36,971 research outputs found
Interactions Between Strike-Slip And Thrust Tectonics: Controls on Sand Distributions Through Miocene Basin Arrays, Southern Italy
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MS002: E. W. Bertner in Academic Regalia Shaking hands with Jesse Jones, Accompanied by P. P. Butler, Dr. W. H. Moursund, and Dr. W. R. White
No full textE. W. Bertner receiving an honorary Doctor of Laws degree from Baylor at a ceremony in his Rice Hotel apartment. Bertner is in academic regalia shaking hands with Jesse Jones, and accompanied by P. P. Butler, Dr. W. H. Moursund, and Dr. W. R. White. See more at Ernst William Bertner, MD Papers and its finding aid.https://digitalcommons.library.tmc.edu/bertner/1002/thumbnail.jp
The structure and kinematics of substrate entrainment into high concentration sandy turbidites: a field example from the Gorgoglione "flysch" of southern Italy
No full textSandy turbidites commonly show evidence for significant dynamic coupling with their substrate. The resulting deformation can be described using structural kinematic methods, linked to palaeoflow indicators, to better understand the links between flow and entrainment processes. A field example from the syn-orogenic Gorgoglione Flysch, a succession of upper Miocene turbidites deposited into a deforming array of thrust-top basins in the southern Apennine thrust belt, Italy, is described. The succession contains metre-scale packages of alternating sandy turbidites and shales but is notable for containing > 100 m thick, massive sandbodies. These are structureless apart from sporadic horizons of aligned mud clasts. Commonly, the substrate beneath the massive sandbodies is deformed, with minor folds and thrusts verging in the direction of palaeoflow determined from tool marks and flutes at the base of these sandbodies. Structural studies from the base of a selected massive sandbody have identified that the substrate mud has been injected upwards, with flames sheared over in the direction of palaeoflow. Thus the substrate has deformed and become entrained during emplacement of the massive sandy body. At some locations, the substrate can be traced into the overlying deposit, with substrate clay beds becoming boudinaged and entrained into the sandbody. Analysis of the orientation of the mud clasts indicates that this bed disruption and incorporation into the sandy massive- bed turbidite was an organized, viscous process. These features indicate that significant shear stress was partitioned out of the flow and onto the substrate. The incorporation and disruption of substrate into the sandbody suggest that post-disruption strains increase upwards – implying that displacement gradients increased into the flow. These behaviours, showing variations in strain partitioning between the flow and its substrate, are explored in terms of evolving flow dynamics and substrate rheology
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Inversion tectonics and structural inheritance in collision mountain belts: An example from the Alps-Apennine system [Tettonica da inversione ed eredità strutturale nelle catene collisionali: un esempio dal sistema Alpi-Appennino]
No full textThe structure of continental lithosphere shows complex variety that is inherited into orogenic belts and influences the localization of contractional structures during mountain building. In the Alps- Apennine system the pre-orogenic template can include arrays of extensional faults. While in some areas of the outer orogenic zones these inherited features may simply reactivate under inversion, more commonly faults show complex, partial reactivation structures. In volumes of distributed strain, pre-orogenic faults may serve to nu- cleate large-scale buckle folds located along, or close to basement- cover interfaces. These different patterns of basement reactivation may reflect spatially-varying strength-depth profiles in continental lithosphere that are themselves inherited from spatially-distinct geo- logical histories. Even when not themselves reactivating, basement faults can control deformation in the overlying sedimentary cover by offsetting otherwise regionally-extensive detachment horizons. The 3D geometry of thrust systems can be strongly compartimentalized by pre-existing cross-faults, such as the oblique lineaments of the Apennines. A comparison between the outer, the intermediate and the inner orogenic zones, with examples from both the Alps and the Apennines, illustrates that the propensity for fault reactivation during mountain building depends on the rheological contrasts between the fault zone and surrounding rocks
Structural inheritance in mountain belts: an Alpine-Apennine perspective
No full textThe geological structure of continental lithosphere shows complex variety that is inherited into orogenic belts and influences the localization and amplification of contractional structures during mountain building. In the Alpine-Apennine sector together with other sectors of the Tethyan orogenic system the pre-orogenic crustal template can include arrays of extensional faults. Other faults can form adjacent to the evolving mountain belt and subsequently become incorporated as the thrust belts migrate into their forelands. While in some areas these inherited features may simply reactivate under inversion, more commonly faults show complex, partial reactivation structures. In volumes of distributed strain, faults may serve to nucleate large-scale buckle folds, for example, along basement-cover interfaces. These different patterns of basement reactivation may reflect spatially varying strength-depth profiles in continental lithosphere that are themselves inherited from spatially-distinct geological histories. Even when not themselves reactivating, basement faults can control deformation in the overlying sedimentary cover by offsetting otherwise regionally extensive detachment horizons. The 3D form of thrust systems can be strongly compartmentalized by pre-existing cross-faults, such as the oblique lineaments of the Apennines. On a large-scale, the distribution of pre-existing faults and other weaknesses may affect the propensity for orogenic contraction in basement and therefore directly control larger-scale tectonic processes. In the central Mediterranean the evolution of slab roll-back and the related growth of overlying extensional basins (e.g. Tyrrhenian Sea) may be strongly modulated by the distribution of rift-related weak zones in the adjacent continental crust. The subduction of continental crust will strongly depend on the inherited structure of this crust, specifically the distribution of deep crust of basic composition. This develops relatively higher densities associated with eclogite metamorphism which act in turn to reduce the buoyancy of thickened continental crust that otherwise serves to inhibit further shortening. Investigating all these aspects, from the scale of bulk crustal compositions to the geometry, timing and strength of earlier fault zones preserved in orogenic belts requires the integration of substantial multidisciplinary geological data sets. The extent to which continental orogenic belts represent the amplification of inherited geological heterogeneities as opposed to self-ordered phenomena modulated by the syntectonic environment remains unclear. © 2006 Elsevier Ltd. All rights reserved
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