TY - JOUR
T1 - Cenozoic crustal extension in southeastern Arizona and implications for models of core-complex development
AU - Arca, M. Serkan
AU - Kapp, Paul
AU - Johnson, Roy A.
N1 - Funding Information:
We thank ConocoPhillips and Robert Krantz for the release of 2D seismic data to the University of Arizona. This study has benefited from helpful discussions with John Spencer, Mark Gettings, Susan Beck, George Zandt, George Gehrels, and Steve Richard. We also thank Dr. Fabrizio Storti and two anonymous reviewers for suggestions that significantly improved the manuscript. We thank Kiriaki Xiluri for computer support; Doug Hirschberg for ARCGIS support; AZGS for contributions of geologic maps; Trey Wagner and Mark Warren for helpful insights in seismic data processing and interpretation; Facundo Fuentes, Moussa Bari and Mark Warren for field assistance and U–Pb sample collection; Victor Valencia and Maurico Mejia–Ibanez for help in U–Pb data analysis; NSF-EAR 0443387 and 0732436 for support of the Arizona LaserChron Center; Christian Manthei for help in petrographic analysis. Seismic processing and interpretation software used in this research were provided by Landmark Graphics Corporation via the Landmark University Grant Program. Financial support for Serkan Arca was provided by the SEG Chevron-Texaco E&P and Michael C. Forrest Scholarship and by the BP Corporation .
PY - 2010/6
Y1 - 2010/6
N2 - In conventional models of Cordilleran-style metamorphic core-complex development, initial extension occurs along a breakaway fault, which subsequently is deformed into a synform and abandoned in response to isostatic rebound and new faults breaking forward in the dominant transport direction. The Catalina core complex and associated geology in southeastern Arizona have been pointed to as a type example of this model. From southwest to northeast, the region is characterized by the NW-SE trending Tucson basin, the Catalina core complex, the San Pedro trough and the Galiuro Mountains. The Catalina core complex is bounded by the top-to-the-southwest Catalina detachment fault along its southwestern flank and the low-angle, northeast-dipping San Pedro fault along its northeastern flank. The Galiuro Mountains expose non-mylonitic rocks and are separated from the San Pedro trough to the southwest by a system of low- to moderate-angle southwest-dipping normal faults. This Galiuro fault system is widely interpreted to be the breakaway zone for the Catalina core complex. It is inferred to be folded into a synform beneath the San Pedro trough, to resurface to the southwest as the San Pedro fault, and to have been abandoned during slip along the younger Catalina detachment. This study aimed to test this model through analysis of field relations and geochronological age constraints, and reprocessing and interpretation of 2-D seismic reflection data from the Catalina core complex and San Pedro trough. In contrast to predictions of the conventional breakaway zone model, we raise the possibility of a moderate-angle, southwest-dipping detachment fault beneath the San Pedro trough that could extend to mid-crustal depths beneath the eastern flank of the Catalina Mountains. We present an alternative kinematic model in which extension was accommodated by a pair of top-to-the-southwest normal-fault systems (the Catalina and Galiuro detachment faults), with the only major difference between the two being the magnitude of displacement, which was greater for the Catalina detachment.
AB - In conventional models of Cordilleran-style metamorphic core-complex development, initial extension occurs along a breakaway fault, which subsequently is deformed into a synform and abandoned in response to isostatic rebound and new faults breaking forward in the dominant transport direction. The Catalina core complex and associated geology in southeastern Arizona have been pointed to as a type example of this model. From southwest to northeast, the region is characterized by the NW-SE trending Tucson basin, the Catalina core complex, the San Pedro trough and the Galiuro Mountains. The Catalina core complex is bounded by the top-to-the-southwest Catalina detachment fault along its southwestern flank and the low-angle, northeast-dipping San Pedro fault along its northeastern flank. The Galiuro Mountains expose non-mylonitic rocks and are separated from the San Pedro trough to the southwest by a system of low- to moderate-angle southwest-dipping normal faults. This Galiuro fault system is widely interpreted to be the breakaway zone for the Catalina core complex. It is inferred to be folded into a synform beneath the San Pedro trough, to resurface to the southwest as the San Pedro fault, and to have been abandoned during slip along the younger Catalina detachment. This study aimed to test this model through analysis of field relations and geochronological age constraints, and reprocessing and interpretation of 2-D seismic reflection data from the Catalina core complex and San Pedro trough. In contrast to predictions of the conventional breakaway zone model, we raise the possibility of a moderate-angle, southwest-dipping detachment fault beneath the San Pedro trough that could extend to mid-crustal depths beneath the eastern flank of the Catalina Mountains. We present an alternative kinematic model in which extension was accommodated by a pair of top-to-the-southwest normal-fault systems (the Catalina and Galiuro detachment faults), with the only major difference between the two being the magnitude of displacement, which was greater for the Catalina detachment.
KW - Breakaway zone
KW - Crustal extension
KW - Detachment fault
KW - Metamorphic core complex
KW - San Pedro trough
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U2 - 10.1016/j.tecto.2010.03.021
DO - 10.1016/j.tecto.2010.03.021
M3 - Article
AN - SCOPUS:77953809923
VL - 488
SP - 174
EP - 190
JO - Tectonophysics
JF - Tectonophysics
SN - 0040-1951
IS - 1-4
ER -