basal Complex and prism cover are structurally
overlain by the Oceanic Allochthon, a ≤1.5-km thick
sequence of thrust sheets including deep-water clay, nannofossil and radiolarian ooze, volcanogenic turbidite and
tuffaceous beds of late middle Eocene to early Miocene
age (Saunders et al., 1984; Jones, 2009). These rocks,
partly coeval with the Basal Complex, are interpreted to
have been deposited at bathyal to abyssal depths along the
outer margin of the forearc basin, and thrusted onto the
accretionary prism for ≥20 km on a shallow west-dipping
fault beginning at 16 Ma (Torrini & Speed, 1989).
The Barbados accretionary prism is unconformably
capped by a southwestward-dipping arch of Pleistocene
and Holocene back-reef, reef, and fore-reef sediments
(Mesolella et al., 1970; Schellmann & Radtke, 2004). The
upraised coral reefs, completely eroded in the Scotland
District, include three main terraces formed during the
long-term uplift of the Barbados Ridge and documenting
middle and late Pleistocene glacio-eustatic fluctuations.
The older coral reefs are locally folded and reach their
highest elevation in the central-northern part of the island
(Taylor & Mann, 1991). The two main reef steps are
known as the First High Cliff, located close to the coastline at 20–60 m a.s.l., and the Second High Cliff at 130–
200 m a.s.l. (Fig. 3a; Donovan, 2005).
The Antilles arc
The Lesser Antilles volcanic arc extends for ca. 800 km
(Fig. 2). Three groups of islands can be distinguished
petrologically. The northern group (Saba to Montserrat)
is dominated by andesite, with minor dacite and rare rhyolite; small volumes of basalt (≤5 km3) occur locally as
blocks in pyroclastic deposits (Rea & Baker, 1980). The
central group includes the largest islands (Guadeloupe,
Dominica, Martinique, St Lucia) and is also characterized
by predominant andesite, with some basalt, dacite and
rare rhyolite. The southern group includes St Vincent,
dominated by basalt and basaltic andesite, and the Grenadine islands, where rock types range from picritic or ankaramitic basalts to andesite and rare dacite (Rea, 1982;
Macdonald et al., 2000).
Explosive eruptions of Lesser Antilles volcanoes (e.g.
Mount Pelee on Martinique in 1902; Lacroix, 1904; La
Soufriere on St Vincent in 1902, 1979 and 1995; Brazier
et al., 1982) have long been documented to be the source
of ash-fall deposits on Barbados. Air-fall tephra, which
are produced by different mechanisms (Vulcanian activity, dome collapse, ash-venting, phreatic explosion; Bonadonna et al., 2002), represented most ejecta during the La
Soufriere eruption in 1902, when ≥28% of the air-fall
tephra were carried eastward towards the Atlantic Ocean
by anti-trade winds, at altitudes between 7 and 16 km
(Carey & Sigurdsson, 1978).
The Orinoco sedimentary system
The Orinoco River catchment occupies ca. 1.1 106 km2
in northern South America (Fig. 2). The Andes and
Caribbean Mountains in the west and north (ca. 15%
mountainous part of the basin) have strong relief with
steep slopes and sharp peaks with active alpine glaciers.
They are made of terrigenous and carbonate sedimentary
and metasedimentary rocks, along with felsic to mafic plutonic rocks. Orogeny began in the late Oligocene and
peaked in the Pliocene, exerting a major influence in the
development of the Amazon and Orinoco River systems
(Hoorn, 1993; Hoorn et al., 1995). The Guyana Shield
(ca. 35% of the basin) is largely of low relief with dense
vegetation and deeply weathered soils, but locally
approaches 3000 m a.s.l. It consists of felsic to intermediate granitoids and gneisses overlain by quartzites (Gibbs
& Barron, 1983). The Llanos region (50% of the basin) is
a retro-belt foreland basin filled with sediments derived
mostly from the rising Andean orogen in the west, and
reworked widely by fluvial processes during the flood season and by eolian processes during the dry winter season
(Johnsson et al., 1991).
The Orinoco is the third largest river in the world in
terms of annual water discharge (36 000 m3 s 1); the
estimated annual sediment flux (150 50 106 t/a, 50%
of which deposited in the delta) consists of 80% mud and
20% sand (Meade, 1994; Warne et al., 2002). The delta
has a strongly seasonal tropical climate, with uniform
temperatures throughout the year (25–28°C) and annual
rainfall ranging from 1.2 to 3.6 m. The low- to moderateenergy broad shelf is affected by a combination of easterly
trade winds, tides (1.4–1.9 m) and littoral currents, with
rare major storms and hurricanes (Aslan et al., 2003).
The northwest-directed Guyana Current, responsible for
the presence of mud banks along much of the northeast
coast of South America (Allison & Lee, 2004), transports
between 100 and 200 106 t/a of suspended sediment from
the Amazon delta to the Orinoco region, an amount comparable to the total sediment discharge of the Orinoco
(Van Andel, 1967; Eisma & Van Der Marel, 1971; Eisma
et al., 1978; Kuehl et al., 1986; Warne et al., 2002).
The Orinoco deep-sea fan is characterized by a welldeveloped braided pattern (Belderson et al., 1984). This
relatively sand-rich turbidite system is controlled by the
compressional structures of the Barbados prism, and
consequently does not display the classic fan geometry
(Callec et al., 2010). A channel-levee complex characterizes the upper part close to the Trinidad-Venezuelan
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
5
M. Limonta et al.
continental slope. Fold-thrust deformation, mud diapirism and mud volcanism induce frequent and massive
gravity deposits (Deville et al., 2006).
Orinoco sands are quartzose, with a few feldspars (Kfeldspar ≫ plagioclase) and metasedimentary to minor
plutonic and sedimentary rock fragments (Potter, 1978;
Johnsson et al., 1988, 1991). Sands of the Apure River
tributary are quartzo-lithic in the Andean upper reaches,
with epidote, amphibole, zircon and garnet as main heavy
minerals. Due to reworking of weathered foreland-basin
sediments, unstable components are progressively diluted
with increasing distance from the mountain front, and
Apure sand becomes eventually almost as quartzose as that
of the Orinoco in the distal course (Johnsson et al., 1988).
Epidote and amphibole do not show downstream changes,
whereas zircon tends to be enriched and apatite and garnet
selectively depleted (Morton & Johnsson, 1993).
Heavy-mineral analyses of modern sediments on the
Guyana Shelf allowed recognition of different provinces
(Nota, 1958; Imbrie & Van Andel, 1964): (1) the area offshore of the Orinoco Delta, characterized by an epidoteamphibole suite; (2) the adjacent shelf in the west offshore
Trinidad, characterized by a zircon-epidote suite; (3) the
area offshore the Guyana Shield in the east, characterized
by a staurolite-rich suite. Other heavy minerals, found
also farther east offshore the Essequibo and Demerara
deltas, include sillimanite, tourmaline, rutile and andalusite. Garnet and kyanite are minor; hypersthene occurs
locally.
SAMPLING AND ANALYTICAL
METHODS
To investigate the compositional variability in modern sediments derived from the Barbados accretionary prism and
to compare the composition of daughter sands and parent
sandstones, in July 2011 to March 2013 we collected 22
medium to coarse-grained sand samples on beaches and
river beds (mostly gully to creek) from coastal Barbados,
five silt samples of river mud, and 13 bedrock samples from
the Basal Complex, ranging from coarse siltstone to medium-grained sandstone. Eight sand samples from main rivers of northern South America (Orinoco, Maroni,
Amazon) and beaches from the Lesser Antilles (Dominica,
Martinique) were also analyzed for comparison. Petrographic analysis of modern sands and Cenozoic sandstones
was carried out by counting 400 points in each thin section
by the Gazzi–Dickinson method (Ingersoll et al., 1984).
