Braided Meandering Coastal India, Ray_chakraborty 2002
Transcript of Braided Meandering Coastal India, Ray_chakraborty 2002
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Lower Gondwana fluvial succession of the PenchKanhan valley,
India: stratigraphic architecture and depositional controls
Sanghamitra Ray1, Tapan Chakraborty*
Geological Studies Unit, Indian Statistical Institute, 203 B.T. Road, Calcutta 700 035, India
Received 11 September 2000; accepted 9 November 2001
Abstract
The Lower Permian Barakar and overlying Motur Formations, in the southeastern part of the Satpura Gondwana basin,
India, reveal contrasting lithology and alluvial architecture. Barakar Formation (f225 m thick) consists of laterally extensive 5-
to 20-m-thick multistoreyed, multilateral coarse-grained sandstone bodies. In the upper part of the formation, a few 1.5- to 11-
m-thick coal carbonaceous shale units alternate with the thick sandstone bodies. In contrast, the Motur Formation is
characterised by a thick (f500 m thick) succession of red mudstone with usually isolated, comparatively thinner (115 m
thick) sandstone bodies. The multistoreyed Barakar sandstone bodies are inferred to represent deposition in sandy braided
streams. Earlier workers inferred development of the associated coal/carbonaceous shale units in contemporaneous floodplains.
The present study, on the other hand, indicates that the coalcarbonaceous shale units accumulated in an extensive vegetated
marshland with small channels and lakes, and were temporally and spatially unrelated to the Barakar braided rivers.Sedimentologic and stratigraphic data suggest that during periods of active subsidence of the basin floor, the braided alluvial
plain was transformed to an extensive, low-gradient wetland, and at times of tectonic quiescence, elevated source regions forced
the braided system to prograde over the coal-forming marshland. Thicker (115 m) sandstone bodies embedded in the red
mudstones of the Motur Formation are inferred as channel fills. Whereas the thinner (0.22.0 m) sandstone sheets, at places
occurring as wings of the channel sandstones, represent leveesplay complexes of the Motur channels. The red mudstone
intervals perhaps represent the alluvial floodplain environment. Abundant calcareous nodules within mudstones are inferred to
record development of calcareous paleosols on the floodplain deposits. Dominance of mudrocks, the smaller dimension as well
as isolated nature of the channel fills and well-developed levee deposits in the Motur Formation, are suggestive of deposition in
an anastomosed fluvial system characterised by multiple, laterally stable channel levee complexes flanked by extensive
floodplains. Occurrence of coal in the Barakar Formation and red mudstone with calcareous paleosols in the Motur Formation
indicates a change of paleoclimate from humid (in Barakar) to semi-arid type (in Motur) during the Lower Permian time in the
Satpura Gondwana basin. There is no independent evidence of major tectonic reorganisation (stratigraphic discordance, changeof paleocurrent pattern) of the basin during the transition from Barakar to Motur Formation. It is inferred that the change from
the thick multistoreyed, multilateral sandstone sheets of Barakar Formation to that of the isolated, thinner sandstone bodies
0037-0738/02/$ - see front matterD 2002 Elsevier Science B.V. All rights reserved.P I I : S 0 0 3 7 - 0 7 3 8 ( 0 1 ) 0 0 2 6 0 - 3
* Corresponding author. Fax: +91-33-5776680.
E-mail address: [email protected] (T. Chakraborty).1 Present address: South African Museum, Cape Town, South Africa.
www.elsevier.com/locate/sedgeo
Sedimentary Geology 151 (2002) 243271
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within thick mudstones of the Motur Formation reflects response of the alluvial system to increasing climatic aridity rather than
to increasing rate of basin subsidence. D 2002 Elsevier Science B.V. All rights reserved.
Keywords: Gondwana; Satpura Basin; Permian; Fluvial deposits; Alluvial architecture; Climate
1. Introduction
Comparison of modern stream processes and their
deposits provides powerful tools for the analysis and
interpretation of ancient alluvial facies (cf. Allen,
1965; Walker and Cant, 1984; Smith et al., 1989;
Khan et al., 1997). Because of the limitation of time
span of human observation and record, controls on the
large-scale architecture of alluvial successions are less
clearly understood (Blum and Tornqvist, 2000). Com-
puter simulations, laboratory experiments and deduc-
tions from ancient fluvial deposits suggest that
tectonism and climate exert major controls in shaping
the stratigraphic architecture of alluvial successions
(Mackey and Bridge, 1995; Heller and Paola, 1996;
Olsen et al., 1995; Martinsen et al., 1999). Earlier
works highlighted the role of tectonism in controlling
the architecture of the alluvial sandstone bodies (Bla-
key and Gubitosa, 1984; Kraus and Middleton, 1987).
The role of climate in controlling the sand body
architecture is, however, increasingly emphasised inrecent times (Smith, 1994; Fielding and Webb, 1996;
Pedley and Frostick, 1999; Blum and Tornqvist, 2000).
It is, however, difficult to desegregate the climatic
signals from that produced by tectonism in an alluvial
succession (Pedley and Frostick, 1999).
Indian Gondwana sediments comprise a thick suc-
cession of fluvial deposits (Veevers and Tewari, 1995)
and evidences for several major climatic shifts have
been documented independently from the succession
on the basis of the palynological studies (Kar, 1976;
Tiwari, 1996; Veevers and Tewari, 1995). Transitionfrom Lower Permian coal-bearing Barakar Formation
to the overlying red mudstone-dominated Motur For-
mation in the eastern part of the Satpura Gondwana
Basin (Fig. 1, Table 1) is believed to coincide with
such a climatic shift (Veevers and Tewari, 1995). The
upper part of the Barakar Formation shows thick
sandstone bodies alternating with coalcarbonaceous
shale units, whereas the overlying Motur Formation is
dominated by thick succession of red mudstone inter-
layered with thinner sandstone units. In an earlier
study, Casshyap and Qidwai (1971) interpreted Bar-
akar sandstones as deposits of low-sinuosity braided
rivers, Barakar coal seams as floodplain sediments of
these braided streams and Motur Formation as mean-
dering river deposits on the basis of broad lithology
and detailed paleocurrent analysis. We undertook a re-
examination of these two formations with an aim to
understand the possible controls of changing facies
and alluvial architecture across these two units.
The purpose of this paper is to present a detailed
facies analysis of the Barakar and Motur Formations.
The analysis shows that simple braided and mean-
dering river facies models are inconsistent with the
internal characteristics of the Barakar and Motur
Formations, respectively. We present an alternative
interpretation for the deposition of the Motur and
Barakar sediments and argue that the remarkable
changes in the lithology and architecture from Barakar
to Motur Formations were dominantly driven by a
climatic shift across the Barakar Motur transition
rather than changes in the tectonic regime.
2. Geological background
Gondwana sedimentary successions occur in sev-
eral disparate basins in Peninsular India (Robinson,
1967; Fig. 1a) of which the Satpura Gondwana Basin is
the westernmost. Crookshank (1936) first published a
detailed geological account of the basin and subdivided
the sedimentary fill into seven major stratigraphic units
(Table 1). Traditionally, Gondwana succession in Indiahas been divided into Lower and Upper subdivisions
based on the floral content and presence or absence of
coal-bearing strata. In the Satpura Basin, contact be-
tween Bijori and Pachmarhi Formations marks the
boundary between the two subdivisions (Table 1).
In order to assess the regional climatic regime, it is
necessary to correlate the age and stratigraphic posi-
tion of the Barakar and Motur Formations of the
Satpura Basin with the sedimentary successions of
the other Gondwana basins. Although independent
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Fig. 1. (a) Different Gondwana basins of Peninsular India (after Robinson, 1967). (b) Details of the study area. (c) Geological map of the s
dispersion of the paleocurrent directions. The circled numbers beside rose diagrams denote the number of observations. Bold lines marked A, B
sections in Motur Formation (see Fig. 9); bold lines denoted by BK-I and BK-II mark the locations of measured logs in the upper part of the
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age data including reports of fossils from the Barakar
and Motur Formations of the Satpura Basin are vir-
tually absent, in the following, we attempt to summa-
rise the available information. Palynological studies
indicate that top of the Barakar Formation in other
Gondwana basins marks the transition from Lower to
Table 1
The stratigraphic succession of the Satpura Gondwana Basin (modified after Raja Rao, 1983; Bandyopadhyay and Sengupta, 1999)
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Friend et al., 1979, 2001) and lower boundaries of the
stories are designated as fifth-order bounding surfaces
(Fig. 2). The fifth-order surfaces are flat to distinctly
concave upward and are strewn with coarser sandstone
and claystone clasts. These surfaces lap on to or are
truncated by the sixth-order surfaces and in some cases
are truncated by other fifth-order surfaces (Fig. 2).
Coset of planar or trough cross-strata characterises
the sandstone storeys. In some cases, set or coset
bounding surfaces that are inclined to the fifth-order
surfaces can be recognised within the storeys. Theseinclined set or coset boundaries are designated third-
order surfaces in the Barakar and Motur Formations
and represent either lateral or downcurrent macroform
accretion surfaces. The fourth-order surfaces of Mialls
(1988) scheme, representing the preserved top of the
macroforms, are uncommon in the studied sections.
