JOURNAL OF SEDIMENTARY PETROLOGY, VOL. 46, NO. 1, P. 234-239
FIGS. 1-5, MARCH 1976
Copyright © 1976, The Society of Ecenomic Paleontologistsand Mineralogists
T R A C E FOSSILS I N T H E L O W E R T A L F O R M A T I O N
MUSSOORIE AND THEIR
ENVIRONMENTAL
OF
SIGNIFICANCE 1
D. M. B A N E R J E E AND M. J. NARAIN
Department of Geology, University of Delhi, Delhi-ll0007 (India)
ABSTRACT: In the course of lithological mapping of the Krol-Tal succession near Mussoorie
in Garhwal Himalaya, a variety of trace fossils have been recorded, occurring as ridge like
epireliefs in the Lower Tal micaceous sandstones. So far, only two variety of trails have
been identified, boil1 belonging to ichnogenus ,4ulichnites. A comprehensive study of lithological variations, sedimentary structures, fossils, and close association with shallow-water
marine phosphorites in the area, together with the distribution of trace fossils vis-a-vis the
types of sandstone has given an indication of depositional conditions prevailing at the time
of deposition of Lower Tal sediments.
INTRODUCTION
Geological mapping in the Mussoorle area of
Garhwa] Himalaya has revealed several trace
fossils in the middle and upper layers of the
subgreywacke and micaeeous sandstone, belonging to the Psammitic and Pelitic Members
of the Lower Tal Formation (Table 1). The
best preserved section is exposed along the
Mussoorie-Tehri Road and the trace fossils are
seen between Batagad and Masrana (Fig. 1).
These animal trails occur as ridges and grooves
with positive epirelief and rarely as passively
filled full reliefs.
Sediments of the Lower Tal Formation have
recently acquired economic significance due to
discovery of sedimentary phosphorite in its
lower part, associated with bedded chert, carbonaceous shale, and phyllites. Mode in which
the bedded phosphorites originate has always
been a debatable subject. It is however presumed that these phosphorites were formed in
shallow parts of the ocean basin, in view of the
association of oneolites and stromatolitie structures in the related sediments. The Lower Tal
Formation is believed to be Middle Jurassic and
Lower Cretaceous on the basis of scanty fossils.
Auden (1934) discovered some poorly preserved
molluscs in Upper Tal sediments, and Wadia
(1953) reported belemnite, coral, and gastropod
assemblage of Jurassic age without commenting
on specific morphologies. Black shales of the
Pelitic Member of the Lower Tal Formation
1Manuscript received December 27, 1974; revised
April 24, 1975.
234
near Surkhet, southeast of Mussoorie has
yielded Posidonia ornati, a pelecypod of Jurassic
age (Srivastava, 1963). Some crustaceans
(Esteria maryinata Defretin) from the Bagi
area, located east of Surkhet, probably indicate
a Neocomian age for the Pelitic Member. Gansset (1964) noted "vermicular tubes" in the
Upper Tal shales, without specifying what these
tubes are.
The Upper Tal Formation is predominantly
arenaceous and consists of rippled and crossbedded arkoses and orthoquartzites in the lower
part, while the uppermost part is made up of
lumachellh type limestone containing badly preserved lamellibranch, coral, and gastropod shells.
This limestone passes into the Subathu Limestone (Tertiary). The lower limit of the Tal
Formation is conventionally put below the
phosphate-chert member, which overlies the
Upper Krol Dolomite with localized disconfortuities. However, there is growing feeling
and evidence in favor of considering the KrolTal boundary as continuous, without any break
(Patwardhan and Ahluwalia, 1973).
The record of trace fossils from the Lower
Tal Formation is significant, because it reflects
the burrowing activities of the clams, snails and
related biota during the deposition of Lower
Tal sediments. Like the poor body fossil assemblage, the trace fossils are also scanty and
of restricted occurrence. The litholog (Fig. 2)
shows the vertical distribution of Tal sediments,
fossils, biogenic structures, common physical
sedimentary structures, grain size frequency,
and probable depth of sedimentation.
TRACE FOSSILS IN L O W E R TAL F O R M A T I O N
235
TAI~LE 1.--Stratigraphie succession in Mussoorie Area
Thickness
Upper Tal
Formation
Lower Tal
Formation
Upper Krol
Formation
Shelly calcareous grit.
