Search results for "structural"

Badlands in the Tabernas Basin, Betic Chain

2014

The complex badland landscape at Tabernas results from a combination of relief amplitude generated by tectonic uplift since the Pliocene and reactivated several times during the Pleistocene, the properties of the Tortonian sedimentary rocks and a predominantly arid climate. The landscape is dominated by deep incision of the main river systems, which continues in part of the headwater tributaries, and characterized by contrasting slope morphologies and a variety of microecosystems. The Tabernas badlands exhibit a diversity of landforms resulting from the combination of multi-age soil surface components that allow a variety of processes to operate at different rates. These are dominated by ri…

1993

The miocene deposits of the Quesa basin (Betic foreland) outcrops in the central part of the Valencia province (Spain). Quesa basin is a subsiding hanging-wall basin related to an ENE-WSW listric fault system. The deposits of this basin are formed by a 440 metres thick sequence of red clays, containing few intercalations of sandstones and micritic white limestones, and breccias. The upper 70 metres of this sequence is a wedge-shaped unit composed by breccias containing megablocks, wich interfinger with tabular limestones towards the central part of the basin. The breccias are foot-wall derived debris fiow deposits formed during normal faulting. A mammal site close to the base of the breccia…

Deep structural setting of the North American-Caribbean plate boundary in eastern Guatemala

2009

Se presenta un modelo bidimensional de gravedad para determinar la estructura en profundidad del sistema de fallas lateral-izquierda de Motagua-Polochic, que son parte del límite de las placas América del Norte y del Caribe. Estos elementos tectónicos, sismicamente activos, atraviesan oeste-este la región de Guatemala y se sobreponen a una línea de sutura donde afloran cuerpos ophiolíticos. En las principales zonas de desplazamiento de las fallas se han desarrollado cuencas de pull-apart y regiones de restricción (push-up). El análisis estructural de algunas de estas fallas, situadas a lo largo del valle Izabal y del valle Motagua, en combinación con los datos obtenidos del satélite, ha per…

Results of the DEKORP 1 (BELCORP-DEKORP) deep seismic reflection studies in the western part of the Rhenish Massif

1991

Summary Within the DEKORP project (DEKORP: Deutsches Kontinentales Reflexionsseismisches Programm) a joint deep seismic reflection venture with the BELCORP (Belgian Continental Reflection Seismic Programme) group of the Belgian Geological Survey was carried out in 1987 across the Rhenish Massif, a part of the mid-European Variscides. This orogenic belt developed in the Upper Devonian/Carboniferous. Mostly Devonian rocks crop out at the surface. The Rhenish Massif is bordered by two sedimentary troughs: the sub-Variscan Foredeep in the north and the Permo-Carboniferous Saar-Nahe Basin in the south. In the east-west direction it is subdivided by the axial depression of the Eifel Nord-Sud Zone…

Geoarchaeological investigations of a prominent quay wall in ancient Corcyra: Implications for harbour development, palaeoenvironmental changes and t…

2018

Abstract In antiquity, the harbour-city of Corcyra (modern: Corfu) was a prevailing naval power in the Mediterranean and had several harbours to host a considerable fleet. Today, these harbours are totally or partly silted and concealed under modern urban infrastructure. Comprehensive geoarchaeological studies were conducted on the northeastern fringe of the Analipsis Peninsula where excavations have revealed the archaeological remains of a massive quay wall (Pierri and Arion sites). These remains are located east of known ancient harbour structures that belong to the Alkinoos Harbour. Our study aimed to reconstruct the palaeoenvironmental setting of the harbour facilities at the Pierri sit…

Strong intracontinental lithospheric deformation in South China: Implications from seismic observations and geodynamic modeling

2014

Abstract Classical plate tectonics theory predicts concentrated deformation at plate boundaries and weak deformation within plates. Yet, the existence of intracontinental orogens shows that highly deformed regions can occur within continental plates, which is geodynamically incompletely understood. Shear wave splitting measurements in South China show belt-parallel (i.e. NE–SW) fast directions beneath the Wulingshan-Xuefengshan Belts, while no dominant fast direction is found in the cratonic Sichuan Basin. Tomographic studies in the mantle in the same area show that the thickness of lithosphere beneath the intracontinental orogen is larger than that beneath the cratonic Sichuan Basin. In or…

Morphological characterization of calanchi (badland) hillslope connectivity

2017

Calanchi, a type of Italian badlands created by a combination of water erosion processes and local geomorphological and tectonic controls, is a striking example of long-term landscape evolution. In small temporal/spatial scales, the calanchi exhibit many of the geomorphic processes and landforms that may be observed in fluvial landscapes, hence they may be considered as micro-basins where geomorphic dynamics and landscape features can be related. The goal of this research is testing the use of simple morphometric variables for assessing sediment connectivity of calanchi landforms. In order to detect the morphological characteristics controlling the landscape connectivity of calanchi basins,…

Architecture and tectono-stratigraphic evolution of the intramontane Baza Basin (Bétics, SE-Spain): Constraints from seismic imaging

2017

The Baza basin is a large Neogene intramontane basin in the Bétic Cordillera of southern Spain that formed during the Tortonian (late Miocene). The Bétic Cordillera was produced by NW–SE oblique convergence between the Eurasian and African Plates. Three seismic reflection lines (each 18 km long; vibroseis method) were acquired across the Baza basin to reveal the architecture of the sedimentary infill and faulting during basin formation. We applied rather conventional CDP data processing followed by first arrival P-wave tomography to provide complementary structural information and establish velocity models for the post-stack migration. These images show a highly asymmetric structure for the…

Structural control on the presence and character of calas: Observations from Balearic Islands limestones rock coast macroforms

2013

Calas are characteristic embayed rocky coastline landforms related to steep-sided drowned valleys that were deeply incised during low sea-level stages into carbonate plateaus. This paper studies the factors that control the presence and character of calas in three different islands of the Balearic Archipelago (Mallorca, Menorca and Formentera) by means of Digital Elevation Model (DEM) reconstructions, embayment and catchment morphometric analysis and through the compilation of fault and joint orientations. All islands exhibit emerged carbonate platforms (Upper Miocene in age) characterised by horizontal or very gently-dipping bedding. Two distinct patterns observed at all study sites are th…

Structurally controlled drainage basin development in the south of Menorca (Western Mediterranean, Spain)

2005

Abstract The south of Menorca consists of a gently folded Upper Miocene carbonate platform over which a drainage system has developed. Three areas with different drainage characteristics have been delimited: the central area, the eastern area and the western area. The central area is characterised by deep streams with steep slopes, whereas the western and eastern areas have slightly incised streams with gentle slopes. The drainage development has been controlled by the inversion of a normal fault in Pliocene times, resulting in a wide anticline with a NNE–SSW orientation. The deep streams of the central area follow the faults associated with this anticline. The amount of incision achieved b…