Isolated plano-concave as well as convexo-planar
sandstone bodies encased within mudstone are com-
mon in the Motur Formation and their bounding
surfaces are also designated as fifth-order surfaces
(Fig. 2). Set and coset bounding surfaces assigned firstand second orders in Mialls (1988) scheme are recog-
nisable in all the sections but have not been marked in
the architectural drawings.
4.2. Barakar Formation
Poor exposures of the Barakar Formation do not
allow detailed reconstruction of vertical and lateral
profiles but plan exposures allow collection of paleo-
current data presented in Fig. 1c. Details of the facies
were observed and sedimentological profiles were
constructed from open cast coal mines in the study
area. Two major facies associations can be recognised:
thick multistorey sandstone association (BFA-I) and
carbonaceous shalecoal association (BFA-II).
4.2.1. Thick multistorey sandstone association (BFA-I)
4.2.1.1. Description. The BFA-I sandstone bodies
delimited from the over- and underlying coalshale
succession by the sixth-order bounding surfaces aretypically sheet-like and vary in thickness from 5 to 20
m (Fig. 3). In quarry faces oriented nearly transverse
to flow, the thicker sandstone bodies can be traced
laterally over the entire length of the quarry ( > 1 km).
Examination of the adjacent quarries and bore-hole
data suggests that many of them are several kilometres
wide and alternate with subregionally extensive coal
carbonaceous shale units (Rai and Shukla, 1977;
Western Coalfields Limited, unpublished data). The
lower bounding surfaces of the sandstone bodies are
erosional in nature, whereas upper contacts are sharpto gradational over short distances. The sandstone
bodies show slight upward fining of the grain size.
The BFA-I sandstone bodies are multistoreyed in
nature. The storey bounding (fifth order) surfaces are
flat to concave-up (Fig. 3b) and are marked by granule-
rich sandstone and intraformational shale fragments.
Storeys are 1.5 to more than 5 m thick, and in sections
oriented transverse to flow directions, can be traced for
a few hundred metres (Fig. 3a,b). The width/thickness
ratios of the storeys are usually >50 and they may
Fig. 2. Schematic drawing showing the hierarchy of bounding surfaces observed within Barakar and Motur Formations of the study area.
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show slight coarsening or fining upward trend. Al-
though most storeys are in direct contact with others, at
a few places, they are separated by laterally impersis-
tent, up to 20-cm-thick, grey mudstones (Fig. 4a).
The storeys are characterised dominantly by cosetsof decimetre- to centimetre-scale planar and trough
cross-strata. Isolated large clay clasts in places mark
coset-bounding surfaces. Basal parts of the storeys
show large downcurrent-dipping compound cross-
strata (Fig. 5) that are overlain by cosets of planar
and trough cross-strata. In some flow parallel sections,
coset-bounding (3rd order) surfaces display a small
downcurrent inclination with respect to the fifth-order
surfaces. In a single isolated case, lateral-accretion
macroforms could be recognised, where the third-
order surfaces dip westward against the north
north west mean paleocurrent direction measured
from the associated cross-strata. Paleocurrents meas-
ured from Barakar Formation show a unimodal pat-
tern and at the level of individual exposures arecharacterised by low dispersion with consistency ratio
(sensu Rao and Sengupta, 1972) varying between
89.0% and 98.9% (for paleocurrent roses, see Fig. 1c).
4.2.1.2. Interpretation. Individual storeys, in places
with concave-up erosional lower boundaries, and
internally consisting of unidirectionally oriented dec-
imetre-scale planar and trough cross-strata with
locally developed fining-upward grain-size trend, sug-
gest deposition in fluvial channel (Collinson, 1996;
Fig. 3. (a) Photomosaic of Barakar sediments in the Tuti open cast quarry. Note the coal seam (No. III), IHS and the gleyed paleosol unit in the
lower right corner of the photo. (b) Line drawing prepared from the photomosaic showing the major bounding surfaces within Barakar sand
body. Note the concave-upward geometry of many fifth-order surfaces.
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Khan et al., 1997). Compound cross-beds are inferred
to represent in-channel macroforms that grew through
the accretion of smaller bedforms on its lee (Bank,
1973; Chakraborty, 1999). Low-angle downcurrentinclination of the third-order surfaces observed at a
few places probably indicates presence of large-scale
frontally accreting macroforms (Haszeldine, 1983).
Sheet-like geometry of the storeys, dominantly coarse
sand size of the deposits, absence or presence of thin,
impersistent veneers of mudstone, locally developed
DA-elements and low dispersion of the paleocurrent
data collectively suggest a low-sinuosity braided pat-
tern of the Barakar river (Bristow and Best, 1993;
Miall, 1988; Chakraborty et al., 2000). In this context,
lateral accretion surfaces noted in a single exposure of
the BFA-I probably denote sidewise accretion of the
braid bars in zones of local flow expansion (Bridge et
al., 1986; Bristow, 1993). Thin mudstone units are
interpreted as bar-top fines or small floodplain depos-
its in the braided alluvial plain. The major sandstone
bodies of BFA-I produced by the superposition of
individual storeys represent the channel belts of the
Barakar river system. High stacking density and in-
terconnectedness of the channel-fill sandstone units
(storeys) and paucity of mudstone probably indicate
either (i) a high avulsion frequency within a multiple-
channel braided system with poorly developed flood-plain or (ii) a low subsidence rate or (iii) a suitable
combination of these two factors (Mackey and Bridge,
1995; Heller and Paola, 1996). Amalgamated nature
of the coarse-grained BFA-I sandstone bodies, their
thickness on the order of tens of metres and lateral
extent on the scale of kilometres probably imply that
the supply of the coarse clastic far exceeded the
accommodation space created by the basin subsidence
resulting in sandy braided channels wandering back
and forth across the entire alluvial plain.
4.2.2. Coalcarbonaceous shale association (BFA-II)
4.2.2.1. Description. This association alternates with
thick sandstone bodies of BFA-I and comprises an
interlayed succession of coal, carbonaceous shale,
sandshale heterolithic units, sheet-like thin beds of
medium- to fine-grained sandstone and relatively
uncommon lenticular sandstone bodies. The individual
BFA-II successions varies in thickness from 1.5 to
>11 m. Persistent thin laminae characterise the shales,
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whereas parallel laminae, wave or combined flowripple (Fig. 6) and small cross-strata are typical of
heterolithic or fine sandstone units. The thicker units
of BFA-II are sheet-like and can be laterally traced for
many kilometres across the PenchKanhan coalfield
area (Rai and Shukla, 1977; Western Coalfields
Limited, unpublished data). The thinner units of
BFA-II, however, pinch out within several tens to
few hundreds of metres.
The BFA-II succession associated with the topmost
coal seam (seam number III of PenchKanhan coal-
field area, sensu Rai and Shukla, 1977) exposed intwo quarry sections have been shown in Fig. 4a (for
location of the sections, refer to Fig. 1c). The basal
part of the BFA-II succession is marked by the coal
seam that is overlain by a set of inclined heterolithic
strata (IHS, Thomas et al., 1987). In the Tuti quarry to
the east (Fig. 3a), IHS set is overlain by a succession
of structureless, hardened, greenish grey mudstone
containing iron-oxide-lined fractures and poorly deve-
loped iron oxide nodules. This is followed upward by
an alternation of wave/combined flow rippled fine
Fig. 4. (a) Log through the upper part of the Barakar Formation exposed at the two open cast quarries. Position of the logs (BK-I and BK-II
shown in Fig. 1c). For explanation of the symbols, see Fig. 8B. (b) Explanation of symbols used in the log diagrams of this paper.
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sandstone sheets and carbonaceous shale (log BK-I,
Fig. 4a). In the Panara quarry to the west (log BK-II,
Fig. 4a), the IHS unit is erosively overlain by BFA-I
sandstone. In spite of local variation in the BFA-II
successions, many of the adjacent quarries show coal
seam number III to be persistently overlain by inc-
lined heterolithic strata thereby constituting a coarsen-
ing-upward trend in the lower part of the BFA-II
succession.
The relative inclination of the individual stratum
of the IHS sets, with respect to the generalised dip of
the succession, varies between 15j and 2j (Fig. 7).
The IHS set consists of gradationally alternating very
fine sand (110 mm) and carbonaceous shale (340
mm). Well-developed wave and combine flow ripples
and climbing ripple lamination (Fig. 5) are typical of
the sandy strata and are separated by shale laminae
with rare burrows. The inclined heterolithic strata
Fig. 5. Large downdipping compound cross-strata within BFA-I; Panara open cast quarry, Kanhan valley.
Fig. 6. Wave-ripple lamination in the heterolithic facies of the BFA-II; Datla open cast quarry, Kanhan Valley.
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show a non-erosive, downlapping relationship with
the underlying coal seam (Figs. 3a and 7) and are
marked by distinct fining of grain size in the downdip
direction.
4.2.2.2. Interpretation. Sedimentary structures andlithology indicate accumulation of BFA-II rocks in
shallow, ponded water environment. The laminated
carbonaceous shales are inferred to represent deposi-
tion in lakes that covered part of the low-lying
marshland environment and the sheet-like thin sand-
stone units might represent either distal crevasse
splay or storm-emplaced sediments within the lakes.
