Comment on: Fürsich et al., 2023, Miocene instead of Jurassic: the importance of sound fieldwork for paleontological data analysis

Abstract

Abstract We published a series of papers regarding the oldest turritellids, naticids, their paleoecological interaction, and gastropod biozonation, which are of Oxfordian in age, from the Jhura pond section, Kutch, western India. Recently, an Oxfordian age was challenged by Fürsich et al. (2023) and they argued for a Cenozoic age. The authors reproduced a local geological map based on regional data where the Jhura pond section sediments were overlying the Bhuj Formation. In the original regional data, there was no Bhuj Formation and the introduction of the Bhuj Formation served to show that Jhura pond section sediments were “allochthonous”. Other lines of argument against our conclusions (e.g., identification of associated bivalve fauna, foraminiferal assemblage, and geological context) were brought forward. There were additional inconsistencies, such as the reworking of Oxfordian fossils, in their comment/opinion pieces. The only hard evidence was the report of a microfaunal assemblage, but the taxa were identified at the generic level and most of the genera appear in the Jurassic or even earlier. Here we provide detailed and concrete evidence explaining features at the Jhura pond section, such as the subvertical nature of the beds, the ooid-bearing lithologies, the presence of various Oxfordian fossils, the difference in turritellids, naticid assemblages, and differences in the diversity curves between the present beds and the lower Miocene Chhasra Formation of Kutch. Detailed paleoecological analyses (both gastropods and bivalves) speak for two paleocommunities. We, therefore, reiterate that the present Jhura pond section sediments are Oxfordian in age and validate all the interpretations and conclusions that we have made in our previous papers.