scholarly journals Source rock characterization of mesozoic to cenozoic organic matter rich marls and shales of the Eratosthenes Seamount, Eastern Mediterranean Sea

2018 ◽  
Vol 73 ◽  
pp. 49 ◽  
Author(s):  
Sebastian Grohmann ◽  
Susanne W. Fietz ◽  
Ralf Littke ◽  
Samer Bou Daher ◽  
Maria Fernanda Romero-Sarmiento ◽  
...  
Keyword(s):  
Organic Matter ◽  
Mediterranean Sea ◽  
Source Rock ◽  
Eastern Mediterranean ◽  
Source Rocks ◽  
Eastern Mediterranean Sea ◽  
Potential Source Rock ◽  
Levant Basin ◽  
Rock Characterization ◽  
Rock Eval

Several significant hydrocarbon accumulations were discovered over the past decade in the Levant Basin, Eastern Mediterranean Sea. Onshore studies have investigated potential source rock intervals to the east and south of the Levant Basin, whereas its offshore western margin is still relatively underexplored. Only a few cores were recovered from four boreholes offshore southern Cyprus by the Ocean Drilling Program (ODP) during the drilling campaign Leg 160 in 1995. These wells transect the Eratosthenes Seamount, a drowned bathymetric high, and recovered a thick sequence of both pre- and post-Messinian sedimentary rocks, containing mainly marine marls and shales. In this study, 122 core samples of Late Cretaceous to Messinian age were analyzed in order to identify organic-matter-rich intervals and to determine their depositional environment as well as their source rock potential and thermal maturity. Both Total Organic and Inorganic Carbon (TOC, TIC) analyses as well as Rock-Eval pyrolysis were firstly performed for the complete set of samples whereas Total Sulfur (TS) analysis was only carried out on samples containing significant amount of organic matter (>0.3 wt.% TOC). Based on the Rock-Eval results, eight samples were selected for organic petrographic investigations and twelve samples for analysis of major aliphatic hydrocarbon compounds. The organic content is highly variable in the analyzed samples (0–9.3 wt.%). TS/TOC as well as several biomarker ratios (e.g. Pr/Ph < 2) indicate a deposition under dysoxic conditions for the organic matter-rich sections, which were probably reached during sporadically active upwelling periods. Results prove potential oil prone Type II kerogen source rock intervals of fair to very good quality being present in Turonian to Coniacian (average: TOC = 0.93 wt.%, HI = 319 mg HC/g TOC) and in Bartonian to Priabonian (average: TOC = 4.8 wt.%, HI = 469 mg HC/g TOC) intervals. A precise determination of the actual source rock thickness is prevented by low core recovery rates for the respective intervals. All analyzed samples are immature to early mature. However, the presence of deeper buried, thermally mature source rocks and hydrocarbon migration is indicated by the observation of solid bitumen impregnation in one Upper Cretaceous and in one Lower Eocene sample.

The seaweed resources of Israel in the Eastern Mediterranean Sea

2020 ◽  
Vol 63 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Alvaro Israel ◽  
Alexander Golberg ◽  
Amir Neori
Keyword(s):  
Global Change ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Suez Canal ◽  
Cultural Tradition ◽  
Marine Environments ◽  
Seaweed Cultivation ◽  
Eastern Mediterranean Sea ◽  
Levant Basin ◽  
Marine Flora

AbstractIn spite of the natural harsh marine environments and continuous global change stressors affecting the Levant basin, the Israeli marine flora in the Eastern Mediterranean Sea is quite diverse, with about 300 recognized species. Such high seaweed biodiversity for a small maritime area is remarkable compared to the ca. 1200 species described for the entire Eastern Mediterranean Sea. Since about the year 1890, the Levant basin has been hosting over 115 seaweeds species that migrated from the Indo-Pacific through the Suez Canal. Indeed, approximately 16% of the marine flora is regarded as invasive or exotic to the Israeli shores, in a process that constantly reshapes seaweed populations and their biodiversity. In spite of significant contributions by Israeli scientists to the general biology and technologies for seaweed cultivation worldwide, Israel has little historical and cultural tradition of commercial seaweed cultivation, or use. At present, only two commercial companies are engaged in land-based seaweed cultivation (Ulva sp. and Gracilaria sp.) with a number of products marketed locally and abroad. Recently, offshore cultivation and biorefinery approaches have been explored, but not yet commercialized.