Also, we counted ca. 100 granules on the >2 mm class of
two coarse-sand samples, and ca. 100 points within each of
three representative sandstone granules. Heavy-mineral
analyses were carried out on 22 bulk-sand samples, on a
quartered aliquot of the 32–355 or 32–500 lm class
obtained by dry-sieving for another eight sand samples and
by wet sieving after crushing or gentle disaggregation for
the 13 sandstone samples, and on a quartered aliquot of the
15–63 lm class obtained by wet-sieving for the five mud
6
samples. Heavy minerals were separated by centrifuging in
Na polytungstate (density ca. 2.90 g cm 3), and recovered
by partial freezing with liquid nitrogen. On grain mounts,
200–250 transparent heavy-mineral grains were either
point-counted at suitable regular spacing to obtain real volume percentages (samples rich in transparent heavy minerals) or counted by the area method (all sandstones and
modern sediments rich in Fe-carbonate or altered grains;
Mange & Maurer, 1992). Dubious grains were checked
with Raman spectroscopy (Ando & Garzanti, 2014). The
ZTR index (sum of zircon, tourmaline and rutile over total
transparent heavy minerals; Hubert, 1962) defines the
‘mineralogical stability’ of the assemblage. Heavy-mineral
concentration was calculated as the volume percentage of
total (HMC) and transparent (tHMC) heavy minerals
(Garzanti & Ando, 2007a). In Barbados sands and sandstones, the tHMC index does not exceed 1. Transparentheavy-mineral concentration thus ranges from extremely
poor (tHMC < 0.1) to very poor (0.1 ≤ tHMC < 0.5) and
poor (0.5 ≤ tHMC < 1). Heavy-mineral assemblages are
somewhat richer in river sands from northern South America, and extremely rich (20 ≤ tHMC < 50) in volcaniclastic beach sands of the Lesser Antilles. Specific attention
was dedicated to the surface features of detrital minerals;
for each species, the percentage of corroded, etched, deeply
etched and skeletal grains was quantitatively recorded following the operational classification of Ando et al. (2012).
Size and elongation of detrital grains were measured by
image analysis of digital photographs using ImageJ software (http://rsbweb.nih.gov/ij). Grain roundness was
assessed by visual comparison with classical charts (Krumbein, 1941; Powers, 1953). Detrital components are listed
in order of abundance throughout the text.
Chemical analyses of two volcaniclastic beach sands of
the Lesser Antilles were carried out at ACME Laboratories (Vancouver) on a quartered aliquot of the 63–
2000 lm class separated by wet sieving. Following a lithium metaborate/tetraborate fusion and nitric acid digestion, major oxides and several minor elements were
determined by ICP-ES and trace elements by ICP-MS. A
separate split was digested in aqua regia and analyzed for
Mo, Ni, Cu, Ag, Au, Zn, Cd, Hg, Tl, Pb, As, Sb, Bi, Se.
For detailed information on adopted procedures, standards
used and precision for various elements of group 4A–4B
see http://acmelab.com. The Chemical Index of Alteration was calculated following Nesbitt & Young (1982).
PETROGRAPHY AND HEAVY MINERALS
We will illustrate here the petrographic and mineralogical
features of Cenozoic sandstones of the Basal Complex and
of the modern sands derived from them on Barbados
island. Next, we will describe the composition of
carbonaticlastic beach sands in the rest of Barbados, of
volcaniclastic beach sands in Martinique and Dominica
islands, and of river sands from northern South America
(Fig. 4, Table 1).
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 4. Petrography of Orinoco and Barbados sands (all photos with crossed polars; blue bar = 250 lm). Grain size control on Orinoco bedload sand: (a) slate (Lms) and phyllite rock fragments (white arrows), as well as epidote (black arrow), are concentrated in the
fine sand fraction; (b) quartz (Q) with minor feldspars (P = plagioclase) make up the medium sand fraction. (c) Recycled quartz associated with siltstone (Ls) and radiolarite (ch) rock fragments derived from turbidites and hemipelagic oozes of the Scotland District. (d)
Siltstone rock fragments and quartz grains – displaying etch pits and lobate outlines indicative of weathering in subequatorial soils –
document recycling of turbidites fed long distance from South America. (e) Radiolarian-rich clasts. (f) Calcareous grains eroded from
Pleistocene carbonates (Lc), mixed with allochems (a = coralline alga; b = bioclast; i = intraclast) and euhedral plagioclase and pyroxene (p) derived from ash layers in beach sand of western Barbados.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
7
0
0
0
0
1
1
5
1
5
3
2
3
2
3
3
4
0
88
6
88
83
70
72
17
79
14
KF
6
4
3
3
1
0
6
36
6
0
0
1
1
P
5
3
3
3
0
0
9
7
4
0
0
0
1
Lv
0
0
0
0
0
0
0
0
0
90
7
7
7
Lc
2
2
0
0
1
0
2
0
0
0
0
1
2
Ls
10
7
8
6
3
0
7
0
0
0
0
0
0
Lm
0
0
0
0
0
0
0
0
0
0
0
0
0
Lu
1
2
2
4
0
0
1
0
0
0
0
0
0
Mi
1
1
2
2
2
16
1
54
10
5
7
1
1
HM
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
210
6
184
17
222
208
181
22
MI*
0.6
0.8
44
6
0.4
0.5
0.2
0.2
1.4
1.4
0.5
7.9
0.7
tHMC
Zircon
44
29
0
0
0
0
15
10
5
5
46
1
1
Tourmaline
12
10
0
0
0
0
7
4
4
2
2
7
2
Ti oxides
6
7
0
0
0
0
1
1
5
4
5
0
0
Titanite
0
0
0
0
0
0
1
1
3
2
0
0
0
Epidote
27
32
0
0
1
1
33
22
74
15
24
0
24
Garnet
3
2
0
0
0
0
4
2
1
1
2
35
4
Chloritoid
3
3
0
0
0
0
3
4
3
3
0
0
0
Staurolite
1
1
0
0
0
0
1
1
0
0
1
55
0
Al2SiO5
0
0
0
0
1
4
5
7
0
0
0
2
7
Amphiboles
1
4
22
19
3
4
1
2
1
1
18
0
30
Clinopyroxene
0
0
7
3
42
14
12
8
2
2
1
0
15
0
0
71
16
44
10
14
9
1
2
0
0
18
Hypersthene
0
0
0
0
8
5
1
1
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Q, quartz; KF, K-feldspar; P, plagioclase; L, aphanitic lithic grains (Lv, volcanic; Lc, carbonate; Ls, terrigenous and chert; Lm, metamorphic; Lu, ultramafic); MI, mica; HM, heavy minerals; tHMC, transparent
heavy-mineral concentration (Garzanti & Ando, 2007a). The Metamorphic Index MI* expresses the average rank of metamorphic rock fragments in each sample, and varies from 100 (very low-grade metamorphic source
rocks) to 500 (high-grade metamorphic source rocks; Garzanti & Vezzoli, 2003). The Al2SiO5 mineral group includes andalusite, kyanite and sillimanite; other heavy minerals are mostly apatite.
Sandstones
Modern sediments
Lesser Antilles
(Martinique, Dominica)
Barbados sands
(Quaternary reefs)
Barbados sands
(Scotland Distrinct)
Barbados muds
(Scotland Distrinct)
Orinoco River
Maroni River
Amazon River
Basal complex
Granules
Q
Olivine
8
Others
Table 1. Petrography and heavy minerals in Cenozoic sandstones of the Basal Complex, and in modern sediments of Barbados island, Lesser Antilles arc, and rivers of northern South America
(mean values in bold; standard deviation in italics)
M. Limonta et al.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
Parent sandstones and sandstone clasts
Very-fine-grained Cenozoic sandstones of the Basal Complex are quartzose to feldspatho-litho-quartzose metasedimentaclastic and mica-rich, whereas fine to mediumgrained sandstones are quartzose and may contain variable
amounts of intrabasinal grains, including bioclasts (nummulitids, echinoids, bryozoans, algae). Glaucony is locally
common and phosphates may occur, as well as calcite
cement and replacements. Heavy-mineral assemblages
range from poor and epidote-dominated in finer-grained
feldspatho-litho-quartzose sandstones (tHMC up to 1.2,
ZTR as low as 7) to extremely poor and zircon-dominated
in coarser quartzarenites (tHMC as low as 0.1, ZTR up to
94). Associated minerals are tourmaline, rutile, garnet,
chloritoid, and minor staurolite, anatase, brookite, apatite,
titanite, lawsonite (Fig. 5a), andalusite, sillimanite, and
kyanite. Beta-fergusonite (Y) – a rare mineral found in
pegmatites and granites (Fig. 5b) – and xenotime were
detected with Raman spectroscopy and with a pocket
spectrometer in one sample each. Hornblende or clinopyroxene occur rarely, suggesting chemical weathering at
subequatorial latitudes and extensive post-depositional
dissolution. Textural evidence indicates that epidote is
detrital and not grown during burial diagenesis.
