Fossil Discoveries in India

Azmi, R. J.

doi:10.1126/science.282.5389.627c

Cited by 9 publications

(3 citation statements)

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“…In response to a claim for Mesoproterozoic animal trace fossils from the Lower Vindhyan Chorhat Sandstone at Chorhat (9), Rafat J. Azmi argued that the presence of Cambrian skeletal fossils in beds conformably overlying the Chorhat removed any need to postulate a Mesoproterozoic age (10). In the debate that followed (11)(12)(13)(14)(15)(16)(17)(18)(19), errors in Azmi's reports were taken to suggest that they were fundamentally flawed and that the skeletal fossils did not exist (20).…”

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confidence: 99%

The controversial “Cambrian” fossils of the Vindhyan are real but more than a billion years older

Bengtson¹,

Belivanova²,

Rasmussen

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

105

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The age of the Vindhyan sedimentary basin in central India is controversial, because geochronology indicating early Proterozoic ages clashes with reports of Cambrian fossils. We present here an integrated paleontologic-geochronologic investigation to resolve this conundrum. New sampling of Lower Vindhyan phosphoritic stromatolitic dolomites from the northern flank of the Vindhyans confirms the presence of fossils most closely resembling those found elsewhere in Cambrian deposits: annulated tubes, embryolike globules with polygonal surface pattern, and filamentous and coccoidal microbial fabrics similar to Girvanella and Renalcis. None of the fossils, however, can be ascribed to uniquely Cambrian or Ediacaran taxa. Indeed, the embryo-like globules are not interpreted as fossils at all but as former gas bubbles trapped in mucus-rich cyanobacterial mats. Direct dating of the same fossiliferous phosphorite yielded a Pb-Pb isochron of 1,650 ؎ 89 (2) million years ago, confirming the Paleoproterozoic age of the fossils. New U-Pb geochronology of zircons from tuffaceous mudrocks in the Lower Vindhyan Porcellanite Formation on the southern flank of the Vindhyans give comparable ages. The Vindhyan phosphorites provide a window of 3-dimensionally preserved Paleoproterozoic fossils resembling filamentous and coccoidal cyanobacteria and filamentous eukaryotic algae, as well as problematic forms. Like Neoproterozoic phosphorites a billion years later, the Vindhyan deposits offer important new insights into the nature and diversity of life, and in particular, the early evolution of multicellular eukaryotes.geochronology ͉ India ͉ Mesoproterozoic ͉ paleontology ͉ Paleoproterozoic

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mentioning

confidence: 99%

The controversial “Cambrian” fossils of the Vindhyan are real but more than a billion years older

Bengtson¹,

Belivanova²,

Rasmussen

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

105

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“…Accepting them as traces, given an underlying assumption that they must have been made by animals, would clash with the general absence of animal body fossils before the Ediacaran, and this perceived anomaly has influenced their interpretation. Thus reports of motile multicellularity in the early rock record (e.g., 6, 7) have met with one of two responses: The rocks have been misdated, or the fossils have been misinterpreted (e.g., 8,9). This is akin to a paleontological version of the Heisenberg uncertainty principle.…”

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confidence: 99%

New and Ancient Trace Makers

Bengtson

Rasmussen

2009

Science

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“…It hosts the thickest Proterozoic sedimentary succession of the Indian subcontinent, referred to as the 'Vindhyan Supergroup'. The Lower Vindhyan (Semri Group) and the Upper Vindhyan (Kaimur, Rewa and Bhander Groups) successions have been extensively studied in terms of palaeobiology (Azmi, 1998, Azmi et al, 2008Bengtson et al, 2009;Bengtson et al, 2017;De 2003De , 2006Kumar and Pandey, 2008;Kumar and Sharma, 2012;Kumar and Srivastava, 2003;Retallack et al, 2021;Seilacher et al, 1998;Sharma, 2006;Sharma andShukla, 2009a, 2009b;Srivastava, 2002Srivastava, , 2011Srivastava, , 2012 and geochronology (Bickford et al, 2017;Colleps et al, 2021;George et al, 2018;Gilleaudeau et al, 2018;Gopalan et al, 2013;Kumar et al, 2001;Kumar et al, 2002;Lan et al, 2020Lan et al, , 2021Malone et al, 2008;McKenzie et al, 2011;Mishra et al, 2018;Rasmussen et al, 2002;Ray et al, 2002Ray et al, , 2003Ray, 2006;Sarangi et al, 2004;Tripathy and Singh, 2015;Turner et al, 2014) to constrain their depositional ages. Robust geochronological constraints based on zircon ages of the tuffaceous unit of Semri Group (Fig.…”

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confidence: 99%

Detrital zircon U-Pb ages of Proterozoic and Cretaceous sandstones of Narmada region in Central India: Implications for provenance and the closure age of the Vindhyan Basin

Kumari¹,

Tandon²,

Kallukalam³

et al. 2023

Preprint

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This study presents detrital zircon U-Pb ages of the Upper Bhander Sandstones from the Bhopal inlier, and the overlying Cretaceous sandstones from Jabalpur, Central India. These data are combined with existing palaeobiological evidence to address the issue of lack of convergence between geochronology and biochronology of the Upper Vindhyan succession in central India. The age-spectra of Upper Bhander Sandstone show the dominance of detrital zircon population between 1500-1900 Ma, a subordinate cluster of 2400-2600 Ma, and a single youngest zircon grain of ~770 Ma. These detrital zircon ages correlate with the timing of granite magmatism in Bundelkhand, Aravalli and Central Indian Tectonic Zone (CITZ), implying their derivation from these terranes. The finding of a single zircon of 770 + 12 Ma, supports the premise that Vindhyan deposition extended in to the late Tonian. Cretaceous sandstones of the Jabalpur and Lameta Formations contain zircon grains of ~550 Ma and ~700-800 Ma age. Except for the evidence from this youngest Vindhyan sedimentary sequence, no rocks of Late Neoproterozoic-Early Cambrian age have so far been reported from Central India, which can be correlated with these zircon ages. Comparable age-spectra of the Upper Bhander and the Cretaceous sandstones indicates that the proximal Vindhyan sandstones could have supplied detritus to these younger sandstones. These Cretaceous sandstones also constitute a window to understand the geology of the pre-Cretaceous eroded terrain, and support the premise that the Vindhyan sedimentation did not terminate at 1000 Ma.

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Fossil Discoveries in India

Cited by 9 publications

References 1 publication

The controversial “Cambrian” fossils of the Vindhyan are real but more than a billion years older

The controversial “Cambrian” fossils of the Vindhyan are real but more than a billion years older

New and Ancient Trace Makers

Detrital zircon U-Pb ages of Proterozoic and Cretaceous sandstones of Narmada region in Central India: Implications for provenance and the closure age of the Vindhyan Basin

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