Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis
A combined geochronological and petrological study of pelitic migmatites from the northwestern flank of the eastern Himalayan syntaxis has constrained the timing and P-T conditions of two high-grade metamorphic events that affected the south Lhasa block (Asian margin) and provides new insight into t...
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| Format: | Journal article |
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2014
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| _version_ | 1797051824817045504 |
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| author | Palin, R Searle, M St-Onge, MR Waters, D Roberts, N Horstwood, M Parrish, R Weller, O Chen, S Yang, J |
| author_facet | Palin, R Searle, M St-Onge, MR Waters, D Roberts, N Horstwood, M Parrish, R Weller, O Chen, S Yang, J |
| author_sort | Palin, R |
| collection | OXFORD |
| description | A combined geochronological and petrological study of pelitic migmatites from the northwestern flank of the eastern Himalayan syntaxis has constrained the timing and P-T conditions of two high-grade metamorphic events that affected the south Lhasa block (Asian margin) and provides new insight into the tectonothermal evolution of the India-Asia collision. U(-Th)-Pb dating of in situ monazite shows that upper amphibolite-facies sillimanite-grade metamorphism and consequent partial melting occurred between c. 71 and 50 Ma at P-T conditions above 6.3 ± 1.2 kbar and 750 ± 30 °C. Further partial melting at upper amphibolite-facies kyanite-grade conditions occurred between c. 44 and 33 Ma at minimum P-T conditions of 10.4 ± 1.0 kbar and 698 ± 20 °C. These data are interpreted to record a south Lhasa block mid-crustal sillimanite-grade melting event in the Late Cretaceous to Early Eocene related to regional heat advection caused by coeval and prolonged emplacement of Gangdese batholith units. This was followed by a higher pressure and lower temperature kyanite-grade melting event during the Middle Eocene to Early Oligocene associated with deformation and crustal thickening in the south Lhasa block, coeval with kyanite-grade metamorphism along the Himalaya, as a result of the on-going India-Asia collision. These partially-melted crustal lithologies offer potential sources (or otherwise analogs for sources) for the Miocene emplacement of adakitic intrusions previously documented in the eastern Himalayan syntaxis region. © 2013 International Association for Gondwana Research. |
| first_indexed | 2024-03-06T18:24:51Z |
| format | Journal article |
| id | oxford-uuid:07982400-5ef9-4582-8afc-b1bc188a8340 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T18:24:51Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | oxford-uuid:07982400-5ef9-4582-8afc-b1bc188a83402022-03-26T09:08:27ZMonazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxisJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:07982400-5ef9-4582-8afc-b1bc188a8340Symplectic Elements at Oxford2014Palin, RSearle, MSt-Onge, MRWaters, DRoberts, NHorstwood, MParrish, RWeller, OChen, SYang, JA combined geochronological and petrological study of pelitic migmatites from the northwestern flank of the eastern Himalayan syntaxis has constrained the timing and P-T conditions of two high-grade metamorphic events that affected the south Lhasa block (Asian margin) and provides new insight into the tectonothermal evolution of the India-Asia collision. U(-Th)-Pb dating of in situ monazite shows that upper amphibolite-facies sillimanite-grade metamorphism and consequent partial melting occurred between c. 71 and 50 Ma at P-T conditions above 6.3 ± 1.2 kbar and 750 ± 30 °C. Further partial melting at upper amphibolite-facies kyanite-grade conditions occurred between c. 44 and 33 Ma at minimum P-T conditions of 10.4 ± 1.0 kbar and 698 ± 20 °C. These data are interpreted to record a south Lhasa block mid-crustal sillimanite-grade melting event in the Late Cretaceous to Early Eocene related to regional heat advection caused by coeval and prolonged emplacement of Gangdese batholith units. This was followed by a higher pressure and lower temperature kyanite-grade melting event during the Middle Eocene to Early Oligocene associated with deformation and crustal thickening in the south Lhasa block, coeval with kyanite-grade metamorphism along the Himalaya, as a result of the on-going India-Asia collision. These partially-melted crustal lithologies offer potential sources (or otherwise analogs for sources) for the Miocene emplacement of adakitic intrusions previously documented in the eastern Himalayan syntaxis region. © 2013 International Association for Gondwana Research. |
| spellingShingle | Palin, R Searle, M St-Onge, MR Waters, D Roberts, N Horstwood, M Parrish, R Weller, O Chen, S Yang, J Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title_full | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title_fullStr | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title_full_unstemmed | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title_short | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
| title_sort | monazite geochronology and petrology of kyanite and sillimanite grade migmatites from the northwestern flank of the eastern himalayan syntaxis |
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