Geochronometric study of a Tertiary lamprophyre, MacMillan Pass, Yukon Territory

Description

During 1977, Archer, Cathro and Associates Limited noted a number of conformable or paraconformable sills, at least 30 cm thick, of locally vesicular porphyritic augite-hornblende-biotite lamprophyre. Potassium argon analyses of biotite and hornblende indicate a concordant Upper Eocene age. Rubidium strontium isotopic data indicates a 87 Sr/86 Sr ratio of 0.7066. The calculated initial ratio, using a 40.3 Ma age, is 0.7065. This initial ratio is not unreasonable for alkalic igneous rocks in anorogenic settings.

Resources

Name Format Description Link
Yukon Geological Survey publication metadata HTML https://data.geology.gov.yk.ca/Reference/42529
Original metadata (https://open.yukon.ca) HTML https://open.yukon.ca/information/0d93189b-519e-4a6d-8400-e745ac3d6214
Report PDF https://ygsftp.gov.yk.ca/publications/mir/min_in_rep77.pdf

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