A comparative study of the petrochemistry of the tholeiitic rocks of India |
| |
| Authors: | A C Chatterjee |
| |
| Institution: | 1. Vikram University, Uijain
|
| |
| Abstract: | A comparative study of the petro-chemistry of the tholeiitic rocks (Cuddapah, Gwalior, Rajmahal and the Deccan traps) is made employing various crystallization parameters such as the differentiation index (D. I.) and the solidification index (S. I.). The D. I. values of the upper Deccan traps are much higher than those of the lower traps, rocks of intermediate composition being rare. The S. I. values of the Deccan traps allow them to be classified into three categories i.e., (1) the lower trap with higher S. I. values, (2) the differentiated upper division traps, (3) the unusual rock types of Western India. Murata’s alkali-silica diagram, based on all the available analyses of the traps (Pre-Cambrian to Eocene), indicates that, following the chemical definition, it is not possible to group the entire upper Deccan trap flows under the tholeiites. All the Precambrian traps are not tholeiitic either. There is a clear relationship between optical and petro-chemical characters. Attention is drawn to the difficulties in the application of Barth’s «f-norm » to trace the cooling history of the rocks crystallizing at a later stage. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
