Search results for "stratigraphy"
showing 10 items of 904 documents
Rill flow resistance law under sediment transport
2021
Abstract Purpose In this paper, a deduced flow resistance equation for open-channel flow was tested using measurements carried out in mobile bed rills with sediment-laden flows and fixed bed rills. The main aims were to (i) assess the effect of sediment transport on rill flow resistance, and (ii) test the slope-flow velocity relationship in fixed bed rills. Methods The following analysis was developed: (i) a relationship between the Γ function of the velocity profile, the rill slope and the Froude number was calibrated using measurements carried out on fixed bed rills; (ii) the component of Darcy-Weisbach friction factor due to sediment transport was deduced using the corresponding measurem…
Formation processes at a high resolution Middle Paleolithic site: Cueva Antón (Murcia, Spain)
2013
Cueva Anton is a Middle Paleolithic rockshelter located in the valley of the River Mula (Murcia, Spain). The archeological investigation of the site, which began with salvage work in 1991, resumed in 2006 and is still ongoing, uncovered a succession spanning most of MIS 3 and MIS 4 (ca. 75–36 ka) and featuring a well preserved human occupation record. This paper presents the first information about site stratigraphy and site formation processes. Geoarcheological data collected in the field and through micromorphological observation show that the archeological succession at Cueva Anton is mainly composed of alluvial sediments, with thin intercalations of gravitational and slope material. The…
Permian-Cenozoic deep-water carbonate rocks of the Southern Tethyan Domain. The case of Central Sicily
2016
We present an integrated stratigraphy of the outcropping and buried Permian-Cenozoic deep-water carbonate successions, forming some of the tectonic units mostly buried beneath the Late Neogene sedimentary cover in the fold and thrust belt of Central Sicily. Three main successions, pertaining to the well known Lercara, Imerese and Sicanian domains, have been reconstructed on the basis of a detailed facies analysis, seismostratigraphic interpretation, bio -stratigraphy (mostly based on palynological data) and comparison between outcropping and subsurface deep-water sediments. The main results reveal a continuous sedimentation of the deep-water Southern Tethyan Sicilian succession since the Pe…
Charcot-Marie-Tooth disease: Genetic and clinical spectrum in a Spanish clinical series
2013
Objectives: To determine the genetic distribution and the phenotypic correlation of an extensive series of patients with Charcot-Marie-Tooth disease in a geographically well-defined Mediterranean area. Methods: A thorough genetic screening, including most of the known genes involved in this disease, was performed and analyzed in this longitudinal descriptive study. Clinical data were analyzed and compared among the genetic subgroups. Results: Molecular diagnosis was accomplished in 365 of 438 patients (83.3%), with a higher success rate in demyelinating forms of the disease. The CMT1A duplication (PMP22 gene) was the most frequent genetic diagnosis (50.4%), followed by mutations in the GJB1…
Tetrapod footprint ichno-associations from French Permian basins. Comparisons with other Euramerican ichnofaunas.
2006
21 pages; In order to take into account the studies of the European and American (USA) collections carried out by one of the authors, and of the recent nomenclatural revisions from new footprint discoveries, which have occurred during the last decade, the authors present a critical review of the French Permian palichnofauna. The distribution of the ichnospecies in the stratigraphy of the Lodève Basin, taken as a reference, is outlined. The ichno-associations are then compared with those of other French (Provence), European (Italy, Germany) and USA basins. Based on the ages of different ichnofossiliferous formations, three successive ichnofaunal units can be distinguished in the Permian of E…
Stratigraphy and stage boundaries in reference sections of the Upper Cretaceous Chalk in the east of the Paris Basin: the “Craie 700” Provins borehol…
2005
Abstract The Provins boreholes (Poigny: Craie 701, and Sainte-Colombe: Craie 702) drilled in 1999 as part of the “Craie 700” project initiated by the Paris Basin Geologists' Association provide reference sections for the Upper Cretaceous of the eastern part of the Paris Basin. The lithology of the Cretaceous drilled at Poigny and Sainte-Colombe is presented in two logs displaying major litho-events that provide lines of correlation. Bio-events are expressed by the appearance/disappearance of index species of fossils. Foraminifera give a biozonation close to that defined by previous work on the Anglo-Paris Basin. Some of these bio-events provide a second set of lines useful for correlation. …
Lower Bashkirian fusulinoideans from the upper part of the Tagnana Formation (Carboniferous, NW Algeria)
2021
The upper member of the Tagnana Formation of the Djebel Bechar Group (informally the Tagnana-3 or Tagnana Ill member) yielded fusulinoideans and other related foraminifera of the genera Pseudoendothyra (rare), Pseudostajfella (Semistaffella) (rare), Millerella, Pseudonovel/a, Plectostaffella, Eostaffella and Mediocris. The presence of Eostaffellina (rare) and Endostaffella is doubtful. The difference between Millerella and Eostaffella cannot be adequately defined by evolute versus involute coiling. Pseudonovella Kireeva, 1949 is redefined to include Seminovella Rauzer-Chernousova, 1951. The foraminifera are from two samples, one from close to the top and the other from near the base of the …
Una fauna de foraminíferos en el Mioceno continental de la localidad de Buñol (provincia de Valencia)
1984
A fauna of benthonic forarninifera was found in the continental Miocene from Buñol (Valencia, Spain). This fauna was considered as autochthonous, Two species were identified: <i>Rosalina douvillei</i>(CUSHMAN) and <i>Quinqueloculinai seminula</i> (LINNÉ). A few number of planktonic individuals were found. These individuals were refered to the species <i>Globorotalia</i> cf. <i>mayeri</i> CUSHMAN & ELLISOR. The paleoenvironmental characteristics of this outcrops, taken into account the information obtained from benthonic foraminifera, and the bioestratigraphic data obtained from planktonic foraminifera are discussed.<br><br>En e…
Testing a portable laser-induced breakdown spectroscopy system on geological samples.
2012
9 pages; International audience; This paper illustrates the potentialities of a home-made portable LIBS (laser-induced breakdown spectroscopy) instrument in Earth sciences, more particularly in geochemically recognizing (i) tephra layers in lacustrine sediments and (ii) fossilization processes in ammonites. Abundances for selected lines of Al, Ca, Fe, Ti, Ba and Na were determined in lacustrine chalk sediments of the Jura, where the Laacher See Tephra (LST) layer is recorded. A statistical treatment of elemental maps produced from the section of a sedimentary column containing the LST event allows instrumental conditions to be optimized. Accumulating spectra from close shot positions gives …
The Monte San Nicola section (Sicily) revisited: A potential unit-stratotype of the Gelasian Stage
2022
The Monte San Nicola area (Southern Sicily) offers a spectacular exposure of open-marine sediments that were employed in 1998 for defining the Global Stratotype Section and Point (GSSP) of the Gelasian Stage (Upper Pliocene). After the lowering of the Pliocene/Pleistocene boundary to ca. 2.6 Ma in 2010, the Gelasian GSSP has been redefined as the base of both the Pleistocene Series and the Quaternary Period, which increased its importance and visibility within the scientific community. However, documentation on the Monte San Nicola reference section is still sparse. In the light of its renewed status, we decided to undertake a complete revision of the Gelasian Stage in its type area, in ord…