Stimulation of Low-Temperature Dissolution of Organic Matter of Brown Coal, Composition of Bitumoids

In this investigation, we showed that high salinity promoted by hydrothermal inputs, reducing conditions of sediments with high content in organic matter, and the occurrence of an appropriate clay mineral precursor provide a suitable framework for low-temperature illitization processes. We studied the sedimentary illitization process that occurs in carbonaceous sediments from a lake with saline waters (Sochagota Lake, Colombia) located at a tropical latitude. Water isotopic composition suggests that high salinity was produced by hydrothermal contribution. Materials accumulated in the Sochagota Lake’s southern entrance are organic matter-poor sediments that contain detrital kaolinite and quartz. On the other hand, materials formed at the central segment and near the lake exit (north portion) are enriched in organic matter and characterized by the crystallization of Fe-sulfides. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray spectrometry (EDX) data allowed for the identification of illite and illite-dioctahedral vermiculite mixed layers (I-DV), which are absent in the southern sediments. High humidity and temperate climate caused the formation of small-sized metastable intermediates of I-DV particles by the weathering of the source rocks in the Sochagota Lake Basin. These particles were deposited in the low-energy lake environments (middle and north part). The interaction of these sediments enriched in organic matter with the saline waters of the lake enriched in hydrothermal K caused a reducing environment that favored Fe mobilization processes and its incorporation to I-DV mixed layers that acted as mineral precursor for fast low temperature illitization, revealing that in geothermal areas clays in lakes favor a hydrothermal K uptake.

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Hydrocarbon Generative Properties and Maturity of Cretaceous and Eocene Sediments in the Middle Kura Depression, Azerbaijan

10.2118/207041-ms ◽

2021 ◽

Author(s):

Shahin Khosrov Akhundov ◽

Mushfig Farhad Tagiyev ◽

Arastun Ismail Khuduzade ◽

Natig Namig Aliyev

Keyword(s):

Organic Matter ◽

Brown Coal ◽

Lower Cretaceous ◽

Vitrinite Reflectance ◽

Sedimentary Cover ◽

Hard Coal ◽

Marine Origin ◽

Formation Conditions ◽

Lesser Caucasus ◽

Reflectance Data

Abstract Meso-Cenozoic sedimentary cover in the Middle Kura depression located between the Greater and Lesser Caucasus mountain structures contains numerous oil accumulations. According to studies in the Cretaceous and Paleogene strata, sedimentary organic matter is of mixed clastic-marine origin. Moderate amounts of organic matter have been recorded in the Eocene sediments (on average 0.70%), in the Upper and Lower Cretaceous average values made up 0.39% и 0.42%, respectively. Analysis of bitumoid composition suggests that in a number of areas bitumoids have experienced a widespread movement across the sedimentary strata. The results of measurements on isolated samples indicate that the Cretaceous strata have only advanced to the initial hard-coal stage of organic transformation (0.48-0.55%Ro). On vitrinite reflectance data the Eocene deposits in studied areas of the Middle Kura depression have reached initial (brown-coal) stage of catagenetic transformation (±0.48Ro%; est. paleotemperature of 85°C). Nonetheless, analysis of formation conditions of commercial HC accumulations found earlier in the Eocene strata allows considering them the most prospective in the Middle Kura depression.

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Potential Production of Carbon Gases and Their Responses to Paleoclimate Conditions: An Example From Xiaolongtan Basin, Southeast Tibetan Plateau

Frontiers in Earth Science ◽

10.3389/feart.2021.582062 ◽

2021 ◽

Vol 9 ◽

Author(s):

Gen Wang ◽

Yongli Wang ◽

Zhifu Wei ◽

Zepeng Sun ◽

Wei He ◽

...

Keyword(s):

