气候变化领域集成服务门户(CCPortal): Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA

CCPortal

DOI	10.1130/B35665.1
	Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA
	Waldien T.S.; Roeske S.M.; Benowitz J.A.; Twelker E.; Miller M.S.
发表日期	2021
ISSN	167606
起始页码	691
结束页码	716
卷号	133
英文摘要	Terrane accretion forms lithospheric-scale fault systems that commonly experience long and complex slip histories. Unraveling the evolution of these suture zone fault systems yields valuable information regarding the relative importance of various upper crustal structures and their linkage through the lithosphere. We present new bedrock geologic mapping and geochronology data documenting the geologic evolution of reactivated shortening structures and adjacent metamorphic rocks in the Alaska Range suture zone at the inboard margin of the Wrangellia composite terrane in the eastern Alaska Range, Alaska, USA. Detrital zircon uranium-lead (U-Pb) age spectra from metamorphic rocks in our study area reveal two distinct metasedimentary belts. The Maclaren schist occupies the inboard (northern) belt, which was derived from terranes along the western margin of North America during the mid- to Late Cretaceous. In contrast, the Clearwater metasediments occupy the outboard (southern) belt, which was derived from arcs built on the Wrangellia composite terrane during the Late Jurassic to Early Cretaceous. A newly discovered locality of Alaska-type zoned ultramafic bodies within the Clearwater metasediments provides an additional link to the Wrangellia composite terrane. The Maclaren and Clearwater metasedimentary belts are presently juxtaposed by the newly identified Valdez Creek fault, which is an upper crustal reactivation of the Valdez Creek shear zone, the Late Cretaceous plate boundary that initially brought them together. 40/39Ar mica ages reveal independent post-collisional thermal histories of hanging wall and footwall rocks until reactivation localized on the Valdez Creek fault after ca. 32 Ma. Slip on the Valdez Creek fault expanded into a thrust system that progressed southward to the Broxson Gulch fault at the southern margin of the suture zone and eventually into the Wrangellia terrane. Detrital zircon U-Pb age spectra and clast assemblages from fault-bounded Cenozoic gravel deposits indicate that the thrust system was active during the Oligocene and into the Pliocene, likely as a far-field result of ongoing flat-slab subduction and accretion of the Yakutat microplate. The Valdez Creek fault was the primary reactivated structure in the suture zone, likely due to its linkage with the reactivated boundary zone between the Wrangellia composite terrane and North America in the lithospheric mantle. © 2020 Geological Society of America
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184700
作者单位	Department of Earth and Planetary Sciences, University of California, Shields Avenue Davis, Davis, California 95616, United States; Geophysical Institute, University of Alaska, 900 Yukon Drive Fairbanks, Fairbanks, Alaska 99775, United States; Alaska Division of Geological and Geophysical Surveys, 3354 College Road, Fairbanks, Alaska 99709, United States; Research School of Earth Sciences, Australian National University, Building 142,Mills Road, Canberra, ACT 2601, Australia
推荐引用方式 GB/T 7714	Waldien T.S.,Roeske S.M.,Benowitz J.A.,et al. Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA[J],2021,133.
APA	Waldien T.S.,Roeske S.M.,Benowitz J.A.,Twelker E.,&Miller M.S..(2021).Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA.Bulletin of the Geological Society of America,133.
MLA	Waldien T.S.,et al."Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA".Bulletin of the Geological Society of America 133(2021).