Integrated Sequence Stratigraphy of the Middle Jurassic (Bajocian-Callovian) Chiltan Formation in the Lower Indus Basin, Pakistan
Detailed sedimentological analysis of the Jurassic (Bajocian-Callovian) Chiltan Formation has been accomplished from the Middle Indus Basin, Pakistan. We have discriminated six different microfacies that deciphered a carbonate barrier-inlet shelf platform depositional setting. These facies represented the lagoonal tidal inlets (CHF 1 facies), carbonate shoals (CHF 2 facies), fore shore (CHF 3 facies), supra tidal (CHF 4 facies), wash over fans (CHF 5) and near shore (CHF 6 facies) setting. The record of the smaller benthic foraminifera (Lenticulina subalta, lenticulina vobulus and planularia protracta) confirms a middle Jurassic (Bajocian-Callovian) age of the unit. This biostratigraphic calibration suggests that the deposition of the Chiltan Formation correspond to a second order cycle (17 Ma) which encompasses a composite transgressive systems tract and various third order cycles and systems tracts. The long and short term sea level fluctuations show a close match with global sea level curve.
KeywordsJurassic Indus basin Sequence stratigraphy Pakistan
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