Occurrence of organic matter-rich deposits (Middle Jurassic to Lower Cretaceous) from Qalikuh locality, Zagros Basin, South–West of Iran: A possible oil shale resource

2015 ◽  
Vol 143 ◽  
pp. 34-42 ◽  
Author(s):  
Ali Rasouli ◽  
Ali Shekarifard ◽  
Farhang Jalali Farahani ◽  
Mustafa Verşan Kök ◽  
Manouchehr Daryabandeh ◽  
...  
2020 ◽  
Author(s):  
Kseniya Mikhailova ◽  
Victoria Ershova ◽  
Mikhail Rogov ◽  
Boris Pokrovsky ◽  
Oleg Vereshchagin

<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>


2021 ◽  
Vol 238 ◽  
pp. 103714
Author(s):  
Arka Rudra ◽  
Hamed Sanei ◽  
H.P. Nytoft ◽  
H.I. Petersen ◽  
Carlette Blok ◽  
...  

2004 ◽  
Vol 6 (5) ◽  
pp. 441-447 ◽  
Author(s):  
A. B. MacKenzie ◽  
G. T. Cook ◽  
J Barth ◽  
P Gulliver ◽  
P McDonald
Keyword(s):  

2021 ◽  
Author(s):  
Shahin Khosrov Akhundov ◽  
Mushfig Farhad Tagiyev ◽  
Arastun Ismail Khuduzade ◽  
Natig Namig Aliyev

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.


2018 ◽  
Vol 480 (1) ◽  
pp. 611-614
Author(s):  
D. A. Bushnev ◽  
N. S. Burdelnaya ◽  
I. V. Goncharov ◽  
V. V. Samoylenko ◽  
M. A. Veklich

2017 ◽  
pp. 34-43
Author(s):  
E. E. Oksenoyd ◽  
V. A. Volkov ◽  
E. V. Oleynik ◽  
G. P. Myasnikova

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.


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