Lack of in situ tree trunks or extensive root horizons
indicates that much of the plant detritus was allochth-
onous (cf. Rai and Shukla, 1977). High water table in
the poorly drained marshes locally produced anaero-bic reducing environment favouring formation of peat
(Duchaufour, 1982). High ash content of the coal
(Raja Rao, 1983) and the intercalated sandstone and
shale partings imply formation in the low-lying
marshland rather than in raised peat bogs (McCabe,
1984; Collinson, 1996; Jorgensen and Fielding,
1996). Small lenticular sandstone beds are inferred
as small channel-fill deposits. The depositional sce-
nario envisioned for BFA-II succession comprises
extensive, poorly drained swamps with a mosaic of
lakes and sluggish drainage channels such as that
occurring in Mississippi delta plain (Tye and Cole-
man, 1989; Aslan and Autin, 1999) or Cumberland
marshes (Smith et al., 1989).
In the absence of erosional lower bounding surfa-
ces and unidirectional current-generated bedforms inthe IHS sets, it seems unlikely that they formed from
the lateral migration of point bars of sinuous rivers (cf.
Fielding et al., 1993). A coarsening upward trend in
the lower part of the BFA-II succession coupled with
the dominance of wave-generated structures, down-
lapping nature of the heterolithic strata and abrupt
fining of the IHS set in the downdip direction suggest
that the IHS set probably formed through the pro-
gradation of a subaqueous levee complex or small
lake delta (cf. Perez-Arlucea and Smith, 1999).
As the crevasse splays or deltas filled up the smallfloodplain lakes, vegetation encroached upon them
forming incipient soil profiles. Destruction of stratifi-
cation, inclined fracture planes and iron oxide nodules
in greenish mudstone overlying IHS in the Tuti quarry
(Fig. 3a) probably represent such incipient gleyed
paleosols. Wave-rippled fine-grained sandstones with-
in carbonaceous shale at the top of the BFA-II succes-
sion of the Tuti quarry probably represent another
episode of subaqueous progradation of crevasse sheets
in the Barakar wetland.
Fig. 7. Photo showing low-angle inclined heterolithic strata of the Panara quarry. Note downlapping nature of the IHS set on the underlying coal
seam. BFA-I sandstone erosively overlies the IHS set (see log BK-II, Fig. 4a). Human figure for scale.
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4.2.3. Barakar depositional system
The alternation of thick sandstone and coalcar-
bonaceous shale units in many Gondwana basins has
been previously attributed to deposition in fluvialchannel and associated interchannel floodplain envi-
ronments (Banerjee, 1960; Casshyap and Qidwai,
1971; Casshyap, 1979). Our inference of braided
stream deposition for the BFA-I sandstone bodies is
in agreement with that of Casshyap and Qidwai
(1971), but it is difficult to reconcile a floodplain
origin for the BFA-II rocks for the following reasons.
(1) Observation of modern braided rivers suggests
that the floodplain in braided river alluvial plain is
usually small and discontinuous (Brierly, 1991; Rein-
fields and Nanson, 1993) and their deposit have a low
preservation potential (Walker and Cant, 1984). Com-
pacted thickness of up to 15 m and high lateral extent
of the coal-bearing fine-grained sediments of BFA-II
is inconsistent with the above observations from the
modern braided stream systems. In contrast, our
interpretation of thin mudstone units interlayered with
channel-fill storeys of BFA-I as floodplain or bar-top
fines is consistent with the observations from the
modern braided river systems.
(2) Over the entire studied area, the coal and as-
sociated shale facies lack any demonstrable lateral in-
tertonguing relationship with the sandstone of BFA-I.(3) Presence of lacustrine features (persistent lam-
inations in silt, wave ripples, etc.) over a large area
occupied by the BFA-II succession indicates rapid
regional rise of water table rather than existence of
small ponds that are common in alluvial floodplains.
(4) Instead of fining upwards succession, common
in floodplain deposits (Collinson, 1996), the lower
part of the BFA-II is coarsening upward with coal at
the base and heterolithic or sandstone beds occurring
upward.
These features suggest that the depositional milieurepresented by these two associations was spatially
unrelated and was temporally separated. We infer that
vertical transition of BFA-I to BFA-II indicates a
major reorganisation of the alluvial plain when brai-
ded channel system was replaced by an extensive,
vegetated wetland.
Such sharp temporal changes between sandy braid
plain and low-gradient wetland can be brought about
by tectonism (Haszeldine and Anderton, 1980) or by
climatic changes (Fielding and Webb, 1996). On the
basis of remarkable regularity of alternating sandstone
and coalshale intervals occurring over several hun-
dred metres of stratigraphic thickness, Fielding and
Webb (1996) inferred a Milankovich climatic forcingfor such changes in the Bainmedart Coal Measures of
Antarctica. In the Barakar Formation, which is older
than Bainmedart Coal Measures of Antarctica (Vee-
vers and Tewari, 1995, their Fig. 45), BFA-I and BFA-
II alternations are limited only in the upper 100 m of
the succession and lack such regularity. Sandstone
bodies occurring in-between two coal shale succes-
sions vary in thickness from 3 to 18 m (Rai and
Shukla, 1977; Western Coalfields, unpublished data).
We believe such irregular nature of alternation of BFA-
I and BFA-II is more consistent with episodic tectonic
movements than regular periodicity of climatic fluctu-
ations driven by orbital forcing mechanism (cf. Has-
zeldine and Anderton, 1980; Fielding and Webb,
1996). At times of increased tectonic activity, the basin
floor subsided rapidly transforming the entire alluvial
plain into a low-gradient, waterlogged marshland that
favoured accumulation of peat and development of
gleyed paleosols at places. Sluggish channels, lakes
and muddy lake deltas characterised the extensive
vegetated marshland milieu (cf. Smith et al., 1989;
Aslan and Autin, 1999). During periods of tectonic
quiescence, the elevated source region forced thebraided fluvial system to prograde over the peat-
accumulating wetland (Alexander and Leeder, 1987;
Blair and Bilodeau, 1988).
4.3. Motur Formation
Red mudstone-dominated Motur Formation can be
subdivided into three broad facies associations: thick
sandstone association (MFA-I), thin sandstone asso-
ciation (MFA-II) and red mudstone association (MFA-
III). Lack of exposure precludes continuous loggingthrough the entire succession, but composite logs (Fig.
8) spread across the study area display the vertical
succession of these facies associations.
4.3.1. Thick sandstone association (MFA-I)
4.3.1.1. Description. The sand bodies vary from 0.8
to >15 m, but are mostly 12 m thick and are made up
of cross-bedded very coarse- to medium-grained sand-
stone. The sand bodies are sheet-like to lenticular in
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geometry with flat to concave-upward fifth-order
lower bounding surfaces (Fig. 9), usually single
storeyed and encased within the mudstone of MFA-
III (described later). In a few cases where flow normal
dimension is measurable in the exposure, the sand
bodies have width/depth ratio around 20. The sand-
stone units usually show a fining-upward grain size
trend together with upward decreasing scale of sedi-
Fig. 8. Lithologs through the different well-exposed transects through the Motur Formation of the study area. For the location of the individual
sections, see Fig. 1c. For symbols, refer to Fig. 4b.
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mentary structures, and eventually grade into the
overlying red mudstone. Lateral accretion surfaces
characterise few of the fining-upward sandstone units
(Fig. 10a, the lower sandstone body). Paleocurrent
direction measured from trough cross-strata of these
thicker sandstone bodies is usually unimodal and
vector mean directions of paleocurrent data measured
from different outcrops vary from 291j to 22j (total
number of observations 109; Figs. 1c and 9).A single sandstone body (the upper sandstone body
in Fig. 10a,b) occurring in the Pench River section has
features somewhat different from those described
above. The sandstone unit is about 3.5 m thick and
shows a little change in thickness over few hundred
metres across the entire outcrop. This sandstone body,
coarser than most other MFA-I units, is made up of
pebbly, very coarse-grained sandstone, has an ero-
sional, undulating base and lacks well-developed
fining-upward trend. Internally, the unit shows few
laterally extensive subhorizontal erosion surfaces
(Fig. 10a,b) and each of the lithosomes bounded by
these surfaces consists mostly of small (up to 25 cm)trough cross-strata that at places are abruptly overlain
by thin (
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4.3.1.2. Interpretation. The erosively based, lentic-
ular sandstones of MFA-I with their fining-upward
trend and unimodally oriented cross-beds are inferred
to represent fluvial channels fills. Occurrence ofsingle-storeyed sand bodies with limited lateral and
vertical dimension (when compared to storey dimen-
sion of BFA-I) with enveloping red mudstone implies
that the channels were smaller, as compared to BFA-I
channels, and were mostly confined within the mud-
depositing environment of MFA-III (see below). Pres-
ence of lateral accretion surfaces with well-developed
fining-upward trend within some of the sand bodies
(lower sand body in Fig. 10a,b) indicates point bar
accretion in these channels.