ACCURATE RECOGNITION OF SOURCE ROCK CHARACTER IN THE JURASSIC OF THE NORTH WEST SHELF, WESTERN AUSTRALIA

1992 ◽  
Vol 32 (1) ◽  
pp. 289 ◽  
Author(s):  
John Scott
Keyword(s):  
Source Rock ◽  
Organic Material ◽  
Source Rocks ◽  
Higher Plant ◽  
Pyrolysis Gas ◽  
Screening Analysis ◽  
North West ◽  
The North ◽  
Potential Source Rock ◽  
Rock Eval

The main potential source rock intervals are generally well defined on the North West Shelf by screening analysis such as Rock-Eval. The type of product from the source rocks is not well defined, owing to inadequacies in current screening analysis techniques. The implications of poor definition of source type in acreage assessment are obvious. The type of product is dependent on the level of organic maturity of the source rock, the ability of products to migrate out of the source rock and on the type of organic material present. The type of kerogen present is frequently determined by Rock-Eval pyrolysis. However, Rock-Eval has severe limitations in defining product type when there is a significant input of terrestrial organic material. This problem has been recognised in Australian terrestrial/continental sequences but also occurs where marine source rock facies contain terrestrially-derived higher plant material. Pyrolysis-gas chromatography as applied to source rock analysis provides, by molecular typing, a better method of estimating the type of products of the kerogen breakdown than bulk chemical analysis such as Rock-Eval pyrolysis.

scholarly journals Source Rock Characterization of Silurian Tanezzuft and Devonian Awaynat Wanin Formations the Northern Edge of the Murzuq Basin, South West Libya

2020 ◽  
Vol 4 (1) ◽  
pp. 1-13
Author(s):  
Aboglila S
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Depositional Environments ◽  
Source Rocks ◽  
Thermal Maturity ◽  
Maturity Level ◽  
Geochemical Parameters ◽  
Northern Edge ◽  
Rock Characterization ◽  
Tanezzuft Formation

Drill cutting samples (n = 92) from the Devonian Awaynat Wanin Formation and Silurian Tanezzuft Formation, sampled from three wells F1, G1 and H1, locate in the northern edge of the Murzuq basin (approximately 700 kilometers south of Tripoli). The studied samples were analyzed in the objective of their organic geochemical assessment such as the type of organic matter, depositional conditions and thermal maturity level. A bulk geochemical parameters and precise biomarkers were estimated, using chromatography-mass spectrometry (GC-MS) to reveal a diversity of their geochemical characterizations. The rock formations are having varied organic matter contents, ranged from fair to excellent. The total organic carbon (TOC) reached about 9.1 wt%, ranging from 0.6 to 2.93 wt% (Awaynat Wanin), 0.5 to 2.54 wt% (Tanezzuft) and 0.52 to 9.1 wt% (Hot Shale). The cutting samples are ranged oil-prone organic matter (OM) of hydrogen index (HI) ranged between 98 –396 mg HC/g TOC, related kerogen types are type II and II/III, with oxygen index (OI): 6 - 190 with one sample have value of 366 mg CO2/g. Thermal maturity of these source rocks is different, ranging from immature to mature and oil window in the most of Tanezzuft Formation and Hot Shale samples, as reflected from the production index data (PI: 0.08 - 034). Tmax and vitrinite reflectance Ro% data (Tmax: 435 – 454 & Ro%: 0.46 - 1.38) for the Awaynat Wanin. Biomarker ratios of specific hydrocarbons extracted from represented samples (n = 9), were moreover used to study thermal maturity level and depositional environments. Pristine/Phytane (Pr/Ph) ratios of 1.65 - 2.23 indicated anoxic to suboxic conditions of depositional marine shale and lacustrine source rock.

scholarly journals Source rock potential of the Late Miocene Metochia formation of Gavdos Island, Greece

