Siwalik Fauna – Geology Notes – For W.B.C.S. Examination.
শিবালিক প্রাণিকুল – ভূতত্ত্ব নোট – WBCS পরীক্ষা।
The Tatrot and Pinjor faunas belonging to the Upper Siwalik Subgroup are well known from Pakistan, India and Nepal. The faunas along with proposed biostratigraphic interval-zones/range-zones/faunal-zones for the Upper Siwalik Subgroup of Potwar Plateau, Mangla-Samwal area and Pabbi Hills (all in Pakistan), Chandigarh-Jammu regions (India), and Surai Khola, Rato Khola and Kathmandu Valley (all in Nepal) are discussed. Despite the presence of a two-million year unconformity at the base of the Tatrot Formation, the type locality has yielded rich Tatrot Fauna.Continue Reading Siwalik Fauna – Geology Notes – For W.B.C.S. Examination.
The Mangla-Samwal, Chandigarh-Jammu, Surai Khola and Rato Khola areas have yielded both Tatrot and Pinjor faunas, whereas Pabbi Hills and Lokhundol Formation of the Kathmandu Valley have yielded Pinjor Fauna. The Pinjor Fauna is well developed in the type locality of Chandigarh as compared to other localities in Pakistan, India and Nepal. In the last five decades, 54 characteristic taxa for the Pinjor Fauna are recorded from the Chandigarh region. In Pakistan, abundant magnetostratigraphic data are available and workers clubbed mammalian taxa and proposed biostratigraphic zones for the Middle and Upper Siwalik subgroups. However, the rich Tatrot and Pinjor faunas are known from the Chandigarh and Jammu regions, but magnetostratigraphic data are scanty. Two biostratigraphic interval-zones, Elephas planifrons Interval-Zone (3.6-2.6Ma) and Equus sivalensis Interval-Zone (2.6-0.6 Ma), are recognized for the Indian Upper Siwalik. In Nepal, scanty Tatrot and Pinjor faunas are developed and the associated magnetostratigraphic dates do not tally with the recovered characteristic mammalian taxa. Thus, it is not possible to recognize the interval-zones in Nepal.
The red bed sequence of the Lower Siwaliks around Ramnagar and the Nagrota Formation of the Upper Siwaliks in the Uttarbeni–Parmandal section are the two highly fossiliferous intervals of the Siwaliks of Jammu Sub-Himalaya, India. The Lower Siwalik mammalian fauna of Ramnagar is best represented in its upper 350 m interval. Small and medium sized forms, mostly belonging to browsing species, dominate the mammalian assemblage. The Ramnagar fauna represents the Chinji mammalian fauna (Middle Miocene) of the Potwar Plateau, Pakistan. The assemblage indicates a woodland-type ecosystem having substantial forest component and subordinately developed grassy subareas.
The mammalian fauna of the Nagrota Formation in the Uttarbeni–Parmandal section, in contrast, exhibits relatively low species diversity, but considerable increase in the mean body size and progressive hypsodonty of the cheek teeth in the herbivores. This becomes more pronounced above the 2.5 Ma old volcanic tuff layers occurring at the middle of the formation. Broadly, a savanna-type ecosystem is indicated by the mammalian communities of Nagrota Formation, which appears to have been dominated by grassland communities above the tuff zone. The above-tuff faunal zone of the Nagrota Formation can be correlated with the Pinjor faunal zone (Plio-Pleistocene) of the Siwalik Hills, Punjab.
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