scholarly journals Evidence for 40–41 km of dextral slip on the southern Death Valley fault: Implications for the Eastern California shear zone and extensional tectonics

Geology ◽  
2021 ◽  
Author(s):  
Terry L. Pavlis ◽  
Ghislain Trullenque
Keyword(s):  
Slip System ◽  
Shear Zone ◽  
Late Miocene ◽  
Time Window ◽  
Strike Slip ◽  
Death Valley ◽  
Published Data ◽  
Extensional Tectonics ◽  
Fault Rocks ◽  
Eastern California Shear Zone

Recognition of a pair of pre-Neogene markers together with analysis of published data indicate ~40 km of dextral slip across the southern Death Valley fault zone, California, USA. Stratigraphic overlaps on fault rocks indicate much of the dextral slip predates the late Miocene, placing a significant fraction of the dextral slip in the same time window as regional extension and challenging interpretations that the modern strike-slip system became active post–6–3 Ma. However, these results are consistent with regional evidence that dextral transtension began by ca. 12 Ma.

scholarly journals From ductile to brittle, late- to post-orogenic evolution of the Betic Cordillera: Structural insights from the northeastern Internal zones

2013 ◽  
Vol 184 (4-5) ◽  
pp. 405-425 ◽  
Author(s):  
Romain Augier ◽  
Laurent Jolivet ◽  
Damien Do couto ◽  
François Negro
Keyword(s):  
Shear Zone ◽  
Sedimentary Cover ◽  
Active Faults ◽  
Sedimentary Basins ◽  
Strike Slip ◽  
Betic Cordillera ◽  
Small Scale ◽  
Extensional Tectonics ◽  
Stress Regime ◽  
Meso Scale

Abstract Relations between Alpine detachment-bounded metamorphic domes, crustal-scale strike-slip fault zones and sedimentary basins in the Internal zones of the Betic cordillera are still matter of debate. Current tectonic interpretations of these basins vary from late-orogenic extensional structures to compressional ones associated with strike-slip motions along major still active faults. Structural investigations including new field mapping, meso-scale faults recognition, palaeostress analysis of brittle small-scale faults systems were performed in the sedimentary cover of the Almanzora corridor and the Huércal-Overa basins, located either in the hanging wall unit of the Filabres extensional shear zone or at the termination of the Alhama de Murcia sinistral fault zone. In parallel, a detailed study of the ductile and the ductile-brittle deformation was carried out in the footwall unit of the Filabres extensional shear zone, in the Nevado-Fílabride complex. Three main brittle events were recognised in the basin cover including two extensional events that occurred prior to a weak tectonic inversion of the basin during a third, still active event. The first one, D1b is characterized by the development a first stress regime consistent with ~NW-SE extensional tectonics. Besides, the consistency between the latest ductile and the brittle kinematics for the Filabres extensional shear zone and the activity of meso-scale fault systems that primarily control the main SW-NE depocentres allow concluding to a top-to-the-NW continuum of strain during the final exhumation of the Nevado-Filábride complex. The resulting overall half-graben architecture of the basins is then related to the combination of the formation of the metamorphic domes that added a local control superimposed on the regional deformation. Indeed, after a consistent top-to-the-west shearing prevailing during most of the Nevado-Filábride exhumation, final exhumation stages were in turn, characterised by important kinematics changes with a subordinate top-to-the-NW sense of shear (D1b). The onset of sedimentation in the basins occurred shortly after the crossing of the ductile-brittle transition in the underlying metamorphic domes at ca. 14 Ma into SW-NE fault-bounded troughs. Tectonic subsidence was then maintained during D2b while extensional kinematics changed to N-S or even locally to SSW-NNE. Extensional tectonics then lasted most of the Tortonian during the final tectonic denudation increments of the Sierra de los Filabres achieved at ca. 9-8 Ma. Intramontane basins are therefore genuinely extensional and clearly related to the latest exhumation stages of the Nevado-Filábride complex in the back-arc domain. Conversely, at ca. 8 Ma, basins started to record a ~N-S to NNW-SSE compressional stress regime (D3b) and ceased to be active depocentres while shortening within the Internal zones then recorded only the Iberia/Africa convergence. The weak inversion of the basins however resulted either in the reactivation of originally extensional faults such as the Alhama de Murcia fault or the basin individualisation and a progressive water exchange reduction with the Atlantic ocean and is thus proposed to be directly responsible for the Late Miocene salinity crises.

scholarly journals Recurring extensional and strike-slip tectonics after the Neoproterozoic collisional events in the southern Mantiqueira province

2012 ◽  
Vol 84 (2) ◽  
pp. 347-376 ◽  
Author(s):  
Renato P. Almeida ◽  
Maurício G. M. Santos ◽  
Antonio R.S. Fragoso-Cesar ◽  
Liliane Janikian ◽  
Gelson L. Fambrini
Keyword(s):  
Sedimentary Basins ◽  
Strike Slip ◽  
Southeastern Brazil ◽  
Published Data ◽  
Southern Brazil ◽  
Extensional Tectonics ◽  
Geochronological Data ◽  
Tectonic Events ◽  
Brasiliano Orogeny ◽  
Paleostress Analysis

In Eastern South America, a series of fault-bounded sedimentary basins that crop out from Southern Uruguay to Southeastern Brazil were formed after the main collisional deformation of the Brasiliano Orogeny and record the tectonic events that affected the region from the Middle Ediacaran onwards. We address the problem of discerning the basin-forming tectonics from the later deformational events through paleostress analysis of more than 600 fault-slip data, mainly from the Camaquã Basin (Southern Brazil), sorted by stratigraphic level and cross-cutting relationships of superposed striations, and integrated with available stratigraphic and geochronological data. Our results show that the Camaquã Basin was formed by at least two distinct extensional events, and that rapid paleostress changes took place in the region a few tens of million years after the major collision (c.a. 630 Ma), probably due to the interplay between local active extensional tectonics and the distal effects of the continued amalgamation of plates and terranes at the margins of the still-forming Gondwana Plate. Preliminary paleostress data from the Castro Basin and published data from the Itajaí Basin suggest that these events had a regional nature.

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