Quartzite, arkose, grit and shale.
..............
Local Disconformity . . . . . . . . . . . . . . .
Calcareous Member
-Ferrugenous limestone and calcarenite.
Psammitic Member
-Subgreywacke, siltstone, micaeeous
sandstone shale.
-Silty shale, siltstone, black micaceous
Pelitic Member
sandstone and shale with pyrite.
-Phosphate-pelletal bedded and reworked
Phosphate-chert Member
with chert layer.
Bedded chert.
-Argillaceous limestone with brecciation
Transition Zone
and stromatolites.
Dolomite, limestone
and red shales
Description of Trace Fossils
These trails occur as positive epireliefs on
jointed and fractured micaceous sandstone surfaces (Fig. 3) thereby making it difficult to
collect a complete specimen. In cross-section,
mica flakes lie in a plane normal to the course
of the trail and oblique to the bedding. Along
the sides, the mica flakes stand vertically and
parallel with the trail (Fig. 4a). The trails are
0.5 to 1 cm deep and 3 cm wide, and may taper
to 2.5 cm on the ends; observed length is about
60 cm. By gentle tapping the positive epirelief
can be removed to expose the negative epirelief,
and in this process the median discontinuity
plane breaks the structure into two symmetrical
halves. The trails are straight to smoothly
arched. The median discontinuity plane is
formed by the assymmetrically sloping epirelief,
which shows steeper slopes of the two lobes on
the same side. In some specimens, a lateral
discontinuity plane is also present.
Another variety of trail has been recorded
in this area with uniform width of 3.75 cm
throughout their 40 to 75 cm length (Fig. 5)
consisting of two equal parts with straight to
slightly meandering structure. The median discontinuity plane is formed ,by the junction of
two gently sloping surfaces of the convex
epirelief (Fig. 4b). The relief depth is 1 cm.
The structure looks as if a pair of half tubes are
lying obliquely by their sides. Our field observations indicate that these trails invariably
occur crossing each other and it was felt that
the older trail is displaced upward by the
younger trail, without any damage to the older
structure. However, after studying the photographs and sketches of these trails, R. W. Frey
(Personal communication, 1975) suggested that
20 m
1,300 m
5m
500 m
150 m
10-40 m
200 m
the reverse should be true. In his opinion, it is
the upper trail which is younger, and this
juxtaposition is merely the place where a later
formed trail crossed over the earlier formed
one. The older trail was not obliterated at the
junction simply because they were semi-consolidated by mucous etc. and therefore more
firm than the surrounding sediments.
The curved shape of these bilobate trails may
have been the result of displacement of moving
snail from its straight course down the southeasterly dip of the bed which coincides with the
local sediment transport direction, as indicated
by current ripples and cross laminations.
Remarks : - - T h e specimen can be compared with
Rouaultia de Tromelin, 1877 (Hiintzschel, 1962),
but differ from it in their greater width ( > 1
cm) and indistinct lateral furrows. Similar
forms have been reported from the Bhander
Limestone (Upper Vindhyan) of Rewa District
and named as Rouaultia rewanensis n. sp. by
Verma and Prasad (1968). Nereites sp. (Crimes,
1970, p. 104, plate 1,b) from the Lower Cambrian to Silurian turbidites of Welseh and
Leinster sequences has fairly close physical resemblance with the trails described here. However Nereites belong to a vastly different facies.
Glaessner (1969, p. 388-389, Fig. 9c) used the
invalid name Rouaultia de Tromelin (Hiintzsche], 1965, p. 80) for one of his specimen from
the Arumbera Formation (lower Paleozoic) of
Australia. This form has close similarity with
the two ichnospecies described above. However,
the closest comparison could be made with
ichnogenus Aulichnites Fenton and Fenton, 1937
(HS.ntzschel, 1962) characterized by bilobate
trails and simple body structure. The authors
236
D. M. B A N E R / E E A N D M. Y. N A R A I N
Index
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@ TRACE
FOSSIL LOCATION
l.--Geological sketch map of a part of Mussoorie Synform showing location of trace fossil occur(@). Legend: 1. Limestone, dolomite and argillaceous limestone. 2. Phosphorite with bedded
3. Silty shale• 4. Subgreywacke, siltstone, micaceous sandstone. 5. Calcarenite and ferruginous lime6. Calcareous grit, quartzite and green shale.
had considered the two types of trail described
here as belonging to two distinct ichnogenera.
