Search results for "STRATIGRAPHY"
showing 10 items of 904 documents
Apport des ammonites au cadre biostratigraphique et chronostratigraphique du Haut-Atlas de Rich au cours du Lias (Maroc).
2007
11 pages
Données lithostratigraphiques et biostratigraphiques sur le Lias dans le cadre de deux transects du Haut-Atlas central (Beni Mellal et Midelt-Errachi…
2007
14 pages
Nouvelles données sur les ammonites du Sinémurien et du Pliensbachien basal du Haut Atlas central (Maroc). Taxonomie et implications stratigraphiques…
2010
44 pages; La description de 25 taxons dont une nouvelle espèce [Parasteroceras (Paroxynoticeras ?) scaphitoides nov. sp.] dans la région de Béni-Méllal, Midelt et Erachidia apporte de nouvelles informations sur la stratigraphie et la paléogéographie des ammonites du Sinémurien - Pliensbachien basal du Haut Atlas central. Pour cette période sept unités stratigraphiques peuvent être mises en évidence sur la base de taxons d'affinité téthysienne. Cet endémisme méditerranéen s'exprime au niveau du genre (Bouhamidoceras gr. zizense, Dudresnayiceras gr. suessiforme) mais le plus souvent, au niveau de l'espèce ou de la sous-espèce [Angulaticeras cf. coquandi, A. angustisulcatum, Arnioceras gr. rej…
Enregistrement du cycle du carbone au Pliensbachien (Jurassique inférieur) sur la marge sud téthysienne (Amellago, Haut-Atlas Central, Maroc)
2018
International audience; Le Pliensbachien s’inscrit dans un contexte climatique greenhouse au Jurassique, en période de dislocation de la Pangée. De récentes études dans le domaine nord-ouest téthysien ont démontré une certaine variabilité climatique soutenue notamment par des variations isotopiques remarquables dans le cycle du carbone, comparables en amplitude et en durée à d’autres événements du Toarcien (e.g. T-OAE). Malgré la multiplication des travaux le long de la marge nord téthysienne avec la mise en évidence de changements géodynamiques importants, la marge sud n’a jamais été étudiée à haute résolution. Nous proposons, dans un cadre biostratigraphique extrêmement précis (ammonites …
Lettura stratigrafica degli elevati e restituzione 3d della Chiesa
2009
Il contributo riguarda lo studio architettonico della chiesa attraverso un percorso metodologico che parte del rilievo architettonico e dalla lettura stratigrafica degli elevati fino all'ipotesi di ricostruzione virtuale dell'edificio The contribution concerns the architectural study of the church through a methodological path that is part of the architectural survey and from the stratigraphic reading of the elevated to the hypothesis of virtual reconstruction of the building
2020
Abstract. Quantifying the hydraulic properties of single fractures is a fundamental requirement to understand fluid flow in fractured reservoirs. For an ideal planar fracture, the effective flow is proportional to the cube of the fracture aperture. In contrast, real fractures are rarely planar, and correcting the cubic law in terms of fracture roughness has therefore been a subject of numerous studies in the past. Several empirical relationships between hydraulic and mechanical aperture have been proposed based on statistical variations of the aperture field. However, often, they exhibit non-unique solutions, attributed to the geometrical variety of naturally occurring fractures. In this st…
Simulating permeability reduction by clay mineral nanopores in a tight sandstone by combining computer X-ray microtomography and focussed ion beam sc…
2021
Solid earth 12(1), 1 - 14 (2021). doi:10.5194/se-12-1-2021
2020
Abstract. Residual pressure can be preserved in mineral inclusions, e.g. quartz-in-garnet, after exhumation due to differential expansion between inclusion and host crystals. Raman spectroscopy has been applied to infer the residual pressure and provides information on the entrapment temperature and pressure conditions. However, the amount of residual pressure relaxation cannot be directly measured. An underestimation or overestimation of residual pressure may lead to significant errors between calculated and actual entrapment pressure. This study focuses on three mechanisms responsible for the residual pressure modification: (1) viscous creep; (2) plastic yield; (3) proximity of inclusion …
Freshening of the Mediterranean Salt Giant: controversies and certainties around the terminal (Upper Gypsum and Lago-Mare) phases of the Messinian Sa…
2021
The late Miocene evolution of the Mediterranean Basin is characterized by major changes in connectivity, climate and tectonic activity resulting in unprecedented environmental and ecological disruptions. During the Messinian Salinity Crisis (MSC, 5.97-5.33 Ma) this culminated in most scenarios first in the precipitation of gypsum around the Mediterranean margins (Stage 1, 5.97-5.60 Ma) and subsequently > 2 km of halite on the basin floor, which formed the so-called Mediterranean Salt Giant (Stage 2, 5.60-5.55 Ma). The final MSC Stage 3, however, was characterized by a "low-salinity crisis", when a second calcium-sulfate unit (Upper Gypsum; substage 3.1, 5.55-5.42 Ma) showing (bio)geochemica…
The late Hauterivian Faraoni "Oceanic Anoxic Event" at Río Argos (southern Spain): an assessment on the level of oxygen depletion.
2013
14 pages; International audience; An integrated study of multiple geochemical proxies (TOC, δ13Ccarb, trace metallic elements, iron speciation) on the late Hauterivian Faraoni Oceanic Anoxic Event has been performed along the hemi-pelagic section of Río Argos (south-eastern Spain) in order to better constrain the environmental perturbations linked to this event in the Subbetic domain. In the studied section, the TOC is relatively low (b0.5 wt.%) except for one sample at the base of the Faraoni horizon, where it reaches 1.5 wt.%. The δ13Ccarb signal is characterized by a minor long-term increase, primarily attributed to an enhanced organic matter burial. However, both organic and isotopic si…