Inversion of transfer zones in salt-bearing extensional systems: insights from analogue modeling

This work uses sandbox analogue models to analyze the formation and subsequent inversion of a decoupled extensional system comprised of two segmented half-grabens with thick early syn-rift salt. The segmented half grabens strike perpendicular to the direction of extension and subsequent shortening. Rifting created first a basement topography that was infilled by model salt, followed by a second phase of extension and sedimentation, followed afterwards by inversion. During the second phase of extension, syn-rift syncline minibasins developed above the basement extensional system and extended beyond the confines of the fault blocks. Sedimentary downbuilding and extension initiated the migration of model salt to the basement highs, forming salt anticlines, reactive diapirs, and salt walls perpendicular to the direction of extension, except for along the transfer zone where a slightly oblique salt anticline developed. Inversion resulted in decoupled cover and basement thrust systems. Thrusts in the cover system nucleated along squeezed salt structures and along primary welds. New primary welds developed where the cover sequence touched down on basement thrust tips due to uplift, salt extrusion, and syn-contractional downbuilding caused by loading of syn-contractional sedimentation. Model geometries reveal the control imposed by the basement configuration and distribution of salt in the development of a thrust front from the inversion of a salt-bearing extensional system. In 3D, the interaction of salt migrating from adjacent syn-rift basins can modify the expected salt structure geometry, which may in turn influence the location and style of thrust in the cover sequence upon inversion. Results are compared to the northern Lusitanian Basin, offshore Portugal and the Is&agrave;bena area of the South-Central Pyrenees, Spain.</p

Evaluating the Use of QoS for Video Delivery in Vehicular Networks

In a near future, video transmission capabilities in intelligent vehicular networks will be essential for deploying high-demanded multimedia services for drivers and passengers. Applications and services like video on demand, iTV, context-aware video commercials, touristic information, driving assis-tance, multimedia e-call, etc., will be part of the common multimedia service-set of future transportation systems. However, wireless vehicular networks introduce several constraints that may seriously impact on the final quality of the video content delivery process. Factors like the shared-medium communication model, the limited bandwidth, the unconstrained delays, the signal propagation issues, and the node mobility, will be the ones that will degrade video delivery performance, so it will be a hard task to guarantee the minimum quality of service required by video applications. In this work, we will study how these factors impact on the received video quality by using a detailed simulation model of a urban vehicular network scenario. We will apply different techniques to reduce the video quality degradation produced by the transmission impairments like (a) Intra-refresh video coding modes, (b) frame partitioning (tiles/slices), and (c) quality of service at the Medium Access Control (MAC) level. So, we will learn how these techniques are able to fight against the network impairments produced by the hostile environment typically found in vehicular network scenarios. The experiments were carried out with a simulation environment based on the OMNeT++, Veins and SUMO simulators. Results show that the combination of the proposed techniques significantly improves the robustness of video transmission in vehicular networks, paving the way, with a wise collaboration with other techniques, to achieve a robust video delivery system that supports multimedia applications in future intelligent transportation systems

A Simulation Tool for Evaluating Video Streaming Architectures in Vehicular Network Scenarios

An integrated simulation tool called Video Delivery Simulation Framework over Vehicular Networks (VDSF-VN) is presented. This framework is intended to allow users to conduct experiments related to video transmission in vehicular networks by means of simulation. Research on this topic requires the use of many independent tools, such as traffic and network simulators, intermediate frameworks, video encoders and decoders, converters, platform-dependent scripting languages, data visualisation packages and spreadsheets, and some other tasks are performed manually. The lack of tools necessary to carry out all these tasks in an integrated and efficient way formed the motivation for the development of the VDSF-VN framework. It is managed via two user-friendly applications, GatcomSUMO and GatcomVideo, which allow all the necessary tasks to be accomplished. The first is primarily used to build the network scenario and set up the traffic flows, whereas the second involves the delivery process of the whole video, encoding/decoding video, running simulations, and processing all the experimental results to automatically provide the requested figures, tables and reports. This multiplatform framework is intended to fill the existing gap in this field, and has been successfully used in several experimental tests of vehicular network

Tectonostratigraphic Evolution of the orange basin, sw Africa

The Orange Basin is a Late Jurassic to present day basin located on the volcanic-rifted passive margin of SW Africa. 2D seismic data and structural restoration techniques were used to develop a tectonostratigraphic model of the basin consisting of a syn-rift and a post-rift megasequences separated by an Early Cretaceous break-up unconformity. The post-rift megasequence is characterised by gravity tectonics where extensional faults transferred displacement downdip into a deep water fold and thrust belt (DWFTB). Gravity gliding tectonics occurred through a combination of cratonic uplift and thermal subsidence and stopped via deltaic progradation and associated differential sedimentary loading

Simulation Framework for Evaluating Video Delivery Services over Vehicular Networks

Vehicular Ad-hoc Networks contribute to the Intelligent Transportation Systems by providing a set of services related to traffic, mobility, safe driving, and infotainment applications. One of the most challenging applications is video delivery, since it has to deal with several hurdles typically found in wireless communications, like high node mobility, bandwidth limitations and high loss rates. In this work, we propose an integrated simulation framework that will provide a multilayer view of a particular video delivery session with a bunch of simulation results at physical (i.e., collisions), MAC (i.e., packet delay), application (i.e.,%of lost frames), and user levels (i.e., perceptual video quality). With this tool, we can analyze the performance of video streaming over vehicular networks with a high level of detail, giving us the keys to better understand and, as a consequence, improve video delivery services