This was however not true. R. W. Frey (Pers.
Comm., 1975) suggested that both the trace
fossils belong to a single ichnogenus Aulichhires. The assymmetry of the first ichnospecies
is probably the result of current drift which
could not affect the second type of trace fossil
because of their formation at quieter moments
of sedimentation.
Bathymetric considerations and the distribution of the body fossils in sediments indicate
that these Aulichnites trails may have been
caused by snail like animals.
E N V I R O N M E N T
OF
DEPOSITION
Trails described in this paper have been recorded only from thickly bedded mieaceous
sandstone (subgreywacke) of the Psammite
Member of the Lower Tal Formation. The sub-
F:G. 2.--Litholog showing relationship between different observed parameters used for environmental
interpretation. Legend: 1. Fossiliferous limestone. 2. Calcareous shaly quartzite. 3. Shaly and phyllitic
quartzite. 4. Subgreywacke. 5. Orthoquartzite. 6. Carbonaceous shale. 7. Shale and phyllite. 8. Bedded
chert. 9. Pelletal phosphorite. 10. Bedded phosphorite with chert. 11. Calcarenite. 12. Reworked phosphorite
TRACE FOSSILS /N LOWER TAL FORMATION
LITHOLOG
SHOWING
PARAMETERS
RELATIONSHIP B E T W E E N D I F F E R E N T
OBSERVED
FOR E N V I R O N M E N T A L I N T E R P R E T A T I O N '
USED
Primary
Sedimentary
Structure
~
237
LE GE NO
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and frag'mental dolomite. 13. Stromatolitic dolomite. 14. Krol Dolomite. 15. Irregular sharp contact. 16.
Transition gradual but rapid. 17, Distinct flat contact. 18. Gradual transitional contact. 19. Transition gradual but hardly visible. 20. Irregular with gradual transition, 21. Lenticular wavy laminations. 22. Cross
bedding. 23. Striations, 24. Current tipples 10-20 cm Wave Length ( < 5 cm high). 25. Wave tipple
lamination with pointed top. 26. Mud cracks. 27. Disrupted parallel lamination, 28. Lenficular lamknae. 29.
Load cast, 30. Lenticular wavy bedding (1-5 m). 31. Lenticular wavy Bedding (:> 5 m). 32. Concretions
( < 5 cm). 33. Nodules. 34, Dendrites. 35. Fragmental inclusions. 36. Trails (parallel to bedding).
37. Trails (cutting across the bedding), 38. Stromatolific algal structures. 39, Fossil fragments. 40.
Echinoids. 41. Corals. 43. Lamellibranchs. 43. Gastropods. 44. Coarse sand 2-0.5 ram. 45. Medium sand
0.5-0.25 mm. 46. Fine sand 0.25-0,0625 ram. 47. Silt 0.0625-0.004 ram, 48. Clay < 0.004 ram.
238
D. M. B A N E R J E E
AND
3I. J. N A R A I N
FIG.
3.--Bilobate trail of slightly assymmetrical
Aulichnltes in micaceous silty sandstone showing
convex epirelief (hammer gives scale).
greywacke type of rocks are interlayered with
reddish green to chocolate colored shaly layers.
The thin arenaceous interbedded layers (2-3 cm
thick) show profuse development of current
ripples, many displaying interference pattern.
The first type of trail was found amidst thinly
laminated sandy layers that show ripple-drift
cross-laminations in vertical section. Some of
the layers higher up in the sequence show smalI
load casts and convolution of ripple laminations.
Mica flakes & sand
Course of
Bedding
~on
Course of
trail
Bedding
Median
Mica
flakes & sand
B
Fro. 4.--a. Sketch o{ vertical cross section of the
assvmmetrical trail showing sand grains and mica
flake orientation, h Sketch of vertical cross section
of undisturbed Aulichnites trail showing mica flake
orientation and position of median and slope of the
ridges
F1G. 5.---Undisturbed Aulichnites trail showing
overriding relationship--(hammer gives scale).
