Research Projects

Molar-Tooth Structures (MTS) are crack-filled fabric, often ptygmatically folded, restricted to Meso-Neoproterozoic carbonate rocks, remained a long-standing enigma in carbonate sedimentology. Their worldwide but time-restricted occurrences, uniformity in crystal size, and formation near the sea floor suggest multiple hypotheses for their origin. Proposed mechanisms include earthquake- or storm-induced liquefaction, sediment dewatering, CO₂ clathrate decomposition, global tectonics, unique ocean chemistry, and microbial contributions. However, early cementation appears essential for crack preservation, as evidenced by the absence of any detrital infilling. MTS show a distinct time-bound occurrence that coincides with major changes in Earth's biogeochemical cycles, the proliferation of microbial mats, and the earliest evidence for multicellular life. The question is why this interval differs from those before and after, remains unresolved. Identifying MTS formation mechanisms could not only elucidate these differences but also inform us about the preconditions for the emergence of multicellular life. In India, the Mesoproterozoic Rohtas and early Neoproterozoic Bhander Limestones of the Vindhyan Supergroup in the Vindhyan Basin (Central India), and the Late Neoproterozoic Mangurda Limestone of the Penganga Group in the Pranhita-Godavari Basin (South India), are notable for their extensive development of MTS. Despite their abundance and wide temporal distribution, Indian MTS remain vastly understudied (Sarkar & Bose, 1992; Bose et al., 2012). In the Neoproterozoic Bhander Limestone, MTS commonly occur between stromatolitic horizons, suggesting a close link with the waxing and waning of microbial buildups. These stromatolites typically exhibit cyclicity with alternating dark and light laminae. In contrast, MTS in the Mesoproterozoic Rohtas Limestone are not associated with stromatolites. In the Late Neoproterozoic Mangurda Limestone, MTS lie above a thick stromatolitic horizon (Sarkar & Bose, 1992). This pattern indicates that the occurrence of MTS during microbial mat proliferation across diverse marine facies may not be incidental. The distinctly different depositional associations across three stratigraphic units spanning the Mesoproterozoic to Late Neoproterozoic within the Vindhyan and Pranhita-Godavari basins will be investigated to evaluate MTS genesis, stratigraphic context, and paleoenvironmental implications, while testing their linkage with microbial proliferation and the evolutionary backdrop of multicellular life. The research aims to address key questions about MTS formation, including their driving mechanisms, biogeochemical influences, and temporal confinement to the Proterozoic. It also explores their implications for reconstructing ancient seawater chemistry, Proterozoic paleoclimate, and depositional environments during critical periods of Earth's evolutionary history and also Precambrian geobiological evolution.