2017 ◽  
Vol 47 (2) ◽  
pp. 871
Author(s):  
I. Pyliotis ◽  
A. Zelilidis ◽  
N. Pasadakis ◽  
G. Panagopoulos ◽  
E. Manoutsoglou
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Late Miocene ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Low Oxygen ◽  
Crete Island ◽  
Good Potential ◽  
The Rich ◽  
Rock Eval

Rock-Eval method was used to analyze 53 samples from late Miocene Metochia Formation of Gavdos Island (south of Crete Island) in order to characterize the contained organic matter and to evaluate its potential as source rock. The samples were collected from Metochia Section which consists of about 100 m thick marlssapropels alternations. Organic matter analysis showed that the studied succession could be subdivided into two parts. The lower one, which is generally rich in organic matter and the upper one, which is poor. In the lower part the rich horizons in organic matter are characterized by Kerogen type II, III and IV, with low oxygen content, and with fair to very good potential for gas and/or oil hydrocarbon generation. Additionally, the studied samples are thermally immature. Taking into account that the studied area has never been buried in such a depth to reach conditions of maturation, as well as, that the studied section in Gavdos is connected with Messara basin located in the northeastern and, finally, that the main part of Gavdos basin, which is situated between Gavdos and Crete islands, has continuously encountered subsidence, we could conclude that sediments of Metochia Formation could act as source rocks but in the more deep central part of the Gavdos basin.

The lipid geochemistry of a Recent sapropel and associated sediments from the Hellenic Outer Ridge, eastern Mediterranean Sea

1986 ◽  
Vol 319 (1550) ◽  
pp. 375-415 ◽  
Keyword(s):  
Gas Chromatography ◽  
Organic Matter ◽  
Mediterranean Sea ◽  
Lipid Composition ◽  
Eastern Mediterranean ◽  
Biological Marker ◽  
Gas Chromatography Mass Spectrometry ◽  
Eastern Mediterranean Sea ◽  
Sediment Types ◽  
Wide Range

Five sections (0-7, 29-36, 53-60, 78-85 and 104-111 cm), of a 0-2 m sediment core from the Hellenic Outer Ridge, in the eastern Mediterranean Sea, have been examined for lipids. Three of these sections were from a 73 cm thick S 1 ( ca . 6000—9000 years b.p.) sapropel layer, one from an upper ooze layer and one from a lower marl. The lipids were extracted and the major classes analysed in detail by gas chromatography and computerized gas chromatography—mass spectrometry. In all sections, the n -alkanes were dominated by C 25 —C 31 components, showing a high odd-over-even predominance, with smaller amounts of lower chain-length components. The acyclic ketone fraction consisted mainly of C 37 —C 39 di- and triunsaturated alken-2-ones and alken-3-ones. Alkanols, ranging from C 12 —C 32 with a high even-odd preponderance, were present in all sections, maximizing at n -C 22 or n -C 26 . The sapropel contained abundant phytol (up to 7000 ng g -1 dry sediment), and considerable amounts of 22 :1, 24:1 and 26 :1 n -alkenols; in the non-sapropelic sediment, phytol was only a minor com ponent, and no n -alkenols were detected. In addition to these alcohols, the sapropel also contained C 28 —C 32 1,13-, 1,14- and 1,15- diols and 15-keto-alkan-l-ols, the 30 :0 compound predominating in both series. In all sections, fatty acids were the most abundant lipid class. These were mainly C 12 —C 30 straight-chain compounds, maximizing at 16:0 with a high even—odd predominance; most were saturated, but C 16 , C 18 , C 20 , C 22 and C 24 monoenoic acids and small amounts of C 16 , C 18 , C 20 , C 22 and C 24 polyenoic acids were present. A range of branched and cyclic acids were also identified. The non-sapropelic upper and lower sediments differed from the sapropel in containing higher levels of branched acids (especially C 15 and C 17 iso- and anteiso-compounds) and C 18 monoenoic acids: these differences could be related to differing inputs, especially in terms of microbial communities. The sterol distributions of the sapropel displayed a wide range of structures (C 26 —C 31 ), totalling over sixty different components. These included both 4-methyland 4-desmethylnuclei, a variety of C 8 —C 11 side-chains, and encompassed Δ 5 , Δ 5,22 , Δ 5,24 , Δ 5,24(28) , Δ 22 , Δ 24(28) , Δ 7 and Δ 8(14) unsaturation plus a range of fully saturated stands. Major components were 4α, 23, 24-trimethyl-5α-cholest-22-en-3β-ol (dinosterol), cholest-5-en-3|I-ol (cholesterol), 24-methylcholesta-5,22-dien-3β-ol and 24-ethylcholest-5-en-3β-ol. In contrast, the non-sapropelic sediments contained very low levels of only a few sterols, chiefly cholesterol and dinosterol, probably due to input differences. In addition to sterols, the sapropel also contained small amounts of stanones and sterenes. A significant terrigenous input of lipids is evident throughout the core (especially from the n -alkane data), but the sapropel lipid composition appears to be predominantly of marine origin. Individual ‘biological marker’ lipids suggest inputs from Dinophycean and Haptophycean algae to the sapropel. Potential contributions of lipids from organisms such as foraminifera and pteropods, remains of which were observed in the sediment, are difficult to assess due to a paucity of data on the lipid compositions of such organisms. The lipids of the non-sapropelic sediments showed a much less prominent marine signal, especially in terms of the lower levels of phytol and sterols and the higher relative abundance of terrestrial n -alkanes. Two main models have been proposed to explain the formation of organic-rich sapropel facies; (i) stagnation of the water column and the establishment of anoxic conditions in bottom water and sediments, resulting in enhanced preservation of sedimentary organic matter, and (ii) increased biological production providing an increased input of organic matter to the sediments. The lipid composition strongly suggests that this sapropel received a large marine-derived input of organic matter. Since this was less evident in the overlying and underlying sediments, sapropel deposition appears to have been associated with an increased autochthonous input. The anoxic nature of the sapropel, by restricting degradation to anaerobic processes, will also have contributed to the differences in lipid composition between the sediment types. Little diagenesis of lipids in the sapropel was evident. Small amounts of sterenes and 5β(H)-stands were present, probably formed by dehydration and reduction, respectively, of precursor sterols. Diagenetic dehydration of phytol may have contributed to the presence of minor amounts of certain other isoprenoid lipids.