Thin, graded layers also occur sparingly in the
lower part of the sequence, characterized by
thin, parallel laminations. This assemblage of
sedimentary structures perhaps reflect the deposition of these subgreywacke-type sediments
in the depth zone characteristic of midway between near-shore and distal turbidite environments. Detailed study of similar environments
have been carried out in other parts of the
world (Crimes, 1973). The second variety of
trail occurs a little higher in the sequence in
an almost identical lithology but lacking in
mud-rich shaly layers. The sandstones containing this form show a higher order of sorting,
uniform grain size (0.10 ram), well preserved
oscillation ripple marks, and they indicate a
transition to, and interlayering with, detrital,
bluish-grey limestone and marl. The overlying
sediments were probably deposited in shallow
water tidal flats with typical sedimentary structures. Association of such environmental conditions with abundant Aulichnites trails represents the Cru~iana facies of Seilacher (1962)
and Crimes (1970).
The overlying Upper Tal Formation is predominantly composed of littoral sediments (orthoquartzite, arkosic sandstone, fragmental and
detrital limestone, etc.) with well-preserved
shallow-water primary sedimentary structures.
The lower part of the Lower Tal Formation is
characterized by a chert-shale phosphorite association, which reflects a partly reducing environment in shallow marine waters ; it is represented by reworked phosphate pellets, perfect
to near perfect rounding of grains, and presence
of oneolites and stromatolites in the transitional
zone.
TRACE FOSSILS IN LOWER
Such rapid fluctuations of water depth from
midway between proximal and distal turbidite
zones to shallow tidal flat environments perhaps
suggest very unstable shelf conditions during
the Krol-Tal sedimentation, in which repeated
marine transgression and regression were related to the local tectonic movements.
ACKNOWLEDGMENTS
W e are grateful to Dr. Robert W. Frey of
University of Georgia, U.S.A., for identification
of the trace fossils, critical review of the manuscript and m a n y useful suggestions for the improvement of the paper and to Shri K. K. V e r m a
of the Geological Survey of India and Dr. S. B.
Bhatia of Chandigarh University for initial
help with identification. Shri V. Ramesh prepared the sketches and helped d u r i n g the field
work. Financial assistance from W a d i a Institute of H i m a l a y a n Geology, Delhi for the field
trip is thankfully acknowledged.
REFERENCES
AUDEN, J. B., 1934, The geology of Krol Belt:
Records, Geol. Survey India, v. 67, p. 461--471.
CRIMES, T. P., 1970, The significance of trace fossils
in sedimentology, stratigraphy, and palaeoecology
with examples from Lower Palaeozoic strata: in
Crimes, T. P., and J. C. Harper (eds.), Trace
TAL FORMATION
239
Fossils, Geol. Jour. Special Issue No. 3, Liverpool, p. 101-126.
, 1973, From limestone to distal turbidites: A
facies and trace fossil analysis in the Zumaya
flysch (Paleocene-Eocene), North Spain: Sedimentology, v. 20, p. 105-131.
GANSSER, A., 1964, Geology of the Himalayas, Interscience Publ. Co., New York, p. 85-91.
GLAESSNER, M. F., 1969, Trace fossils from the
Precambrian and Cambrian: Lethaia, v. 2, p.
369393.
H~NTZSCHEL, W., 1962, Trace fossils and problematiea: in Moore, R. C. (ed.), Treatise on Invertebrate Paleontology, Part W (Mist) Geol.
Soc. America, p. W177-W245.
, 1965, Vestigia invertebratorum and problematica, Foss. Cat. No. 108.
PATWARDHAN, A. M., AND A. D. AHLUWAL~A, 1973,
A note on the Origin of Mussoorie Phosphorite
in the Lower Himalaya, India and its Paleogeographic Implications: Mineral. Deposita, v.
8, p. 379-387.
SELACHER, A., 1964, Biogenic sedimentary structures: in Imbrie, J., and N. D. Newell (eds.),
Approaches to Palaeoecology, J. Wiley and Sons,
New York, p. 296-316.
SRIVASrAVA, R. N., 1963, Fossil lamellibranchs from
the Lower Tal Shales of Mussoorie-Dehradun
area, U.P.: Geol. Survey India Misc. Pub. No.
15, p. 269-272.
VERMA, K. K., AND K. N. PRASAD, 1968, On the
occurrence of some trace fossils in the Bhander
Limestone (Upper Vindhyau) of Rewa District,
M.P.: Current Science, v. 19, p. 557-558.
WADIA, D. N., 1953, Geology of India, Macmillan,
London, p. 422---425.