1,721,027 research outputs found
Tracking biogeochemical signatures recorded during migration history of hydrocarbon rich fluids
No full textSpatial association of mud volcano and sandstone intrusions, Boyadag anticline, western Turkmenistan
Full text linkAcknowledgements The Authors are indebted with Dr. Barbara Cerasetti, scientific coordinator of the Italian Archaeological Program in Turkmenistan (Dipartimento di Storia, Culture, Civiltà – Università di Bologna – Ministero per gli Affari Esteri – MAE), for the logistical help before and during the field activities in Turkmenistan. Our thanks to the administration of the National Institute of Deserts, Flora and Fauna, to the Turkmenistan Government and to Dr Aman Nigarov for the fruitful assistance in the field. We thank Prof. Marco Antonellini for the discussions on sandstone intrusions. The authors are indebted to the reviewers J. Peakall, P. Imbert, A. Hurst and an anonymous reviewer for the very helpful comments to the manuscript. Funding was provided by Prof. G. Gabbianelli for the field survey and by PRIN 2009 grants to Prof. Rossella Capozzi.Peer reviewe
Due personalità del dibattito sul presidenzialismo nell’Italia del secondo dopoguerra: Mario Vinciguerra ed Edgardo Sogno
No full textll saggio ricostruisce le posizioni in tema di presidenzialismo di Mario Vincioguerra e di Edgardo Sogno. Per Vinciguerra il presidenzialismo si giustificava con ragioni di carattere storico, per Sogno la propensione per il preisdenzialismo aveva un carattere tecnocratic
Tracing marine ingressions in continental deposits: the Bearpaw sea of west-central Alberta
No full textA genetic model of hydrocarbon-derived carbonate chimneys in shelfal fine-grained sediments: The Enza River field, Northern Apennines (Italy)
Full text linkMethane Derived Authigenic Carbonate (MDAC) concretions have been recently exposed in the Pleistocene Argille Azzurre Fm. outcropping along the Enza riverbanks, Northern Apennines foothills, Italy.
The relations between the sediment deposition, the coeval tectonic deformation and the MDAC concretions have been investigated to unravel the mechanism of methane migration through the sediments and the processes leading to MDAC occurrence. The biogenic methane responsible for the formation of MDAC chimneys and slabs has been generated in the organic-rich Pliocene sediments located in the Po Plain subsurface. The gas migrated up-dip towards the Northern Apennines foothills. The MDAC cements are mainly composed of dolomite, whose precipitation requires thousand years and the absence of SO4 in the pore fluids. According with the sedimentation rates of the MDAC-hosting Pleistocene succession, the Sulphate Methane Transition Zone migrated upwards faster than time required for dolomite precipitation.
Therefore, the connate water migrating together with the methane could have acted as second DIC source, allowing the MDAC formation also in the methane-rich zone
Evolution of the Western Interior Seaway in west-central Alberta (late Campanian, Canada): Implications for hydrocarbon exploration
Full text linkThis study presents the first integrated, high-resolution stratigraphic analysis of a large area of the Cretaceous
Western Interior Basin in Alberta (western Canada), providing new tools to discriminate sedimentary processes
and stratigraphic patterns of transgressive-regressive (T-R) cycles in correlative marine and non-marine domains.
