Rapid Middle to Late Miocene Slip Along the Zanskar Normal Fault, Greater Himalayan Range, NW, India: Constraints from Low-Temperature Thermochronometry

The Zanskar normal fault (ZF) is a NW-striking, moderately NE-dipping, normal fault that bounds the northern flank of the Greater Himalaya Range, NW India. The ZF is the far west continuation of the South Tibetan Detachment System (STDS), a major arc-parallel normal sense shear zone that spans the length of the Himalayan orogen. Detailed new zircon and apatite (U-Th)/He (ZHe and AHe) and apatite fission-track (AFT) thermochronometric data from high-grade (amphibolite-migmatite) Greater Himalayan Sequence (GHS) metamorphic rocks, exposed in the footwall immediately adjacent to the ZF, provide constraints on the middle Miocene to present exhumation history of the footwall. The overlap of these elevation invariant mean ZHe, AFT, and AHe thermochronometric ages, indicate rapid cooling between ~14-10 Ma. Inverse modeling of ZHe, AHe, and AFT thermochronometric data yield patterns that suggest: (1) a pulse of rapid normal slip along the ZF at ~14-13 Ma and rapid exhumation of the footwall between ~14-10 Ma at rates of 0.2-2.5 mm/yr, and (2) slow exhumation and/or quiescence between ~9 Ma to the present day. We suggest that the period of rapid normal slip along the ZF can be best explained by southward extrusion of the GHS by a modified channel flow mechanism and/or by an increase in gravitational potential energy as a consequence of a slab break-off event.

Name thesis:degree_name

Master of Science (MS)

Discipline thesis:degree_discipline

Geological Sciences

Year dc:date.available

2015

Author dc:creator

• Shurtleff, Brett L.

Contributors dc:contributor

• Jeffrey Lee
• Chris Mattinson
• Anne Egger

• Zanskar
• Himalaya
• Thermochronology
• Normal-fault
• South Tibetan Detachment System
• Earth Sciences
• Geology
• Tectonics and Structure

Language dc:language

English

Repository record dc:identifier

https://digitalcommons.cwu.edu/etd/203

OAI identifier oai:identifier

oai:digitalcommons.cwu.edu:etd-1215