Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system
The Himalayan orogen represents a “Composite Orogenic System” in which channel flow, wedge extrusion, and thrust stacking operate in separate “Orogenic Domains” with distinct rheologies and crustal positions. We analyze 104 samples from the metamorphic core (Greater Himalayan Sequence, GHS) and boun...
| Autori principali: | , , , , |
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| Natura: | Journal article |
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Wiley Periodicals, Inc. on behalf of American Geophysical Union
2016
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| _version_ | 1826285414116229120 |
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| author | Parsons, A Law, R Lloyd, G Phillips, R Searle, M |
| author_facet | Parsons, A Law, R Lloyd, G Phillips, R Searle, M |
| author_sort | Parsons, A |
| collection | OXFORD |
| description | The Himalayan orogen represents a “Composite Orogenic System” in which channel flow, wedge extrusion, and thrust stacking operate in separate “Orogenic Domains” with distinct rheologies and crustal positions. We analyze 104 samples from the metamorphic core (Greater Himalayan Sequence, GHS) and bounding units of the Annapurna‐Dhaulagiri Himalaya, central Nepal. Optical microscopy and electron backscatter diffraction (EBSD) analyses provide a record of deformation microstructures and an indication of active crystal slip systems, strain geometries, and deformation temperatures. These data, combined with existing thermobarometry and geochronology data are used to construct detailed deformation temperature profiles for the GHS. The profiles define a three‐stage thermokinematic evolution from midcrustal channel flow (Stage 1, >700°C to 550–650°C), to rigid wedge extrusion (Stage 2, 400–600°C) and duplexing (Stage 3, <280–400°C). These tectonic processes are not mutually exclusive, but are confined to separate rheologically distinct Orogenic Domains that form the modular components of a Composite Orogenic System. These Orogenic Domains may be active at the same time at different depths/positions within the orogen. The thermokinematic evolution of the Annapurna‐Dhaulagiri Himalaya describes the migration of the GHS through these Orogenic Domains and reflects the spatial and temporal variability in rheological boundary conditions that govern orogenic systems. |
| first_indexed | 2024-03-07T01:28:28Z |
| format | Journal article |
| id | oxford-uuid:92c53e9e-3acd-4743-8269-1dbf612c37ef |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:28:28Z |
| publishDate | 2016 |
| publisher | Wiley Periodicals, Inc. on behalf of American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:92c53e9e-3acd-4743-8269-1dbf612c37ef2022-03-26T23:27:51ZThermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic systemJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:92c53e9e-3acd-4743-8269-1dbf612c37efSymplectic Elements at OxfordWiley Periodicals, Inc. on behalf of American Geophysical Union2016Parsons, ALaw, RLloyd, GPhillips, RSearle, MThe Himalayan orogen represents a “Composite Orogenic System” in which channel flow, wedge extrusion, and thrust stacking operate in separate “Orogenic Domains” with distinct rheologies and crustal positions. We analyze 104 samples from the metamorphic core (Greater Himalayan Sequence, GHS) and bounding units of the Annapurna‐Dhaulagiri Himalaya, central Nepal. Optical microscopy and electron backscatter diffraction (EBSD) analyses provide a record of deformation microstructures and an indication of active crystal slip systems, strain geometries, and deformation temperatures. These data, combined with existing thermobarometry and geochronology data are used to construct detailed deformation temperature profiles for the GHS. The profiles define a three‐stage thermokinematic evolution from midcrustal channel flow (Stage 1, >700°C to 550–650°C), to rigid wedge extrusion (Stage 2, 400–600°C) and duplexing (Stage 3, <280–400°C). These tectonic processes are not mutually exclusive, but are confined to separate rheologically distinct Orogenic Domains that form the modular components of a Composite Orogenic System. These Orogenic Domains may be active at the same time at different depths/positions within the orogen. The thermokinematic evolution of the Annapurna‐Dhaulagiri Himalaya describes the migration of the GHS through these Orogenic Domains and reflects the spatial and temporal variability in rheological boundary conditions that govern orogenic systems. |
| spellingShingle | Parsons, A Law, R Lloyd, G Phillips, R Searle, M Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title | Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title_full | Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title_fullStr | Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title_full_unstemmed | Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title_short | Thermo‐kinematic evolution of the Annapurna‐Dhaulagiri Himalaya, central Nepal: The composite orogenic system |
| title_sort | thermo kinematic evolution of the annapurna dhaulagiri himalaya central nepal the composite orogenic system |
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