However, the coarse-grained sandstone sheet of the
Pench River section (upper sand body in Fig. 10b,c)
that lacks well-defined fining-upward grain size or
thinning-upward trend of the sedimentary structures
and contains impersistent mudstone lenses, resembles
sheet-braided stream deposits dominated by the verti-
cal accretion of the smaller bedforms (Williams, 1971;
Fedo and Cooper, 1990; McCormick and Grotzinger,
1993). Subhorizontal internal bounding surfaces
within this sheet sandstone body imply dominantly
vertical aggradation of shallow, wide channels. Thin,
grey mudstone lenses probably indicate rapid flow
stage fluctuations. This sandstone body probably rep-resents deposition from high-energy flood event that
swept across a large tract of the Motur alluvial plain
and closely resembles the ephemeral sheet-flood
deposits (McKee et al., 1967; Williams, 1971; Tun-
bridge, 1981). Rarity of such coarse-grained, extensive
sheet sandstone bodies within the Motur Formation
indicates the rarity of intense flood events that couldtransport the huge amount of coarse clastics.
4.3.2. Thin sandstone association (MFA-II)
4.3.2.1. Description. The sediments of this associa-
tion are medium- to muddy, fine-grained sandstone
and are thinner than sandstone bodies of MFA-I, and
range in thickness between 0.20 and 2.0 m. The
sandstone usually occurs as isolated units but may
be connected laterally to thicker MFA-I sandston e
bodies. At a flat lower bounding surface, much greater
lateral extent relative to their thickness is typical of
these sandstone units. The upper contact of the sand-
stone unit is usually sharp, but may show a gradational
passage to overlying mudstone facies. Paleocurrents
measured from these sandstone units show an east or
westward divergence from the northward paleocurrent
direction revealed by the MFA-I sandstone bodies
(Figs. 1c and 12a). Depending on the geometry and
the internal features, three distinctive types of sand-
stone units can be recognised within MFA-II.
(A) This is the most common type of sandstone
unit and shows a sharply defined sheet-like or wedge-shaped geometry. At places, the upper surface of the
sandstones units is convex upward (Fig. 11). It varies
in thickness from 50 cm to about 160 cm. The lower
Fig. 11. Photograph showing the sheet-like MFA-II sandstone units inferred to represent crevasse splay deposits. Note slightly convex-up shape
of the two thinner sandstone units and overlying thick MFA-I sandstone body. Section in Pench River near Richhora village.
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Fig. 12. (a) Line drawing showing geometry of a levee complex (type B sandstone, MFA-II) exposed in a section east of Fig. 9. Coarse-grained M
side of the section progressively fines away from the channel sand body. Note also the low-angle clinoform internal bounding surfaces within the
paleocurrent data from main sand body and the finer grained levee sandstone. A unit of grey mudstone siltstone embedded with thin sandst
Photomosaic depicting a slightly oblique view of the levee complex detailed in (a).
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part of the sandstone unit contains small- to medium-
scale trough cross-beds overlain by parallel lamination
or ripple cross lamination. Tops of the sandstone units
at places are calcareous and show colour mottling.(B) These sandstone units are laterally linked with
thicker channel sand bodies of MFA-I and resemble
winged sand bodies described by others (cf. Stear,
1983; Mjos et al., 1993). The type B sandstone units
may be up to 3 m thick. The sandstone beds are
typically wedge shaped and are characterised by
clinoform geometry and a low-angle downlapping
relationship of the internal bounding surfaces with
the underlying mudstone. The units show a fining of
grain size away from the main MFA-I sandstone body(Fig. 12a,b). Parts of the exposure proximal to the
MFA-I sand bodies are coarse grained with medium-
scale trough cross-strata, whereas parts further away
from the MFA-I sandstone bodies are characterised by
muddy fine-grained sandstone with small cross-strata
or ripple cross-lamination (Fig. 12a,b). At places,
Fig. 13. (a) MFA-II sheet sandstone units exposed in the Richhora section. Lower part of the exposure (marked Y) comprises greenish grey
mudstonesandstone alternation. Features of gleyed paleosol are common in this part. Note undulating top (arrows) of the overlying sheet
sandstone body (marked X) and grey mudstone that fills in the depressions resulting from the bed-top irregularities. The view represents about
3 m of Motur succession, near Richhora. (b) Details of the internal features of the sheet sandstone (marked X) in (a). Note undulating basal
surface, form-discordant and bi-directional nature of the foreset laminae, transition of dipping foreset laminae into low-angle laminae and
abundant mud flasers within the sandstone bed.
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desiccation cracks occur near top of the sandstone
unit. The paleoflow directions measured from the
distal part of the clinoform unit show a divergence
with those measured from the laterally linked MFA-Isandstone body (Fig. 12a).
(C) These sandstone units are characterised by flat
to undulating base, wavy top and internal wave-ge-
nerated sedimentary structures (Fig. 13a,b). The sandy
beds are sharply overlain by grey or molted greenish
red claystone that drapes over the undulating bed top
(Fig. 13a). Internal cross-strata show lensoid and
pinch-and-swell geometry, variable foreset dip direc-
tion, form discordance, common mud flasers and
locally grade into low-angle undulating laminae
(Fig. 13b).
4.3.2.2. Interpretation. Reduced thickness, greater
lateral extent, smaller internal structures, finer grain
size and flat base of these sandstone units are inferred to
indicate deposition from shallow, wide flows outside
the deeper channels represented by MFA-I sandstones.
Flat base and convex top of the type A sandstone
resemble the depositional geometry of crevasse lobes
(Collinson, 1996; Mjos et al., 1993). Colour mottling
and calcareous nature of the top of these sandstone
units are inferred to indicate incipient pedogenesis of
the exposed crevasse lobes (Collinson, 1996; Bownand Kraus, 1987). Type B sandstone resembles the
wing (cf. Stear, 1983) of the channel sandstones and
is inferred to represent fluvial levee (Mjos et al., 1993;
Nadon, 1994). The clinoform geometry of these sand-
stones, their lateral fining and divergence of paleocur-
rent with that of the related MFA-I channel sandstone
bodies are consistent with a levee interpretation (cf.
Fielding et al., 1993; Michaelson et al., 2000). Desic-
cation features indicate subaerial to near-emergent
condition for these units. The clinoform geometry
and the downlapping relationship are inferred to denotethe relief of the successive channel overbank interface
close to the channel margin (cf. Nadon, 1994).
Tabular to pinch-and-swell sand bodies and inter-
nal wave-generated sedimentary structures of type C
sandstone units provide evidences for their deposition
under oscillatory flow (cf. Brenchley et al., 1993;
Midtgaard, 1996). Dark grey to greenish grey colour
of the claystone enclosing type C sandstone units
and burrows in this succession probably indicate their
deposition in water-logged low-lying areas of the
flood basin. Small intrafloodplain channels or cre-
vasse channels supplied the sand to the localised
floodplain ponds that were subsequently reworked
by waves (cf. Smith et al., 1989). Large (metre-scale)bed-top irregularity produced by these wave-gener-
ated bedforms was at places preserved during subse-
quent periods of rapid rise of the lake-water level (Fig.
13a, cf. Browne and Plint, 1994). Top of these type C
sandstones were marked by periods of slow deposi-
tion between two floods and favoured infestations by
burrowing organisms.
4.3.3. Red mudstone association (MFA-III)
4.3.3.1. Description. Red mudstone with interlay-
ered thin (less than a cm to 10 cm) sandstone and
siltstone beds comprise the bulk lithology. At a few
places, the mudstone is green, greenish or dark grey.
Claystone/mudstone in some exposures show well-
developed thin laminae but are mostly massive. Cal-
careous concretions (Fig. 14), fossil woods (Fig. 15)
and organic traces (Fig. 16) are common.
Occurrence of calcareous concretions is a hallmark
of the Motur red mudstone. The nodules are 1 to >15
cm in diameter and vary in shape from highly irreg-
ular to vertically elongated and tubular (Fig. 14).
Some of the vertically elongated nodules taper down-ward. Reworked calcareous nodules occur as dis-
persed pebbles at the base of MFA-I and MFA-II
sandstones (Fig. 17). The cores of larger vertically
elongated nodules at places show tubular holes and
radiating cracks filled with sparry calcite cement (Fig.
18). Nodular zones are often associated with carbo-
nate-filled, inclined cracks that are up to 60 cm long in
the sections.
The nodule-rich mudstone develops a distinctive
vertical succession that is typically about 1 m thick but
may be up to 3 m thick (Fig. 19). The base of thesuccession is marked by green or red mudstone and
followed upward by a zone of dispersed nodules.
Dispersed nodules become vertically elongated, and
then coalesce to develop larger and more equant-
shaped nodules higher in the profile (Fig. 19). At
places near the top of the nodule-rich succession,
coalesced nodules form limestone beds that are sub-
parallel to primary stratification. Erosively emplaced
sheet-like sandstone unit (Fig. 19) usually overlies the
succession. However, in some sections, nodular zones
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are thinner (V20 cm) and lack well-developed sequen-
tial arrangement of the different units described above.
Microscopic examinations show that the nodular
mudstones are characterised by pervasive micritic
cement as well as micritic nodules/glaebules of a
variety of shape and internal fabric. At many places,
micritic nodules show circumgranular and radiating
cracks filled with micritic and sparry calcite (Fig. 20).
Detrital siliciclastic grains frequently have corroded
margins and are coated with thin films of isopachous
clay or micrite or micro-spar cement (Fig. 21). The
greenish grey mudstones associated with type C
Fig. 14. Photograph showing elongated to irregular-shaped calcareous nodules with Motur red mudstone. Pench River section.
