Karakoram Shear Zone at Agham, the N-tip of the Pangong Range, Ladakh, NW India

Contents:
a) Folds and thrusts
b) Main Rock Types
c) Inside the Batholith: Structures and Rock Types
d) Hbl-Granites: Anatexis of Gabbros

a) Folds and thrusts

Figure 1a)  Thrusts in the vicinity of Agham: attitude of axial plane 100/20S.	Figure 1b)  detail of a.

 

Figure 2a)  Thrusts in the vicinity of Agham: attitude.	Figure 2b)  Detail of a.

 

Figure 3a)  Thrust stack. Tractor at base for scale. Notice a steep granite dyke in light colours.	Figure 3b)  Another thrust stack N34 19' 40.7 E77 50' 38.8". Bt schist 30 m from the contact with a gabbroic body (to the left on photo). Fault plane: 320-340 / 10-25 E, slickenline 24 towards 80 (thrusting toward W) associated with subhorizontal fold axis trending 130.

 

Figure 4a)  Thrust plane, 160-180/20E.	Figure 4b)  Another thrust plane.

 

Figure 5a)  Thrust and drag fold. Ligher layer is a Ms-gneiss, representing a granite sheared at greenschist facies.	Figure 5b)  Break up during folding and thrusting.

 

Figure 6a)  Thrusting breaking up a light-grey layer Ms-gneiss, representing a granite sheared at greenschist facies, inside a Bt-schist.	Figure 6b)  Same as (a).

 

Figure 7a)  Large scale contact between gabbro body to the N (right) and Bt-schists to the south (left) with two crenulations. Contact trending 280. Photograph looking towards NW. Contact is at N34 19' 30.8" and E77 50' 59.2"	Figure 7b)  Detail of contact, showing silicified gabbro to the right (fractured and sheared).

Figure 8a)  Granite dykes intruding supracrustal sequence (mostly biotite schist).South of the contact between gabbro and supracrustals at N34 19' 30.8" and E77 50' 59.2"	Figure 8b)  Same wall as a, branching granite dykes.

 

Figure 6a)  Two crenulation: an early, steep one, at mm scale visible as lines, and a broad, open one, plunging gently to the left.	Figure 6b)  Detail of a.

 

Figure 7a)  Different degrees of straining of coarse gabbro. The entire package is retrogressed to greenschist facies, but preserve locally original primary igneous texture despite shearing and retrogression.	Figure 7b)  Lamprophyre (minette) dyke cross-cutting greenschist facies shear fabric. The dyke rocks are not sheared nor retrogressed.