Sandstone granules – representing the coarsest tail of
modern fluvial sands – contain monocrystalline and polycrystalline quartz (Q 74 16, Qp/Q 14 3), significant
plagioclase and K-feldspar (F 9 6, P/F 60 25),
shale/slate to phyllite/schist/metapelite lithics, and
felsitic volcanic rock fragments (Lsm 12 9, Lv 5 3).
Composition is more variable than quartzose Orinoco
sand and ranges from quartzose to litho-quartzose and
feldspatho-litho-quartzose (Velbel, 1980; Johnsson et al.,
1988, 1991).
Daughter sands and muds
The medium- to coarse-grained river and beach sands of
the Scotland District, principally derived from recycling
of Cenozoic sandstones of the Basal Complex, are mainly
quartzose (Fig. 4c). Predominant monocrystalline quartz
(Q ≤ 95, Qp/Q ≤ 10) commonly shows rounded outlines
and deep etching features (Fig. 4d), as a consequence of
both recycling and chemical weathering in the mature
soils developed in subequatorial climate. A few plagioclase
and K-feldspar grains are invariably present (F 2 1, P/
F 50 20), and low-rank metasedimentary (slate, phyllite, metasiltstone), mafic to felsic volcanic, and radiolarian-chert grains occur (Lm ≤ 4; Lv ≤ 3; Lch ≤ 2).
Calcareous grains derived from the Pleistocene reefal cap
may be quite abundant (Lc ≤ 55), as well as shale/siltstone grains recycled from turbiditic mudrocks
(Lp ≤ 15). Granules in coarse fluvial sands include monocrystalline and subordinately polycrystalline quartz, sandstone, siltstone and shale clasts derived from Cenozoic
turbidites, calcareous grains eroded from the Pleistocene
reefal cap, and locally abundant clasts rich in radiolaria
(Fig. 4e). Soil clasts are also common. Heavy-mineral
assemblages range from epidote-dominated to zircon-rich
with metasedimentary minerals recycled from accreted
turbidites (tourmaline, andalusite, garnet, staurolite,
(a)
(b)
(c)
(d)
Fig. 5. Raman spectra of particular heavy minerals in Cenozoic Basal Complex turbidites (a, b) and modern Martinique beach sand
(c, d). (a) Detrital lawsonite, indicating ultimate provenance from blueschist-facies rocks of the Caribbean Mountains (Morton &
Johnsson, 1993; Pindell et al., 2009; Vincent et al., 2014); (b) Detrital mineral determined as beta-fergusonite (Y) by comparison with
Raman spectrum RRUFF R070600 (shown in orange for comparison; www.rruff.info); (c) green brown kaersutitic hornblende; (d)
reddish-brown oxy-hornblende. Microphotographs show lawsonite and beta-fergusonite (Y) grains at parallel and crossed polars (a, b)
and pleochroism of amphibole grains (c, d).
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
9
M. Limonta et al.
chloritoid, rare sillimanite; tHMC 0.2 0.2). Fluvial
muds are epidote-dominated (tHMC 1.4 1.4). Rare
amphiboles, together with very low heavy-mineral concentrations, reflect intense diagenetic dissolution in parent sandstones. Epidote grains are invariably corroded in
both modern sediments (96 3%) and bedrock sandstones (93 10%).
In beach sand of the Scotland District, garnet is mainly
of upper-fine sand size, zircon, tourmaline and epidote
mainly of lower-fine sand size, and rutile and apatite of
upper very-fine sand size. Garnet, tourmaline and rutile
are mainly angular, epidote mainly subangular, and zircon
and apatite mainly subrounded.
Carbonaticlastic beaches
Beach sands along the north-eastern, south-eastern,
southern, and western coast of Barbados consist monotonously of reworked bioclasts and other allochemical
detritus, reflecting erosion of up-raised Pleistocene reef
terraces and recent reefs (Fig. 4f). These calcareous
sands include very poor to extremely poor heavy-mineral
assemblages, dominated by augitic clinopyroxene and
hypersthene in subequal amounts (tHMC 0.1 0.1).
Variable amounts of the same pyroxene types occur also
in sands of the Scotland District, revealing reworking of
widespread ash-fall tephra derived from Lesser Antilles
volcanoes. Minor green-brown kaersutitic hornblende
occurs in the northeast, whereas olivine is ubiquitous
but most abundant in beach sands to the west and south
(Fig. 6). This reflects the trend displayed along the Lesser Antilles arc, from dominant andesites and subordinate mafic and felsic products in the central group of
islands including St Lucia, to increasing abundance of
basalts in the southern group of islands including St
Vincent.
The few zircon grains in calcareous beach sands are of
upper-fine sand size and subrounded to rounded. On both
sides of Barbados, pyroxene and olivine grains are commonly euhedral, range from very angular to subrounded,
and are coarser-grained and less corroded than other
detrital minerals, suggesting a distinct, neovolcanic origin
(Fig. 7e). They are mostly of lower-medium sand size,
and range from upper-fine sand to lower-coarse sand. Pyroxenes are mostly corroded (81 13%), subordinately
unweathered (15 13%), and rarely etched (4 6%).
Fig. 6. Petrography and heavy minerals in modern sediments and Cenozoic sandstones from Barbados, the Lesser Antilles, and rivers
of northern South America. Q = quartz; F = feldspar; L = lithic fragments (Lv = volcanic; Lc = carbonate; Lm = metamorphic).
ZTR = zircon + tourmaline + rutile; Grt = garnet; MM = chloritoid + staurolite + andalusite + kyanite + sillimanite; Ep = epidotegroup minerals; Amp = amphibole; Cpx = clinopyroxene; Hy = hypersthene; Ol = olivine; & = other transparent heavy minerals,
including titanite, apatite and lawsonite.
10
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 7. Bulk petrography (a, b) and heavy minerals (c, d, e, f) reveal multiple sources for modern Barbados sediments and superimposed chemical effects during weathering and diagenesis. (a) Barbados sands, sharply distinct from volcaniclastic sands generated in
the Lesser Antilles arc, are chiefly recycled from Cenozoic turbidites or eroded from Quaternary reefs. (b) Relative to parent sandstones, Barbados sands are depleted in metamorphic lithics and enriched in sedimentary lithics eroded from Cenozoic turbiditic mudrocks or Quaternary calcarenites. (c) Heavy-mineral suites of Barbados sediments: muds are markedly enriched in epidote, whereas
medium and coarse-grained sands are heavy-mineral-poor and relatively enriched in more durable zircon, tourmaline, Ti oxides
(ZTR), garnet and metasedimentary minerals (MM). (d) Neovolcanic heavy-mineral suites vary from hypersthene-dominated and
amphibole-bearing in Dominica and Martinique to richer in augite and olivine-bearing in southern Barbados, reflecting the southward
trend from andesitic to more mafic activity along the Lesser Antilles arc. (e) In the Windy Hill river-mouth sand (Scotland District),
euhedral shape reveals the neovolcanic origin of pyroxene grains (Aug = augite; Hy = hypersthene); other heavy minerals are subangular to subrounded and recycled from Cenozoic turbidites. (f) As in equatorial Africa and contrasting with cold mountain regions
(Alps, Himalaya) or arid deserts (Namibia), sands of northern South America and sands and sandstones of Barbados (sandstone data
after Vincent et al., 2014) have low garnet/MM ratio and high andalusite/MM ratio, pointing to selective dissolution of garnet and
relative enrichment in andalusite in hot-humid subequatorial climates (Garzanti et al., 2013b). Ls = sedimentary lithics; other parameters as in Fig. 6.
Volcaniclastic beaches
The studied beach sands from Martinique island are
litho-feldspathic volcaniclastic. They consist largely of
single minerals (plagioclase, pyroxene, amphibole), suggesting selective destruction of labile pyroclastic rock
fragments by wave action in the coastal environment. Volcanic lithics are mainly microlitic, but mafic types also
occur, reflecting andesitic to basaltic volcanic activity.
The studied beach sand from Dominica island is quartzolitho-feldspathic volcaniclastic. Relatively high quartz
content reflects occurrence of andesite-dacite lava domes
and pyroclastic flows. Heavy-mineral assemblages are
invariably extremely rich (tHMC 37 1) and pyroxenedominated (Fig. 6). In the St Pierre beach, hypersthene is
dominant, augitic clinopyroxene subordinate, and kaersutitic hornblende minor. In southern Martinique and
Dominica, hypersthene still dominates over augite, but
green-brown kaersutitic hornblende is much more common (Fig. 5c), and reddish-brown oxy-hornblende may
occur (Fig. 5d). Pyroxenes and amphibole grains are
mostly unweathered (85 10%), subordinately corroded
(14 9%) and rarely etched (1 1%).
