Thermal history of crystalline nappes of the Maria fold and thrust belt, west central Arizona

Journal Article · Sat Nov 10 04:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB12p20049· OSTI ID:5262883

Knapp, J H ^[1]; Heizler, M T ^[2]

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1. Massachusetts Inst. of Tech., Cambridge (USA)
2. State Univ. of New York, Albany (USA)

The thermal history of the crust in west central Arizona, as documented by {sup 40}Ar/{sup 39}Ar step-heating analysis of mineral suites from crystalline nappes of the Maria fold and thrust belt, is characterized by three distinct stages for Late Cretaceous and Tertiary time. Regional heating of the crust occurred during basement-involved folding and thrust faulting in middle Late Cretaceous time and represents the earliest phase recorded by the {sup 40}/{sup 39}Ar data. The second stage was dominated by uplift and slow cooling (5-10C/m.y.) of the crust throughout latest Cretaceous and early Tertiary time. Tectonic denudation in late Oligocene to early Miocene time resulted in rapid uplift and cooling of midcrustal rocks in the footwall of the Whipple-Buckskin-Rawhide detachment system, marking the final thermal signature in the region. Partially outgassed hornblende in the northern Granite Wash Mountains reflects temperatures of {approximately}450C, whereas complete resetting of hornblende at Mesquite Mountain suggests that this area attained temperatures in excess of 500C. In contrast, data from the northern Plomosa Mountains indicate that this area did not attain temperatures sufficient to completely degas biotite or K-feldspar during Late Cretaceous time. Either (1) lower plate rocks were still sufficiently hot following Late Cretaceous heating that argon clocks were set simply due to rapid cooling or (2) the area experienced a renewed thermal input associated with extension, causing argon loss from previously cool rocks. Based on consideration of diffusion domain behavior in K-feldspars, the authors infer that a renewed thermal pulse was associated with the early stages of extension and was related to the cause for crustal weakening.

• OSTI ID: 5262883
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:B12; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
AMPHIBOLE
ARGON 39
ARGON 40
ARGON ISOTOPES
ARIZONA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOTITE
CENOZOIC ERA
CONTINENTAL CRUST
COOLING
CRETACEOUS PERIOD
DEFORMATION
DEGASSING
DEVELOPED COUNTRIES
EARTH CRUST
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION IX
FELDSPARS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GROUND UPLIFT
HEATING
HORNBLENDE
ISOTOPE DATING
ISOTOPES
LIGHT NUCLEI
MESOZOIC ERA
MICA
MINERALS
MOUNTAINS
MUSCOVITE
NORTH AMERICA
NUCLEI
RADIOISOTOPES
RESERVOIR TEMPERATURE
SILICATE MINERALS
STABLE ISOTOPES
TECTONICS
TERTIARY PERIOD
THERMAL ANALYSIS
USA
YEARS LIVING RADIOISOTOPES