Kinematics of the Greater Himalayan sequence, Dhaulagiri Himal ...

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7. Conclusions
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Detailed lithologic mapping, in conjunction with quartz c-axis data, has constrained the
structural position of the Ramgarh thrust and the MCT. Previous studies had placed the
Ramgarh thrust within the Greater Himalayan sequence, as defined in this study, in central
Nepal. The results of this study are consistent with interpretations that equate the Ramgarh
thrust with the MCT at the base of the Greater Himalayan sequence more than 8 km south of the
previously mapped locations in the Kali Gandaki valley.
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Quartz c-axis fabrics and geothermometric data are interpreted to show that the Greater
Himalayan sequence exposed in the Kali Gandaki valley in central Nepal was pervasively
deformed during extrusion. This deformation is characterized by a dominant top-to-the-south
sense of shear that is observed across the Greater Himalayan sequence from its base up into its
migmatitic upper portion. Quartz c-axis fabrics were not preserved in the calc-silicate and
orthogneiss dominated parts of the Greater Himalayan sequence.
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Estimations of vorticity help quantify the flow kinematics in the Greater Himalayan
sequence exposed in central Nepal. Our data add to a limited, but expanding kinematic database
from across the orogen that, at a first order, define a general change in vorticity across the
Greater Himalayan sequence with structural position. Vorticity values from this study average
0.67, show a significant component of pure shear deformation (53%), and corroborate previous
investigations indicating that deformation within the Greater Himalayan sequence is dominantly
characterized by a combination of pure shear and simple shear strain (Grasemann et al. 1999;
Law et al. 2004; Jessup et al. 2006; Carosi et al. 2006, 2007). While more data are needed to
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