Search results for "Early Toarcian"

showing 3 items of 3 documents

THE EARLY TOARCIAN ANOXIC EVENT IN THE TETHYAN DOMAIN: USE OF HIGH-RESOLUTION GEOCHEMICAL RECORDS FOR PALAEOCEANOGRAPHIC RECONSTRUCTIONS

2007

Early Toarcian Oceanic Anoxic Event
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Petrography and high-resolution geochemical records of Lower Jurassic manganese-rich deposits from Monte Mangart, Julian Alps

2016

Deposits with unusually high Mn contents sampled at Monte Mangart in the Julian Alps include organic-rich marlstone and black shale with interbedded manganoan and siliceous limestone, which were deposited during the early Toarcian Oceanic Anoxic Event. Mn enrichment during that period has been related to global sea-level change coincident with increasing subsidence rate. The formation of Fe-Mn nodules, marking a hardground at the base of the Monte Mangart section, seems to be triggered by release of Mn from remote hydrothermal vents into a region of relatively elevated submarine topography where oxidizing conditions prevailed. However, very high Mn contents in carbonate phases above the har…

GeochemistrySettore GEO/07 - Petrologia E PetrografiaPaleontologyengineering.materialOceanographyCarbonate hardgroundsEarly Toarcian Mn-bearing deposits Anoxic Event Stable isotope stratigraphy Rare earth elementsAnoxic watersDiagenesisSettore GEO/08 - Geochimica E VulcanologiaPetrographyEarth scienceschemistry.chemical_compoundPaleontologychemistryMarlengineeringCarbonatePyriteEarly Toarcian Mn-bearing deposits Anoxic Event Stable isotope stratigraphy Rare earth elementsEcology Evolution Behavior and SystematicsGeologyEarth-Surface ProcessesHydrothermal vent
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Gastropods from upper Pliensbachian–Toarcian (Lower Jurassic) sediments of Causses Basin, southern France and their recovery after the early Toarcian…

2015

AbstractA gastropod fauna has been studied from upper Pliensbachian – upper Toarcian deposits of two sections of the Causses Basin (southern France) in order to investigate the mode of recovery after the early Toarcian anoxic event. The fauna consists of 15 species, one of which is new (Bathrotomaria kronzwilmesorumsp. nov.). Their stratigraphical distribution shows two peaks of diversity – in the Bifrons Zone (Bifrons Subzone) and in the Aalensis Zone (Mactra Subzone) – which reflect brief times during which the oxygen content and bottom consistency favoured the settlement of a relatively diversified fauna. In the Variabilis–Pseudoradiosa zones, gastropods are only represented by two speci…

MactraSystematicsbiologyearly Toarcian anoxic eventFaunaGastropodaSpecies diversityGeologyStructural basinbiology.organism_classificationAnoxic watersGastropoda; Lower Jurassic; PalaeobiogeographyPaleontologyPalaeobiogeographyTaxonLower JurassicGastropodaFrancesystematicsGeology[ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology
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