Washtawa Fm
Period:
Jurassic
Age Interval:
Bathonian to Oxfordian (mid-Jurassic)
Province:
W.India Kutch Basin
Type Locality and Naming
Local: Southern flank of Washtawa Dome (Biswas, 1977)
Lithology and Thickness
Claystone and Sandstone. The formation is consisting of dominantly shales and sandstone alternations. The sandstone is current bedded with gypsiferous bands. The top of the formation is marked by a zone of fossiliferous bands in the upper part of the topmost shale beds, well exposed at the base of the Kanthkoti Hills. In type area the thick is +205 m
Lithology Pattern:
Sandy claystone
Relationships and Distribution
Lower contact
Not exposed
Upper contact
Not given
Regional extent
GeoJSON
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Fossils
Megafossils observed are pelecypods, Gastropods, Ammonites and Belmenites
Age
The formation is equivalent to upper section of the Khadir Fm. Based on field relationship and equivalence a Bathonian to Oxfordian (Middle Jurassic) has been assigned.
Age Span:
Beginning stage:
Callovian
Fraction up in beginning stage:
0.5
Beginning date (Ma):
163.41
Ending stage:
Oxfordian
Fraction up in the ending stage:
0.5
Ending date (Ma):
158.16
Depositional setting
The facies pattern, lithological association, fauna and distribution suggest shallowing of depositional environment from sub littoral to littoral from west to east.
Depositional pattern:
Additional Information
Compiler:
Modified from Jitendriya Mishra (2009) Kutch-Saurasthra Basin, Chap. 17 in ONGC Bull 44