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Full-Text Articles in Physical Sciences and Mathematics
Reconstructing The Transition From Laramide Contraction To Rio Grande Rift Extension, Aaron Conley
Reconstructing The Transition From Laramide Contraction To Rio Grande Rift Extension, Aaron Conley
Open Access Theses & Dissertations
Exposure of tilted Eocene-Oligocene volcanic and sedimentary units unconformably overlying folded and thrusted Mesozoic rocks in the southern Indio Mountains provide an important geologic record of the transition from Laramide contraction to Rio Grande rift extension. Detailed geologic mapping and cross-section reconstruction combined with sedimentary analysis and geo/thermochronologic methods are used to test the hypothesis that Laramide contractional structures and post-Laramide topography focused ignimbrite and sedimentary deposition within two paleovalleys located in the northwest and northeast portions of the study area. Laramide deformation in the study area is confined to Mesozoic units and includes a series of low-angle thrust faults …
Understanding The Contractional History Of Surprise Canyon, California Through Digital Field Mapping, 3d Modeling, And U-Pb Zircon Geochronology, Joshua A. Cobb
Understanding The Contractional History Of Surprise Canyon, California Through Digital Field Mapping, 3d Modeling, And U-Pb Zircon Geochronology, Joshua A. Cobb
Open Access Theses & Dissertations
Detailed digital mapping of lower-middle Surprise Canyon has revealed a more complex structure than previously interpreted. Rock units derived from the metamorphosed equivalents of the Pahrump Group exposed in Surprise Canyon display juxtapositions inconsistent with stratigraphic variations suggested in previous studies. This study proposes a contractional history of the central Panamint Mountains defined by two kinematically distinct and geochronologically constrained deformation events. D1 is characterized by a shallow dipping, NNW striking L and LS tectonite fabric ubiquitously observed in all metasedimentary and basement units. F1 folds are mesoscopic in scale and isoclinal with an axial planar S1 foliation. A prominent …
Structural And Geochronologic History Of Southern Alaskan Blueschists, Erik M. Day
Structural And Geochronologic History Of Southern Alaskan Blueschists, Erik M. Day
Open Access Theses & Dissertations
Detrital zircon data are presented from the Liberty Creek blueschist in the central Chugach Mountains which indicate two distinct periods of the preservation of blueschist facies metamorphism along the southern Alaskan margin. A maximum depositional age of ~136 Ma demonstrates that the Liberty Creek schist was deposited long after the Jurassic cooling ages (196-185 Ma; Lopez-Carmona et al., 2011) recorded in western Alaskan blueschist bodies, revealing two blueschist preservation events. This Early Cretaceous depositional age also indicates that there have been major reorganizations within this subduction complex because the Potter Creek assemblage, directly south of the Liberty Creek schist, is …