A Mathematical Approach to the Petrogenesis of the Upper Siwalik Conglomerates (L. Pleistocene) of the Jammu Region, Northwest India

In sedimentary petrography, interpretation of the source and process from the response data i.e., characteristics of the deposited sediment is a convention. The best suited mathematical technique in such an exercise is 'Principal Component Analysis'. Applying this technique to the Upper Siwalik Conglomerates of Jammu region, northwest India (Lower Pleistocene, Cromerian) five components were extracted representing 68% of total variation in the conglomerate system. Components C₁, C₂ and C₄ were identified with erosion and transporting processes (size, size sorting and shape), C₃ with composition (quartzite and sandstone pebble proportions) and C₅ with depositional processes (orientation and packing). Also, the analysis suggests that instead of three values of each of size and size sorting, and four values of shape used in the investigation, one measure of each of size, size sorting and shape is quite sufficient to explain the total variation in the petrographic properties of the Upper Siwalik Conglomerates of Jammu region.