摘要
The present study deals with the petrographic interpretation of Talchir Formation sandstone, in and around Chirimiri area, Koriya district, Chhattisgarh state India located in Son-Mahanadi basin. This basin is an elongate graben showing northwest-southeast trend and considered to be one of the largest intra-cratonic rift basins of Indian peninsula. Talchir Formation is the lowermost unit of thick classical Gondwana sedimentary succession and rests unconformably on Precambrian basement. The petrographic studies consisting of point count show the presence of quartz as a dominant framework mineral with subordinate amounts of feldspars and rock fragments. The data plot in the fields of cratonic interior and transitional margin of continental block provenance. In the Qt (quartz)-F (feldspar)-L (lithic fragments) triangular diagram, indicating the source of these sediments was located in transitional margin and continental block provenance. The petrographic classification suggests that this formation in the study area dominantly contains compositionally immature to submature arkosic, sub-arkosic and lithic-arkosic sandstones. The bivariate plot between Qp/(F+R) vs. Qt/(F+R) indicates changes in climatic conditions from semi-arid to semi-humid during Permo-Carboniferous period.
The present study deals with the petrographic interpretation of Talchir Formation sandstone, in and around Chirimiri area, Koriya district, Chhattisgarh state India located in Son-Mahanadi basin. This basin is an elongate graben showing northwest-southeast trend and considered to be one of the largest intra-cratonic rift basins of Indian peninsula. Talchir Formation is the lowermost unit of thick classical Gondwana sedimentary succession and rests unconformably on Precambrian basement. The petrographic studies consisting of point count show the presence of quartz as a dominant framework mineral with subordinate amounts of feldspars and rock fragments. The data plot in the fields of cratonic interior and transitional margin of continental block provenance. In the Qt (quartz)-F (feldspar)-L (lithic fragments) triangular diagram, indicating the source of these sediments was located in transitional margin and continental block provenance. The petrographic classification suggests that this formation in the study area dominantly contains compositionally immature to submature arkosic, sub-arkosic and lithic-arkosic sandstones. The bivariate plot between Qp/(F+R) vs. Qt/(F+R) indicates changes in climatic conditions from semi-arid to semi-humid during Permo-Carboniferous period.
