Is there any significant strike-slip offset on the western margin of the Nanga Parbat-Haramosh Massif (NPHM)?

If the NPHM were due to indentation tectonics, evidence of significant strike-slip should be found on both margins of the massif. Mylonites of the MMT zone do show apparent strike-slip ductile components, of the correct complementary sense, but these do not have to be from indentation, and alternatively could be due to refolding of MMT overthrusting fabrics during the rise of the antiformal NPHM. Brittle faults, which also have permitted rise of the NPHM, are abundant in a zone on and near the western margin; our data indicate that these have overwhelmingly dominant dip-slip motion. Fibre-coated slip surfaces with dominant strike-slip are only found as subsidiary features in the highly fractured accommodation zones adjacent to large brittle faults, including the Sassi-Shahbatot Fault. We suggest that the apparent large right-lateral offset of the Indus River across that fault is not due to strike-slip displacement. The eastern margin of the massif has much less brittle faulting than the western marginal zone; it is mostly a zone of flexure of the MMT to moderate and steep easterly dips. Those brittle faults that do occur here have dominant dip-slip displacements permitting rise of the NPHM.

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