Journal article
Nd and Sr isotopic constraints on the petrogenesis of the west side of the northern Coast Mountains Batholith, Alaskan and Canadian Cordillera
Canadian journal of earth sciences, Vol.28(6), pp.939-946
Geological Association of Canada--Mineralogical Association of Canada (GAC-MAC) annual general meeting, symposium on Geological transect: northwestern Canadian Cordillera
06/1991
DOI: 10.1139/e91-085
Abstract
Nd and Sr isotopic ratios are reported from 15 samples of plutons of the N Coast Mountains batholith (CMB), between the Alexander- Wrangellia terrain and the Stikine terrain of SE Alaska. Samples of plutons that are part of the late Cretaceous-Eocene CMB suite have a range in initial epsilon Nd of -3.0 to -0.2 and (super 87) Sr/ (super 86) Sr of 0.70494-0.70607. There is no correlation of isotopic ratio with age, lithology, or geographic location of these plutons. Two plutons that are probably older than the bulk of the CMB plutons have present-day epsilon Nd values of -6.8 to - 2.6. The late Cretaceous-Eocene plutons have Nd depleted-mantle model ages (t (sub DM) ) of 620-1070 m.y. These data indicate that the northern CMB must contain a significant component of old, evolved continental crust. The presence of an old crustal component is further demonstrated by inherited zircons of average early Proterozoic age contained in some plutons. The mid- to late- Proterozoic t (sub DM) ages of the CMB plutons are therefore a result of a mixture of early Proterozoic crustal material with younger, juvenile crust. The most likely source of this old crustal component is the Yukon-Tanana terrain, a fragment composed of ancient crustal material that occurs within and directly to the west of the N CMB. The juvenile component is probably a combination of material derived from the mantle and from anatexis of the surrounding juvenile terrains.
Details
- Title: Subtitle
- Nd and Sr isotopic constraints on the petrogenesis of the west side of the northern Coast Mountains Batholith, Alaskan and Canadian Cordillera
- Creators
- Scott D Samson - University of ArizonaP. Jonathan Patchett - University of ArizonaWilliam C McClelland - University of ArizonaGeorge E Gehrels - University of Arizona
- Contributors
- R. G Anderson (Editor) - Geol. Surv. Can., Cordilleran Div. Vancouver, BC CAN Canada
- Resource Type
- Journal article
- Publication Details
- Canadian journal of earth sciences, Vol.28(6), pp.939-946
- Conference
- Geological Association of Canada--Mineralogical Association of Canada (GAC-MAC) annual general meeting, symposium on Geological transect: northwestern Canadian Cordillera
- Publisher
- National Research Council of Canada
- DOI
- 10.1139/e91-085
- ISSN
- 0008-4077
- eISSN
- 1480-3313
- Alternative title
- Contributions to the geology and geophysics of northwestern British Columbia and southeastern Alaska--Contributions a la geologie et a la geophysique du nord-ouest de la Colombie-Britannique et du sud-est de l'Alaska
- Language
- English; French
- Date published
- 06/1991
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229303802771
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