Jhagadia Fm

SUBSURFACE: Named after Jhagadi village. Well Broach-6 (depth interval 1728-1952m), It is of 224 m thickness. [Original Publication: Sudhakar, R. and Roy, T.K. (1959) Progress report on the geology of the tertiary formations of Broach and Surat districts (1958-59). Unpublished report of ONGC.]. The nomenclature of this formation was given by the above authors after the outcropping sections observed near Jhagadia Village during field mapping. Reference well: i) Pakhajan-1 (depth interval 1680-1924 m); ii) Dadhal-1 (depth interval 145 – 289 m); iii) Cambay-40 (depth interval 650 – 885 m); iv) Nawagam-22 (depth interval 405 – 695 m), In Pakhajan-1, the thickness is 244m while in Dadhala-1, in Cambay-40 and Nawagam-22 the thickness is 144m, 235m and 290m, respectively.

Sandy claystone. In the type section, the formation consists of alternations of chocolate brown to reddish-brown claystone, sandy claystone and sandstone. In reference section, the formation consists of alternations of brown to reddish-brown claystone and sandstone. The maximum thickness has been encountered in the type section which is 928 m in Broach-6. The thickness in reference section i.e. Pakhajan-1, Siswa-1 and Nawagaon-22 is 849 m, 310 m and 150 m.

[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)]

The formation is poorly fossiliferous in the subsurface and unfossiliferous in the outcrops.