INTEGRATED BIOSTRATIGRAPHY AND PALAEOENVIRONMENT OF THE MIDDLE JURASSIC SEDIMENTS AT KULDHAR (JAISALMER), WESTERN INDIA

摘要

Stratigraphically controlled new ammonite collections from the Middle Jurassic sediments of Kuldhar (Jaisalmer, western India) indicate a Late Bathonian-early Late Callovian age. Previous records by different authors of Dhosaites primus and Perisphinctes (Dichotomosphinctes) aff. subhelenae from the top of the section suggest an age straddling Early to early Middle Oxfordian. The present study, besides documenting a rich ammonite fauna from Kuldhar (66 specimens), also identifies seventeen lithologic beds recording 7 ammonite zones and 2 subzones. These biozones are correlated with those of the adjoining Kachchh basin (western India) and the standard ammonite zones of the European and Submediterranean provinces. Additionally, based on an integrated multi-proxy approach using occurrences of benthic foraminifers, ostracods, nannofossils, belemnites, and trace fossils, the palaeoenvironment of the Kuldhar section is inferred.