气候变化领域集成服务门户(CCPortal): Thermochronology of sandstone-hosted secondary Fe- and Mn-oxides near Moab, Utah: Record of paleo-fluid flow along a fault

CCPortal

DOI	10.1130/B31627.1
	Thermochronology of sandstone-hosted secondary Fe- and Mn-oxides near Moab, Utah: Record of paleo-fluid flow along a fault
	Garcia V.H.; Reiners P.W.; Shuster D.L.; Idleman B.; Zeitler P.K.
发表日期	2018
ISSN	167606
起始页码	93
结束页码	113
卷号	130 期号:2021-01-02
英文摘要	Secondary Fe- and Mn-oxides are locally common near faults and fractures within sandstones of the Colorado Plateau in the form of cements, concretions, and fracturefill material. However, little is known about how and why these oxides formed, and less is understood about when they formed. In this study, we integrated field observations, detailed scanning electron microscope and petrographic observations, and (U-Th)/He and 40Ar/39Ar dating to better understand the formation of Fe- and Mn-oxides from three fault zones in Flat Iron Mesa, Utah. Most Feand Mn-oxide (U-Th)/He ages range from 0.50 to 3.4 Ma, which are much younger than 40Ar/39Ar ages of 25-20 Ma from a previous study. Current40Ar/39Ar ages on a Mn-oxide sample from this study yielded a plateau age of 3.6 ± 0.08 Ma. 4He/3He diffusion data from Fe- and Mn-oxides are consistent with the presence of multiple diffusion domains with varying He retentivity. Predicted fractional radiogenic He retention over 3.6 m.y. at nearsurface temperatures for the bulk samples, with domain proportions of the diffusion experiments, is ~90% for Fe-oxide and ~45% for Mn-oxide. The multidomain behavior exhibited by the oxides and the variability observed in (U-Th)/He ages among aliquots are consistent with variable amounts of diffusive loss of He within dated aliquots. Using 4He/3He data and He bulk ages, step-age plots indicate a high fractional release plateau at ca. 3.6 Ma, concordant with 40Ar/39Ar dating and most of the oldest (U-Th)/He ages observed. Taken together, these results are most consistent with formation of Flat Iron Mesa Fe- and Mn-oxides near the surface (< 0.5 km) at 3.6 Ma, due to hydrologic changes, fault activity, or both. Our data and interpretations suggest that erosional exhumation rates over ~1-4 m.y. time scales may be variable in the central Colorado Plateau, possibly driven by local effects, and they are not spatially uniform over large regions. © 2017 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/185107
作者单位	Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, AZ 85721, United States; Department of Earth and Planetary Science, University of California-Berkeley, 307 McCone Hall, Berkeley, CA 94720, United States; Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, United States; Department of Earth and Environmental Sciences, Lehigh University, 1 West Packer Avenue, Bethlehem, PA 18015, United States
推荐引用方式 GB/T 7714	Garcia V.H.,Reiners P.W.,Shuster D.L.,et al. Thermochronology of sandstone-hosted secondary Fe- and Mn-oxides near Moab, Utah: Record of paleo-fluid flow along a fault[J],2018,130(2021-01-02).
APA	Garcia V.H.,Reiners P.W.,Shuster D.L.,Idleman B.,&Zeitler P.K..(2018).Thermochronology of sandstone-hosted secondary Fe- and Mn-oxides near Moab, Utah: Record of paleo-fluid flow along a fault.Bulletin of the Geological Society of America,130(2021-01-02).
MLA	Garcia V.H.,et al."Thermochronology of sandstone-hosted secondary Fe- and Mn-oxides near Moab, Utah: Record of paleo-fluid flow along a fault".Bulletin of the Geological Society of America 130.2021-01-02(2018).