Volcaniclastic beach sands have 52.4 0.3 SiO2. Most
alkaline and alkaline-earth elements (Na, K, Rb, Sr, Ba),
as well as REE, Th, U, Zr, Hf, Nb, Ta, Cr and Ni, are
low relative to sands produced by erosion of andesitic volcanoes in Mediterranean settings (own unpublished data).
The Eu anomaly is mildly negative (Eu/Eu* 0.88). Fe
and Mn are relatively high, and negative loss on ignition
in St Pierre beach indicates occurrence of magnetite, oxidized during heating in the laboratory. CIA values of 46
indicate negligible weathering.
Rivers of northern South America
The studied bedload sand of the Orinoco River is quartzose. The fine tail of the sand distribution contains less
feldspar and a few more low-rank metasedimentary rock
fragments (Fig. 4a), whereas the medium to coarse sand
fraction chiefly consists of quartz with K-feldspar, plagioclase and few sandstone/metasandstone rock fragments
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
11
M. Limonta et al.
(Fig. 4b). The poor heavy-mineral population includes
zircon associated with epidote, amphibole and minor
rutile, tourmaline, garnet, staurolite and clinopyroxene.
The medium sand fraction (>250 lm) includes mainly
amphiboles, tourmaline, fibrolitic sillimanite, zircon,
andalusite, augite, garnet and staurolite, and does not contain epidote. Concentration of less dense heavy minerals
(2.9–3.2 g cm 3; fibrolitic sillimanite, tourmaline, andalusite, amphibole) in the coarse tail of the size distribution
is explained by the settling-equivalence principle (Rubey,
1933; Garzanti et al., 2008). Epidote, however, is unexpectedly finer-grained than much denser minerals such as
garnet and zircon, and its anomalous concentration in the
fine tail of the size distribution indicates provenance from
a distinct orogenic source (i.e. the low-grade rocks of the
Caribbean Mountains).
The studied bedload sand of the Maroni River, which
drains the Guyana Shield, is quartzose with a rich heavymineral assemblage dominated by garnet and staurolite
(Fig. 6). The sampled bedload sands of the Amazon
River, including its Solim~oes and Madeira tributaries, are
feldspatho-litho-quartzose with common felsitic and microlitic volcanic lithics and sedimentary/metasedimentary (shale/slate, siltstone/metasiltstone, phyllite/schist)
rock fragments. The poor heavy-mineral assemblages
include amphiboles, epidote, hypersthene, augitic clinopyroxene, andalusite, garnet, tourmaline and zircon.
SUBDUCTION COMPLEX PROVENANCE
Modern sands on Barbados island reflect mixing in various proportions of detritus eroded from different siliciclastic, volcaniclastic and carbonate sources (Fig. 7).
These include Cenozoic turbidites ultimately derived
long-distance from the northernmost segment of the Andean orogen, the Caribbean mountains and the Guyana
Shield, ash-fall tephra ejected from the Antilles island
arc, and the reefal cap, reflecting local biogenic production during the Pleistocene and Holocene. Such a composite signature – with a dominance of detritus recycled
from Cenozoic turbidites ultimately derived from a large
orogenic belt mixed in variable amounts with detritus
reworked from melange, oceanic sediments and younger
volcaniclastic and reefal units – represent the typical mark
of sediments derived from subduction complexes formed
by tectonic accretion above trenches choked with thick
sections of remnant-ocean turbidites, and thus large
enough to be exposed subaerially (Subduction Complex
Provenance of Garzanti et al., 2007, 2013a).
Although geological processes and geometries of convergence are varied, and every subduction system with its
associated wedge of accreted oceanic rocks displays peculiar features, the comparison of modern sands on Barbados with those shed by larger accretionary wedges such as
the Indo-Burman Ranges and Andaman-Nicobar Ridge
can illuminate the distinctive signatures of Subduction
Complex Provenance. This may help us to infer the
12
occurrence and reconstruct the polarity of such paleotectonic settings from provenance analysis of ancient stratigraphic successions. Mixing of detritus largely recycled
from offscraped turbidites (Recycled Clastic Provenance)
with volcanic and ophiolitic detritus (Volcanic Arc and
Ophiolite Provenance) is observed commonly, but mixing
proportions and end-member compositions may vary
considerably. On Barbados as on the Andaman-Nicobar
Ridge, chert grains do occur but only locally (Fig. 4), and
are never dominant as predicted in the original definition
of Subduction Complex Provenance (Dickinson &
Suczek, 1979, p. 2176).
The recycled-clastic component
Subduction complexes large enough to reach above sealevel – and thus become a source of sediments – must be
tectonically fed by huge volumes of turbidites progressively off-scraped at the trench. In turn, such a large
amount of detritus implies that the ultimate source should
be a large and actively uplifted and eroded mountain belt
such as an Himalayan-type orogen or an Andean-type
cordillera (Garzanti et al., 2007). Sediment is transferred
from the eroding orogen via an integrated fluvio-deltaicturbiditic conveyor belt to another subduction zone with
either the same eastward/northeastward polarity (e.g.
Himalayan detritus supplied to the Makran and BurmaSunda trenches; Fig. 1a) or opposite westward polarity
(e.g. Alpine detritus supplied to the Apenninic foredeep,
or Andean detritus supplied to the Barbados trench via
the Orinoco River and Fan; Fig. 1b).
Turbiditic rocks representing the bulk of material
accreted in subduction complexes range from mud-dominated distal-fan units to generally younger sand-dominated
proximal-fan units (Garzanti et al., 2013a); also calcareous
turbidites may be prominent, as for the Helminthoid Flysch of the northern Apennines (Zuffa, 1987; Garzanti
et al., 1998, 2002a; Di Giulio et al., 2003). The mineralogy
of such parent siliciclastic rocks is controlled by their
source-rock lithology and geodynamic setting, as well as by
the intensity of chemical processes during the sedimentary
cycle, including both pre-depositional weathering and diagenesis (Johnsson, 1993; Morton & Hallsworth, 2007).
Daughter sands on Barbados are quartzose, and contain
mostly monocrystalline quartz with rounded outline or
deep etch pits (Fig. 4d) and depleted heavy-mineral assemblages with mainly stable and semi-stable minerals including andalusite, one of the most stable minerals in equatorial
climates (Garzanti et al., 2013b). This reflects both subequatorial weathering in the paleo-Orinoco catchment and
diagenetic dissolution in Cenozoic sandstones, but potentially also weathering in the modern humid tropical climate
of the Caribbeans (Fig. 7f; Johnsson & Stallard, 1989).
The volcanic-arc component
Neovolcanic detritus derived from active volcanoes
and transported across the forearc region, as well as
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
paleovolcanic detritus recycled from older volcaniclastic
units, occur commonly in accretionary prisms (Garzanti
et al., 2013a). Mineralogical signatures characterized by
augitic clinopyroxene associated with frequently abundant or even dominant hypersthene reflect the character
of subduction-related magmas (Garzanti & Ando, 2007b).
Basaltic source rocks may be documented by the abundance or even local predominance of olivine over pyroxene and of durable lathwork lithics over plagioclase,
reflecting scarcity of plagioclase phenocrysts in mafic parent lavas. Provenance from andesitic and more felsic
products is instead revealed by abundant single minerals
– also because of extensive occurrence of friable pumicerich pyroclastic deposits – and by presence of reddishbrown oxy-hornblende, green-brown kaersutitic hornblende and biotite.
The ophiolitic component
The presence or absence of ophiolitic detritus in sediments derived from subduction complexes is strictly
related to the polarity of the subduction zone. In convergent settings associated with eastward/north-eastward
subduction (Doglioni et al., 2007), complete sections of
forearc lithosphere may be obducted during early collision
stages, as for peri-Arabic and peri-Indian ophiolites
exposed along the Alpine-Himalayan orogenic system.
