DOI: 10.1016/j.epsl.2018.08.021
Scopus记录号: 2-s2.0-85051975954
论文题名: Single-crystal hematite (U–Th)/He dates and fluid inclusions document widespread Cryogenian sand injection in crystalline basement
作者: Jensen J.L. ; Siddoway C.S. ; Reiners P.W. ; Ault A.K. ; Thomson S.N. ; Steele-MacInnis M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 500 起始页码: 145
结束页码: 155
语种: 英语
英文关键词: detrital zircon geochronology
; fission-track thermochronometry
; fluid inclusion microthermometry
; Front Range
; hematite (U–Th)/He thermochronometry
; sand injectites
Scopus关键词: Buildings
; Chlorine compounds
; Diffusion in liquids
; Fission reactions
; Geochronology
; Grain size and shape
; Groundwater
; Helium
; Metamorphic rocks
; Mineralogy
; Phosphate minerals
; Sand
; Silicate minerals
; Single crystals
; Zircon
; Detrital zircon
; Fluid inclusion microthermometry
; Front Range
; Hematite mineralization
; Polycrystalline aggregates
; Sandstone intrusions
; Thermochronometry
; Zircon fission tracks
; Hematite
; basement rock
; crystal
; crystalline rock
; dating method
; fluid inclusion
; geothermometry
; hematite
; mineralization
; remobilization
; Colorado
; Front Range
; Rocky Mountains
; United States
英文摘要: The Tavakaiv Quartzite (informal) in Colorado, USA, is one of the world's largest basement-hosted clastic injectite systems and provides a glimpse into the tectonic and near-surface environment of ancient North America. The age, origin, and significance of Tavakaiv injectites has been debated for over a century, owing to inherent difficulties with assigning absolute age constraints to unfossiliferous sandstone intrusions. Here, we apply an innovative combination of single-crystal hematite (U–Th)/He thermochronometry and fluid inclusion microthermometry to hematite mineralization associated with the injectites to document the age and ambient fluid conditions of Tavakaiv injectite formation. Our approach confirms individual hematite crystals comprising commonly analyzed polycrystalline aggregates are the He diffusion domains and that hematite (U–Th)/He closure temperature increases with crystal size. We apply apatite and zircon fission-track thermochronometry to the Tavakaiv Quartzite and host rock to account for the consequences of Phanerozoic orogenic episodes on the hematite (U–Th)/He dates and explain the observed trends between hematite He date and crystal size. Our results indicate that hematite formed 676 ± 26 million years ago (arithmetic mean date ±1σ), constraining the timing of the Tavakaiv injection event. Fluid inclusion studies reveal that this mineralizing fluid was at least 200 °C and saline (>20 wt% CaCl2 equiv.). Comparison of new and previously published detrital zircon U–Pb age populations from quartzite samples yield a sediment source common to Tavakaiv bodies across a broader region and illuminate the greater areal extent of the Cryogenian injection event. We interpret that formation of basement-penetrating fracture arrays was associated with crustal extension within Rodinia at this time. This was accompanied by sand remobilization that promoted widespread sand injection within horsts bounding Neoproterozoic rift basins. The resulting sand injectites served as permeable pathways for contemporaneous circulation of saline groundwater, driven by fluid gradients in extensional and/or transtensional basins. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109680
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Department of Geology, Colorado College, Colorado Springs, CO 80903, United States; Department of Geology, Utah State University, Logan, UT 84322, United States; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
Recommended Citation:
Jensen J.L.,Siddoway C.S.,Reiners P.W.,et al. Single-crystal hematite (U–Th)/He dates and fluid inclusions document widespread Cryogenian sand injection in crystalline basement[J]. Earth and Planetary Science Letters,2018-01-01,500