Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

B. K. Nagaraja Rao ¹

Affiliations
1 1-10-222, Ashoknagar, Hyderabad-500 020, IN

Abstract

A natural arch is carved by the agencies of nature in the Nagari Quartzite, exposed on the Tirumala hills. It is suggested that this may owe its origin to jointing and stream action.

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S. S. Nayak ¹, C. V. Kasi Viswanathan ¹, T. A. K. Reddy ¹, B. K. Nagaraja Rao ¹

Affiliations
1 Geological Survey of India, IN

Abstract

Rocks of kimberlitic affinity hitherto not recorded are recognized near Maddur, Mahaboobnagar district, Andhra Pradesh. These are identified as olivine lamproites based on the paucity of garnet and picro-ilmenite. However, major element data have similarity with lamproitcs of Western Australia. Petrography is similar to pipe No.5 of Wajrakarur. K₂O is, however, less. The kimberlitic rocks are located in the area intersected by NE-SW (Major) and NW-SE (Intermediate) lineaments and form the northern cluster of kimberlites in Andhra Pradesh. This new location of a kimberlitic province has widened the scope for diamond prospecting in Andhra Pradesh.

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