Oceanic crustal rocks are predominant in ophiolitecapped accretionary wedges from Cyprus to Makran and
the Andaman Islands (Ricou, 1972; Moores et al., 1984;
Pedersen et al., 2010). Detritus consequently includes
abundant mafic volcanic/metavolcanic to igneous/metaigneous rock fragments (lathwork to boninite, diabase/
metadiabase, epidosite, plagiogranite, gabbro, mafic/
ultramafic cumulate) and heavy-mineral suites dominated
by clinopyroxene, epidote and actinolite (Garzanti et al.,
2000). Mantle peridotites are instead widely unroofed in
the northern Oman mountains, which represent a fully
developed obduction orogen formed during north-eastward continental subduction of the Arabian continental
margin. Sands shed by the Sama’il Ophiolite are thus
characterized by widespread ultramafic rock fragments,
whereas enstatite associated with subordinate olivine and
spinel dominates the heavy-mineral assemblages (Garzanti et al., 2002b).
Instead, ophiolitic units do not occur on Barbados
island, which is part of an arc-trench system associated
with westward subduction, slab roll-back and back-arc
extension (Bigi et al., 2003). The oceanic plate is subducted steeply, and the decollement plane is much too shallow
(<1 km) to involve the ultramafic mantle and mafic crustal
rocks of the subducting oceanic lithosphere (Underwood,
2007). Consequently, only turbidites and abyssal sediments off-scraped at the trench occur in the Barbados
subduction complex. Lack of ophiolitic mantle source
rocks is reflected by the complete absence of ultramafic
rock fragments, enstatite and spinel in modern Barbados
sands.
Because detrital signatures reflect and can reveal the
nature and geometry of converging plates, high-resolution
petrographic and heavy-mineral analyses of stratigraphic
successions may shed light on earlier episodes of plate
convergence, and provide useful clues to infer the polarity
and inclination of ancient subduction zones, and to reconstruct processes of tectonic detachment and accretion at
the trench.
MIXED PROVENANCE OF CENOZOIC
TURBIDITES
It has long been recognized that the turbidites exposed on
Barbados island were ultimately derived from the Orinoco
river system (Velbel, 1985). Coarser sandstones are quartzose with very poor zircon or zircon-tourmaline heavy-mineral suites, whereas finer sandstones are feldspatho-lithoquartzose metamorphiclastic with richer, epidote-dominated suites. A similar compositional range is shown by
modern sediments in the Scotland District, where medium
to coarse-grained sands are mainly quartzose (Fig. 7a) with
less feldspars and metamorphic rock fragments than parent
sandstones (Fig. 7b). Heavy-mineral concentration
decreases with increasing grain size (tHMC 1.4 1.4 in
mud samples vs. tHMC 0.3 0.2 in sand samples). Epidote concentration varies considerably, being an order of
magnitude higher in mud samples (Fig. 7c). Such mineralogical variability matches the different composition of
the finer vs. coarser sand fractions of modern Orinoco sand
(Fig. 4a, b). Even considering the effect of more extensive
diagenetic dissolution in coarser and more permeable parent sandstones, this indicates two ultimate distinct sources
of detritus. The coarser quartzose fraction including zircon-rich suites associated with garnet, andalusite, staurolite and kyanite points to cratonic sources of the Guyana
Shield undergoing particularly strong subequatorial
weathering (Johnsson et al., 1991), whereas the finergrained fraction enriched in metamorphic detritus and epidote suggests provenance from the transpressive northern
tip of the Andean orogenic belt including the Caribbean
Mountains (Morton & Johnsson, 1993; Pindell et al.,
2009; Vincent et al., 2014). Moreover, andalusite represents 1% of transparent heavy minerals at most in the
studied turbidites of the Basal Complex, whereas it reaches
as much as 20% in the coarse-grained Cattlewash beach
sand (Fig. 3). This points to grain-size control as well as to
distinct provenance of the turbiditic source rocks exposed
locally. The latter may have been derived in greater proportion from either the Guyana Shield or the Amazon
River, which carries today common andalusite contributed
largely from its Madeira tributary.
EVIDENCE OF ASH-FALL DISPERSAL
Modern sands all around Barbados contain variable
amounts of relatively fresh and commonly euhedral
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
13
M. Limonta et al.
clinopyroxene and hypersthene grains that cannot be
derived from Cenozoic turbidites and their pelagic covers nor from the Quaternary reefal cap, but reflect recycling of ash-fall tephra ejected from Lesser Antilles
volcanoes (Fig. 8; Borg & Banner, 1996; Muhs et al.,
2007). Occurrence of kaersutitic hornblende and biotite
in northern Barbados and most common olivine in
southern Barbados (Fig. 7d) parallels the trend displayed along the Lesser Antilles arc, from dominant
andesites and minor dacites in the northern and central
groups of islands to basaltic andesites and basalts in the
southern group of islands.
The neovolcanic component is most easily quantified in
beach sands of western and southern Barbados, which are
derived from Quaternary reefs and do not contain any significant siliciclastic component other than that derived
from ash-fall layers. Pyroxenes and other volcanic heavy
minerals represent ≤0.5% of the bulk framework; total
neovolcanic contribution is ≤1% including plagioclase
and volcanic rock fragments (Fig. 4f).
The neovolcanic component is more difficult to quantify in river and beach sands of the Scotland District,
where volcaniclastic layers are intercalated in the Cenozoic succession (Speed et al., 1991; Donovan, 2005). Neovolcanic and paleovolcanic detritus can be discriminated
by looking at the morphology and corrosion features of
detrital grains (Zuffa, 1985; Critelli & Ingersoll, 1995).
Although most susceptible to weathering and corrosion
during diagenesis (Morton & Hallsworth, 2007), pyroxene
grains are largely euhedral and less corroded than other
detrital minerals (Fig. 7e). We conclude that they are
dominantly of neovolcanic origin, and that most of those
originally present in the Cenozoic source rocks were
Fig. 8. Sand dispersal in the Caribbean region. The Barbados
subduction complex is charged along strike by turbiditic systems
fed principally from the Orinoco River in the south. The island
also receives ash-fall tephra from the Lesser Antilles in the west.
14
selectively lost during diagenesis. Neovolcanic heavy minerals in modern sands of the Scotland District can thus be
calculated to represent 0.05 0.05% of the bulk framework. Total neovolcanic detritus is very minor (ca. 0.1%)
and strongly diluted by the other siliciclastic sources in
the east, where the grain size of detrital pyroxenes is possibly only slightly finer than in the west. Pyroxenes are
absent or negligible in modern muds, suggesting that
tephra particles finer than fine sand are blown away farther east into the Atlantic Ocean. Contributions from
other external sources, including loess from North America or dust blown from Africa, are not documented in our
mud samples.
CONCLUSION
As invariably is the case with orogenic sediments, ‘Subduction Complex Provenance’ is composite. Sand recycled dominantly from accreted turbidites fed longdistance from a large orogenic belt mixes with subordinate
amounts of detritus from other sources, including oceanic
sediments and melange, arc-related volcanic layers, and
shallow-water reefal limestones so widespread in tropical
settings. Barbados island consists of deformed deep-water
mudrocks and turbiditic sandstones offscraped at the
trench and unconformably overlain by Pleistocene and
Holocene coral reefs. In contrast to the Andaman ridge,
no ophiolites occur in the Barbados subduction complex,
formed above a westward subduction zone with a decollement plane much too shallow to involve the subducting
oceanic lithosphere. The quartzose composition of modern sands on Barbados contrasts sharply with volcanic
detritus rich in plagioclase, pyroxenes and lithic fragments produced in the Lesser Antilles arc, and reflects
long-distance multicyclic sediment transfer from subequatorial northern South America. The volcaniclastic component is present on Barbados, as revealed by the
ubiquitous presence of hypersthene and clinopyroxene,
but only in minor percentage (<1%) and derived through
airborne transport by the prevailing anti-trade winds in
the upper troposphere (Fig. 8). Occurrence of kaersutitic
hornblende and biotite in the north and more common
olivine in the south parallels the compositional trend from
mainly andesites to increasing abundance of basalts from
north to south along the Lesser Antilles arc.
Provenance studies of modern sands represent the only
way to document the complexities inherent with fourdimensional multistep paths of long-distance sediment
dispersal and of the compositional and textural modifications associated with chemical dissolution during weathering and diagenesis. The insights thus gathered can be
applied in the analysis of ancient sedimentary successions
to reconstruct the spatial relationships with distant orogenic sources, to infer the geometry and inclination of
ancient subduction zones, and to ultimately produce reasonably accurate paleogeographic maps at continental
scale.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
ACKNOWLEDGEMENTS
We are very grateful to Raymond Ingersoll and Hasley
Vincent for their helpful advice and careful review. Hella
Wittmann-Oeltze, Christian France-Lanord, Catherine
Chauvel, Silvia Bragherio and Anna Stefanelli kindly
helped us to obtain additional sand samples of river and
beach sands from Central and South America. Giovanni
Vezzoli and Marta Padoan carried out bulk-petrography
and heavy-mineral analyses of Amazon sand samples.
