scholarly journals Geochemical features and genetic mechanism of deep-water source rocks in the Senegal basin, West Africa

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2641-2649
Author(s):  
Yiping Wu ◽  
Jianjun Wang ◽  
Qing Wang ◽  
Haowu Li ◽  
Ningning Zhang ◽  
...  
Keyword(s):  
Deep Water ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Water Environment ◽  
Euphotic Zone ◽  
Source Rocks ◽  
Genetic Mechanism ◽  
Shelf Area ◽  
Carbonate Platforms ◽  
Organic Facies

This paper discusses the maturity of source rocks of the Senegal basin through basin simulation, so as to get a better understanding of oil-source correlation. Based on the analysis of pyrolysis chromatography and total organic carbon (TOC) data of core samples taken from 11 wells, the model of Cenomanian-Turonian marine sediment-organic facies was established, and the genetic mechanism of high-quality source rocks was clarified. The results show that source rocks in the Senegal Basin may occur in the Aptian-Albian of Lower Cretaceous and Cenomanian-Turonian of Upper Cretaceous. One is hybrid organic facies in the shallow carbonate platforms in the shelf area and is characterized by moderate to high TOC (<3%) and hidrogen index ? HI, (100-400 mg HC/g). The other is well-preserved marine facies in continental slope to abyssal sea, with high TOC (>3%) and high HI (max 900 mg HC/g TOC). Molecular fossils originating from aryl carotene are the indicator of the existence of euphotic zone in the ancient ocean. The compounds of aryl isoprenes and sulfurous aryl isoprenes are detected in the black shale samples of well DSDP 367. They rooted in photosynthetic green sulfur bacteria and the carbon isotope value of these compounds is higher 10?~15? than those of fossil molecules of algae and cyanobacteria. Two packages of oil-prone source rocks separately occurr in the Aptian-Albian of Lower Cretaceous and Cenomanian-Turonian of Upper Cretaceous. High-graded marine source rocks of the Senegal Basin may occur in a sulfurous, anoxic deep-water environment with sufficient carbon sequestration.

scholarly journals Cretaceous ammonites from Fuerteventura, Canary Islands

1992 ◽  
Vol 129 (6) ◽  
pp. 763-769 ◽  
Author(s):  
Otto Renz ◽  
Daniel Bernoulli ◽  
Lukas Hottinger
Keyword(s):  
Canary Islands ◽  
Deep Water ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Basal Complex ◽  
Paper Document ◽  
Ocean Boundary

AbstractMesozoic deep-water sediments occurring on the island of Fuerteventura were deposited near the continent–ocean boundary adjacent to the African margin. During Tertiary times, they were uplifted and intruded by ultramafic, mafic and alkaline plutons and dykes and are now exposed as part of the ‘Basal Complex’ of the island. These sediments reflect more or less continuous hemipelagic and turbiditic deposition during most of Jurassic and Cretaceous times. Two ammonites, described in this paper, document a Valanginian to Hauterivian age for part of the Lower Cretaceous siliciclastic turbidites, and a latest Albian to early Cenomanian age for part of the Upper Cretaceous hemipelagic limestones.

CONTINENTAL SHELF BASINS ON THE WEST TASMANIA MARGIN

1992 ◽  
Vol 32 (1) ◽  
pp. 231 ◽  
Author(s):  
A.M.G. Moore ◽  
J.B. Willcox ◽  
N.F. Exon ◽  
G.W. O'Brien
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Strike Slip ◽  
Source Rocks ◽  
Fault System ◽  
The West ◽  
Shallow Marine

The continental margin of western Tasmania is underlain by the southern Otway Basin and the Sorell Basin. The latter lies mainly under the continental slope, but it includes four sub-basins (the King Island, Sandy Cape, Strahan and Port Davey sub-basins) underlying the continental shelf. In general, these depocentres are interpreted to have formed at the 'relieving bends' of a major left-lateral strike-slip fault system, associated with 'southern margin' extension and breakup (seafloor spreading). The sedimentary fill could have commenced in the Jurassic; however, the southernmost sub-basins (Strahan and Port Davey) may be Late Cretaceous and Paleocene, respectively.Maximum sediment thickness is about 4300 m in the southern Otway Basin, 3600 m in the King Island Sub-basin, 5100 m in the Sandy Cape Basin, 6500 m in the Strahan Sub-basin, and 3000 m in the Port Davey Sub-basin. Megasequences in the shelf basins are similar to those in the Otway Basin, and are generally separated by unconformities. There are Lower Cretaceous non-marine conglomerates, sandstones and mudstones, which probably include the undated red beds recovered in two wells, and Upper Cretaceous shallow marine to non-marine conglomerates, sandstones and mudstones. The Cainozoic sequence often commences with a basal conglomerate, and includes Paleocene to Lower Eocene shallow marine sandstones, mudstones and marl, Eocene shallow marine limestones, marls and sandstones, and Oligocene and younger shallow marine marls and limestones.The presence of active source rocks has been demonstrated by the occurrence of free oil near TD in the Cape Sorell-1 well (Strahan Sub-basin), and thermogenic gas from surficial sediments recovered from the upper continental slope and the Sandy Cape Sub-basin. Geohistory maturation modelling of wells and source rock 'kitchens' has shown that the best locations for liquid hydrocarbon entrapment in the southern Otway Basin are in structural positions marginward of the Prawn-1 well location. In such positions, basal Lower Cretaceous source rocks could charge overlying Pretty Hill Sandstone reservoirs. In the King Island Sub-Basin, the sediments encountered by the Clam-1 well are thermally immature, though hydrocarbons generated from within mature Lower Cretaceous rocks in adjacent depocentres could charge traps, providing that suitable migration pathways are present. Whilst no wells have been drilled in the Sandy Cape Sub-basin, basal Cretaceous potential source rocks are considered to have entered the oil window in the early Late Cretaceous, and are now capable of generating gas/condensate. Upper Cretaceous rocks appear to have entered the oil window in the Paleocene. In the Strahan Sub-Basin, mature Cretaceous sediments in the depocentres are available to traps, though considerable migration distances would be required.It is concluded that the west Tasmania margin, which has five strike-slip related depocentres and the potential to have generated and entrapped hydrocarbons, is worthy of further consideration by the exploration industry. The more prospective areas are the southern Otway Basin, and the Sandy Cape and Strahan sub-basins of the Sorell Basin.

