Fission-track thermochronology of the Wind River Range and other basement-cored uplifts in the Rocky Mountain foreland

Miscellaneous · Mon Jan 01 00:00:00 EST 1990

OSTI ID:5928125

Cerveny, III, P F

Fission-track analysis of apatites from basement rocks of the Laramide foreland provides information about the timing, magnitude, and apparent rate of uplift of the mountain ranges in this area. One hundred thirty-five samples were collected from various mountain ranges in the Wyoming and northern Colorado foreland, with special emphasis on the Wind River Range. Apatite ages from the flanks of the range indicate that uplift may have initiated in the Wind Rivers by about 85 Ma, but was definitely occurring by 75 Ma. Weaker evidence suggests that uplift had commenced by 100 Ma. Data from Green River Lakes and Fremont Peak in the northern part of the range indicate that uplift/cooling was occurring around 62 Ma, and was most rapid between 60 and 57 Ma. Apparent uplift rates vary from 94 m/m.y. to 246 m/m.y. in this section of the Wind Rivers. Samples from a drill hole in the central Wind Rivers have apatite ages ranging from 37 Ma to 86 Ma, confirm the rapid uplift event at 60 Ma, and suggest a significant cooling event at approximately 42 Ma involving nearly 2 km of the rock column. Ages from the Medicine Bow and bighorn ranges suggest possible uplift as early as 100 Ma. Evidence confirm that uplift was definitely occurring by 75 Ma throughout the foreland, and continued through at least 58 Ma. Data from the Beartooth Range, Park Range, and Laramie Range suggest a rapid uplift/cooling event at about 62 Ma. Data collected from Precambrian/Cambrian boundary localities throughout Wyoming indicate that the basement surface was largely within a zone of partial track annealing prior to the Laramide orogeny, and has been uplifted no more than about 5-6 km relative to the present day surface.

• Research Organization: Wyoming Univ., Laramie, WY (United States)
• OSTI ID: 5928125
• Resource Relation: Other Information: Thesis (Ph.D)
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
54 ENVIRONMENTAL SCIENCES
APATITES
FISSION TRACKS
GEOLOGIC FORMATIONS
AGE ESTIMATION
TECTONICS
ROCKY MOUNTAINS
BASEMENT ROCK
BOREHOLES
COLORADO
COOLING
DEPTH
GROUND UPLIFT
OROGENESIS
PRECAMBRIAN ERA
SAMPLING
WYOMING
ZIRCON
CAVITIES
DEVELOPED COUNTRIES
DIMENSIONS
FEDERAL REGION VIII
GEOLOGIC AGES
MINERALS
MOUNTAINS
NORTH AMERICA
PARTICLE TRACKS
PHOSPHATE MINERALS
SILICATE MINERALS
USA
580000* - Geosciences
540211 - Environment
Terrestrial- Basic Studies- Radiometric Techniques- (1990-)