Organic Matter ◽

Tibetan Plateau ◽

Low Temperature ◽

Organic Carbon ◽

Carbon Cycle ◽

Higher Plants ◽

The Tibetan Plateau ◽

Climate Conditions ◽

Burial Flux ◽

Carbon Gases

Uplift of the Tibetan Plateau plays a significant and lasting role in the variations of climate conditions and global carbon cycle. However, our knowledge is limited due to the lack of long-sequence records revealing rates of CO2 and CH4 production, hampering our understanding of the relationship between paleoclimatic conditions, carbon cycling and greenhouse gas flux. Here, we present a combination of paleoclimate records and low-temperature thermal simulation results from sediments of the Xiaolongtan Basin at the southeastern margin of the Qinghai-Tibetan Plateau, spanning the late Miocene (14.1 ∼ 11.6 Ma). The n-alkane-derived proxies suggested that the sources of organic matter were obviously different: a mixed source including lower organisms and terrestrial higher plants for the Dongshengqiao Formation from 14.1 to 12.6 Ma, and a predominant contribution from terrestrial higher plants for Xiaolongtan Formation between 12.6 and 11.6 Ma. The paleoclimate was generally warm and humid as reflected by the lipid biomarkers, consistent with previous studies. In addition, the carbon gases (including CO2 and hydrocarbon gases) generated by the low-temperature thermal simulation experiments indicated a production rate of CO2 and CH4 were as high as 88,000 ml/kg rock and 4,000 ml/kg rock, respectively, implying there were certain amounts of carbon gases generated and released into the atmosphere during their shallow burial stage. Besides, the calculated production rate of carbon gases and the estimated burial flux of organic carbon varied in response to the variations of paleoclimate conditions. Based on these observations, we propose that the climate conditions predominantly controlled the formation and accumulation of organic matter, which consequently affected the production of carbon gases and burial flux of organic carbon. The results presented here may provide a significant insight into the carbon cycle in the southeast of the Tibetan Plateau.

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Evaluation of the lipid fraction of pyrochars organic matter in the aspect of negative effects on soil

BIO Web of Conferences ◽

10.1051/bioconf/20201700156 ◽

2020 ◽

Vol 17 ◽

pp. 00156

Author(s):

Rodion Okunev ◽

Elena Smirnova ◽

Kamil Giniyatullin ◽

Irina Guseva

Keyword(s):

Organic Matter ◽

Low Temperature ◽

Pyrolysis Temperature ◽

Lipid Fraction ◽

Total Content ◽

Negative Effects ◽

Polycyclic Aromatic ◽

Negative Effect ◽

Pahs Concentration ◽

Low Temperature Pyrolysis

The evaluation of the possible negative effect of pyrochars on soils based on the analysis of the content of lipid fraction and polycyclic aromatic hydrocarbons (PAHs) of organic matter was evaluated. Eight species of pyrochar were obtained from the crop and wood residues (linden, willow, corn, millet) by two pyrolysis regimes: low-temperature pyrolysis (<400°C) and high-temperature pyrolysis (400–600°C). The largest amount of lipid fraction (from 0.54 to 2.78%) and PAHs were found in pyrochars obtained at a low pyrolysis temperature. The total content of PAHs in the studied samples ranged from 8.49 to 603.21 μg/kg. According to the PAHs content, pyrochar was the most adverse for application to the soil, obtained from the residues of millet of low-temperature pyrolysis, however, at a high pyrolysis temperature, the safest product with the lowest PAHs concentration and a significant amount of lipid fraction was formed. Using an incubation experiment by measuring substrate-induced respiration in soil-pyrochar mixtures, it was shown that the application of this meliorant can also increase the emission of carbon dioxide from soils in a short time. The results of the experiments showed that it is necessary to precisely control the conditions of pyrolysis and carefully select the material for pyrochar in order to obtain the products with most favourable amounts of lipid fraction and PAHs content.

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Sandstone-Hosted Uranium Deposits as a Possible Source for Critical Elements: The Eureka Mine Case, Castell-Estaó, Catalonia

Minerals ◽

10.3390/min10010034 ◽

2019 ◽

Vol 10 (1) ◽

pp. 34 ◽

Cited By ~ 1

Author(s):

Montgarri Castillo-Oliver ◽

Joan Carles Melgarejo ◽

Lisard Torró ◽

Cristina Villanova-de-Benavent ◽

Marc Campeny ◽

...

Keyword(s):

Organic Matter ◽

Low Temperature ◽

Black Shales ◽

Hydrothermal Fluids ◽

Uranium Deposits ◽

Critical Metals ◽

Fine Grained ◽

Critical Elements ◽

By Products ◽

Red Bed

The Eureka deposit in Castell-estaó in the Catalan Pyrenees is a Cu–U–V deposit, hosted by Triassic red-bed sandstones, and classified here as a low-temperature, sandstone-hosted stratabound metamorphite U deposit. The main mineralisation is stratabound, related to coal-bearing units and produced during the Alpine deformation by migration of hydrothermal fluids. In this stage, the original sedimentary and diagenetic components (quartz and calcite, micas, hematite and locally apatite) were replaced by a complex sequence of roscoelite, fine-grained REE phosphates, sulphides and Ni–Co arsenides and sulpharsenides, Ag–Pb selenides, bismuth phases, sulphosalts and uraninite. The black shales of the Silurian sediments underlying the deposit and the nearby Carboniferous volcanoclastic rocks are interpreted as the source of the redox-sensitive elements concentrated in Eureka. The sulphur source is related to leaching of the evaporitic Keuper facies. The REE transport would be facilitated by SO4-rich solutions. The reduction of these solutions by interaction with organic matter resulted in the widespread precipitation of REE and redox-sensitive elements, including many critical metals (V, Bi, Sb, Co), whereas barite precipitated in the oxidized domains. The occurrence of similar enrichments in critical elements can be expected in other similar large uranium deposits, which could be a source of these elements as by-products.

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