Fig. 15. Petrified wood fossil within Motur sandstone. South of Datla.
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MFA-II sandstones at places show destruction of
primary layered fabric, corroded quartz grains and
small iron oxide concretions.
4.3.3.2. Interpretation. Red mudstone encasing most
of the MFA-I and MFA-II sandstone bodies is inter-
preted to represent deposition in the overbank areas of
the Motur alluvial plain. Laminated red mudstones
probably represent undisturbed suspension settlement
in the overbank areas. However, activities of burrow-
ing organism, plant roots (inferred from the presence
of both tubular calcareous nodules as well as abundant
Fig. 17. Photograph showing the contact between the top of the calcareous paleosol profile and overlying cross-bedded MFA-II sandstone unit.
Note coalesced nodules at the top of the soil profile and abundance of calcareous nodules (arrows) in the sandstone derived from the underlying
soil profile. Near village Richhora.
Fig. 16. Bedding plane view of burrows at the sandstonemudstone interface within Motur Formation at Richhora Section (Fig. 13).
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silicified woods), and diagenetic changes related to the
development of soil profiles probably rendered bulk of
the Motur mudrocks structureless (cf. Nadon, 1994).
High proportion of the clays in the Motur Formation
implies that extensive, low-energy floodplain environ-
ments surrounded fluvial channels. Pervasive red pig-
mentation of the mudstone denotes oxidising envir-
onment and a generally low water table.
Reworked calcareous nodules within MFA-I and
MFA-II sand bodies imply their syndepositional ori-
gin. Calcareous nodules and its vertical succession areinferred to be related to the soil profiles that developed
over the subaerial floodplain sediments. Pervasive
micritic cement, corrosion and isopachous envelop of
micrite or micro-spar around detrital grains, micro-
spar-filled cracks of different orders are commonly
associated with paleosol deposits (Brewer and Slee-
man, 1964; Nagtegaal, 1969; Esteban and Klappa,
1983). Tubular shape of the calcareous nodules typi-
cally resembles calcified root tubes or rhizocretion in
the soil profile. We infer that the elongate calcareous
nodules that grew around the plant roots and the
central voids, created by the subsequent decay of the
vegetal matter, were later filled-up by sparry calcite.
Bedding-parallel limestone horizons formed of coa-lesced nodules probably resulted from the combined
effect of increasing density of roots up the profile as
well as increased precipitation of calcium carbonate in
the upper part of the soil horizon. Micritic glaebules
with circumgranular and radiating cracks are com-
monly attributed to shrinkswell cycles operative in
the solum (Nagtegaal, 1969; Goudie, 1983; Esteban
and Klappa, 1983). The green-coloured mudstones at
the base of the nodular zones probably represent the
groundwater tables near the base of the soil profiles
where intergranular pore spaces were perennially satu-
rated preventing oxidation of the iron (Buurman,
1980). Thin calcareous mudstone units that lack dis-
tinctive vertical succession probably represent incipi-
Fig. 19. A field sketch showing paleosol profile developed within
Motur red mudstone (MFA-III). Note upward increase in the size
and density of calcareous nodules in red mudstone.
Fig. 18. A view of a large calcareous nodule within Motur mudstone
(MFA-III). Note circular holes (arrowed) filled with a mixture of
clay and micritic carbonate and well-developed radiating cracks
around the holes. The tubular features are inferred to represent relict
root pores in Motur calcareous paleosols. Exposure near Barkuhi.
Lens cap for scale.
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ent soil profile that could not develop into thick soil
horizon due to comparatively higher rate of sedimen-
tation.
Locally developed grey mudstone (those associ-
ated type C sandstone of MFA-II) and occurrence of
corroded quartz grains and iron oxide nodules within
it probably indicate development of incipient gleyed
paleosols (Buurman, 1980). The occurrence of these
grey mudstone-gleyed paleosol successions with type
C sandstones of MFA-II is indicative of their associ-
Fig. 20. Photomicrograph shows a glaebule within Motur mudstone. Note well-developed circumgranular and radiating cracks filled with sparry
calcite cement. X-nicols. Bar scale=1 mm.
Fig. 21. Photomicrograph showing an isopachous rim of sparry cement around a corroded quartz grain within mudstone. X-nicols. Bar scale=
1 mm.
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ation with small floodplain lakes (cf. Zaleha, 1997b;
Kraus, 1999).
Development of pedogenic calcrete is typical of
semi-arid to arid climate, with precipitation exceedingseveral hundreds of millimetres per year and a sea-
sonal distribution of the rainfall pattern (Goudie,
1983; Retallack, 1990; Tandon and Gibling, 1994).
Significant thickness of some of the nodular calcare-
ous zones (possible Bk horizon) indicates precipita-
tion on the higher side of the range and low water
table allowing seepage to some depth below the
exposed surface. In the overall stratigraphic context
of the Motur Formation, thinner calcretes or gleyed
paleosols are probably attributable to changing geo-
morphic setting rather than to change in the climate
within the Motur alluvial plain.
4.3.4. Motur depositional system
The Motur depositional system was characterised
by a mosaic of main channels (thicker sand bodies of
MFA-I) intimately associated with numerous crevasse
splay/levee deposits (types A and B sandstones of
MFA-II) and surrounded by extensive mud-depositing
flood basin (MFA-III). Occurrences of lateral accre-
tion surfaces within MFA-I sand bodies denoting
lateral migration of the sinuous channels are few in
the study area. General paucity of lateral accretionsurfaces, limited lateral extent and flanking levee
deposits of many of the MFA-I sandstone bodies
indicate that the channels were not very mobile and
in many of the cases probably were confined and
stable within the floodplain fines.
General character of the Motur Formation of the
study area marked by the dominance of flood basin
mudstone encasing numerous crevasse sheets and fewer
isolated channel sandstone bodies,bears striking resem-
blance to the anastomosing fluvial deposits (Tornqvist,
1993; Nadon, 1994; Morozova and Smith, 1999;Makaske, 2001). Although contemporaneity among
these channel sandstone bodies cannot be demonstra-
ted, as is the case for the most ancient anastomosing
fluvial deposits (cf. Makaske, 2001), the abovemen-
tioned similarities are strongly suggestive of deposition
of the Motur Formation from a mud-dominated anasto-
mosing fluvial system.
The exposed areas of the floodplain were subjected
to soil-forming processes resulting in formation of
caliche profiles of varying thickness. Variable thick-
ness of the caliche deposits was plausibly controlled by
the time available for soil-forming processes, which in
turn was related to geomorphic stability and rate of
sedimentation in that particular area (cf. Bown andKraus, 1987; Kraus, 1999). The red coloration of the
floodplain fines and calcareous soil profiles indicate a
semi-arid climate with seasonal rainfall pattern during
Motur sedimentation. Localised, ponding of water in
the floodbasin resulted in small lakes, in which some of
the splay sand bodies were subaqueously emplaced and
were subsequently reworked by wave action. Gleyed
paleosols developed sporadically near these floodplain
depressions.
It should be noted that Casshyap and Qidwai
(1971) inferred a meandering pattern for the Motur
Formation from the evidence of higher variance of
paleocurrent azimuth (compared to those of under-
lying Barakar Formation) and overall mudstone-
dominated lithology. The paucity of well-developed
lateral accretion surfaces in the channel sand bodies
on the contrary demonstrates rarity of typical mean-
dering channels. Since the crevasse channels develop
oblique to the main channels (Smith et al., 1989;
Perez-Arlucea and Smith, 1999), the paleocurrent
direction measured from smaller sandstone lenses or
sheets are expected to show slightly divergent direc-
tion and higher dispersion (cf. Figs. 1c and 12).Amalgamation of paleocurrent data from all the sand-
stone units of both MFA-I and MFA-II will therefore,
tend to increase the dispersion value, as observed by
Casshyap and Qidwai (1971) leading them to a
meandering channel interpretation for Motur Forma-
tion.
The coarse-grained, sheet sandstone body of the
Pench River section (upper sand body in Fig. 10a,b)
probably is not consistent with the inferred deposition
from anastomosed channels. Coarse grain size, lack of
fining-upward internal organisation and amalgamationof sheet-like lithosomes across horizontal bounding
surfaces probably represent vertically stacked sand-
stone units deposited by shallow, wide braided chan-
nels. We infer the causative mechanism to be high
magnitude flood that resulted in high-velocity shal-
low, wide flow carrying a heavy load of pebbly
coarse-grained sand. Rarity of such sandstone units
within the Motur Formation of the study area indicates
a low frequency of catastrophic flood events in the
Motur catchment area.
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5. Discussion
Both the Barakar and Motur Formations of the
eastern part of the Satpura Basin are alluvial depositsthough they differ markedly in facies and alluvial
architecture. The alluvial successions of the Barakar
Formation are characteristically mud poor and are
made up of thick (f20 m) multistoreyed, multilateral
sandstone bodies. Individual channel-fill units are up
to 5 m thick and more than few hundred metres wide
in flow transverse sections. In contrast, Motur chan-
nel-fill sandstone units are thinner (usually 12 m),
and occur as isolated sand bodies enveloped by red
mudstone. Decreasing interconnectedness of the chan-
nel-fill sandstone bodies along with an increasing
proportion of floodplain fines, as displayed by Bar-
akar and Motur Formations, have often been
explained in terms of increased rate of basin subsi-
dence (Blakey and Gubitosa, 1984; Kraus and Mid-
dleton, 1987; Bristow and Best, 1993). However,
climatic changes can also produce remarkable effects
on river channel patterns and are thus capable of
effecting major changes in the architectural pattern
of the resultant deposits (Pedley and Frostick, 1999;
Blum and Tornqvist, 2000). In the following, we shall
examine the evidences of allogenic factors that might
have influenced changing facies and architectureacross the Barakar and Motur Formations.
