## Electronic Theses and Dissertations

1995

Master Thesis

M.Sc.

#### Department

Civil and Environmental Engineering

Simpson, Frank,

Geochemistry.

#### Rights

info:eu-repo/semantics/openAccess

The study area is bounded between longitudes $73\sp\circ\ 45\sp\prime$ E and $73\sp\circ\ 55\sp\prime$ E and latitudes $19\sp\circ\ 30\sp\prime$N and $19\sp\circ\ 40\sp\prime$N. It comprises three tribal villages in the Deccan Trap region of the Western Ghats, Maharashtra State, India. The bedrock is massive tholeiitic basalt of the Thakurvadi Formation. The petrography and geochemistry of the 47 samples collected mainly from hand-dug wells and blastholes were examined in order to determine their petrogenesis and to establish the geochemical stratigraphy of the Thakurvadi Formation. Petrographically the rocks are porphyritic to microphyric and aphyric, fine- to medium-grained massive basalts. They are commonly amygdaloidal filled with zeolites. Two suites were defined on the basis of phenocryst content: Suite No 1 with olivine, plagioclase, clinopyroxene assemblages, and Suite No 2 with olivine, plagioclase, clinopyroxene, and magnetite assemblages. Chemically the rocks are altered and show variation in compostion, with increases in K$\sb2$O content and relatively small increases in Na$\sb2$O content. An attempt has been made to establish a stratigraphic sequence for 40 rock samples within the middle Thakurvadi Formation. In order to achieve uniformity of approach with the previous investigations, the samples were arranged in the increasing order to their elevation, and were plotted against the trace element chemistry and petrographic features at the interval of 20-30 m. The results of the present study indicate no physiographic breaks in the rock chemistry. Marker horizon(s) such as Giant PIagioclase Basalts (2-5 cm) are not present; hence no distinct boundary or intra-formational sub-divisions were recognised. This suggests that the study area probably belongs to flows that show petrographically two distinct suites, but shows an overlap in chemistry. Because lavas pinch out and dip, it is difficult to correlate the chemical types in the study area with that of the reference section. (Abstract shortened by UMI.)Dept. of Geology and Geological Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1994 .A345. Source: Masters Abstracts International, Volume: 34-02, page: 0682. Advisers: Frank Simpson; T. E. Smith. Thesis (M.Sc.)--University of Windsor (Canada), 1995.