U-PB AGES AND SM-ND SIGNATURE OF 2 SUBSURFACE GRANITES FROM THE FORT SIMPSON MAGNETIC HIGH, NORTHWEST CANADA

被引:56
作者
VILLENEUVE, ME [1 ]
THERIAULT, RJ [1 ]
ROSS, GM [1 ]
机构
[1] INST SEDIMENTARY & PETR GEOL, CALGARY T2L 2A7, ALBERTA, CANADA
关键词
D O I
10.1139/e91-091
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Two undeformed biotite granites recovered from exploratory hydrocarbon drill holes that penetrated basement in the Fort Simpson magnetic high were analyzed for U-Pb zircon geochronology and Sm-Nd isotopic composition. Both samples give crystallization ages of 1845 Ma, with errors of less than 5 Ma. This age overlaps with the waning stages of magmatism in the Great Bear magmatic zone of Wopmay Orogen, 200 km to the east. One sample has an initial epsilon(Nd) of +1.3 and a T(DM) of 2.14 Ga, whereas the other yielded an initial epsilon(Nd) of -2.1 and a T(DM) of 2.45 Ga. The latter sample indicates that Early Proterozoic light rare-earth element enriched lithosphere with a crustal history dating back to at least 2.45 Ga is present in the subsurface west of Wopmay Orogen.
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页码:1003 / 1008
页数:6
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