Since there has been no report of marine strata in
the study area, we assume that eustatic base level did
not exert any tangible control on the depositional
pattern of the sedimentary succession under investi-
gation. Therefore, the major factors that might have
controlled the large-scale architecture of the alluvial
deposits were climate and tectonism.
Coal and calcretes form in exclusive climatic con-
ditions. Coal formation is favoured by a humid
climate with rainfall distributed throughout the yearand a waterlogged reducing environment. Calcretes,
on the other hand, are typical of semi-arid climate
characterised by a net moisture deficit with precipita-
tion in the range of 400600 mm/year, and strongly
seasonal pattern of the rainfall (Goudie, 1983; Tandon
and Gibling, 1994). Thus, occurrence of grey mud-
stone and coal in the Barakar Formation indicates
climatic regime quite different from that prevailing
during the deposition of red mudstone and calcretes of
the Motur Formation. It should be noted that Barakar
Formation gradationally overlies glaciogenic deposits
of Talchir Formation and is often inferred as perigla-
cial fluvial system. Palynological studies from differ-
ent Gondwana basins of India also indicate a cold andhumid climate for Barakar Formation and warmer
climate for Motur and equivalent stratigraphic units
(Tiwari, 1996; Veevers and Tewari, 1995).
Semi-arid climate, as compared to arid or humid
ones, is known to enhance the sediment supply
probably through increasing rate of chemical weath-
ering and decreasing vegetation cover (Schumm,
1993). Also the modern day dryland rivers are known
for their higher concentration of suspended load,
about 20 times more than that of the perennial systems
with comparable size of the drainage basin (Reid and
Frostick, 1987). A higher proportion of fine-grained
sediments in the Motur Formation and its inferred
semi-arid climate is consistent with the above two
observations from the modern fluvial systems. It has
also been documented from the historical records of
modern rivers of Arizona that one of the principal
ways in which rivers adjust to decreased precipitation
is by decreasing their depth and width and an asso-
ciated increase in the rate of floodplain aggradation
(Hereford, 1984). We invoke the same cause and
effect relationship to account for the relative decrease
in the sandstone body dimension and increase in theproportion of preserved floodplain fines in the Motur
Formation. Similar transition from sandy/gravelly
deposits of braided streams to sandmud alternation
of meandering streams recorded from many Quater-
nary alluvial deposits has been attributed to climatic
changes (Blum and Tornqvist, 2000).
It is difficult to assess rate of sedimentation (the
proxy for rate of tectonic subsidence) in the absence
of well-constrained age data. Examination of the
large-scale sedimentary packages in seismic profile
often allows correlation of the sedimentation withepisodes of tectonic movements (e.g., Ruffel and
Shelton, 1999). In the absence of these data, we
depend on the evidence observable from outcrop-scale
exposures and stratigraphic relationships. The studied
sections, however, do not show any features that may
indicate increased rate of tectonic subsidence at the
Barakar Motur transition. On the contrary, lack of
any stratigraphic discordance between the formations
and very similar northerly paleocurrent pattern of both
the formations argues against any major tectonic event
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in the Satpura Gondwana Basin during Barakar
Motur transition. There is no tangible increase in the
occurrence of soft sediment deformation features in
the Motur Formation, which otherwise might haveimplied more frequent tectonic movement.
Variation in the proportion and interconnectedness
of the channel-belt sandstones, occurring over a thick-
ness of several hundred metres, and broadly similar to
those observed at BarakarMotur transition, has also
been reported from the Miocene Siwalik deposits of
northern Pakistan. On the basis of available palyno-
logical data that suggest persistence of tropical mon-
soonal climate throughout the deposition of the
Siwalik Group, Zaleha (1997a) attributed the changes
in alluvial architecture to the megafan lobe switching
driven by tectonic and autocyclic processes. In a later
study, Friend et al. (2001), however, suggested that the
climatic control for such changes could not be ruled
out altogether from the field evidences. More impor-
tantly and in contradiction to the prevalent notion, they
pointed out that decreasing proportion of mud and
increasing interconnectedness of the sandstone storeys
at the ChinjiNagri transition coincide with the in-
creasing (not decreasing) rate of sedimentation (a
proxy to basin subsidence) as calculated from well-
constrained magnetic reversal chronology of the Siwa-
lik succession. Similar changes of alluvial architectureand associated changing sand/mud ratio from many
Neogene or Quaternary successions, where allogenic
controls are better constrained, have been attributed to
climatic and not tectonic changes (Smith, 1994; Blum
and Tornqvist, 2000). The case studies discussed here
and many more suggest that the hypothesis that assigns
tectonic processes as the sole allogenic control for
changing alluvial architecture is not supported by
current research.
In the Satpura Gondwana basin, sedimentological
evidences suggest marked climatic shift at the Bara-karMotur transition. This interpretation is strongly
supported by regional palynological studies. On the
other hand, there is no independent evidence of in-
creased rate of tectonic subsidence at this time. Al-
though definitive correlation of the architectural
changes to specific allogenic forcing mechanisms
would require more data, our investigation strongly
suggests that the changing facies and alluvial architec-
ture across Barakar Motur Formations were driven by
climatic changes.
6. Conclusions
(a) The upper part of the Barakar Formation in the
eastern part of the Satpura Gondwana Basin is char-acterised by alternating thick, coarse-grained, multi-
storeyed channel sandstones and laterally extensive
coalcarbonaceous shale units. In contrast, overlying
Motur Formation is characterised by thinner, isolated
channel sandstones embedded in a thick succession of
red mudstone.
(b) Available sedimentological evidence suggests
episodic reorganisation of the Barakar alluvial plain to
an extensive peat-accumulating swamp. Tectonic
movement of the basin floor probably controlled al-
ternation of braidplain and muddy wetlands. Periods
of higher subsidence favoured development of peat
swamps, whereas periods of quiescence coincided
with the progradation of the braided alluvial system
across the basin.
(c) Presence of coal in the Barakar Formation and
presence of calcretes in the Motur Formation indicate
marked shift in climate from humid to semi-arid at the
BarakarMotur transition.
(d) By analogy to modern fluvial systems, increased
proportion of mudstone, decreased thickness of the
channel sandstone bodies and their isolated nature in
the Motur Formation, are attributed to increasing cli-matic aridity and adjustment of the fluvial system to
such changes.
(e) Lack of independent evidence of changing rate
of tectonic subsidence during BarakarMotur transi-
tion and evidence of climatic shift during the same
period are construed to indicate climatic influence in
establishing contrasting fluvial style and markedly
different alluvial architectural pattern across the Bar-
akarMotur transition.
Acknowledgements
We gratefully acknowledge the General Managers
of Kanhan and Pench Valley Coalfields of Western
Coalfield Limited for permission to work in the dif-
ferent open cast mines in this area. We are thankful to S.
Bandyopadhyay who encouraged us to take up this
work. We are grateful to P. Ghosh for his invaluable
assistance during fieldwork and help in identifying the
paleosols in the Motur Formation. We also thank S.N.
S. Ray, T. Chakraborty / Sedimentary Geology 151 (2002) 243271268
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7/27/2019 Braided Meandering Coastal India, Ray_chakraborty 2002
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Sarkar, S. Chakraborty and Sanjoy Ghosh for help
during the field work. A.K. Das drafted the line draw-
ings. We gratefully acknowledge the infrastructural
facilities provided by Indian Statistical Institute, andfinancial assistance received from the Department of
Science and Technology, New Delhi (Grant no. ESS/
23/VES/072/99) for the research work. The earlier
version of the manuscript benefited from the critical
comments from C. Chakraborty, P. Ghosh and S.N.
Sarkar. Thoughtful comments by Timothy Cross and
Chris Fielding and Chief Editor Andrew Miall helped
improve the manuscript considerably.
References
Alexander, J., Leeder, M.R., 1987. Active tectonic control of allu-
vial architecture. In: Ethridge, F.G., Flores, R.M., Harvey, M.D.
(Eds.), Recent Developments in Fluvial Sedimentology. Special
Publication - SEPM, vol. 39, pp. 243252.
Allen, J.R.L., 1965. The sedimentation and paleogeography of the
Old Red Sandstone of Anglesey, North Wales. Proceedings of
the Yorkshire Geological Society 35, pp. 139185.
Aslan, A., Autin, W.J., 1999. Evolution of the Holocene Mississippi
River floodplain, Ferriday, Louisiana: insights on the origin of
fine-grained floodplains. Journal of Sedimentary Research 69,
800815.
Bandyopadhyay, S., Sengupta, D.P., 1999. Middle Triassic verte-
brate of India. Journal of African Earth Sciences 29, 233 241.Banerjee, I., 1960. Stratigraphy and sedimentation in South Karan-
pura Coalfield, Bihar. Quarterly Journal of the Geological, Min-
ing and Metallurgical Society of India 36, 189203.
