Microbial mat records in siliciclastic rocks: Examples from Four Indian Proterozoic basins and their modern equivalents in Gulf of Cambay
| Autor: | Arvind Kumar Singh, Pradip Samanta, Nivedita Chakraborty, Santanu Banerjee, Subir Kumar Sarkar, Soumik Mukhopadhyay, Partha Pratim Chakraborty |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Palaeonvironmental Implications
Modern Environment Vindhyan-Supergroup Paleontology Precambrian Reticulate Sequence Architecture Group (stratigraphy) Rampur Shale Microbial mat Proterozoic Formations South-Africa Earth-Surface Processes Microbial Mat Related Structures Thermal Event Proterozoic Sediment Induced Sedimentary Structures Geology Rb-Sr Chorhat Sandstone Rajasthan Wrinkle Structures Deposits Siliciclastic Supergroup |
| Zdroj: | Journal of Asian Earth Sciences. 91:362-377 |
| ISSN: | 1367-9120 |
| DOI: | 10.1016/j.jseaes.2014.03.002 |
| Popis: | Microbial mat-related structures (MRS) in siliciclastics have been investigated from four Proterozic formations in India, namely the Marwar Supergroup, the Vindhyan Supergroup, the Chhatisgarh Supergroup and the Khariar Group for their spectral variations, genetic aspects, palaeo-environmental significance and influence on sequence stratigraphic architecture. The maximum diversification of MRS has been experienced in shallow marine coastal Precambrian successions. Observations made from modern environment as well as Precambrian rock records clearly indicates that the features like petee ridges, sandcracks, gas domes, multi-directed ripples, reticulate surfaces, sieve-like surfaces and setulf are most likely to form in the shallowest part of the marine basins, in upper intertidal to supratidal conditions while wrinkle structures, roll-up structures and patchy ripples had a broader range of palaeogeographic settings from the supratidal to subtidal conditions. Discoidal microbial colony (DMC) represents a special variety of the mat-layer feature in modern environment that may have diverse internal architecture, sometimes falsely resembles Ediacaran medusoids. The uniqueness in sequence stratigraphic architecture of the microbial mat-covered sediment is reflected by the presence of more amalgamated HSTs compare to that of TSTs. The preservation of forced and normal regressive deposits on low-gradient epeiric shelf under low continental freeboard indicates microbial mat-infested sea-floor impedes erosion and concomitant sediment supply may facilitate formation and preservation of regressive packages. (C) 2014 Elsevier Ltd. All rights reserved. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect