Serau Fm
Type Locality and Naming
SUBSURFACE: Well Serau East-1 (depth interval 1735 m to 2080 m), its thickness is of 345 m. [Original Publication: Roy Choudhary, S.C., Mathur, R.B., and Mishra, G.S., 1972: Subsurface stratigraphy of Tharad-Serau area, N.W. Gujarat, Bull. ONGC. Vol. 9(2)].
The sequence consisting of basal conglomerate and thick succession of sandstone with minor inter beds of shale and overlying the Pre-Cambrian granite in well Serau East-1 has been designated as the Serau Formation. In subsequent works this name has been retained.
Lithology and Thickness
Sandstone. In type section, the formation consists of basal conglomerate and thick succession of sandstone with minor interbeds of shale. Conglomerate consists of pink, weathered granite fragments, granite wash and sand derived from granite basement. Sandstone is white to pale brown, fine- to medium-grained, current-bedded, micaceous with ferruginous stains and coatings. The sandstone is proto-quartzite with dominant strained and fractured quartz and minor amounts of feldspars, quartzitic rock fragments and detrital cherts. Heavy minerals like tourmaline and zircon occur in traces.
[Figure 2: Generalized stratigraphy of the Cambay Basin. (from Jaiswal and Bhattacharya, 2018, J.EarthSyst.Sci., 127:65)]
Relationships and Distribution
Lower contact
The formation has unconformable relationship with the underlying Pre-Cambrian basement granite.
Upper contact
The formation has unconformable relationship with the overlying Deccan Traps Fm. The formation is overlain by the Olpad Fm where the Deccan Traps Fm is not developed.
Regional extent
It is encountered only in extreme northwestern margin of Cambay Basin in Sanchor-Patan Block, the formation has been encountered only in one well Serau East-1. The formation is considered equivalent to outcropping Sarnu Fm in Barmer basin of Rajasthan in the north, to outcropping Bhuj Fm of Kutch Basin, to Himmatnagar Sandstone Fm and Nimar Sandstone Fm to southeast, and to the Wadhawan Fm and Dhrangadhra Fm of Saurashtra to the south west of Serau area.
GeoJSON
Fossils
The formation is devoid of fauna except some spores and pollens.
Age
Depositional setting
Additional Information