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

S. Balakrishna ¹

Affiliations
1 Department of Geology, Osmania University, Hyderabad, IN

Abstract

Sound velocities, both longitudinal and torsional, are measured in some metamorphic rocks by employmg the ultrasonic pulse method involving the phenomenon of total internal reflection. Their variation in these rocks with the grain size has been examined in detail. Velocities decrease with increasing grain size and in fact vary linearly. The effect of granular structure on the transmission of sound is also studied. The effect of temperature on the velocities of sound in metamorphic rocks in a range of 3°-110° c has been thoroughly investigated. An attempt has also been made to correlate the variation of velocities with the petrogenetic history of the rock.

Full Text

     

S. Balakrishna ¹, G. Christopher ¹, M. S. Vijaya Raghava ¹

Affiliations
1 Department of Geology, Osmania University, Hyderabad, IN

Abstract

Granites of the Osmania University area, Hyderabad, have been studied in detail in order to understand their geological setting and magnetic anomalies. An area comprising nearly 8 sq. miles has been mapped for structural elements and the distribution of pink and grey granites in the field have been marked out. The area has been divided into a square grid of 200 meters interval and vertical intensity of magnetic field has been measured at nearly 600 stations and a magnetic anomaly map has been prepared. It is interesting to note that the magnetic anomaly map follows the distribution of various types of granites and the location of dykes in the field. A few magnetic highs have been noted and these are generally correlatable to the grey granite massifs.

Full Text