40Ar/39Ar data from rocks collected in the 2015 Wrangellia mineral assessment project area, Mount Hayes A-5, Mount Hayes B-6, and Talkeetna Mountains D-2 quadrangles, Alaska
Dates
Publication Date
2017
Start Date
2015
End Date
2017
File Modification Date
2017-04-04 17:40:00
Citation
Benowitz, J.A., Layer, P.W., Wypych, Alicja, and Twelker, Evan, 2017, 40Ar/39Ar data from rocks collected in the 2015 Wrangellia mineral assessment project area, Mount Hayes A-5, Mount Hayes B-6, and Talkeetna Mountains D-2 quadrangles, Alaska: Alaska Division of Geological & Geophysical Surveys, http://doi.org/10.14509/29699.
Summary
This report presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) Wrangellia Mineral Assessment project, part of a multi-year effort focusing on improving the publicly available geoscientific information for the western Wrangellia terrane. The samples described in this report were selected and analyzed to improve our understanding of the geology and structural history of the Wrangellia Mineral Assessment project area. A metagabbro rock sample returned a Late Triassic crystallization age consistent with regional ages for Nikolai Greenstone-related magmatism; however, the two amphibole separates ages do not overlap, and have larger [...]
Summary
This report presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) Wrangellia Mineral Assessment project, part of a multi-year effort focusing on improving the publicly available geoscientific information for the western Wrangellia terrane. The samples described in this report were selected and analyzed to improve our understanding of the geology and structural history of the Wrangellia Mineral Assessment project area. A metagabbro rock sample returned a Late Triassic crystallization age consistent with regional ages for Nikolai Greenstone-related magmatism; however, the two amphibole separates ages do not overlap, and have larger errors than expected due to alteration. An Early Cretaceous age obtained on a syenogranite pluton could correspond to similar ages of an Early Cretaceous porphyry event within the Grubstake Cu-Au porphyry system, Slana Region. Finally, we obtained Oligocene ages for a dacitic dike and a schist; the schist age constrains the timing of displacement on a thrust fault in the area. Analyses were performed by the University of Alaska Fairbanks (UAF) Geochronology Laboratory, and results were reported by Jeff Benowitz and Paul Layer. Products included in this data release are a summary of sample collection methods, the laboratory report, analytical data tables and associated metadata, and plots of the 40Ar/39Ar age spectra and Ca/K and Cl/K ratios.
The DGGS Mineral Resources section carried out geologic mapping and sampling in the eastern Denali Highway region between Watana Creek and Paxson from July 29 through August 7, 2015. The project focused on characterization of a broad section of Wrangellia stratigraphy, including Late Triassic rocks of the Ni-Cu-Co-PGE- and Cu-Ag-mineralized Wrangellia large igneous province, as well as modern geochemical characterizations of skarn-, vein-, and basalt-hosted Cu mineralization. The samples described in this report were selected and analyzed to improve our understanding of the geology and structural history of the Wrangellia Mineral Assessment project area.