Bank, N.L., 1973. Origin and significance of some downcurrent-
dipping cross-stratified sets. Journal of Sedimentary Petrology
43, 423427.
Blair, T.C., Bilodeau, W.L., 1988. Development of tectonic cyclo-
therms in rift, pull-apart, and foreland basins: sedimentary res-
ponse to episodic tectonism. Geology 16, 517 520.
Blakey, R.C., Gubitosa, R., 1984. Controls of sandstone body geo-
metry and architecture in the Chinle Formation (Upper Triassic)
Colorado Plateau. Sedimentary Geology 38, 51 86.
Blum, M.D., Tornqvist, T.E., 2000. Fluvial response to climate and
sea-level change: a review and look forward. Sedimentology 47(Suppl. 1), 228.
Bown, T.M., Kraus, M.J., 1987. Integration of channel and flood-
plain suites: I. Development of the sequences and lateral rela-
tions of alluvial paleosols. Journal of Sedimentary Petrology 57,
587601.
Brenchley, P.J., Pickerill, R.K., Stromberg, S.G., 1993. The role of
wave reworking on the architecture of storm sandstone facies,
Bell Island Group (Lower Ordovician), eastern Newfoundland.
Sedimentology 40, 359382.
Brewer, R., Sleeman, J.R., 1964. Glaebules: their definition, classi-
fication and interpretation. Journal of Soil Sciences 15, 66 78.
Bridge, J.S., Smith, N.D., Trent, F., Gabel, S.L., Bernstein, P., 1986.
Sedimentology and morphology of a low-sinuousity river: Cal-
amus River, Nebraska Sandhills. Sedimentology 33, 851870.
Brierly, G.J., 1991. Floodplain sedimentology of the Squamish Riv-
er, British Columbia: relevance of element analysis. Sedimen-tology 38, 735 750.
Bristow, C.S., 1993. Sedimentology of the Rough rock: a Carbon-
iferous braided river sheet sandstone in northern England. In:
Best, J.L., Bristow, C.S. (Eds.), Braided Rivers, Geological So-
ciety Special Publication, vol. 75, pp. 291304.
Bristow, C.S., Best, J.L., 1993. Braided rivers: perspectivesand prob-
lems. In: Best, J.L., Bristow, C.S. (Eds.), Braided Rivers, Geo-
logical Society Special Publication, vol. 75, pp. 1 11.
Browne, G.H., Plint, A.G., 1994. Alternating braidplain and lacus-
trine deposition in a strike-slip setting: the Pennsylvanian Boss
Point Formation of the Cumberland basin, Maritime Canada.
Journal of Sedimentary Research B64 (1), 4059.
Buurman, P., 1980. Palaeosols in the Reading Beds (Paleocene) of
Alum Bay, Isle of Wright, U.K. Sedimentology 27, 593 606.
Casshyap, S.M., 1979. Patterns of sedimentation in Gondwana ba-
sins. In: Laskar, B., Raja Rao, C.S. (Eds.), IV International Gond-
wana Symposium, Delhi, India. Hindusthan Publishing, pp.
525551.
Casshyap, S.M., Qidwai, H.A., 1971. Paleocurrent analysis of Low-
er Gondwana sedimentary rocks, Pench valley coalfield, Mad-
hya Pradesh, India. Sedimentary Geology 5, 135146.
Casshyap, S.M., Qidwai, H.A., 1974. Glacial sedimentation of Late
Paleozoic diamictite, Pench valley coalfield, Central India. Bul-
letin of the Geological Society of America 85, 749760.
Chakraborty, T., 1999. Reconstruction of fluvial bars from the Pro-
terozoic Mancheral Quartzite, PranhitaGodavari Valley, India.
In: Smith, N.D., Rogers, J. (Eds.), Fluvial Sedimentology VI,International Association of Sedimentologists, Special Publica-
tion, vol. 28. Blackwell, pp. 449464.
Chakraborty, T., Chakraborty, C., Ghosh, P., 2000. Recognition and
analysis of fluvial deposits: a brief overview. Indian Journal of
Geology 72, 77 106.
Collinson, J.D., 1996. Alluvial sediments. In: Reading, H.G. (Ed.),
Sedimentary Environments: Processes, Facies and Stratigraphy.
Blackwell, Cambridge, USA, pp. 3782.
Crookshank, H., 1936. The geology of the northern slopes of the
Satpuras between the Morand and Sher rivers. Memoirs of the
Geological Survey of India 66 (2), 218.
Duchaufour, P., 1982. Pedology. Allen and Unwin, London, 448 pp.
Esteban, M., Klappa, C.F., 1983. Subaerial exposure environment.
In: Scholle, P.A., Bebout, D.G., Moore, C.H. (Eds.), CarbonateDepositional Environments. Memoir - American Association of
Petroleum Geologists, vol. 33, pp. 254.
Fedo, C.M., Cooper, J.D., 1990. Braided fluvial to marine transi-
tion: the basal lower Cambrian Wood Canyon Formation, South-
ern Marble Mountains, Mojave Deset, California. Journal of
Sedimentary Petrology 60, 220234.
Fielding, C.R., Webb, J.A., 1996. Facies and cyclicity of the Late
Permian Bainmedart Coal Measures in the Northern Prince
Charles Mountains, MacRobertson Land, Antartica. Sedimen-
tology 43, 295 322.
Fielding, C.R., Falkner, A.J., Scott, S.G., 1993. Fluvial response to
S. Ray, T. Chakraborty / Sedimentary Geology 151 (2002) 243271 269
-
7/27/2019 Braided Meandering Coastal India, Ray_chakraborty 2002
28/29
foreland basin overfilling; the Late Permian Rangal Coal Meas-
ures in the Bowen basin, Queensland, Australia. Sedimentary
Geology 85, 475497.
Friend, P.F., Slater, M.J., Williams, R.C., 1979. Vertical and lateral
building of river sandstone bodies, Ebro basin, Spain. Journal ofthe Geological Society 136 (1), 3946.
Friend, P.F., Raza, S.M., Geehan, G., Sheikh, K.A., 2001. Inter-
mediate-scale architectural features of Fluvial Chinji Formation
(Miocene), Siwalik Group, northern Pakistan. Journal of the
Geological Society (London) 158, 163177.
Goudie, A.S., 1983. Calcrete. In: Goudie, A.S., Pye, K. (Eds.),
Chemical Sediments and Geomorphology. Academic Press,
London, pp. 93 131.
Haszeldine, R.S., 1983. Fluvial bars reconstructed from deep
straight channel, Upper Carboniferous coalfield of northeast
England. Journal of Sedimentary Petrology 53, 12231247.
Haszeldine, R.S., Anderton, R., 1980. A braided facies model for
the Westphalin B Coal Measures of north-east England. Nature
5751, 5153.
Heller, P.L., Paola, C., 1996. Downstream changes in alluvial archi-
tecture: an exploration of controls on channel-stacking patterns.
Journal of Sedimentary Research 66 (2), 297306.
Hereford, R., 1984. Climate and ephemeral stream processes: twen-
tieth-century geomorphology and alluvial stratigraphy of the
Little Colorado River, Arizona. Geological Society of America
Bulletin 95, 654668.
Jorgensen, P.J., Fielding, C.R., 1996. Facies architecture of alluvial
floodbasin deposits: three dimensional data from the Upper Tri-
assic Callide Coal Measures of east-central Queensland, Aus-
tralia. Sedimentology 43, 479495.
Kar, R.K., 1976. Miofloristic evidences for climatic vicissitudes in
India during Gondwana. Geophytology 6, 230244.Khan, I.A., Bridge, J.S., Kappelman, J., Wilson, R., 1997. Evolution
of Miocene fluvial environments, eastern Potwar plateau, north-
ern Pakistan. Sedimentology 44, 221251.
Kraus, M.J., 1999. Paleosols in clastic sedimentary rocks. Earth-
Science Reviews 47, 4170.
Kraus, M.J., Middleton, L.T., 1987. Contrasting architecture of two
alluvial suites in different structural setting. In: Ethridge, F.G.,
Flores, R.M., Harvey, M.D. (Eds.), Recent Developments in
Fluvial Sedimentology. Special Publication - SEPM, vol. 39,
pp. 253 262.
Mackey, S.D., Bridge, J.S., 1995. Three dimensional model of al-
luvial stratigraphy: theory and application. Journal of Sedimen-
tary Research B65 (1), 731.
Makaske, B., 2001. Anastomosing rivers: a review of their classi-fication, origin and sedimentary products. Earth-Science Re-
views 53, 149 196.
Martinsen, O.J., Ryseth, A., Helland-Hansen, W., Flesche, H., Tor-
kildsen, G., Idil, S., 1999. Stratigraphic base level and fluvial
architecture: Ericson Sandstone (Campanian), Rock Springs Up-
lift, SW Wyoming, USA. Sedimentology 46, 235259.
McCabe, P.J., 1984. Depositional environments of coal and coal-
bearing strata. In: Rahmani, R.A., Flores, R.A.M. (Eds.), Sed-
imentology of Coal and Coal-Bearing Sequences International
Association of Sedimentologists, Special Publication, vol. 7.