Coal rank and burial history of Cretaceous – Tertiary strata in the Grande Cache and Hinton areas, Alberta, Canada: implications for fossil fuel exploration

1996 ◽  
Vol 33 (6) ◽  
pp. 938-957 ◽  
Author(s):  
W. Kalkreuth ◽  
M. McMechan
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Foreland Basin ◽  
Source Rocks ◽  
Thermal Modelling ◽  
Coal Rank ◽  
Thermal Maturity ◽  
Burial History ◽  
Near Surface ◽  
Coal Measures

The present study discusses coal rank and burial histories for Cretaceous–Tertiary coal measures and thermal maturity of associated source rocks. Coal rank ranges from subbituminous to semianthracite. Coalification maps for selected coal zones indicate a broad coalification maximum east of the deformed belt. In the Pocahontas, Brûlé, and Hinton areas, rank levels appear to be elevated locally due to geothermal anomalies. Thermal modelling indicates that the westward decrease of coal rank in Lower Cretaceous strata is related to a westward decrease in the duration of burial beneath Maastrichtian–Eocene foreland-basin deposits. Upper Cretaceous – Tertiary strata were subjected to relatively low geothermal gradients (< 20 °C/km), whereas Lower Cretaceous strata were exposed to much higher gradients (up to 46 °C/km). Tectonic loading in the foothills had only a minor impact on coalification. At Obed Marsh (Alberta Syncline) thermal modelling suggests that deformation in the thrust belt continued for at least a few million years beyond the 60 Ma age recently suggested by fission-track analysis to indicate the end of Laramide deformation. Petroleum source rock intervals of the study area are currently at various stages of thermal maturity (oil generation window to dry gas zone). Coal seams in the Upper Cretaceous – Tertiary coal measures at and near surface have rank levels suitable for combustion, whereas seams in the Lower Cretaceous coal measures are high-quality metallurgical coals. East of the deformed belt the coal measures occur at depths that at the present time are uneconomic for production.

Aldebarania arenitea, a new genus and species of Astropectinidae (Asteroidea; Echinodermata) from the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina

1995 ◽  
Vol 69 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Daniel B. Blake ◽  
Keith Sturgeon
Keyword(s):  
North Carolina ◽  
Shallow Water ◽  
Phylogenetic Relationships ◽  
Upper Cretaceous ◽  
New Genus ◽  
Water Environment ◽  
New Genus And Species ◽  
Marine Fauna ◽  
Shallow Water Environment

Aldebarania arenitea (Astropectinidae; Asteroidea; Echinodermata) is described from the Rocky Point Member of the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina. A turbulent, shallow-water environment is suggested by sedimentary features, a diverse marine fauna, and the morphology of Aldebarania. Aldebarania appears to be a partial ecological equivalent of living Astropecten and Luidia; however, phylogenetic relationships within the Astropectinidae are unstudied and the origin of similarities is unknown.

scholarly journals Paleoenvironment of the Lower–Middle Cambrian Evaporite Series in the Tarim Basin and Its Impact on the Organic Matter Enrichment of Shallow Water Source Rocks

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 659
Author(s):  
Mingyang Wei ◽  
Zhidong Bao ◽  
Axel Munnecke ◽  
Wei Liu ◽  
G. William M. Harrison ◽  
...  
Keyword(s):  
Organic Matter ◽  
Shallow Water ◽  
Tarim Basin ◽  
Water Environment ◽  
Water Source ◽  
Major Elements ◽  
Source Rocks ◽  
Middle Cambrian ◽  
Sedimentary Environments ◽  
The Impact

Just as in deep-water sedimentary environments, productive source rocks can be developed in an evaporitic platform, where claystones are interbedded with evaporites and carbonates. However, the impact of the paleoenvironment on the organic matter enrichment of shallow water source rocks in an evaporite series has not been well explored. In this study, two wells in the central uplift of the Tarim Basin were systematically sampled and analyzed for a basic geochemical study, including major elements, trace elements, and total organic carbon (TOC), to understand the relationship between TOC and the paleoenvironmental parameters, such as paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity. The results show that the Lower–Middle Cambrian mainly developed in a fluctuating salinity, weak anoxic to anoxic, continuous dry and hot, and proper shallow water environment. The interfingering section of evaporites, carbonates, and claystones of the Awatag Fm. have higher paleoproductivity and higher enrichment of organic matter. Paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity jointly control the organic matter enrichment of shallow water source rocks in the evaporite series. The degree of enrichment of organic matter in shallow water source rocks first increases and then decreases with the increase in paleosalinity. All the samples with high content of organic matter come from the shallower environment of the Awatag Fm.

Lower Cretaceous Source Rocks on the Sw Barents Shelf

2020 ◽  
Author(s):  
A. Hagset ◽  
B. Badics ◽  
S. Grundvåg ◽  
R. Davies ◽  
A. Rotevatn
Keyword(s):  
Lower Cretaceous ◽  
Source Rocks
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