SUPPORTING INFORMATION
Additional Supporting Information may be found in the
online version of this article:
Complete Table Captions for S1 to S4 and Cited References.
Table S1. Location of the studied sand and sandstone
samples from Barbados Island, the Lesser Antilles, and
rivers of northern South America.
Table S2. Bulk-petrography data for modern sands,
sandstone granules in modern sands and Cenozoic sandstones from Barbados Island, the Lesser Antilles and rivers of northern South America.
Table S3. Heavy-mineral data for modern sands, modern muds and Cenozoic sandstones from Barbados Island,
the Lesser Antilles and rivers of northern South America.
Table S4. Chemical composition of volcaniclastic
beach sands of the Lesser Antilles (analyses made at
ACME Laboratories, Vancouver; for information on
adopted procedures, geostandards used and precision for
various elements of group 4A–4B see http://acmelab.
com).
REFERENCES
ALLISON, M.A. & LEE, M.T. (2004) Sediment exchange between
Amazon mudbanks and shore-fringing mangroves in French
Guiana. Mar. Geol., 208, 169–190.
ANDO , E. & GARZANTI, E. (2014) Raman spectroscopy in heavymineral studies. In: Sediment Provenance Studies in Hydrocarbon Exploration and Production (Ed. by Scott R.A., Smyth
H.R., Morton A.C. & Richardson N.) Geol. Soc. London.
Spec. Publ., 386, 395–412.
ANDO , S., GARZANTI, E., PADOAN, M. & LIMONTA, M. (2012)
Corrosion of heavy minerals during weathering and diagenesis: a catalogue for optical analysis. Sed. Geol., 280, 165–178.
ASLAN, A., WHITE, W.A., WARNE, A.G. & GUEVARA, E.H.
(2003) Holocene evolution of the western Orinoco Delta,
Venezuela. Geol. Soc. Am. Bull., 115, 479–498.
BABAIE, H.A., SPEED, R.C., LARUE, D.K. & CLAYPOOL, G.E.
(1992) Source rock and maturation evaluation of the Barbados
accretionary prism. Mar. Petrol. Geol., 9, 623–632.
BECK, C., OGAWA, Y. & DOLAN, J. (1990) Eocene paleogeography of the southeastern Caribbean: relations between sedimentation on the Atlantic abyssal plain at site 672 and
evolution of the South America margin. In: Proceedings of the
Ocean Drilling Program, Scientific Results 110 (Ed. by J.C.
Moore & A. Mascle et al.), pp. 7–15. National Science Foundation, Arlington, TX.
BELDERSON, R.H., KENYON, N.H., STRIDE, A.H. & PELTON,
C.D. (1984) A ‘braided’ distributary system on the Orinoco
deep-sea fan. Mar. Geol., 56, 195–206.
BIGI, S., LENCI, F., DOGLIONI, C., MOORE, J.C., CARMINATI, E. &
SCROCCA, D. (2003) Décollement depth versus accretionary
prism dimension in the Apennines and the Barbados. Tectonics, 22, doi:10.1029/2002TC001410.
BOETTCHER, S.S., JACKSON, J.L., QUINN, M.J. & NEAL, J.E.
(2003) Lithospheric structure and supracrustal hydrocarbon
systems, offshore eastern Trinidad. In: The Circum-Gulf of
Mexico and the Caribbean: Hydrocarbon Habitats, Basin
Formation, and Plate Tectonics (Ed. by Bartolini C., Buffler
R.T. & Blickwede J.) Am. Ass. Petrol. Geol. Memoir., 79,
529–544.
BONADONNA, C., MAYBERRY, G.C., CALDER, E.S., SPARKS,
R.S.J., CHOUX, C., JACKSON, P., LEJEUNE, A.M., LOUGHLIN,
S.C., NORTON, G.E., ROSE, W.I., RYAN, G. & YOUNG, S.R.
(2002) Tephra fallout in the eruption of Soufrière Hills Volcano, Montserrat. Geol. Soc. Lond. Memoir., 21, 483–516.
BORG, L.E. & BANNER, J.L. (1996) Neodymium and strontium
isotopic constraints on soil sources in Barbados, West Indies.
Geochim. Cosmochim. Acta, 60, 4193–4206.
BRAZIER, S., DAVIS, A.N., SIGURDSSON, H. & SPARKS, R.S.J.
(1982) Fall-out and deposition of volcanic ash during the 1979
explosive eruption of the Soufrière of St. Vincent. J. Volcanol.
Geotherm. Res., 14, 335–359.
CALLEC, Y., DEVILLE, E., DESAUBLIAUX, G., GRIBOULARD, R.,
HUYGHE, P., MASCLE, A., MASCLE, G., NOBLE, M., PADRON DE CARILLO, C. & SCHMITZ, J. (2010) The Orinoco
turbidite system: tectonic controls on sea-floor morphology
and sedimentation. Am. Ass. Petrol. Geol. Bull., 94, 869–
887.
CAREY, S.N. & SIGURDSSON, H. (1978) Deep-sea evidence for
distribution of tephra from the mixed magma eruption of the
Soufrière on St. Vincent, 1902: ash turbidites and air fall.
Geology, 6, 271–274.
CRITELLI, S. & INGERSOLL, R.V. (1995) Interpretation of neovolcanic versus palaeovolcanic sand grains: an example from
Miocene deep-marine sandstone of the Topanga Group
(Southern California). Sedimentology, 42, 783–804.
DEVILLE, E., GUERLAIS, S.H., CALLEC, Y., GRIBOULARD, R.,
HUYGHE, P., LALLEMANT, S., MASCLE, A., NOBLE, M. & SCHMITZ, J. (2006) Liquefied vs. stratified sediment mobilization
processes: insight from the south of the Barbados accretionary
prism. Tectonophysics, 428, 33–47.
Di GIULIO, A., CERIANI, A., GHIA, E. & ZUCCA, F. (2003) Composition of modern stream sands derived from sedimentary
source rocks in a temperate climate (Northern Apennines,
Italy). Sed. Geol., 158, 145–161.
DICKINSON, W.R. (1988) Provenance and sediment dispersal in
relation to paleotectonics and paleogeography of sedimentary
basins. In: New Perspectives in Basin Analysis (Ed. by K.L.
Kleinspehn & C. Paola), pp. 3–25. Springer, New York.
DICKINSON, W.R. & SUCZEK, C.A. (1979) Plate tectonics and
sandstone composition. Am. Ass. Petrol. Geol. Bull., 63, 2164–
2172.
DOGLIONI, C., CARMINATI, E., CUFFARO, M. & SCROCCA, D.
(2007) Subduction kinematics and dynamic constraints. Earth
Sci. Rev., 83, 125–175.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
15
M. Limonta et al.
DONOVAN, S.K. (2005) The geology of Barbados: a field guide.
Caribbean J. Earth Sci., 38, 21–33.
EISMA, D. & Van Der MAREL, H.W. (1971) Marine muds along
the Guyana coast and their origin from the Amazon Basin.
Contrib. Mineral. Petrol., 31, 321–334.
EISMA, D., Van Der GAAST, S.J., MARTIN, J.M. & THOMAS, A.J.
(1978) Suspended matter and bottom deposits of the Orinoco
delta: turbidity, mineralogy and elementary composition.
Netherlands J. Sea Res., 12, 224–251.
FAUGERES
, J.C., GONTHIER, E., MASSE, L., PARRA, M., PONS,
J.C. & PUJOL, C. (1991) Quaternary deposits on the South
Barbados accretionary prism. Mar. Geol., 96, 247–267.
FAUGERES
, J.C., GONTHIER, E., GRIBOULARD, R. & MASSE, L.
(1993) Quaternary sandy deposits and canyons on the Venezuelan margin and south Barbados accretionary prism. Mar.
Geol., 110, 115–142.
GARZANTI, E. & ANDO , S. (2007a) Heavy-mineral concentration
in modern sands: implications for provenance interpretation.
In: Heavy Minerals in Use (Ed. by Mange M.A. & Wright
D.T.) Develop. Sedimentol. Series, 58, 517–545. Elsevier,
Amsterdam.
