untitled
<OAI-PMH schemaLocation=http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd>
<responseDate>2018-01-15T18:28:23Z</responseDate>
<request identifier=oai:HAL:insu-01184739v1 verb=GetRecord metadataPrefix=oai_dc>http://api.archives-ouvertes.fr/oai/hal/</request>
<GetRecord>
<record>
<header>
<identifier>oai:HAL:insu-01184739v1</identifier>
<datestamp>2018-01-11</datestamp>
<setSpec>type:ART</setSpec>
<setSpec>subject:sdu</setSpec>
<setSpec>collection:INSU</setSpec>
<setSpec>collection:CNRS</setSpec>
<setSpec>collection:GM</setSpec>
<setSpec>collection:UNIV-STRASBG</setSpec>
<setSpec>collection:AGROPOLIS</setSpec>
<setSpec>collection:B3ESTE</setSpec>
<setSpec>collection:UNIV-AG</setSpec>
<setSpec>collection:UNIV-MONTPELLIER</setSpec>
</header>
<metadata><dc>
<publisher>HAL CCSD</publisher>
<title lang=en>Sedimentary imprints of former ice-sheet margins: Insights from an end-Ordovician archive (SW Libya)</title>
<creator>Girard, Flavia</creator>
<creator>Ghienne, Jean-François</creator>
<creator>Du-Bernard, Xavier</creator>
<creator>Rubino, Jean-Loup</creator>
<contributor>Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS)</contributor>
<contributor>Institut de Physique du Globe de Strasbourg, UMR7516, Université de Strasbourg/EOST, CNRS, Strasbourg ; Institut de physique du globe de Strasbourg (IPGS) ; Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS)</contributor>
<contributor>TOTAL-Scientific and Technical Center Jean Féger (CSTJF) ; Total</contributor>
<description>International audience</description>
<source>ISSN: 0012-8252</source>
<source>Earth-Science Reviews</source>
<publisher>Elsevier</publisher>
<identifier>insu-01184739</identifier>
<identifier>https://hal-insu.archives-ouvertes.fr/insu-01184739</identifier>
<source>https://hal-insu.archives-ouvertes.fr/insu-01184739</source>
<source>Earth-Science Reviews, Elsevier, 2015, pp.259-289. 〈10.1016/j.earscirev.2015.06.006〉</source>
<identifier>DOI : 10.1016/j.earscirev.2015.06.006</identifier>
<relation>info:eu-repo/semantics/altIdentifier/doi/10.1016/j.earscirev.2015.06.006</relation>
<language>en</language>
<subject lang=en>Murzuq Basin</subject>
<subject lang=en>Hirnantian glaciation</subject>
<subject lang=en>Ice front</subject>
<subject lang=en>Tunnel valleys</subject>
<subject lang=en>Glaciotectonic</subject>
<subject lang=en>Supercritical flows</subject>
<subject>[SDU] Sciences of the Universe [physics]</subject>
<type>info:eu-repo/semantics/article</type>
<type>Journal articles</type>
<description lang=en>Fromthe Proterozoic to the Quaternary, the evolution of the Earthwas characterised by recurrent periods of glaciation.However, the margins of many ancient ice-sheets are poorly defined on palaeogeographic reconstructions.The extent and outlines of ancient ice sheets can be better understood through careful documentation ofsediments deposited at the ice-sheet margin. An outstanding example is provided herein based on an end-Ordovician archive in Libya (Tihemboka area, Murzuq Basin). The four sets of structures include: i) subglacialglaciotectonic structures and soft sediment deformations from flowing glacier ice, such as intraformational glacialstriae, intraformational deformation (shear planes, sheath folds), normal microfaults, and large-scaleglaciotectonic folds-and-thrusts; (ii) structures resulting from overpressured subglacial (meltwater) flowssuch as clastic dykes and tunnel valleys; (iii) proglacial depositional structures and facies related to highmagnitudemeltwater floods such as sandstone intraclasts, large-scale bedforms resulting from supercriticalflows, climbing-dune cross-stratification and kettle holes; and (iv) deformation structures resulting from freefloating and nonglacier ice such as ice-keel scours and ice-crystal marks. Such a set of structures points to anice-marginal (essentially continental) depositional setting, and provides an excellent suite of criteria to identifymargins of ancient ice sheets in the stratigraphic record. At a regional scale, a reconstruction through time andspace of the related depositional wedge is proposed. This corresponded to a seismic-scale (N120 m in thickness,40 km in length) ice-marginal wedge in front of an essentially warm-based ice-sheet inducing concomitantlarge-scale glaciotectonic deformation, glacial basin and tunnel valley downcuttings. The related ice-front wasassociated with high-energy meltwater flows feeding a network of deeply incised proglacial channels downstreamand, beyond them, a fluvioglacial deltaic system. Shallow ice-marginal permafrost most likely affectedthe depositional wedge. At a larger scale, the Tihemboka ice-marginal wedge is interpreted as related to a stillstandperiod over the Gondwana platform, developed over an estimated interval of a few thousands of years.Based on these data, the conditions that arose in a particularly favourable context for the development, the preservationand the identification of ice-marginal wedges in the geological record are reviewed. Significantmeltwater-derived sediment deposition and aggradation in an accommodation space resulting either frompreglacial inheritance, glacial downcuttings and/or glacio-isostatic lithospheric flexure, or active tectonic subsidence(>1 Myr) are required for their formation and subsequent preservation.</description>
<date>2015</date>
<contributor>ANR-12-BS06-0014, SeqStrat-Ice, Les glaciations du passé: leçons pour un modèle de stratigraphie séquentielle dédié aux systèmes glaciaires(2012)</contributor>
</dc>
</metadata>
</record>
</GetRecord>
</OAI-PMH>
