U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture
We present U-Pb geochronologic and Hf isotopic data from 29 plutonic samples within the Coast Mountain batholith, north-coastal British Columbia and southeast Alaska. Hf isotopic values do not correlate with age or variation in magmatic flux, but rather they increase systematically from west (ε_(Hf...
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Geological Society of America
2011
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ftcaltechauth:oai:authors.library.caltech.edu:e19wq-e4250 2024-06-23T07:51:36+00:00 U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture Cecil, M. Robinson Gehrels, George Ducea, Mihai N. Patchett, P. Jonathan 2011-08 https://doi.org/10.1130/L134.1 unknown Geological Society of America https://doi.org/10.1130/L134.1 oai:authors.library.caltech.edu:e19wq-e4250 eprintid:24859 resolverid:CaltechAUTHORS:20110815-111358170 info:eu-repo/semantics/closedAccess Other Lithosphere, 3(4), 247-260, (2011-08) info:eu-repo/semantics/article 2011 ftcaltechauth https://doi.org/10.1130/L134.1 2024-06-12T02:00:33Z We present U-Pb geochronologic and Hf isotopic data from 29 plutonic samples within the Coast Mountain batholith, north-coastal British Columbia and southeast Alaska. Hf isotopic values do not correlate with age or variation in magmatic flux, but rather they increase systematically from west (ε_(Hf)[t] = +2 to +5) to east (ε_(Hf)[t] = +10 to +13) in response to changing country rock assemblages. By comparing our pluton Hf data with previously reported Nd-Sr and detrital zircon characteristics of associated country rocks, we identify three crustal domains in an area where crustal affinity is largely obscured by metamorphism and voluminous pluton intrusion: (1) a western domain, emplaced into continental-margin strata of the Banks Island assemblage; (2) a central domain, emplaced into the Alexander terrane; and (3) an eastern domain, underlain by the Stikine terrane and its inferred metamorphic equivalents. Between the interpreted Alexander and Stikine terranes, there is a zone of variable ε_(Hf)(t) (+2 to +13) that coincides with the suture zone separating inboard (Stikine and Yukon-Tanana) from outboard (Alexander and associated) terranes. This variation in ε_(Hf)(t) values apparently results from the structural imbrication of juvenile (Alexander and Stikine) and evolved (Yukon-Tanana) terranes along mid-Cretaceous thrust faults and the latest Cretaceous–early Tertiary Coast shear zone. Shifts in the Hf values of plutons across inferred terranes imply that they are separated at lower- to midcrustal levels by steep boundaries. Correlation between these Hf values and the isotopic character of exposed country rocks further implies the presence of those or similar rocks at magma-generation depths. © 2011 Geological Society of America. Manuscript received: 2 January 2011; revised manuscript received: 3 May 2011; manuscript accepted: 4 May 2010. This work was sponsored by National Science Foundation (NSF) award EAR-0309885 for support of the BATHOLITHS projects, and by EAR-0732436 for support of the Arizona ... Article in Journal/Newspaper Banks Island Alaska Yukon Caltech Authors (California Institute of Technology) Stikine ENVELOPE(-131.803,-131.803,56.699,56.699) Yukon Lithosphere 3 4 247 260 |
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Caltech Authors (California Institute of Technology) |
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description |
We present U-Pb geochronologic and Hf isotopic data from 29 plutonic samples within the Coast Mountain batholith, north-coastal British Columbia and southeast Alaska. Hf isotopic values do not correlate with age or variation in magmatic flux, but rather they increase systematically from west (ε_(Hf)[t] = +2 to +5) to east (ε_(Hf)[t] = +10 to +13) in response to changing country rock assemblages. By comparing our pluton Hf data with previously reported Nd-Sr and detrital zircon characteristics of associated country rocks, we identify three crustal domains in an area where crustal affinity is largely obscured by metamorphism and voluminous pluton intrusion: (1) a western domain, emplaced into continental-margin strata of the Banks Island assemblage; (2) a central domain, emplaced into the Alexander terrane; and (3) an eastern domain, underlain by the Stikine terrane and its inferred metamorphic equivalents. Between the interpreted Alexander and Stikine terranes, there is a zone of variable ε_(Hf)(t) (+2 to +13) that coincides with the suture zone separating inboard (Stikine and Yukon-Tanana) from outboard (Alexander and associated) terranes. This variation in ε_(Hf)(t) values apparently results from the structural imbrication of juvenile (Alexander and Stikine) and evolved (Yukon-Tanana) terranes along mid-Cretaceous thrust faults and the latest Cretaceous–early Tertiary Coast shear zone. Shifts in the Hf values of plutons across inferred terranes imply that they are separated at lower- to midcrustal levels by steep boundaries. Correlation between these Hf values and the isotopic character of exposed country rocks further implies the presence of those or similar rocks at magma-generation depths. © 2011 Geological Society of America. Manuscript received: 2 January 2011; revised manuscript received: 3 May 2011; manuscript accepted: 4 May 2010. This work was sponsored by National Science Foundation (NSF) award EAR-0309885 for support of the BATHOLITHS projects, and by EAR-0732436 for support of the Arizona ... |
format |
Article in Journal/Newspaper |
author |
Cecil, M. Robinson Gehrels, George Ducea, Mihai N. Patchett, P. Jonathan |
spellingShingle |
Cecil, M. Robinson Gehrels, George Ducea, Mihai N. Patchett, P. Jonathan U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
author_facet |
Cecil, M. Robinson Gehrels, George Ducea, Mihai N. Patchett, P. Jonathan |
author_sort |
Cecil, M. Robinson |
title |
U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
title_short |
U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
title_full |
U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
title_fullStr |
U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
title_full_unstemmed |
U-Pb-Hf characterization of the central Coast Mountains batholith: Implications for petrogenesis and crustal architecture |
title_sort |
u-pb-hf characterization of the central coast mountains batholith: implications for petrogenesis and crustal architecture |
publisher |
Geological Society of America |
publishDate |
2011 |
url |
https://doi.org/10.1130/L134.1 |
long_lat |
ENVELOPE(-131.803,-131.803,56.699,56.699) |
geographic |
Stikine Yukon |
geographic_facet |
Stikine Yukon |
genre |
Banks Island Alaska Yukon |
genre_facet |
Banks Island Alaska Yukon |
op_source |
Lithosphere, 3(4), 247-260, (2011-08) |
op_relation |
https://doi.org/10.1130/L134.1 oai:authors.library.caltech.edu:e19wq-e4250 eprintid:24859 resolverid:CaltechAUTHORS:20110815-111358170 |
op_rights |
info:eu-repo/semantics/closedAccess Other |
op_doi |
https://doi.org/10.1130/L134.1 |
container_title |
Lithosphere |
container_volume |
3 |
container_issue |
4 |
container_start_page |
247 |
op_container_end_page |
260 |
_version_ |
1802642712575344640 |