The Northern Calcareous Alps revisited: Formation of a hyperextended margin and mantle exhumation in the Northern Calcareous Alps sector of the Neo-Tethys (Eastern Alps, Austria)

The Neo-Tethys margin evolution is preserved in the Northern Calcareous Alps (Eastern Alps), from Late Permian crustal stretching to Late Triassic oceanization. The Northern Calcareous Alps represent the salt-floored fold-and-thrust belt developed from the salt-influenced Triassic carbonate sedimentary cover of the ancestral European margin of the Neo-Tethys Ocean. A crustal scale model for the margin has been obtained by restoration of regional cross-sections of the Northern Calcareous Alps carbonate platforms. Lithospheric break-up was investigated from remnants of exhumed mantle found within an evaporitic melange, suggesting hyperextended crust underneath the distal Triassic platforms of the Northern Calcareous Alps preceding breakup. By modelling the thermal evolution of the margin in combination with excellent stratigraphic control, a detailed timeline has been established for the evolution of the Neo-Tethys margin, especially around the period of rapid mantle exhumation. Our study indicates that salt-floored carbonate shelfs can be used as a proxy to characterize the margins evolution, from crustal stretching to continental breakup. Diagnostic stratigraphic records are preserved in the carbonate platforms: pre- mantle exhumation carbonates are represented by aggrading isolated carbonate platforms first, followed by expanding and margin wide prograding carbonate shelfs once thermal subsidence dominates. In addition, a distinct clastic sequence is deposited as an immediate response to mantle exhumation, in between the pre- and post-mantle exhumation carbonate factory. Our study proposes a new refined model for the formation of the Neo-Tethys margin and provides new insights for the dynamic coupling of salt-controlled carbonate shelfs and the underlying lithosphere during continental breakup

Inversion of accommodation zones in salt-bearing extensional systems: insights from analog modeling

This work uses sandbox analog models to analyze the formation and subsequent inversion of a decoupled extensional system comprised of two segmented half-grabens separated by a diffuse accommodation zone with thick early syn-rift salt. The segmented half-grabens strike perpendicular to the direction of extension and subsequent shortening. Rifting first created a basement topography that was infilled by model salt, followed by a second phase of extension and sedimentation, followed afterwards by inversion. During the second phase of extension, syn-rift syncline minibasins developed above the basement extensional system and extended beyond the confines of the fault blocks. Sedimentary downbuilding and extension initiated the migration of model salt to the basement highs, forming salt anticlines, reactive diapirs, and salt walls perpendicular to the direction of extension, except for along the intervening accommodation zone where a slightly oblique salt anticline developed. Inversion resulted in decoupled cover and basement thrust systems. Thrusts in the cover system nucleated along squeezed salt structures and along primary welds. New primary welds developed where the cover sequence touched down on basement thrust tips due to uplift, salt extrusion, and syn-contractional downbuilding caused by the loading of syn-contractional sedimentation. Model geometries reveal the control imposed by the basement configuration and distribution of salt in the development of a thrust front from the inversion of a salt-bearing extensional system. In 3D, the interaction of salt migrating from adjacent syn-rift basins can modify the expected salt structure geometry, which may in turn influence the location and style of thrust in the cover sequence upon inversion. Results are compared to the Northern Lusitanian Basin, offshore Portugal, and the Isábena area of the South-Central Pyrenees, Spain

Stretching and contraction of extensional basins with pre-rift salt: a numerical modelling approach

We present a series of 2D thermo-mechanical numerical experiments of thick-skinned crustal extension including a pre-rift salt horizon and subsequent thin-, thick-skinned, or mixed styles of convergence accompanied by surface processes. Extension localization along steep basement faults produces half-graben structures and leads to variations in the original distribution of pre-rift salt. Thick-skinned extension rate and salt rheology control hanging wall accommodation space as well as the locus and timing of minibasin grounding. Upon shortening, extension-related basement steps hinder forward propagation of evolving shallow thrust systems; conversely, if full basin inversion takes place along every individual fault, the regional salt layer is placed back to its pre-extensional configuration, constituting a regionally continuous décollement. Continued shortening and basement involvement deform the shallow fold-thrust structures and locally breaches the shallow décollement. We aim at obtaining a series of structural, stratigraphic and kinematic templates of fold-and-thrust belts involving rift basins with an intervening pre-rift salt horizon. Numerical results are compared to natural cases of salt-related inversion tectonics to better understand their structural evolution

Anatomy and kinematic evolution of an ancient passive margin involved into an orogenic wedge (Western Southern Alps, Varese area, Italy and Switzerland)

We make use of own geological mapping, interpretations of seismic reflection profiles and deep geophysical data to build a lithospheric-scale cross-section across the European Western Southern Alps (Varese area) and to model a progressive restoration from the end of Mesozoic rifting to present-day. Early phases of Alpine orogeny were characterized by Europe-directed thrusting, whereas post-Oligocene shortening led to basement-involving crustal accretion accompanied by backfolding, and consistent with the kinematics of the adjoining Ivrea Zone. Wedging was favored by a significant component of reactivation of the inherited Adriatic rifted margin. Our results also suggest that, during the collisional and post-collisional tectonics, lithosphere dynamics drove diachronically the onset of tectonic phases (i.e., wedging and slab retreat), from east to west, across the Western Southern Alps