Temporal facies and diagenetic evolution of the mixed siliciclastic-carbonate Jajiya Member (Callovian–Oxfordian), Jaisalmer Formation, West India

Ghulam Mohammad BHAT, Abul Hasnat Masood AHMAD

Abstract


Three broad lithofacies – bioturbated packstone- to rudstone, calcareous sandstone and cross-bedded rudstone to packstone are recognized within the Jajiya Member. The facies architecture and stalking pattern suggests deposition related to TST, HST and TST events punctuated by MFZ events in sequence stratigraphic terms. The 11.4 m thick sequence represents two fining upward and three coarsening upward cycles representing bar-bank depositional settings. The framework constituents of these facies were mainly controlled by the depo­sitional conditions through space and time and have greatly influenced their diagenetic evolution. The main diagenetic features observed within the facies include compaction, early cementation and porosity reduction, micritization and neomorphism representing early or syn-depositional and post-depositional changes. Two phases of early mechanical compaction have largely governed porosity development in these facies. However, cementation, micritization and neomorphism have also contributed significantly in this respect. Evidence suggests that marine phreatic and fresh water phreatic environments dominated the diagenetic evolution of these facies. Calcite cementation was first formed, followed by iron oxide, while silica cementation occurred probably at a late stage.

Keywords


temporal facies analysis; diagenesis; petrofacies; Jajiya Member; Jaisalmer Formation; West India

Full Text:

PDF

Refbacks

  • There are currently no refbacks.