We integrate gamma ray well-log analysis, measured sections, and paleontological data to determine sediment
accumulation and distribution during the second-order T-R cycle of the late Campanian Western Interior Seaway
over a previously unstudied area encompassing approximately 97,000 km2 of the Alberta foreland basin. The
Bearpaw Formation, historically regarded as the product of a single transgression, is shown to include two T-R
cycles, whose timing is constrained by new chronostratigraphic data that provides an unprecedented resolution
(~200 kyr) for the Cretaceous of western North America. Seven reference stratigraphic markers were mapped
across the study area from the marine deposits into the fluvial domains. 3D-modelled stratigraphic surfaces and
stratigraphic intervals resulted in isopach maps for consecutive systems tracts, allowing detailed interpretations
of their architecture and patterns of sediment accumulation. Our analysis provides paleogeographic maps for the
Western Interior Seaway, focusing primarily on the evidence of the paleo-coastlines during the documented
cycles. The distribution of fine-grained, primarily marine, sediments resulted in an effective seal for hydrocarbon
accumulation in the Belly River Group. Further oil migration upsection, within the Edmonton group, was prevented
by the occurrence of these sealing units. Data support the interpretation that eustasy provided the main
control on the evolution of the Western Interior Seaway during the late Campanian
Carbon, oxygen and strontium isotopic constraints on fluid sources, temperatures and biogeochemical processes during the formation of seep carbonates - Secchia River site, Northern Apennines
No full textUnderstanding authigenic seep carbonate formation provides clues for hydrocarbon exploration and insights into contributions to gas budgets of marine environments and the atmosphere. Seep carbonates discovered in the outcropping succession along the Secchia riverbanks (near Modena, Italy) belong to the Argille Azzurre Formation of Early Pleistocene age deposited in an upper shelf environment overlying the Miocene foredeep successions, which include hydrocarbon fields. The fluid migration from the hydrocarbon fields, up to the surface, is presently active on land and started in the marine succession during the Late Miocene. Authigenic globular carbonate concretions and carbonate chimneys are interspersed along the strata throughout the section. A comprehensive geochemical characterisation of the carbonates has been carried out to understand the processes leading to their formation. The carbonate concretions are the record of past hydrocarbon vents linked to the Miocene petroleum system of the Northern Apennines. The samples are composed of >Â 50% microcrystalline dolomite. The Î ́13C signatures identify two groups in the samples according to different type of formation processes. Globular concretions have positive values that suggest an influence of CO2 associated to secondary methanogenesis due to microbial degradation of higher hydrocarbons. The analysed chimney, with negative Î ́13C values, is interpreted as former conduit where carbonate precipitation is promoted by Anaerobic Oxidation of Methane coupled with Sulfate Reduction. The Î ́18O range, coupled with 87/86Sr signatures, indicate that the contribution of deep connate water from the Miocene reservoirs is up to 23% during the formation of the globular concretions. The connate water occurrence is also documented by higher ambient temperatures. The different isotope signatures in seep carbonates result from the relative contribution of the recognised gas and water components, linked to different plumbing systems and fluid supply from a well-defined hydrocarbon field. The seep carbonate characteristics have enlightened variations in biogeochemical processes, which can be rarely quantified in ancient and present-day marine environments
Fluid sources and stable isotope signatures in authigenic carbonates from the Northern Apennines, Italy
Full text linkFunding was provided by the Italian PRIN 2009 Project (MIUR research grant to R. Capozzi) and by the Royal Society of Edinburgh (grant to D. Oppo). The authors wish to thank Joachim Reitner (Department of Geobiology, Centre for Geosciences, Georg-August-University of Göttingen, Germany), Stefano Bernasconi (Department of Earth Sciences, Geologisches Institut, ETH Zurich, CH) and Mario Mussi (CNR-Institute for Geosciences and Georesources, CNR-IGG, Pisa) for contributing in the stable isotopes analyses on carbonate samples; and to two anonymous reviewers.Peer reviewe
Carbonate Conduits linked to Hydrocarbon-enriched Fluid Escape
No full textPreface to the Special Volume on Carbonate Conduits linked to Hydrocarbon-enriched Fluid Escape. This special volume emerges from an international workshop held in Bologna between June 29th and July 1st, 2013 as the final act of the Italian national project PRIN 2009 “Carbonate conduits linked to hydrocarbons enriched seepages”. The workshop was attended by 20 specialists in the field, and many of the contributors expressed a strong interest in showcasing their latest achievements in a thematic volume. This issue thus collects state-of-the-art papers focused on various aspects related to the genesis of hydrocarbon-carbonate conduits in marine sequences, covering
temporal windows from Mesozoic up to present
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