Deccan Traps Fm
Type Locality and Naming
Extensive outcrops and sub-surface over nearly half of central India. Example in Cambay: Well Cambay – 11 (depth interval 2482-3487 m), 1005 m thickness [Original Publication: Pandey, J., Singh, N.P., Krishna, B.R., et al. (1993) Lithostratigraphy of Indian Petroliferous Basins, Document III, Cambay Basin, 2 Volumes, KDMIPE, ONGC Publication, pp. 1-166.]
Lithology and Thickness
Basalt. "The volcanic part of the Deccan LIP may have originally totaled > ~ 1.3 million km3 of lava and the portion remaining on peninsular India constitutes about 750,000 km3 (Jay and Widdowson, 2008), covering about 500,000 km2." (from Deccan Volcanic Province, LIP of the Month: http://www.largeigneousprovinces.org/12may). It is comprised of vesicular and non-vesicular dark grey to greenish-grey, melanocratic basalts associated with andesite, trachyte etc. About 14 lava flows are recognized separated by inter-trappean beds. The inter-trappean beds are made of variegated shales, chocolate brown with greenish-grey specks and pockets of calcite. There are many sub-divisions of the Deccan Traps Fm – see the website link above; therefore it should be considered as the Deccan Traps Gr (Group) when the INDPLEX system has been enhanced with these details.
[Figure 1: Rock units and their reference sections in Cambay Basin (after Pandey et al., 1993)]
[Figure 2: Generalized stratigraphy of the Cambay Basin. (from Jaiswal and Bhattacharya, 2018, J.EarthSyst.Sci., 127:65)]
Relationships and Distribution
Lower contact
The group overlies unconformably on a variety of different Mesozoic formations in different basins.
Upper contact
Unconformably underlies the Olpad Fm in the Cambay Basin, and other early Paleogene formations in other basins.
Regional extent
Extensive outcrops and sub-surface over nearly half of central India.
GeoJSON
Fossils
No micro fauna is reported from the inter-trappean beds
Age
Depositional setting
Additional Information
Separate chapter on Deccan Volcanic Province is under preparation by K.V. Subbarao and his team.