Glendonites from Mesozoic succession of eastern Barents sea: distribution, genesis and paleoclimatic implications

2020 ◽  
Author(s):  
Kseniya Mikhailova ◽  
Victoria Ershova ◽  
Mikhail Rogov ◽  
Boris Pokrovsky ◽  
Oleg Vereshchagin
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Sulfate Reduction ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Barents Sea ◽  
Upper Jurassic ◽  
Anaerobic Oxidation Of Methane ◽  
Oxidation Of Methane

<p>Glendonites often used as paleoclimate indicator of cold near-bottom temperature, as these are calcite pseudomorphs of ikaite, a metastable calcium carbonate hexahydrate, precipitates mostly under low temperature (mainly from 0-4<sup>o</sup>C) and may be stabilized by high phosphate concentrations that occurs due to anaerobic oxidation of methane and/or organic matter; dissolved organic carbon, sulfates and amino acid may contribute ikaite formation as well.  Therefore, glendonites-bearing host rocks frequently include glacial deposits that make them useful as a paleoclimate indicator of near-freezing temperature.</p><p>Our study is based on material collected from five wells drilled in eastern Barents Sea: Severo-Murmanskaya, Ledovaya – 1,2; Ludlovskaya – 1,2. The studied glendonites, mainly represented by relatively small rhombohedral pseudomorphs (0,5-2 cm) and rarely by stellate aggregates, collected from Middle Jurassic to Lower Cretaceous shallow marine clastic deposits. They scattered distributed throughout succession. Totally 18 samples of glendonites were studied. The age of host-bearing rocks were defined by fossils: bivalves or ammonites, microfossils or dinoflagellate. Bajocian-Bathonian glendonites were collected from Ledovaya – 1 and Ludlovskaya – 1 and 2 wells; in addition to these occurrences Middle Jurassic glendonites are known also in boreholes drilled at Shtockmanovskoe field. Numerous ‘jarrowite-like’ glendonites of the Middle Volgian (~ latest early Tithonian) age were sampled from Severo-Murmanskaya well. Unique Late Barremian glendonites were found in Ledovaya – 2 well.</p><p>δ<sup>18</sup>O values of Middle Jurassic glendonite concretions range from – 5.4 to –1.7 ‰ Vienna Pee Dee Belemnite (VPDB); for Upper Jurassic – Lower Cretaceous δ<sup>18</sup>O values range from – 4.3 to –1.6 ‰ VPDB; for Lower Cretaceous - δ<sup>18</sup>O values range from – 4.5 to –3.4 ‰ VPDB. Carbon isotope composition for Middle Jurassic glendonite concretions δ<sup>13</sup>C values range from – 33.3 to –22.6 ‰ VPDB; for Upper Jurassic – Lower Cretaceous δ<sup>13</sup>C values range from – 25.1 to –18.4 ‰ VPDB; for Lower Cretaceous - δ<sup>13</sup>C values range from – 30.1 to –25.6 ‰ VPDB.</p><p>Based on δ<sup>18</sup>O data we supposed that seawater had a strong influence on ikaite-derived calcite precipitation. Received data coincide with δ<sup>18</sup>O values reported from other Mesozoic glendonites and Quaternary glendonites formed in cold environments. Values of δ<sup>13</sup>C of glendonites are close to bacterial sulfate reduction and/or anaerobic oxidation of methane or organic matter. Glendonites consist of carbonates forming a number of phases which different in phosphorus and magnesium content. Mg-bearing calcium carbonate and dolomite both include framboidal pyrite, which can indicate (1) lack of strong rock transformations activity and (2) presence of sulfate-reduction bacteria in sediments.</p><p>To conclude, Mesozoic climate was generally warm and studied concretions indicate cold climate excursion in Middle Jurassic, Upper Jurassic-Early Cretaceous and Early Cretaceous.</p><p> </p><p>The study was supported by RFBR, project number 20-35-70012.</p>

Early Cretaceous glendonites of Arctic realm: distributions and their paleoclimate implication

2021 ◽  
Author(s):  
Kseniya Mikhailova ◽  
Victoria Ershova ◽  
Mikhail Rogov
Keyword(s):  
Organic Matter ◽  
Early Cretaceous ◽  
Isotope Composition ◽  
Cold Climate ◽  
The Arctic ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Arctic Canada ◽  
Oxidation Of Methane ◽  
Pee Dee

