Classification of the Paleoproterozoic Gulcheru Formation: Implications on Early Paleogeographic and Tectonic Evolution
- PDF / 37,395 Bytes
- 2 Pages / 595 x 842 pts (A4) Page_size
- 58 Downloads / 171 Views
conclusions. Furthermore, he is concerned about some geological information, mostly regarding the geological map documented in our research article. We respond to each point below. a) Detailed stratigraphic classification of the Gulcheru Formation and its relationship with tectonics of the basin is the main scope of our paper (Majumder and Patranabis-Deb, 2020). To our understanding, neither Lakshminarayana et al. (2001) nor Saha and Tripathy, (2012) dealt with detailed stratigraphic classification of the Gulcheru Formation. Dr. Lakshminarayana has argued that the original interpretations drawn on the subject matter of the area were already published in one form or the other by Geological Survey of India (GSI) (Lakshminarayana et al., 2001) or by Saha and Tripathy (2012). He has also contended that most of the things in our paper is drawn/imitated from Lakshminarayana et al. (2001) and we have covered this by adding some other published points. We completely disagree with the contentions given by Dr. Lakshminarayana and explain them below. Lakshminarayana et al. (2001) presented the stratigraphic framework of whole of the Cuddapah basin (~6 km) and inferred relationship between different stratigraphic units (formation level) and their depositional environments. Generalized description and overall interpretation of each of the formation were taken up. This work is similar to our earlier work (Patranabis-Deb et al., 2012), hence was referred therein. But in Majumder and Patranabis-Deb (2020), we tried to focus only on the basal siliciclastic-carbonate assemblages of the Papaghni succession (~2 km). Detail stratigraphic analysis of the Papaghni Group provided the context for relating Proterozoic developments in the Eastern Dharwar craton, during basin opening phase. Geological mapping on 1:50000 scale along the western and south-western margin of the Papaghni sub-basin, revealed a distinct basal immature coarse siliciclastic unit within the Gulcheru Formation. This very coarse-grained immature clastic unit is completely different from the stratigraphically upper, mineralogically and texturally mature quartz arenite of the formation. The clastic unit gradationally passes up to the Vempalle Formation, which is dominated by stromatolitic dolomite. We are not in agreement with the interpretation that the whole of the Gulcheru Formation was deposited mainly in fluvial (alluvial) environment and the Vempalle Formation to be intertidal and shallow marine deposit (Lakshminarayana et al., 2001). We have interpreted the Daditota Member as fan delta with evidence of wave and tide dominated deposit at the seaward frontal part of the alluvial fan and refer to Majumder et al., 2015 for further explanation. We draw the reference of our own article to avoid unnecessary elaboration of the text commensurate with the purpose and scope of the article. We also interpret the depositional environment of the Karvipalle Member (upper part of the Gulcheru Formation) as a wave and tide dominated foreshore and sandy shoreface deposit with essent
Data Loading...