GARZANTI, E. & ANDO , S. (2007b) Plate tectonics and heavymineral suites of modern sands. In: Heavy Minerals in Use
(Ed. by Mange M.A. & Wright D.T.) Develop. Sedimentol.
Series, 58, 741–763. Elsevier, Amsterdam.
GARZANTI, E. & VEZZOLI, G. (2003) A classification of metamorphic grains in sands based on their composition and grade. J.
Sediment. Res., 73, 830–837.
GARZANTI, E., SCUTELLA , M. & VIDIMARI, C. (1998) Provenance
from ophiolites and oceanic allochthons: modern beach and
river sands from Liguria and the Northern Apennines (Italy).
Ofioliti, 23, 65–82.
GARZANTI, E., ANDO , S. & SCUTELLA , M. (2000) Actualistic
ophiolite provenance: the Cyprus Case. J. Geol., 108, 199–
218.
GARZANTI, E., CANCLINI, S., MORETTI FOGGIA, F. & PETRELLA,
N. (2002a) Unraveling magmatic and orogenic provenances in
modern sands: the back-arc side of the Apennine thrust-belt
(Italy). J. Sediment. Res., 72, 2–17.
GARZANTI, E., VEZZOLI, G. & ANDO , S. (2002b) Modern sand
from obducted ophiolite belts (Oman, U.A.E.). J. Geol., 110,
371–391.
GARZANTI, E., DOGLIONI, C., VEZZOLI, G. & ANDO , S. (2007)
Orogenic belts and orogenic sediment provenances. J. Geol.,
115, 315–334.
GARZANTI, E., VEZZOLI, G. & ANDO , S. (2008) Settling equivalence of detrital minerals and grain-size dependence of sediment composition. Earth Planet. Sci. Lett., 273, 138–151.
GARZANTI, E., LIMONTA, M., RESENTINI, A., BANDOPADHYAY,
P.C., NAJMAN, Y., ANDO , S. & VEZZOLI, G. (2013a) Sediment
recycling at convergent plate margins (Indo-Burman Ranges
and Andaman-Nicobar Ridge). Earth Sci. Rev., 123, 113–132.
GARZANTI, E., PADOAN, M., ANDO , S., RESENTINI, A., VEZZOLI,
G. & LUSTRINO, M. (2013b) Weathering and relative durability
of detrital minerals in equatorial climate: sand petrology and
geochemistry in the East African Rift. J. Geol., 121, 547–580.
GIBBS, A. & BARRON, C.N. (1983) The Guiana Shield reviewed.
Episodes, 2, 7–14.
HILL, R.J. & SCHENK, C.J. (2005) Petroleum geochemistry of oil
and gas from Barbados: implications for distribution of Cretaceous source rocks and regional petroleum prospectivity.
Mar. Petrol. Geol., 22, 917–943.
16
HINDERER, M. (2012) From gullies to mountain belts: a review of
sediment budgets at various scales. Sed. Geol., 280, 21–59.
HOORN, C. (1993) Marine incursions and the influence of Andean tectonics on the Miocene depositional history of northwestern Amazonia; results of a palynostratigraphic study.
Palaeogeogr. Palaeoclimatol. Palaeoecol., 105, 267–309.
HOORN, C., GUERRERO, J., SARMIENTO, G.A. & LORENTE, M.A.
(1995) Andean tectonics as a cause for changing drainage patterns in Miocene northern South America. Geology, 23, 237–
240.
HUBERT, J.F. (1962) A zircon-tourmaline-rutile maturity index
and the interdependence of the composition of heavy minerals
assemblages with the gross composition and texture of sandstones. J. Sediment. Petrol., 32, 440–450.
IMBRIE, J. & VAN ANDEL, T.H. (1964) Vector analysis of heavymineral data. Geol. Soc. Am. Bull., 75, 1131–1156.
INGERSOLL, R.V., BULLARD, T.F., FORD, R.L., GRIMM, J.P.,
PICKLE, J.D. & SARES, S.W. (1984) The effect of grain size on
detrital modes: a test of the Gazzi-Dickinson point-counting
method. J. Sediment. Petrol., 54, 103–116.
INGERSOLL, R.V., DICKINSON, W.R. & GRAHAM, S.A. (2003)
Remnant-ocean submarine fans: largest sedimentary systems
on Earth. In: Extreme Depositional Environments: Mega end
Members in Geologic Time (Ed. by Chan M.A. & Archer A.W.)
Geol. Soc. Am. Spec. Pap., 370, 191–208.
JOHNSSON, M.J. (1993) The system controlling the composition
of clastic sediments. In: Processes Controlling the Composition
of Clastic Sediments (Ed. by Johnsson M.J. & Basu A.) Geol.
Soc. Am. Spec. Pap., 284, 1–19.
JOHNSSON, M.J. & STALLARD, R.F. (1989) Physiographic controls on the composition of sediments derived from volcanic
and sedimentary terrains on Barro Colorado Island, Panama.
J. Sediment. Petrol., 59, 768–781.
JOHNSSON, M.J., STALLARD, R.F. & MEADE, R.H. (1988) Firstcycle quartz arenites in the Orinoco River basin: Venezuela
and Colombia. J. Geol., 96, 263–277.
JOHNSSON, M.J., STALLARD, R.F. & LUNDBERG, N. (1991) Controls on the composition of fluvial sands from a tropical
weathering environment: sands of the Orinoco River drainage
basin, Venezuela and Colombia. Geol. Soc. Am. Bull., 103,
1622–1647.
JONES, R.W. (2009) Stratigraphy, palaeoenvironmental interpretation and uplift history of Barbados based on foraminiferal and other palaeontological evidence. J. Micropal.,
28, 37–44.
KRUMBEIN, W.C. (1941) Measurement and geological significance of shape and roundness of sedimentary particles. J. Sediment. Petrol., 11, 64–72.
KUEHL, S.A., DEMASTER, D.J. & NITTROUER, C.A. (1986) Nature of sediment accumulation on the Amazon continental
shelf. Cont. Shelf Res., 6, 209–225.
LACROIX, A. (1904). La Montagne Pelée et ses éruptions. Masson,
Paris, 662 p.
MACDONALD, R., HAWKESWORTH, C.J. & HEATH, E. (2000) The
Lesser Antilles volcanic chain: a study in arc magmatism.
Earth Sci. Rev., 49, 1–76.
MANGE, M.A. & MAURER, H.F.W. (1992) Heavy Minerals in
Colour. Chapman and Hall, London, 147 pp.
MASCLE, A., ENDIGNOUX, L. & CHENNOUF, T. (1990) Frontal
accretion and piggyback basin development at the southern
edge of the Barbados Ridge accretionary complex. In: Proceedings of the Ocean Drilling Program, Scientific Results 110 (Ed.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Sediment transfer across active margins
by J.C. Moore & A. Mascle et al.), pp. 17–28. National
Science Foundation, Arlington, TX.
MEADE, R.H. (1994) Suspended sediments of the modern Amazon and Orinoco rivers. Quat. Int., 21, 29–39.
MESOLELLA, K.J., SCALY, H.A. & MATHEWS, R.K. (1970) Facies
geometries within Pleistocene reefs of Barbados, West Indies.
Am. Ass. Petrol. Geol. Bull., 54, 1899–1917.
MOORES, E.M., ROBINSON, P.T., MALPAS, J. & XENOPHONOTOS,
C. (1984) Model for the origin of the Troodos massif, Cyprus,
and other mideast ophiolites. Geology, 12, 500–503.
MORLEY, C.K., KING, R., HILLIS, R., TINGAY, M. & BACKE, G.
(2011) Deepwater fold and thrust belt classification, tectonics,
structure and hydrocarbon prospectivity: a review. Earth Sci.
Rev., 104, 41–91.
MORTON, A.C. & HALLSWORTH, C. (2007) Stability of detrital
heavy minerals during burial diagenesis. In: Heavy Minerals
in Use (Ed. by Mange M.A. & Wright D.T.) Develop. Sedimentol. Series, 58, 215–245. Elsevier, Amsterdam.
MORTON, A.C. & JOHNSSON, M.J. (1993) Factors influencing the
composition of detrital heavy mineral suites in Holocene
sands of the Apure River drainage basin, Venezuela. Geol.
Soc. Am. Spec. Pap., 284, 171–185.
MUHS, D.R. (2001) Evolution of soils on Quaternary reef terraces, Barbados, West Indies. Quat. Res., 56, 66–78.
