Search results for "Sediment"

Record of latest Barremian-Cenomanian environmental change in tectonically controlled depressions from the Jura-Burgundy threshold (Jura Mountains, e…

2019

The area of the western Jura Mountains constitutes the former Jura-Burgundy threshold between the Tethys Ocean and the epicontinental Paris Basin Sea. During the Barremian, the area was covered by a shallow-water Urgonian carbonate platform. Tectonic processes influenced the architecture of the Urgonian platform and were notably responsible for the formation of fault-related depressions on top of the Urgonian series, which were subsequently transformed into incised valleys and then to marine depocenters. Their sedimentary infills are mostly represented by the Perte-du-Rhône Formation and record stepwise environmental change on the innermost platform, which was strongly influenced by the nea…

Littoral Dunes on Valencia Coast

2018

The dunes development needs an excess of sediment supply, wind speed able to transport sand to backshore and low atmospheric humidity. Foredunes, dunes fields and Pleistocene fossil dunes are the most characteristics features of the Valencian coast. Fossil dunes are abundant at the southern part. They are the main supply for the Holocene dunes and formed l’Altet field that survived thanks to be just in front of the L’Altet Airport. The foredunes have been mainly destroyed by human action and only few remains still are active. Guardamar and El Saler dune fields had a quite different evolution. Guardamar evolved covering previous fossil dunes and was fixed with pine trees to avoid the sand pr…

Integration of stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)

2013

The seismic microzoning is a technique of analysis of a territory which aims to recognize, at a small scale, the local geological and geomorphologic conditions that may significantly affect the characteristics of the seismic motion, generating stress on structures that could produce permanent and critical effects. In other words, this technique has the objective to predict and evaluate possible site effects as a result of an earthquake. The first phase of the seismic microzoning is the detailed partition of the territory in homogeneous areas with respect to the expected behavior of soils during an earthquake. The seismic micro-zoning is a tool for prevention and reduction of seismic risk pa…

Evolution of coherent turbulent structures and relation with bed-forms formation in a straight flume

2008

The present paper describes some results of experimental work carried out in a rectilinear flume to investigate the interactions between flow turbulence and sediment motion. The analysis is conducted through the comparison between the periodicity of turbulent structures evolving along the channel and the wavelength of bed forms (alternate bars) forming on the bed. The occurrence of turbulent events (inward interaction, ejection, sweep and burst) has been verified through the conditioned quadrant analysis. The quantitative information about the spatial and temporal scale of the events has been obtained through the space-time correlations of the conditioned data. The analysis essentially high…

Controls of mud mound formation: The Early Devonian Kess-Kess carbonates of the Hamar Laghdad, Antiatlas, Morocco

1992

The origin and development of Early Devonian (late Pragian to late Zlichovian; predominantly uppermost Zlichovian as indicated by conodont faunas) mud mounds of the Hamar Laghdad area in the eastern Antiatlas, Morocco, are controlled by extrinsic and intrinsic factors. Extrinsic factors include the existence of a paleohigh (Lochkovian volcaniclastics), unidirectional currents and repeated storm events as well as sea level fluctuations. Intrinsic, biologically induced factors are the preferred growth of organisms on the top and the flanks of the mounds because of more favourable ecological conditions, and a rapid synsedimentary lithification of the steep mound flanks by interskeletal cementa…

Ladinian carbonates of the Cabo Cope Unit (Betic Cordillera, SE Spain): a tethys-maláguide palaeogeographic gateway.

2003

7 pages, 4 figures.

Two-dimensional apparent microfabric of the basal Late Weichselian till and associated shear zone: case study from western Latvia

2008

The examination of glacial sediments in thin sections has become a common procedure in recent years. Apparent sand grain orientation (microfabric) in thin sections is one of the key elements marking certain microstructures. In an attempt to make till micromorphology studies less subjective and investigate the orientation of sand-sized particles in tills, we have developed an image analysis procedure to measure and analyse the spatial distribution of the till microfabric. We studied 13 thin sections of the Weichselian subglacial till and basal shear zone outcropping in the Baltic Sea bluffs at the Ziemupe site in western Latvia. The results were visualized as a two-dimensional grid of rose d…

Polycyclic aromatic hydrocarbons (PAHs) in sediments: Monitoring the evolution of the shore approach area of the Gulf of Gela

2008

Analytical method for PAHs chemical speciation in sediments

2008

The aim of this work is to optimize a method to examine the PAHs chemical speciation during the aging of sediments that is important in order to known the toxicological risk of a polluted area. In particular, we have conducted this research in order to determine if the organic contaminants fate is dependent to sediment characteristics and to study the potential role of humin and alkaline-extractable humic substances in the sequestration of PAHs in sediment. The Polycyclic Aromatic Hydrocarbons (PAHs) include molecules containing fused aromatic rings and are of special concern because of their widespread distribution throughout the environment and their often toxic and carcinogenic propertie…

Applicazione di trasformate wavelet per la riduzione del rumore nelle immagini NMR di rocce sedimentarie

2007

Il sempre crescente interesse verso i Beni Culturali suscita molteplici problematiche inerenti la salvaguardia e la diagnosi del loro stato di conservazione. In questo ambito, lo studio delle caratteristiche, quali ad esempio le proprietà capillari delle rocce sedimentarie, ricopre un’importanza cruciale non solo per studiare lo stato di conservazione ma anche per fornire utili indicazioni sulle possibili tecniche e sui materiali da utilizzare negli eventuali trattamenti di protezione e restauro. Al fine di ottenere approfondite informazioni sulle proprietà capillari, il presente lavoro propone un metodo matematico utile nello studio della cinetica di assorbimento capillare. Lo studio è sta…