Search results for "Outcrop"
showing 10 items of 101 documents
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…
Clastic injection dynamics during ice front oscillations: A case example from Sólheimajökull (Iceland).
2015
18 pages; International audience; Soft-sediment deformation structures are being increasingly used as a tool for reconstructing palaeoenvironments and porewater pressure conditions in glacial settings. However, the potential of hydrofractures and clastic injections in the reconstruction of ice dynamics remains poorly constrained. This paper presents the results of a detailed study of a clastic injection network outcropping in the Sólheimajökull forefield (South Iceland). Sedimentological descriptions are combined with microscopic to macroscopic analyses of clastic injection geometries, sediment-fills, and cross-cutting relationships. The 250 m long and 20 m high exposure observed along the …
Fluid-pressure controlled soft-bed deformation sequence beneath the surging Breiðamerkurjökull (Iceland, Little Ice Age).
2009
16 pages; International audience; The general subject of this paper is subglacial deformation beneath Breiðamerkurjökull, a surging Icelandic glacier. More specifically it discusses the evolution and the role of fluid pressure on the behaviour of subglacial sediments during deformation. During Little Ice Age maximum, the two outcrops studied, North Jökulsarlon (N-Jk) and Brennhola-Alda (BA), were located at 2550 m and 550 m respectively from the front of the Breiðamerkurjökull. Sedimentological analysis at the forefield of the glacier shows thick, coarse glaciofluvial deposits interbedded with thin, fine-grained shallow lacustrine/swamp deposits, overlain by a deformed till unit at N-Jk. BA…
Geological Map of the Rocca Busambra-Corleone region (western Sicily, Italy): explanatory notes
2011
The geology of the Rocca Busambra-Corleone region, in centralwestern Sicily, is relevant to the understanding of the central sector of the Maghrebian-Sicilian fold-and-thrust belt. In the investigated area Mesozoic shallow- and deep-water carbo - nate deposits pertaining respectively to the Trapanese and the Sica - nian successions, and a thick Oligo-Miocene numidian flysch body, crop out. Minor outcrops of Cretaceous-Palaeogene Sicilide complex and syn-orogenic deposits of the Late Serravallian-Early Messinian Castellana Sicula and Terravecchia formations are also present. A structural analysis reveals complex tectonic relationships between the Trapanese carbonate platform tectonic unit (t…
Geochemical characterisation of the alkaline and hyperalkaline groundwater in the Othrys Ophiolite Massif, central Greece
2021
The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to the westernmost of them. In the current study, 33 water samples from cold hyperalkaline and hypothermal (T < 40°C) alkaline springs and 30 gas samples (either dissolved or free) were collected at 17 different sites in and around this wide ophiolite outcrop, aiming to determine the origin of fluids and evidence gas-water-rock interaction processes taking place in the area. Water samples were analysed for their chemical (major ions and trace elements) and isotope (d18O-H2O, d2H-H2O) composition. They can be subdivided into alkaline (pH <11) of both Mg-Ca…
Elevation of the last interglacial highstand in Sicily (Italy): A benchmark of coastal tectonics
2006
Well-preserved MIS 5.5 terraces in Sicily are identified primarily by the index fossil Strombus bubonius, and dated by amino acid racemization (AAR), electron spin resonance (ESR), Uranium/Thorium (U/Th) and thermo luminescence (TL) methods. This review of published data and new results for the island of Sicily and neighbouring small islands of Egadi, Ustica and Lampedusa identifies areas of rapid uplift in the east (up to +175 m, elevation above sea level), slower uplift in the north (+29 m), and relative stability in the northwest (+2/+18 m). In contrast, about 250 km of the southern coastline of Sicily does not appear to contain MIS 5.5 outcrops. In eastern Sicily, correlation of MIS 5.5…
Soil Erosion on Mountain Trails in Eastern Iberian Peninsula
2020
A review on trial erosion shows that soil erosion rates are one to three orders of magnitude higher than the ones recommended as sustainable. This is threatening the sustainable managements of mountain terrains, mainly in the popular hiking paths. The warm temperatures characterize Eastern Spain in winter, which results in visitors from northern Europe to walk in the coastal land mountainous terrain. This increases the pressure to the currently highly visited most popular paths. We selected representative transects of the trails of Serra de Bérnia, Puigcampana, Penyagolosa, Montcabré, Serra del Sit, Aitana, Les Tres Creus, Caroig, Cupurutxo and Circ de la Safor. All the selected study sites…
Effects of the 6th September 2002 earthquake: damage amplification in the south-eastern sector of Palermo explained by GIS technology
2009
During the 6th September 2002 earthquake the highest damage level in Palermo was observed in the SE sector. This is a recent urbanization area where reinforced concrete structures predominate. A detailed analysis of soil properties in Palermo was carried out by City-GIS to investigate a possible role of nearsurface geology on earthquake effects. City-GIS is a tool dedicated to natural hazard evaluation in urban areas. The availability of high density of well log data (stratigraphic and geotechnical) allowed a realistic modeling of surface geology and physical-mechanical properties that control the seismic response. In wide zones of the above mentioned sector of…
Fosildiagénesis del anélido Rotularia spirulaea (Lamarck, 1818) (Polychaeta, Serpulidae) en el Eoceno del dominio pirenaico occidental
2018
The presence of the fossil polychaete Rotularia spirulaea (Lamarck, 1818) in Eocene deposits (middle Lutecian – upper Bartonian and (?) Priabonian) belonging to the western Pyrenean Domain is verified. In this paper, a fossildiagenetic study has been carried out. Fossils from three areas, corresponding to diff erent depositional settings, have been analysed. In area 1, sediments of the Ardanatz Sandstone and Ilundain Marls formations [Pamplona Basin and adjoining areas (Navarre)], were sampled. Here, the specimens of R. spirulaea were not substantially affected by taphonomic reworking and the original microstructure of the carbonate tube is preserved. The test consists of a thick external …
Extensional deformations during Neogene chain building in Sicily
2010
ABSTRACT In the Madonie-Nebrodi Mts (Northern Sicily belt) both Mesozoic carbonate platform/basin-derived deformed successions and Neogene foredeep deposits outcrop. Thrust sheets piled-up southwards in thin-skin piggy-back sequence. The chain building process began during the Oligo-Miocene. The syntectonic deposits involved in the compressional tectonics give evidence that syn-sedimentary extensional faults developed during fold nucleation and amplification. Syn-sedimentary extensional faults affect the foredeep strata at different stratigraphic levels, which are bounded by unconformities. Normal faults and bedding show constant cut-off relationships and are progressively tilted youngwards…