Tectonic significance of an Early Proterozoic two-province boundary in central Arizonaстатья из журнала
Аннотация: Research Article| October 01, 1987 Tectonic significance of an Early Proterozoic two-province boundary in central Arizona KARL E. KARLSTROM; KARL E. KARLSTROM 1Department of Geology, Northern Arizona University, Flagstaff, Arizona 86011 Search for other works by this author on: GSW Google Scholar SAMUEL A. BOWRING; SAMUEL A. BOWRING 2Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar CLAY M. CONWAY CLAY M. CONWAY 3U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, Arizona 86001 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1987) 99 (4): 529–538. https://doi.org/10.1130/0016-7606(1987)99<529:TSOAEP>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation KARL E. KARLSTROM, SAMUEL A. BOWRING, CLAY M. CONWAY; Tectonic significance of an Early Proterozoic two-province boundary in central Arizona. GSA Bulletin 1987;; 99 (4): 529–538. doi: https://doi.org/10.1130/0016-7606(1987)99<529:TSOAEP>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A compilation of U-Pb zircon dates for lower Proterozoic rocks in central Arizona shows that, although rocks tend to be older in the northwest (1800−1696 m.y.) than the southeast (1738−1630 m.y.), there is no single boundary separating distinct geochronologic provinces in Arizona. Instead, the distribution of isotopic ages reflects the presence of two major tectonic provinces separated by a regionally subhorizontal boundary or boundaries. The northwestern part of central Arizona contains the Yavapai Series (1800−1755 m.y.) and calc-alkaline batholiths (1750−1696 m.y.), both believed to represent oceanic island-arc materials. The southeastern part of central Arizona is dominated by the Alder, Red Rock, and Mazatzal Groups and related hypabyssal intrusions (1710−1692 m.y.), with voluminous rhyolitic ash-flow tuffs and quartz arenite believed to record a relatively stable continental tectonic setting.Two working hypotheses emerge to explain the juxtaposition of representatives of these two tectonic provinces over a 100-km-wide zone in central Arizona. One interpretation (model 1) suggests that rocks of the southeast province were deposited with angular unconformity on newly accreted continental crust composed of northwest province rocks. A second interpretation (model 2) suggests that the two areas represent allochthonous terranes that evolved separately and were juxtaposed by large subhorizontal movements on thrusts and strike-slip faults. An important new constraint is that the 1699-m.y.-old strongly peraluminous Crazy Basin Quartz Monzonite was emplaced in the northwest province during ductile deformation at depths greater than 8 km at the same time that rhyolitic ash-flow tuffs and quartz arenite were being deposited in the southeast province. For model 1, this implies a rapid change of tectonic regimes about 1700 Ma, from convergence to uplift, erosion, sedimentation, and possibly extension. For model 2, the differences in crustal level, structural style, and petrologic affinity between ∼1700-m.y.-old rocks in both provinces are believed to result from juxtaposition of different crustal blocks after 1700 Ma. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Год издания: 1987
Авторы: Karl E. Karlstrom, Samuel A. Bowring, Clay M. Conway
Издательство: Geological Society of America
Источник: Geological Society of America Bulletin
Ключевые слова: Geological and Geochemical Analysis, Geology and Paleoclimatology Research, Geochemistry and Geologic Mapping
Открытый доступ: closed
Том: 99
Выпуск: 4
Страницы: 529–529