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The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems

Citation

Brady, Robert John (1998) The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems. Dissertation (Ph.D.), California Institute of Technology. https://resolver.caltech.edu/CaltechTHESIS:02012019-101059213

Abstract

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages, suggest that extension within the breakaway zone occurred rapidly at ~15 Ma, consistent with earlier work (Fitzgerald, 1991). Approximately 400 km2 of the SVM was mapped at a scale of 1:12 000. This mapping shows that extension initiated on a set of steeply west dipping normal faults. Later faults soled into the earlier faults rather than cutting them, requiring motion to continue on both fault sets, with the earlier faults remaining active to dips of less than 30°. Total extension across the SVM is at least ~21 km. The latest deformation to affect the region was isostatic uplift of the footwall to the Lakeside Mine Fault Zone, with resultant formation of a basement dome and associated folding and late stage faulting adjacent to the dome. Seismic reflection data suggest that the crustal thickness of the region is 30 to 35 kilometers. When combined with the high average elevation of the denuded basement block, this suggests that extension of the upper crust has been compensated by emplacement of fluid mid to lower crust. The lower crust and Moho are seismically transparent, so the lower crust is probably not made up of basaltic intrusions; rather, it has probably flowed in from surrounding areas. A mechanical model has been developed which considers the behavior of an elastic upper crust isostatically compensated by flow in the lower crust. This model shows that gradual isostatic upwarping of the thinning region should generate compressional flexural stresses near the base of the elastic upper crust. These stresses may shut down the active faults and force new normal faults to root outside of the extended region.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:South Virgin Mountains, Colorado Plateau, Basin and Range Province, normal faults, Gold Butte, gps, thesis, phd
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Wernicke, Brian P. (advisor)
  • Sieh, Kerry E. (co-advisor)
Thesis Committee:
  • Saleeby, Jason B. (chair)
  • Farley, Kenneth A.
  • Stock, Joann M.
  • Wernicke, Brian P.
  • Sieh, Kerry E.
Defense Date:14 May 1998
Additional Information:Supplemental Files Information: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Western Lime Ridge Sheet: Supplement 1 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis) Date(s) Collected: 1993/1997. Geographic Location Bounding Box: -114.25 Degrees East; -114.308 Degrees West; 36.375 Degrees North; 36.25 Degrees South. Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Tramp Ridge and Lime Ridge Sheet: Supplement 2 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). Date(s) Collected: 1993/1997. Geographic Location Bounding Box: -114.125 Degrees East; -114.25 Degrees West; 36.375 Degrees North; 36.25 Degrees South. Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Azure Ridge Sheet: Supplement 3 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis) Date(s) Collected: 1993/1997. Geographic Location Bounding Box: -114.05 Degrees East; -114.125 Degrees West; 36.375 Degrees North; 36.25 Degrees South. Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Indian Hills to Wheeler Ridge Sheet: Supplement 4 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). Date(s) Collected: 1993/1997. Geographic Location Bounding Box: -114.0 Degrees East; -114.125 Degrees West; 36.25 Degrees North; 36.083 Degrees South. Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Northeastern Wheeler Ridge Sheet: Supplement 5 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). Date(s) Collected: 1993/1997. Geographic Location Bounding Box: -113.92 Degrees East; -114.0 Degrees West; 36.25 Degrees North; 36.125 Degrees South. Explanation for 1:12 000 Scale Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona: Supplement 6 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). Cross-sections A- A' and B- B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona: Supplement 7 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). Reconstructions of Cross-sections A- A' and B - B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona: Supplement 8 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 1: Supplement 9 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 2: Supplement 10 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 3: Supplement 11 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 5: Supplement 12 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 6: Supplement 13 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 7: Supplement 14 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis). BARGE Line 8: Supplement 15 from "The Geology of the Gold Butte Breakaway Zone and the Mechanical Evolution of Normal Fault Systems" (Thesis).
Record Number:CaltechTHESIS:02012019-101059213
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:02012019-101059213
Related URLs:
URLURL TypeDescription
https://doi.org/10.22002/D1.1718DOISupplement 1 in CaltechDATA: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Western Lime Ridge Sheet
https://doi.org/10.22002/D1.1719DOISupplement 2 in CaltechDATA: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Tramp Ridge and Lime Ridge Sheet
https://doi.org/10.22002/D1.1720DOISupplement 3 in CaltechDATA: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Azure Ridge Sheet
https://doi.org/10.22002/D1.1721DOISupplement 4 in CaltechDATA: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Indian Hills to Wheeler Ridge Sheet
https://doi.org/10.22002/D1.1722DOISupplement 5 in CaltechDATA: Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Northeastern Wheeler Ridge Sheet
https://doi.org/10.22002/D1.1723DOISupplement 6 in CaltechDATA: Explanation for 1:12 000 Scale Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona
https://doi.org/10.22002/D1.1724DOISupplement 7 in CaltechDATA: Cross-sections A- A' and B- B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona
https://doi.org/10.22002/D1.1725DOISupplement 8 in CaltechDATA: Reconstructions of Cross-sections A- A' and B - B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona
https://doi.org/10.22002/D1.1726DOISupplement 9 in CaltechDATA: BARGE Line 1
https://doi.org/10.22002/D1.1727DOISupplement 10 in CaltechDATA: BARGE Line 2
https://doi.org/10.22002/D1.1728DOISupplement 11 in CaltechDATA: BARGE Line 3
https://doi.org/10.22002/D1.1729DOISupplement 12 in CaltechDATA: BARGE Line 5
https://doi.org/10.22002/D1.1730DOISupplement 13 in CaltechDATA: BARGE Line 6
https://doi.org/10.22002/D1.1731DOISupplement 14 in CaltechDATA: BARGE Line 7
https://doi.org/10.22002/D1.1732DOISupplement 15 in CaltechDATA: BARGE Line 8
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11380
Collection:CaltechTHESIS
Deposited By: Tony Diaz
Deposited On:01 Feb 2019 19:46
Last Modified:15 Dec 2020 21:39

Thesis Files

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PDF (Thesis) - Final Version
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60MB
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PDF (Plate 1a - Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Western Lime Ridge Sheet) - Supplemental Material
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156MB
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PDF (Plate 1b - Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Tramp Ridge and Lime Ridge Sheet) - Supplemental Material
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266MB
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PDF (Plate 1c - Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Azure Ridge Sheet) - Supplemental Material
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170MB
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PDF (Plate 1d - Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Indian Hills to Wheeler Ridge Sheet) - Supplemental Material
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PDF (Plate 1e - Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona; Northeastern Wheeler Ridge Sheet) - Supplemental Material
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188MB
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PDF (Plate 2 - Explanation for 1:12 000 Scale Geologic Map of the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona) - Supplemental Material
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56MB
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PDF (Plate 3 - Cross-sections A- A' and B- B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona) - Supplemental Material
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9MB
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PDF (Plate 4 - Reconstructions of Cross-sections A- A' and B - B' from the South Virgin Mountains, Southeastern Nevada and Northwestern Arizona) - Supplemental Material
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239MB
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PDF (Plate 5 - BARGE Line 1) - Supplemental Material
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PDF (Plate 9 - BARGE Line 6) - Supplemental Material
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PDF (Plate 10 - BARGE Line 7) - Supplemental Material
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PDF (Plate 11 - BARGE Line 8) - Supplemental Material
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