Depositional environment and diagenesis of the lower part of the Kurnub Sandstone Formation (lower cretaceous), Mahis area, Jordan

1986 ◽  
Vol 49 (1-2) ◽  
pp. 129-141 ◽  
Author(s):  
Hani N. Khoury
Keyword(s):  
Lower Cretaceous ◽  
Depositional Environment ◽  
Sandstone Formation

scholarly journals Stratigraphy and Depositional Environment of Mauddud Formation in Ratawi Oil wells of Southern Iraq

2021 ◽  
Vol 877 (1) ◽  
pp. 012030
Author(s):  
Maha Razaq Manhi ◽  
Hamid Ali Ahmed Alsultani
Keyword(s):  
Deep Sea ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Oil Wells ◽  
Oil Field ◽  
Microfacies Analysis ◽  
Thin Sections ◽  
Southern Iraq

Abstract The Mauddud Formation is Iraq’s most significant and widely distributed Lower Cretaceous formation. This Formation has been investigated at a well-23 and a well-6 within Ratawi oil field southern Iraq. In this work, 75 thin sections were produced and examined. The Mauddud Formation was deposited in a variety of environments within the carbonate platform. According to microfacies analysis studying of the Mauddud Formation contains of twelve microfacies, this microfacies Mudstone to wackestone microfacies, bioclastic mudstone to wackestone microfacies, Miliolids wackestone microfacies,Orbitolina wackestone microfacies, Bioclastic wackestone microfacies, Orbitolina packstone microfacies, Peloidal packstone microfacies, Bioclastic packstone microfacies, Peloidal to Bioclastic packstone microfacies, Bioclastic grainstone microfacies, Peloidal grainstone microfacies, Rudstone microfacies. Deep sea, Shallow open marine, Restricted, Rudist Biostrome, Mid – Ramp, and Shoals are the six depositional environments in the Mauddud Formation based on these microfacies.

scholarly journals The diagenesis of the Lower Triassic Bunter Sandstone Formation, Onshore Denmark

1986 ◽  
Vol 15 ◽  
pp. 1-51
Author(s):  
Stanley Fine
Keyword(s):  
Late Stage ◽  
Depositional Environment ◽  
Sedimentary Facies ◽  
Lower Triassic ◽  
Low Energy ◽  
Ti Oxides ◽  
Arid Conditions ◽  
Sandstone Formation ◽  
Diagenetic Evolution ◽  
Semi Arid

The Lower Triassic Bunter Sandstone Formation is a continental redbed sequence deposited under arid to semi-arid conditions in a low-energy, fluviatile-aeolian sabhka environment. The sediments display many diagenetic features in common with modern and ancient redbeds deposited under similar conditions, but local influences on the diagenetic assemblage by factors such as provenance, structural setting and depositional environment can be ascertained. With burial depths of only 1000-2000 meters, effects of compaction are limited, high intergranular porosities remain, and no clear depth-related patterns are noted. The diagenetic assemblage consists of quartz and feldspar overgrowths, Fe-Ti oxides, carbonates (calcite and dolomite), analcime, authigenic clays, anhydrite and halite. The distribution of authigenic minerals is controlled by sedimentary facies, with greater amounts of poikilotopic anhydrite and halite in sandstones and more abundant dolomite and analcime in claystones and heterolithic sands. In addition, the replacement of ferromagnesian minerals by mixed-layer clays results in the greater abundance of these clays in sandstones relative to claystones. A well-preserved eogenetic assemblage consisting of albite and quartz overgrowths, analcime, dolomite, calcite, gypsum and clays is indicative of highly evaporative conditions and may reflect higher sodium concentrations in the depositional brines associated with the more basinal, low-energy parts of the depositional environment. Such concentrated brines strongly influenced the diagenetic pathways. In contrast, anhydrite and halite are the product of mesogenetic reactions in association with late stage Zechstein brines which invaded the more permeable sands during halokinesis. The strength and character of the depositional brine is an early control on subsequent diagenetic evolution. Within the specific geochemical regime of a given lithofacies, selective reactions occur which characterize particular microenvironments. These reactions impart an early eogenetic imprint upon later diagenetic events.

scholarly journals Depositional environment and burial history of a Lower Cretaceous carbonaceous claystone, Bornholm, Denmark

1996 ◽  
Vol 43 ◽  
pp. 133-142
Author(s):  
H. I. Petersen ◽  
J. A. Bojesen Koefoed ◽  
H. P. Nytoft
Keyword(s):  
Organic Matter ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Lower Jurassic ◽  
Plant Litter ◽  
Burial History ◽  
Transport Distance ◽  
Geochemical Parameters ◽  
Kerogen Type ◽  
History Of

A c. 1 m thick carbonaceous claystone from the type locality of the Lower Cretaceous Skyttegård Member (Rabekke Formation), Bornholm, has been investigated by organic pétrographie and organic geochemical methods in order to assess the depositional environment of the claystone and the thermal maturity of the organic matter. The claystone was deposited in a low-energy, anoxic lake which occasionally was marine influenced. The organic matter is terrestrial and can be classified as kerogen type III and lib. Detrital organic matter and cutinite are characteristic components. The organic matter is allochthonous but the transport distance was short, and the plant material was probably mainly derived from plants growing at the edge of, or nearto, the lake. Source-specific biomarkers such as norisopimarane suggest that the plant litter was derived from a gymnospermous, low-diversity vegetation. Evidence for early angiospermous plants cannot be demonstrated with any certainty. A huminite reflectance value of 0.24%Rm and several geochemical parameters indicate that the organic matter is highly immature. It has only experienced coalification corresponding to the peat stage. Estimates show that, prior to uplift, the claystone was buried to a maximum of approximately 260 m. Reflectance data further suggest that a maximum c. 550 m thick sediment package was removed by erosion prior to deposition of the ?uppermost Jurassic-Lower Cretaceous sediments on Lower Jurassic strata.

scholarly journals An ichthyosaur (Reptilia: Ichthyosauria) specimen from the Lower Cretaceous (Berriasian) Spilsby Sandstone Formation of Nettleton, Lincolnshire, UK

2017 ◽  
Author(s):  
John P. Green ◽  
Dean Lomax
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Sandstone Formation

A fragmentary ichthyosaur specimen collected in situ at Castle Top Quarry in Nettleton, Lincolnshire, UK from exposures of the Lower Cretaceous (Berriasian) Spilsby Sandstone Formation (Subcraspedites ?preplicomphalus Zone) is reported. In general, Early Cretaceous ichthyosaurs from the Berriasian to Barremian are poorly understood. Despite the fragmentary nature of the described specimen, it is the first ichthyosaur reported from this specific zone and adds to the literature another rare ichthyosaur from the Berriasian.

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