U-Pb zircon age data from meta-igneous rocks in the Clearwater Mountains, Mount Hayes A-6 Quadrangle, Alaska
Dates
Publication Date
2016
Start Date
2013
End Date
2016
File Modification Date
2016-05-13 16:11:00
Citation
Twelker, Evan, and O'Sullivan, P.B., 2016, U-Pb zircon age data from meta-igneous rocks in the Clearwater Mountains, Mount Hayes A-6 Quadrangle, Alaska: Alaska Division of Geological & Geophysical Surveys, http://dx.doi.org/10.14509/29663.
Summary
We report U-Pb zircon geochronology results for one metavolcanic and one metaplutonic rock sample from the Mount Hayes A-6 Quadrangle of central Alaska. These samples are representative of rock units assigned to the Clearwater terrane of Jones and others (1987), a sequence of greenschist-grade metavolcanic and metasedimentary rocks of poorly constrained age and tectonic origin. Our results indicate a crystallization age of 277.33 +/- 11.84 Ma for a felsic metavolcanic rock, and a 268.05 +/- 11.64 Ma crystallization age for a granitic metaplutonic unit intruding the former.
Summary
We report U-Pb zircon geochronology results for one metavolcanic and one metaplutonic rock sample from the Mount Hayes A-6 Quadrangle of central Alaska. These samples are representative of rock units assigned to the Clearwater terrane of Jones and others (1987), a sequence of greenschist-grade metavolcanic and metasedimentary rocks of poorly constrained age and tectonic origin. Our results indicate a crystallization age of 277.33 +/- 11.84 Ma for a felsic metavolcanic rock, and a 268.05 +/- 11.64 Ma crystallization age for a granitic metaplutonic unit intruding the former.
The metamorphic rocks of the Clearwater terrane form an alleged tectonostratigraphic terrane approximately 2 by 10 km in extent in the northwestern corner of the Mount Hayes A-6 Quadrangle. Based on limited fossil evidence, the terrane has been variously interpreted as a structurally-bound fragment of a Late Triassic volcanic arc or potentially a window into middle to late Paleozoic metamorphic basement underlying Wrangellia. We applied U-Pb zircon geochronology to two samples of meta-igneous rocks to resolve the uncertainty surrounding the precise age and regional correlations of this terrane.