MUHS, D.R., BUDAHN, J.R., PROSPERO, J.M. & CAREY, S.N.
(2007) Geochemical evidence for African dust inputs to soils
of western Atlantic islands: Barbados, the Bahamas, and Florida. J. Geophys. Res., 112, F02009. doi: 10.1029/
2005JF000445.
NESBITT, H.W. & YOUNG, G.M. (1982) Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature, 299, 715–717.
NOTA, D.J.G. (1958) Sediments of the Western Guiana Shelf.
Mededelingen van de Landbouwhogeschool te Wageningen,
58/2, 1–98. H. Veenman, Wageningen.
PEDERSEN, R.B., SEARLE, M.P., CARTER, A. & BANDOPADHYAY,
P.C. (2010) U-Pb zircon age of the Andaman ophiolite: implications for the beginning of subduction beneath the Andaman-Sumatra arc. J. Geol. Soc. London, 167, 1105–1112.
PINDELL, J.L. & KENNAN, L. (2007) Cenozoic kinematics and
dynamics of oblique collision between two convergent plate
margins: the Caribbean–South America collision in eastern
Venezuela, Trinidad, and Barbados. In: The Paleogene of the
Gulf of Mexico and Caribbean Basins: Processes, Events and
Petroleum Systems (Ed. by L. Kennan, J.L. Pindell & N.C.
Rosen) Transactions of the 27th GCSSEPM Annual Bob F.
Perkins Research Conference, pp. 458–553. GCSSEPM,
Houston, TX.
PINDELL, J.L., KENNAN, L., WRIGHT, D. & ERIKSON, J. (2009)
Clastic domains of sandstones in central/eastern Venezuela,
Trinidad, and Barbados: heavy mineral and tectonic constraints on provenance and palaeogeography. In: The Geology
and Evolution of the Region Between North and South America
(Ed. by James K., Lorente M.A. & Pindell J.) Geol. Soc. London. Spec. Publ., 328, 743–797.
POOLE, E.G. & BARKER, L.H. (1983) The Geology of Barbados.
1:50,000 sheet. Directorate of Overseas Surveys and Government of Barbados, St Michael.
POTTER, P.E. (1978) Petrology and chemistry of modern big
river sands. J. Geol., 86, 423–449.
POTTER, P.E. (1994) Modern sands of South America: composition, provenance and global significance. Geol. Rundsch., 83,
212–232.
POWERS, M.C. (1953) A new roundness scale for sedimentary
particles. J. Sediment. Petrol., 23, 117–119.
PUDSEY, J. & READING, H.G. (1982) Sedimentology and structure of the Scotland Group, Barbados. Geol. Soc. Lond. Spec.
Publ., 10, 291–308.
REA, W.J. (1982) The Lesser Antilles. In: Andesites (Ed. by R.S.
Thorpe), pp. 167–185. Wiley, London.
REA, W.J. & BAKER, P.E. (1980) The geochemical characteristics
and conditions of petrogenesis of the volcanic rocks of the
northern Lesser Antilles – a review. Bull. Volcanol., 43, 325–
336.
RICOU, L.E. (1972) Le croissant ophiolitique peri-Arabe, une
ceinture des nappes au Cretacé supérieur. Rev. Géog. Phys.
Géol. Dynam., 13, 327–349.
RUBEY, W.W. (1933) The size-distribution of heavy minerals
within a water-laid sandstone. J. Sediment. Petrol., 3, 3–29.
€
SAUNDERS, J.B., BERNOULLI, D., MULLER
-MERZ, E., OBER€
, H., PERCH-NIELSEN, K., RIEDEL, W.R., SANFILIPPO,
HANSLI
A. & TORRINI, R. (1984) Stratigraphy of the late Middle
Eocene to early Oligocene in the Bath Cliff section, Barbados.
Micropaleontology, 30, 390–425.
SCHELLMANN, G. & RADTKE, U. (2004) A revised morpho- and
chronostratigraphy of the Late and Middle Pleistocene coral
reef terraces on Southern Barbados (West Indies). Earth Sci.
Rev., 64, 157–187.
SENN, A. (1940) Paleogene of Barbados and its bearing on the
history and structure of Antillean-Caribbean region. Am. Ass.
Petrol. Geol. Bull., 24, 1548–1610.
SPEED, R.C. (1994) Barbados and the Lesser Antilles Forearc.
In: Caribbean Geology: An Introduction (Ed. by S.K. Donovan,
T.A. Jackson), pp. 179–192. University of the West Indies
Publishers’ Association, Kingston.
SPEED, R.C. & LARUE, D.K. (1982) Barbados: architecture and
implications for accretion. J. Geophys. Res., 87, 3633–3643.
SPEED, R.C., BARKER, L.H. & PAYNE, P.L.B. (1991) Geologic
and hydrocarbon evolution of Barbados. J. Petrol. Geol., 14,
323–342.
SPEED, R.C., SPEED, C. & SEDLOCK, R. (2012) Geology and geomorphology of Barbados. Geol. Soc. Am. Spec. Pap., 491, 63.
TAYLOR, F.W. & MANN, P. (1991) Late Quaternary folding of
coral reef terraces, Barbados. Geology, 19, 103–106.
TORRINI, R. & SPEED, R.C. (1989) Tectonic wedging in the forearc basin-accretionary prism transition, Lesser Antilles forearc. J. Geophys. Res., 94, 10549–10584.
TORRINI, R., SPEED, R.C. & MATTIOLI, G.S. (1985) Tectonic relationships between forearc-basin strata and the accretionary
complex at Bath, Barbados. Geol. Soc. Am. Bull., 96, 861–874.
UNDERWOOD, M.B. (2007) Sediment inputs to subduction zones:
why lithostratigraphy and clay mineralogy matters. In: The
Seismogenic Zone of Subduction Thrust Faults (Ed. by T.H.
Dixon, J.C. Moore), pp. 42–85. Columbia University Press,
New York.
Van ANDEL, T.H. (1967) The Orinoco Delta. J. Sediment. Petrol., 37, 297–310.
VELBEL, M.A. (1980) Petrography of subduction zone sandstones. A discussion. J. Sediment. Petrol., 50, 303–304.
VELBEL, M.A. (1985) Mineralogically mature sandstones in
accretionary prisms. J. Sediment. Petrol., 55, 685–690.
VINCENT, H., WACH, G. & KETANNAH, Y. (2014) Heavy mineral
record of Andean uplift and changing sediment sources across
the NE margin of South America: a case study from Trinidad
and Barbados. In: Sediment Provenance Studies in Hydrocarbon
Exploration and Production (Ed. by Scott R.A., Smyth H.R.,
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
17
M. Limonta et al.
Morton A.C. & Richardson N.) Geol. Soc. London. Spec.
Publ., 386, 217–241.
WARNE, A.G., MEADE, R.H., WHITE, W.A., GUEVARA, E.H., GIBEAUT, J., SMYTH, R.C., ASLAN, A. & TREMBLAY, T. (2002)
Regional controls on geomorphology, hydrology, and ecosystem integrity in the Orinoco Delta, Venezuela. Geomorphology, 44, 273–307.
WEBER, J.C., DIXON, T.H., DEMETS, C., AMBEH, W.B., MATTIOLI, P.J.G., SALEH, J., SELLE, G., BILHAM, R. & PEREZ, O.
(2001) GPS estimate of relative motion between the Caribbean and South American plates, and geological implications
for Trinidad and Venezuela. Geology, 29, 75–78.
ZUFFA, G.G. (1985) Optical analysis of arenites: influence of
methodology on compositional results. In: Provenance of
18
Arenites (Ed. by Zuffa G.G.) NATO ASI Series, 148, 165–
189. Reidel, Dordrecht.
ZUFFA, G.G. (1987) Unravelling hinterland and offshore palaeogeography from deep-water arenites. In: Marine Clastic Sedimentology. Concepts and Case Studies (Ed. by J.K. Leggett,
G.G. Zuffa), pp. 39–61. Graham & Trotman, London.
ZUFFA, G.G., NORMARK, W.R., SERRA, F. & BRUNNER, C.A.
(2000) Turbidite megabeds in an oceanic rift valley recording
Jökulhlaups of Pleistocene, Late glacial lakes of the States,
Western United. J. Geol., 108, 253–274.
Manuscript received 06 May 2014; In revised form 26 September 2014; Manuscript accepted 18 October 2014.
© 2014 The Authors
Basin Research © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists