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Vertebrates of Siwalik
Shishir BhardwajM.Sc. Applied Geology
Distribution of Siwalik rocks
Formation of Siwalik basin
General Stratigraphy of Siwalik Group
Lithostratigraphy of Siwalik Group
Sub- phylum Vertebrata
Vertebrate fossil and its Application to Earth Science Research
Vertebrate Fauna in Siwaliks
Climate conditions and Life in Siwaliks
Topics of discussion:
Distribution of Siwalik Rocks
How and when Siwalik basin was formed ???
Activation of MBT – 18.3 Ma Span of sedimentation – 16 to 5 MaRemained repository for detritus until 0.22 Ma
Reactivation of MBT, involving riding of lesser Himalayan rocks on the Sirmaur basin, which was accompanied by the sagging of the crust immediately to the south of rising mountain front
Geological Time scale
Classification of the Siwalik Group
Standard European Equivalent
Age calculated from reversal stratigraphy (in Ma)
Continental equivalent
Pleistocen
e
Pliocene
Miocene
Upper Siwalik
Boulder conglomerate Pinjor Tatrot Dhok Pathan Nagri Chinji Kamlial Muree Group
Cromerian Villafranchian Astian Pontian Sarmatian Tortonian Helvetian Burdigalian
0.5 to 1.5 2.47 5.5 8.5 10.8 14.3 18.3
? Mid-late Villafranchian Early Villafranchian –Ruscinian Turolian L. VellesianE. Turolian Oeningian Pre- Oeningian
Middle SiwalikLower Siwalik
Chronostratigraphic division of Siwalik Succession(Source: Tandon et al. 1998)
Subgroup
Lithology ~Thickness
Upper Siwalik
Predominantly massive conglomerate with red and orange clay as matrix and minor sandstone and earth buff and brown shale
Sandstone, clay and conglomerate
alteration.
2300m
Middle Siwalik
Massive sandstone with minor conglomerate and local variegated shale
Predominantly medium to coarse-
grained sandstone and red clays alteration, soft pebbly with subordinate shale, locally thick prism of conglomerate
1400m to 2000m
Lower Siwalik
Alteration of fine to medium- grained sporadically pebbly sandstone, calcareous cement and prominent chocolate and maroon shale in middle part
Red and mauve shale with intercalations
of medium to fine grained sandstone
1600m
Lithostratigraphy of Siwalik Group (after Karunakaran and Ranga Rao, 1976)
• Fluvial sequence deposited by some contemporaneous Himalayan river (Indo- Brahm River by Pascoe)
Types of depositional environment
Piedmont Outwash Plains
Channel and flood deposit lacustrine
Immature
• The Chordates having flexible vertebrae are known as Vertebrates.
• The sense organs are mostly concentrated in anterior part, situated with a bony case called Skull which is articulated with vertebrae column.
Sub- Phylum Vertebrata
Vertebrate Fossil: Introduction
Fossils are disarticulated in nature.
Most durable parts are commonly preserved as fossils of vertebrates are their bones, teeth and footprints.
• Evolution of different modern species.
• Useful for correlation purpose in CONTINENTAL regions.
• Paleoclimatology, Paleobiogeography, and Paleoecology
• History and Culture
Application in Earth Science Research
Vertebrate Fauna in Siwaliks
Taphonomical features of Fossils in Siwalik region.
Siwalik equivalent in NE part of India is comparatively unfossiliferous.
Vertebrates
Pisces
Tetrapoda
Amphibians
Reptilians
Crocodiles
Tortoises
Squamates:Lizard and
SnakeBirds
Mammals
Insectivora
Primates
Carnivora
Rodentia
Lagomorpha
Ungulates
Ungulates
Perissodactyla
Suidae
Anthracoteriidae
Hippopotamidae
Camelidae
Tragulidae
Cervidae
Giraffidae
Bovoidea
Artiodactyla
Tapiridae
Rhinocerotidae
Equidae
Proboscidea
warm and humid
Tropical evergreen trees
Pigs, elephant, carnivores and artiodactyles
Flood and piedmont deposit
Baluchitherium
Lower Siwalik : 18.3 – 11.5 Ma
Climatic conditions and Life in Siwaliks
Colossochelys atlas Gomphotherium
Oblique left lateral view of thecranium of modern Pongo pygmaeusand Late Miocene Sivapithecus indicusfrom Pakistan. Photo by C.Tarka.(pg. 1198 encyclopedia of human evolution)
Middle Siwalik : 11.5 – 5.1 Ma
Reactivation of MBT and MCT
Uplift of Himadri
Onset of Monsoon
Encroachment of Grass lands
Grass land attracted grazing animals from neighbouring lands
Invasion of exotic fauna (mainly four footed) in Potwar basin
Hipparion antelopinum (3 toed horse)
Hexaprotodon sivalnesis (Hippopotamus)
Deinotherium Giganteum
Vishnutheriun
Upper Siwalik: 5.1- 1.6 Ma
Tropical forest completely replaced by Savannah- type, grassy plains dotted sparsely with trees
Grazing and browsing animals became dominant
Macacus monkeys, and the semia & Semnopithecus apes
Carnivores tigers, hyenas, panthers and cats
The elephants Mastodon sivelensis, Stegodon ganesa
The giraffes Indratherium & Sivatherium
The ungulates rhinos, horses, hippopotami, boars and camels
The Artiodactyles deer, buffaloes, cows, bisons
Stone artefacts show clue for the presence of human –like primate but no body remains have so far been found anywhere in Siwalik.
Stegodon sivalensis Elephas ganesa
Mastodon sivalensis Skull of Sivatherium
• Key Faunal Events:
* Prior to 18 Ma- Establishment of Siwalik Fauna
* 18-14 Ma – Bovids and other ruminants, large hervivores, muroids, cricetidae (deer) dominant
* 14- 9.5 Ma – appearance of Hominids, horses appeared, muroid dominant
* 7.5- 6.5 Ma – Siwalik fauna becomes similar to Eurasia, Sivapitecus become extinct, Deinotherium, Brachytherium, Hystrix (porcupine), Giraffine, Cercopithecids (old world monkeys)
* 7.4 Ma onwards- larger homonids Gigantopithecus disappeard, change environment & climate become arid
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