Please use this identifier to cite or link to this item:
|Title:||DEFORMATION AND STRAIN PATTERNS IN DALASH GRANITE GNEISS OF THE CHAIL METAMORPHICS, LESSER HIM ALAYA, HIMACHAL PRADESH|
EARTH SCIENCE ENGINEERING
|Abstract:||As part of structural and deformational analysis of Anni-Dalash area, structural as well as strain analysis have been carried .out in one of the granites of Dalash area, Kulu district, H.P. Photography was done and rock samples were collected for strain analysis along with careful investigation of structural fabric elements within the granite body and along its contact. Strain analysis was carried out using Rf/O method of both Ramsay and Dunnot to get accurate results. It became evident from field investigation, that Dalash granite gneiss is syn- to late- tectonic to the first.phase of deformation. -The body shows fabric elements related to the earliest deformational phase which fic Ve been., folded and transposed by later S2 foliation belonging to the second phase of deformation. Foliation in the granite gneiss varies from well developed gneissic banding in the margins to poorly preserved mineral align-ments towards the interior. Structural analysis shows that the granite gneiss - has been affected by four phases of deformation. The first phase is characterized by tightly appressed recum-bent folds associated with well developed foliation. NE plunging, reclined, and open to isoclinal folds, mark the second deformational phase. Folds belonging to the third deformational phase are open and NW plunging. These folds are not well. developed in the intrusive body. The effect of the fourth deformation was distinguished in a stereoplot of the fabric data recorded. The strain patterns indicate that flattening as well as constriction (28 ) were prevalent during defor-mation of the granite gneiss. Contours of the various strain parameters run obliquely to the outline of the intrusive body. High values of constrictive strain are restricted to the margins of the granite gneiss. From the structural as well as strain analysis, it has been found out that development of F2 folds with axes parallel to stretching is due to differential ductile thrust transport an: not due to reorientation of the fold axis towards the thrust transport direction. The stru-ctural- set—up of Dalash granite gneiss is similar to that of Signy Island, South Orkney Islands.|
|Appears in Collections:||MASTERS' DISSERTATIONS (Earth Sci.)|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.