scholarly journals Composition and sources of sedimentary organic matter in the deep Eastern Mediterranean Sea

2015 ◽  
Vol 12 (13) ◽  
pp. 9935-9989 ◽  
Author(s):  
R. Pedrosa-Pàmies ◽  
C. Parinos ◽  
A. Sanchez-Vidal ◽  
A. Gogou ◽  
A. Calafat ◽  
...  
Keyword(s):  
Organic Matter ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Sedimentary Organic Matter ◽  
Eastern Mediterranean Sea ◽  
Deep Sea Sediment ◽  
Fine Grained ◽  
Causative Factors ◽  
The Impact

Abstract. Surface sediments collected from deep slopes and basins (1018–4087 m depth) of the oligotrophic Eastern Mediterranean Sea have been analysed for bulk elemental and isotopic composition of organic carbon, total nitrogen and selected lipid biomarkers, jointly with grain size distribution and other geochemical proxies. The distribution and sources of sedimentary organic matter (OM) have been subsequently assessed and general environmental variables, such as water depth and currents, have been examined as causative factors of deep-sea sediment characteristics. Lithogenic and biogenic carbonates are the dominant sedimentary fractions, while both bulk and molecular organic tracers reflect a mixed contribution from autochthonous and allochthonous sources for the sedimentary OM, as indicated by relatively degraded marine OM, terrestrial plant waxes and anthropogenic OM including degraded petroleum by-products, respectively. Wide regional variations have been observed amongst the studied proxies, which reflect the multiple factors controlling sedimentation in the deep Eastern Mediterranean Sea. Our findings highlight the role of deep Eastern Mediterranean basins as depocentres of organic-rich fine-grained sediments (mean 5.4 ± 2.4 μm), with OM accumulation and burial due to aggregation mechanisms and hydrodynamic sorting. A multi-proxy approach is hired to investigate the biogeochemical composition of sediment samples, which sheds new light on the sources and transport mechanisms along with the impact of preservation vs. diagenetic processes on the composition of sedimentary OM in the deep basins of the oligotrophic Eastern Mediterranean Sea.

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