<p>In the middle of 20<sup>th</sup> century glendonites were purposed as an indicator of cold climate. There is no doubt that unique morphology and sizes of pseudomorphs occurring through Precambrian to Quaternary succession indicate uncommon geochemical environment. Here, we present an overview of Early Cretaceous glendonites distribution across Arctic which widely distributed here despite generally greenhouse climate conditions in Early Cretaceous.</p><p>Late Berriasian pseudomorphs are known on northeastern Siberia and Arctic Canada. Valanginian glendonites are the widest ones are described from the Northern and Western Siberia, Spitsbergen and the Arctic Canada. Late Hauterivian concretions were studied on Svalbard. Barremian and lower Aptian glendonites are unknown in this area due to wide distributed continental succession, but late Barremian glendonites were reported from the wells drilled on the Barents Sea shelf. Middle and Upper Aptian glendonites are found on Svalbard,  North Greenland, the Arctic Canada and North-East Russia. Lower Albian glendonites are found on Svalbard, islands of Arctic Canada and the Koryak Uplands.</p><p>Nowadays it is reliable known that the precursor of glendonites is an ikaite - metastable calcium carbonate hexahydrate, forming in a narrow temperature range from 0-4<sup>o</sup>C, mainly in near-bottom conditions. Besides low temperature, high phosphate concentrations that occurs due to anaerobic oxidation of methane and/or organic matter; dissolved organic carbon, sulfates and amino acid may favor to ikaite formation as well. However, glendonites associated with terrigenious rocks, often including glacial deposits, that allow to use them as a paleoclimate indicator.</p><p>Glendonites show a wide variability in form and size: from single crystal blades to stellate aggregates and rosettes, usually ranged from a few mm to dozens of cm. Mineralogical composition of pseudomorph is represented mainly by three calcite phases determining by CL-light. Both δ<sup>18</sup>O and δ<sup>13</sup>C of glendonites are characterized by a broad range of values. Oxygen isotope composition ranges from -14 to -0 ‰ Vienna Pee Dee Belemnite (VPDB), whilst  carbon isotope composition ranges from -52.4 to – 14 ‰ Vienna Pee Dee Belemnite (VPDB).</p><p>Based on received data we suggest that δ<sup>18</sup>O reflects the complex processes involved in ikaite-glendonite transformation, supposing mixing depleted fluids with seawater. Nevertheless, received data coincide with δ<sup>18</sup>O values reported from Paleozoic-Quaternary glendonites formed in near-freezing environments. Values of δ<sup>13</sup>C of glendonites is the result of both mixing seawater inorganic carbon and sedimentary organic diagenesis and close to bacterial sulfate reduction and/or anaerobic oxidation of methane or organic matter.</p><p>To conclude,  Early Cretaceous climate was warm generally, however studied pseudomorphs point to cold episodes in Late Berriasian, Valanginian, Late Hauterivian, Middle-Late Aptian and Early Albian.</p><p>The study was supported by RFBR, project number 20-35-70012.</p>

scholarly journals Sulfate reduction and anaerobic oxidation of methane in sediments of the South-Western Barents Sea

2021 ◽  
Author(s):  
Claudio Argentino ◽  
Kate Alyse Waghorn ◽  
Stefan Bünz ◽  
Giuliana Panieri
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Barents Sea ◽  
Continental Margins ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Geochemical Composition ◽  
Oxidation Of Methane ◽  
Methane Fluxes ◽  
Total Sulfate

Abstract. Anaerobic oxidation of methane (AOM) in marine sediments strongly limits the amount of gas reaching the water column and the atmosphere but its efficiency in counteracting future methane emissions at continental margins remains unclear. Small shifts in methane fluxes due to gas hydrate and submarine permafrost destabilization or enhanced methanogenesis in warming Arctic continental shelves may cause the redox boundary in which AOM occurs, known as Sulfate-Methane Transition Zone (SMTZ), to move closer to seafloor, with potential gas release to bottom waters. Here, we investigated the geochemical composition of pore water (SO42− and DIC concentration, δ13CDIC) and gas (CH4, δ13CCH4) in eight gravity cores collected from Ingøydjupet trough, South-Western Barents Sea. Our results show a remarkable variability in SMTZ depth, ranging from 3.5 m to 29.2 m, and that all methane is efficiently consumed by AOM within the sediment. From linear fitting of the sulfate concentration profiles, we calculated diffusive sulfate fluxes ranging from 1.5 nmol cm−2 d−1 to 12.0 nmol cm−2 d−1. AOM rates obtained for two cores using mixing models are 6.5 nmol cm−2 d−1 and 6.7 nmol cm−2 d−1 and account for only 64 % and 56 % of total sulfate reduction at the SMTZ (SRRtot), respectively. The remaining 36 % and 44 % SRRtot correspond to organoclastic sulfate reduction with rates of 3.7 nmol cm−2 d−1 and 5.3 nmol cm−2 d−1. The shallowest SMTZs ( 20 m. This study provides new insights into the dynamic and biogeochemistry of the SMTZ in marine sediments of continental margins and may help predict the response of the microbial methane filter to future increase in methane fluxes due to ocean warming.

