Volume : 1, Issue : 4, September - 2012
The plutonic and hypabassal rocks in the Lower Siang valley A Petrographic Investigation
P. Bhattacharyya, C. Taye, L. Patra
Abstract :
On the east bank of Siang River at lower Siang valley in between Bodak village and Siang–Yemne river confluence a huge suite of intrusive rocks has been observed. These rocks occur as a pluton and have been thrusted over the Paleocene–Eocene rocks of Yinkiong group. No report has so far been published on this suite of rocks. A detail mapping and petrographic study of this suite have been made for the first time. Petrographic study reveals that the rocks of the suite are composed mainly of gabo, hornblende–gabo, and diorite– plagioclase–diorite, hornblende–diorite, calc–diorite. Some doleritic dikes are found to occur along the periphery of the pluton. Also several dikes of trachyte occur in close association with more voluminous andesitic rocks. These gaboic and dioritic rocks may be viewed as plutonic counterparts of compositionally similar extrusive basaltic and andesitic rocks in the Siang valley. The dikes of dolerite and trachyte might have acted as feeder for the deep seated magma chamber crystallized to form these plutonic rocks and the equivalent volcanic rocks.
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Download PDF Journal DOI : 10.15373/2249555XCite This Article:
P. Bhattacharyya, C. Taye, L. Patra The plutonic and hypabassal rocks in the Lower Siang valley A Petrographic Investigation Global Journal For Research Analysis, Vol: 1, Issue: 4 September 2012