Blackwell, Oxford, pp. 1342.
McCormick, D.S., Grotzinger, J.P., 1993. Distinction of marine
from alluvial facies in the Paleoproterozoic (1.9 GA) Burnside
Formation, Kilohigok basin, N.W.T., Canada. Journal of Sedi-
mentary Petrology 63 (3), 398419.
McKee, E.D., Crosby, E.J., Berryhill Jr., H.L., 1967. Flood deposits,Bijou Creek, Colorado. Journal of Sedimentary Petrology 37,
829851.
Miall, A.D., 1988. Facies architecture in clastic sedimentary basins.
In: Kleinspehn, K., Paola, C. (Eds.), New Perspectives in Basin
Analysis. Springer-Verlag, New York, pp. 67 81.
Michaelson, P., Henderson, R.A., Crosdale, P.J., Mikkelsen, S.O.,
2000. Facies architecture and depositional dynamics of the Up-
per Permian Rangal coal measures, Bowen Basin, Australia.
Journal of Sedimentary Research 70, 879895.
Midtgaard, H.H., 1996. Inner-shelf to lower-shoreface hummocky
sandstone bodies with evidences for geostrophic influenced
combined flow, Lower Cretaceous, West Greenland. Journal of
Sedimentary Research 66, 343353.
Mjos, R., Walderhaug, O., Prestholm, E., 1993. Crevasse splay sand-
stone geometries in the Middle Jurassic Ravenscar Group of
Yorkshire, UK. In: Marzo, M., Puigdefabregas, C. (Eds.), Allu-
vial Sedimentation. International Association of Sedimen-
tologists, Special Publication, vol. 17. Blackwell Scientific
Publication, Oxford, pp. 167 184.
Morozova, G.S., Smith, N.D., 1999. Holocene avulsion history of
the lower Saskatchewan fluvial system, Cumberland Marshes,
Saskatchewan-Manitoba, Canada. In: Smith, N.D., Roger, J.
(Eds.), Fluvial Sedimentology VI. Special Publication of the
International Association of Sedimentologists, vol. 28. Black-
well, Oxford, pp. 231249.
Nadon, G.C., 1994. The genesis and recognition of anastomosed
fluvial deposits: data from the St. Mary River Formation, South-western Alberta, Canada. Journal of Sedimentary Research B64
(4), 451463.
Nagtegaal, P.J.C., 1969. Microstructures in recent and fossil caliche.
Leidse Geologische Mededelingen 42, 131142.
Nandi, A., Raha, P.K., 1998. Palynoflora from Motur Formation,
Satpura Basin, Madhya Pradesh. Indian Minerals 52, 129 132.
Olsen, T., Steel, R., Hogseth, K., Skar, T., Roe, S.-L., 1995. Se-
quential architecture in a fluvial succession: sequence stratigra-
phy in the Upper Cretaceous Mesaverde Group, Price Canyon,
Utah. Journal of Sedimentary Research B65, 265 280.
Pedley, H.M., Frostick, L., 1999. Unravelling tectonic and climatic
signals in sedimentary successions. Journal of the Geological
Society (London) 156, 747.
Perez-Arlucea, M., Smith, N.D., 1999. Depositional patterns follow-ing the 1870s avulsion of the Saskatchewan River (Cumberland
marshes, Saskatchewan, Canada). Journal of Sedimentary Re-
search 69, 6273.
Rai, K.L., Shukla, R.T., 1977. Depositional environment and origin
of coal in PenchKanhan valley coalfield, M.P. India. In: Las-
kar, B., Raja Rao, C.S. (Eds.), 4th International Gondwana
Symposium, Geological Survey of India, Calcutta, pp. 265
277.
Raja Rao, C.S., 1983. Coal resources of Madhya Pradesh, Jammu
and Kashmir (Coalfields of IndiaIII). Bulletins of the Geo-
logical Survey of India A45, 1204.
S. Ray, T. Chakraborty / Sedimentary Geology 151 (2002) 243271270
-
7/27/2019 Braided Meandering Coastal India, Ray_chakraborty 2002
29/29
Rao, J.S., Sengupta, S., 1972. Mathematical techniques for paleo-
current analysis: treatment of direction data. Mathematical Geol-
ogy 40, 235248.
Reid, I., Frostick, L.E., 1987. Flow dynamics and suspended sedi-
ment properties in arid zone flash floods. Hydrological Pro-cesses 1, 239 253.
Reinfields, I., Nanson, G., 1993. Formation of braided river flood-
plains, Waimakariri River, New Zealand. Sedimentology 40,
11131127.
Retallack, G.J., 1990. Soils of the Past. Unwin Hyman, Boston,
520 p.
Robinson, P.L., 1967. The Indian Gondwana Formationsa review.
1st IUGS International Symposium on Gondwana Stratigraphy.
UNESCO, Buenos Aires, pp. 201268.
Rock-Color Chart Committee, 1980. The Rock-Color Chart, Dis-
tributed by Geological Society of America, Boulder.
Ruffel, A., Shelton, R., 1999. The control of sedimentary facies by
climate during phases of crustal extension: examples from Tri-
assic of onshore and offshore England and Northern Ireland.
Journal of the Geological Society (London) 156, 779789.
Schumm, S.A., 1993. River response to base-level change: impli-
cations for sequence stratigraphy. Journal of Geology 101, 279
294.
Smith, G.A., 1994. Climatic influences on continental deposition
during late-stage filling on an extensional basin, southwestern
Arizona. Geological Society of America Bulletin 106, 1212
1228.
Smith, N.D., Cross, T.A., Dufficy, J.P., Clough, S.R., 1989. Anat-
omy of an avulsion. Sedimentology 36, 123.
Smith, R.M.H., Turner, B.R., Hancox, P.J., Rubidge, B.S., Catu-
neau, O., 1998. Trans-Karoo II: 100 million years of changing
terrestrial environments in main Karoo basin. Guide BookGondwana 10 International Conference, University of Cape
Town, South Africa, 117 p.
Stear, W.M., 1983. Morphological characteristics of ephemeral
stream channel and overbank splay sandstone bodies in the
Permian Lower Beaufort Group, Karoo Basin, South Africa.
In: Collinson, J.D., Lewin, J. (Eds.), Modern and Ancient Flu-
vial Systems. International Association of Sedimentologists,
Special Publication., vol. 6, pp. 405420.
Tandon, S.K., Gibling, M.R., 1994. Calcrete and coal in Late Car-
boniferous cyclotherms of nova Scotia, Canada: climate and
sea-level changes linked. Geology 22, 755 758.
Thomas, R.G., Smith, D.G., Wood, J.M., Visser, J., Calverley-
Range, E.A., Koster, E.H., 1987. Inclined heterolithic stratifica-
tionterminology, description, interpretation and significance.
Sedimentary Geology 53, 123179.
Tiwari, R.S., 1996. Palynoevent stratigraphy in Gondwana sequenceof India. Gondwana Nine, 9th International Gondwana Sympo-
sium. Geological Survey of India, vol. 1, pp. 319.
Tornqvist, T.E., 1993. Holocene alternation of meandering and
anastomosing fluvial systems in Rhine Meuse delta (Central
Netherlands) controlled by sea-level rise and substrate erodibil-
ity. Journal of Sedimentary Petrology 63, 683 693.
Tunbridge, I.P., 1981. Sandy high energy flood sedimentation
some criteria for recognition, with an example from the Devon-
ian of SW England. Sedimentary Geology 28, 7095.
Tye, R.S., Coleman, J.M., 1989. Depositional processes and strat-
igraphy of fluvially dominated lacustrine deltas: Mississippi
delta plain. Journal of Sedimentary Petrology 59, 973996.
Veevers, J.J., Tewari, R.C., 1995. Gondwana master basin of pen-
insular India between Tethys and interior of Gondwanaland
Province of Pangea. Geological Society of America, 187.
Walker, R.G., Cant, D.J., 1984. Sandy fluvial system. In: Walker,
R.G. (Ed.), Facies Models, 2nd edn. Geoscience Canada Reprint
Series, vol. 1, pp. 23 31.
Werneburg, R., Schneider, J.S., 1996. The Permian temnospondyle
amphibians of India. Special Papers in Palaeontology 52, 105
128.
Williams, G.E., 1971. Flood deposits of the sand-bed ephemeral
streams of Central Australia. Sedimentology 17, 140.
Willis, B., 1993. Ancient river systems of Himalayan foredeep,
Chinji Village area, northern Pakistan. Sedimentary Geology
88, 176.
Wizevich, M.C., 1992. Sedimentology of Pennsylvanian quartzosesandstone of the Lee Formation, central Appalachian Basin:
fluvial interpretation based on lateral profile analysis. Sedimen-
tary Geology 78, 147.
Zaleha, M.J., 1997a. Intra- and extrabasinal controls on fluvial dep-
osition in the Miocene Indo-Gangetic foreland basin, northern
Pakistan. Sedimentology 44, 369390.
Zaleha, M.J., 1997b. Siwalik paleosols (Miocene, northern Paki-
stan): genesis and controls on their formations. Journal of Sedi-
mentary Petrology 67, 821839.
S. Ray, T. Chakraborty / Sedimentary Geology 151 (2002) 243271 271