Abstract
The Journal of Palaeontological Society of India has often been a popular medium to propagate the proceedings of the Indian Colloquium on Micropalaeontology & Stratigraphy (ICMS), the biennial, national micropalaeontological festival of India. The 28th Colloquium marking 50 years of completion of this meeting was hosted by Savitribai Phule Pune University from 4th to 6th May 2022. Identifying the need to diversify and reinvent ways in which microfossils and stratigraphy could be applied in Earth & Environmental studies, the theme of this meeting was ‘Proxy Development for Decoding Past & Modern Environments’. The present issue of the JPSI is a compilation of selected 15 peer-reviewed research papers presented during the Colloquium, encompassing proxies from palynology to trace fossils, geological time periods from Cretaceous to Recent and geographical localities from the Himalayas to the Lakshadweep.
The issue enlists research work from the northern tip of India to its southern edge. Bhandari et al. (147) study the fossil assemblage from the mudstone units of the Siwalik Group exposed in the Doon Valley, Mohand, in the western Himalayas and document the geographic range of a murine mouse lineage 500 km southeast of its type area in the Potwar Plateau of Pakistan. Tripathy and Pandey (154) precisely observe the behavioural pattern of modern pollen deposition in diverse vegetation and depositional settings of the Barak Valley of Assam from the Indo-Burma Region, with an aim to develop a modern pollen analogue to interpret land-use-land-cover changes in palaeodepositional data for the region. Narsimha et al. (173) present a detailed palynological study of Pre-Tura sediments from 14 wells, to establish biostratigraphy in Dhansiri Valley of Upper Assam Shelf, Assam and Assam-Arakan Basin. They identify Early Permian, Early Cretaceous and Late Maastrichtian sedimentary sequences with intervening unconformities, having different tectonic history and their distinct palynofossil assemblages. Lokho et al. (188) present the first report of two Middle Eocene echinoid taxa from the Sylhet Limestone of Mikir Hills, Assam expanding the geographical extension of Eocene marine echinoids in the northeastern part of India. It offers evidence that the Neotethys Sea was connected through south-western and southern France, NE of Spain, Southern Austria, the Venetian region of Italy Province, Croatia, the Persian Gulf, Oman and Egypt Sindh province of Pakistan and Madagascar during the Middle Eocene. Palynological investigations by Geddada and Narsimha (199) describe Early Cretaceous dinoflagellate cysts and diagnostic spore-pollen assemblage from JM-A Well drilled by ONGC in the Dhansiri Valley of Upper Assam Shelf, providing a point of biostratigraphic and chronological correlation with other wells in the region. Panchang et al. (207) report spatial distribution of 18 pteropod taxa from the low saline regions of Ayeyarwady Delta Shelf placing the region on the world ocean floor map of aragonite deposition. Trivedi et al. (217) describe the spatial distribution of Recent pollen from the Shimla Water Catchment Sanctuary at Kufri, Himachal Pradesh, and statistically differentiate four assemblages, that can be used in the interpretation of palaeovegetation data for changing forest ecologies. Supplementing previous palaeodepositional inferences drawn on the basis of body the fossils, Patil et al. (230) present detailed field and petrographic investigations of the Limestone Member of the Maniyara Fort Formation of Kachchh Basin of western India. They report neomorphism at the top of the Formation and attribute it to subaerial exposure during eustatic sea level fall during the Chattian Stage at the end of the Upper Oligocene. Ambokar et al. (243) report 20 pteropod species from a single location from offshores of Saurashtra, all showing the same state of preservation throughout the Holocene. They attribute the occurrence of bathypelagic species on the shelf to be indicators of temperature rather than that of depth. Sirvi et al. (250) address the controversial stratigraphic position of the sandstone included in the Bagh Formation occurring at Belam Bujurg, District Khargone, Madhya Pradesh and suggest that it is an intercalation within the Sitapuri Bryozoan Limestone and does not represent the Nimar Sandstone. Paranjape et al. (262) identify four sedimentary facies associations in the Cretaceous Sillakudi Formation of the Cauvery Basin, each represented by a distinct ichnology and environment of deposition. The overall succession is interpreted to show initial deepening followed by shallowing. Rajeshkanna and Venkatachalapathy (273) describe the distribution of diatom taxa in the Thamirabarani River in Tamilnadu. The paper that employs indicator taxa to ascertain water quality in the river is accompanied by description and photomicrographs of 36 pinnate and 4 centric diatom taxa. Radhakrishnan et al. (286) present the first taxonomical account of Recent Ostracoda from in the sediments of the Ashtamudi Lake in Kerala, to generate a baseline for future palaeoecological or palaeoenvironmental applications. They identify a strong correlation between the substrate type and ornamentation of the Ostracoda by which they identify four microenvironments within the Lake. Based on Ostracoda distribution in the ecosensitive regions of the Gulf of Mannar, Radhakrishnan et al. (293) report it to be a well-oxygenated, high energy—low sedimentation environment in the region, attributable to longshore currents. Panchang et al. (303) report changes in the distribution of Larger Benthic Foraminifera from the Kavaratti Lagoon of the Lakshadweep Islands in an attempt to identify human-induced changes over three decades in the coral lagoon of the capital island.
138 research papers were presented at the 28th ICMS and the papers in the present proceedings volume serve just as a glimpse of the three-day-long deliberations. I am certain they shall add value to the pre-existing scientific understanding of our fraternity.