Keys to the depositional history of the Posidonia Shale (Toarcian) in the Hils Syncline, northern Germany

. (2014) 'High-pressure methane adsorption and characterization of pores in Posidonia shales and isolated kerogens.', Energy fuels., 28 (5). pp. 2886-2901. Further information on publisher's website:http://dx.doi.org/10.1021/ef402466mPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy Fuels, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/ef402466m. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractSorption capacities and pore characteristics of bulk shales and isolated kerogens have been determined for immature, oil-window and gas-window mature samples from the Lower Toarcian Posidonia Shale formation. Dubinin-Radushkevich (DR) micropore volumes, sorption pore volumes and surface areas of shales and kerogens were determined from CO 2 adsorption isotherms at -78°C and 0°C, and N 2 adsorption isotherms at -196°C. Mercury injection capillary pressure porosimetry, grain density measurements and helium pycnometry were used to determine shale and kerogen densities and total pore volumes.Total porosities decrease through the oil-window and then increase into the gas-window.High-pressure methane isotherms up to 14 MPa were determined at 45, 65 and 85°C on dry shale and at 45 and 65°C on kerogen. Methane excess uptakes at 65°C and 11.5 MPa were in the range 0.056-0.110 mmol g -1 (40-78 scf t -1 ) for dry Posidonia shales and 0.36-0.70 mmol g -1 (253-499 scf t -1 ) for the corresponding dry kerogens. Absolute methane isotherms were calculated by correcting for the gas at bulk gas phase density in the sorption pore volume. The enthalpies of CH 4 adsorption for shales and kerogens at zero surface coverage showed no significant variation with maturity, indicating that the sorption pore volume is the primary control on sorption uptake. The sum of pore volumes measured by a) CO 2 sorption at -78°C and b) mercury injection, are similar to the total porosity for shales. Since mercury in our experiments occupies pores with constrictions larger than ca. 6 nm, we infer that porosity measured by CO 2 adsorption at -78°C in the samples used in this study is largely within pores with effective diameters smaller than 6 nm. The linear correlation between maximum CH 4 surface excess sorption and CO 2 sorption pore volume at -78°C is very strong for both shales and kerogens, and goes through the origin, suggestin...

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“…26 Geological and geochemical history has been reviewed in detail elsewhere. 21,[24][25][26][27][28][29][30] …”

Section: Posidonia Shalesmentioning

confidence: 99%

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

et al. 2014

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“…[18] Data for northern Germany derive from the Wickensen and Hildesheim cores [Jochum, 1993;Brumsack, 1988]: the biostratigraphy of the Wickensen core is given by Littke et al [1991] and that for the Hildesheim core by Loh et al [1986]. Data for the Mögglingen core in southern Germany are from Brumsack [1988], whose biostratigraphic assignments were from Riegraf et al [1984].…”

Section: Chemical Analysismentioning

confidence: 99%

Basinal restriction, black shales, Re‐Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event

et al. 2008

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[1] Profiles of Mo/total organic carbon (TOC) through the Lower Toarcian black shales of the Cleveland Basin, Yorkshire, United Kingdom, and the Posidonia shale of Germany and Switzerland reveal water mass restriction during the interval from late tenuicostatum Zone times to early bifrons Zone times, times which include that of the putative Early Toarcian oceanic anoxic event. The degree of restriction is revealed by crossplots of Mo and TOC concentrations for the Cleveland Basin, which define two linear arrays with regression slopes (ppm/%) of 0.5 and 17. The slope of 0.5 applies to sediment from the upper semicelatum and exaratum Subzones. This value, which is one tenth of that for modern sediments from the Black Sea (Mo/TOC regression slope 4.5), reveals that water mass restriction during this interval was around 10 times more severe than in the modern Black Sea; the renewal frequency of the water mass was between 4 and 40 ka. The Mo/TOC regression slope of 17 applies to the overlying falciferum and commune subzones: the value shows that restriction in this interval was less severe and that the renewal frequency of the water mass was between 10 and 130 years. The more restricted of the two intervals has been termed the Early Toarcian oceanic anoxic event but is shown to be an event caused by basin restriction local to NW Europe. Crossplots of Re, Os, and Mo against TOC show similar trends of increasing element concentration with increase in TOC but with differing slopes. Together with modeling of 187 Os/ 188 Os and d 98 Mo, the element/TOC trends show that drawdown of Re, Os, and Mo was essentially complete during upper semicelatum and exaratum Subzone times (Mo/TOC regression slope of 0.5). Drawdown sensitized the restricted water mass to isotopic change forced by freshwater mixing so that continental inputs of Re, Os, and Mo, via a low-salinity surface layer, created isotopic excursions of up to 1.3% in d 98 Mo and up to 0.6% for 187 Os/ 188 Os. Restriction thereby compromises attempts to date Toarcian black shales, and possibly all black shales, using Re-Os chronology and introduces a confounding influence in the attempts to use d 98 Mo and initial 187 Os/ 188 Os for palaeo-oceanographic interpretation.

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“…7; Littke et al, 1991;Luckge et al, 1999). The area below the line reflects ironlimiting conditions whereas, above, pyrite formation can be limited by the availability of sulfate or organic matter.…”

Section: Insights On Iron and Sulfur Cyclesmentioning

confidence: 99%

Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea)

et al. 2011

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Abstract. In situ oxygen microprofiles, sediment organic carbon content, and pore-water concentrations of nitrate, ammonium, iron, manganese, and sulfides obtained in sediments from the Rhône River prodelta and its adjacent continental shelf were used to constrain a numerical diagenetic model. Results showed that (1) the organic matter from the Rhône River is composed of a fraction of fresh material associated to high first-order degradation rate constants (11-33 yr −1 ); (2) the burial efficiency (burial/input ratio) in the Rhône prodelta (within 3 km of the river outlet) can be up to 80 %, and decreases to ∼20 % on the adjacent continental shelf 10-15 km further offshore; (3) there is a large contribution of anoxic processes to total mineralization in sediments near the river mouth, certainly due to large inputs of fresh organic material combined with high sedimentation rates; (4) diagenetic by-products originally produced during anoxic organic matter mineralization are almost entirely precipitated (> 97 %) and buried in the sediment, which leads to (5) a low contribution of the re-oxidation of reduced products to total oxygen consumption. Consequently, total carbon mineralization rates as based on oxygen consumption rates and using Redfield stoichiometry can be largely underestimated in such River-dominated Ocean Margins (RiOMar) environments.

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Keys to the depositional history of the Posidonia Shale (Toarcian) in the Hils Syncline, northern Germany

Cited by 91 publications

References 34 publications

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

Basinal restriction, black shales, Re‐Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event

Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea)

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