scholarly journals Effects of Temperature and Pressure on Sulfate Reduction and Anaerobic Oxidation of Methane in Hydrothermal Sediments of Guaymas Basin

2004 ◽  
Vol 70 (2) ◽  
pp. 1231-1233 ◽  
Author(s):  
Jens Kallmeyer ◽  
Antje Boetius
Keyword(s):  
Sulfate Reduction ◽  
Deep Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Guaymas Basin ◽  
Oxidation Of Methane ◽  
Hydrothermal Sediments ◽  
Deep Sea Sediments ◽  
Effects Of Temperature ◽  
Temperature And Pressure

ABSTRACT Rates of sulfate reduction (SR) and anaerobic oxidation of methane (AOM) in hydrothermal deep-sea sediments from Guaymas Basin were measured at temperatures of 5 to 200°C and pressures of 1 × 105, 2.2 × 107, and 4.5 × 107 Pa. A maximum SR of several micromoles per cubic centimeter per day was found at between 60 and 95°C and 2.2 × 107 and 4.5 × 107 Pa. Maximal AOM was observed at 35 to 90°C but generally accounted for less than 5% of SR.

scholarly journals Anaerobic oxidation of methane associated with sulfate reduction in a natural freshwater gas source

2015 ◽  
Vol 10 (6) ◽  
pp. 1400-1412 ◽  
Author(s):  
Peer HA Timmers ◽  
Diego A Suarez-Zuluaga ◽  
Minke van Rossem ◽  
Martijn Diender ◽  
Alfons JM Stams ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Oxidation Of Methane ◽  
Gas Source

scholarly journals KEROGEN TYPES OF BAZHENOV FORMATION BASED ON PYROLYSIS DATA AND THEIR COMPARISON WITH OIL PARAMETERS

2017 ◽  
pp. 34-43
Author(s):  
E. E. Oksenoyd ◽  
V. A. Volkov ◽  
E. V. Oleynik ◽  
G. P. Myasnikova
Keyword(s):  
Organic Matter ◽  
Lower Cretaceous ◽  
Alternative Model ◽  
Oil And Gas ◽  
Upper Jurassic ◽  
Gas Content ◽  
Basin Modeling ◽  
Bazhenov Formation ◽  
Gas Bearing

Based on pyrolytic data (3 995 samples from 208 wells) organic matter types of Bazhenov Formation are identified in the central part of Western Siberian basin. Zones of kerogen types I, II, III and mixed I-II and II-III are mapped. Content of sulfur, paraffins, resins and asphaltenes, viscosity, density, temperature and gas content in oils from Upper Jurassic and Lower Cretaceous sediments (3 806 oil pools) are mapped. Oil gradations are identified and distributed. The alternative model of zones of kerogen II and IIS types is presented. The established distributions of organic matter types can be used in basin modeling and in assessment of oil-and-gas bearing prospects.

Geologic Characteristics of Reservoir Accumulation in Suganhu Depression in North Margin of Qaidam Basin

2012 ◽  
Vol 616-618 ◽  
pp. 19-25 ◽  
Author(s):  
Cheng Zhang ◽  
Guang Yang ◽  
Yong Shu Zhang
Keyword(s):  
Organic Matter ◽  
Middle Jurassic ◽  
Qaidam Basin ◽  
Upper Jurassic ◽  
Mature Stage ◽  
Braided River ◽  
Large Area ◽  
Reservoir Properties ◽  
Cap Rock ◽  
Low Porosity

Based on the analysis and testing data of rocks, the basic geologic characteristics of Suganhu depression is discussed. It is concluded that the 200m thickness dark mudstone of inshore shallow lake face in the middle–lower Jurassic stratum is the only source rock of this region. It has the characteristics of high abundance of organic matter and in high mature stage. And the type of organic matter is Ⅱ2.The reservoir properties is controlled by the influences of both the sedimentation and the diagenesis and belong to the low porosity and low permeability ones. The mudstone of Upper Jurassic is the local cap, the ones of braided river face and braided river delta face which existed in the up-middle of the middle Jurassic can be qualified as sealing bed between the sand bodies. Paleocene–eocene mudstone is the regional cap rock. The ability of upper Jurassic sealing bed is good because of the low porosity and permeability and high break pressure. The regional cap rock has the characteristics of big thickness and large area. Both the local and regional cap rock had been able to seal the petroleum and gas before the time of hydrocarbon accumulation of middle Jurassic. In general, Mesozoic formed reservoir–cap combination with the features of lower–generation and upper–reservoir, upper–cap.

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