POTASSIUM-ARGON DATING OF THE LATE TERTIARY VOLCANICS AND MINERALIZATION OF MARYSVALE, UTAH
S>The Tertiary flows and intrusives of the Marysvale, Utah area yield several materials that provide reliable absolute ages by the potassium-argon method. A layered sequence of potassium-bearing mid-Tertiary flows and tuffs of the Bullion Canyon series overlies fossil-bearing Oligocene sedimentary strata of the Wasatch formation. The series is invaded by a quartz monzonite intrusive which contains biotite. A sequence of iate Tertiary volcanic rocks, the Mount Belknap series, contains potassiumbearing glasses and rests upon an old erosional surface which truncates both the Bullion Canyon and the quartz monzonite intrusive. Glassy dikes cut the quartz monzonite intrusive, and diatreme structures containing glass pierce the Bullion Canyon flows. Late Tertiary veins which contain uraninite cut the quartz monzonite intrusive and spread into lenticular masses at the base of the Mourt Belknap flows. The uraninite provides a source of materiai for uranium-lead determinations. The absolute age of the Bullion Canyon series is approximately 30 m.y. and of the quartz monzonite intrusives is approximately 25 m.y. The most reliable age for the glassy dikes and diatremes is believed to be about 20 m.y. The determinations on glassy flows of the Mount Belknap range from 14 to 20 m.y. but alteration apparently accounts for the low ages in this range and the true age for the Mount Belknap is probably about 20 m.y. Sericite frora a nearby leadzinc-silver mine gives an age of 13.5 m.y. and the uraninite dated by uranium-lead method was found to be about 13 m.y. by Donald Miller based on work done at the Lamont Geological Observatory. (auth)
- Research Organization:
- Brookhaven National Lab., Upton, N.Y.; Columbia Univ., New York
- DOE Contract Number:
- AT(30-2)-GEN-16
- NSA Number:
- NSA-17-040989
- OSTI ID:
- 4701109
- Report Number(s):
- BNL-5555
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
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