Geochemical study of the Lac du Bouchet (Hte-Loire, France) Part II: water-sediments-organic matter interactions during the last 2500 years

1995 ◽  
pp. 119-143
Author(s):  
Didier Jézéquel ◽  
Patrick Albéric ◽  
Alain Desprairies ◽  
Marc Evrard ◽  
Dominique Lavergne ◽  
...  
Keyword(s):  
Organic Matter ◽  
Geochemical Study

A Uranium Geochemical Study at the Natural Analogue Site of Needle's Eye. SW Scotland

1988 ◽  
Vol 127 ◽  
Author(s):  
P. D. Roberts ◽  
T. K. Ball ◽  
P. J. Hooker ◽  
A. E. Milodowski
Keyword(s):  
Organic Matter ◽  
High Resolution ◽  
Surface Flow ◽  
Transport Mechanisms ◽  
Upward Flow ◽  
Natural Analogue ◽  
Geochemical Model ◽  
X Ray ◽  
Geochemical Study ◽  
High Resolution Gamma Spectrometry

ABSTRACTA detailed study is being carried out at the Needle's Eye locality, on the Solway Firth, into the movement and fixation of U and its daughter isotopes. The site contains pitchblende veins, some of which have acted as a source of soluble uranium flowing into and through estuarine silts laid down in the last 2000 years or so. A section through these has provided samples for detailed analysis by X-ray fluorescence and neutron activation techniques. High resolution gamma spectrometry has contributed information on the distributions and disequilibria between uranium and its daughters. These data have been combined with analyses from groundwaters to produce a geochemical model of the origins of the U radioisotope distributions and transport mechanisms. There are thought to be two main inputs of dissolved U(VI) into this system; the surface flow of groundwater from the exposures of the mineralisation in the cliff, and upward flow from the bedrock below. The fixation of U in the sediments is controlled by the presence of organic matter in the upper humic layers, and by an iron oxy-hydroxide sorption reaction in the deeper silts at about 110cm. This concentration of U in the silt is divorced from the sub U-234 daughters. In contrast. Th is coherently associated with its daughters within detrital resistate phases. This study is a prelude to a more rigorous modelling investigation in collaboration with the Ecole des Mines de Paris.

Origin of hydrocarbons in the Bach Ho field (The Vietnamese shelf)

2021 ◽  
pp. 4-13
Author(s):  
V. Kerimov ◽  
◽  
R. Mustaev ◽  
Vu Nam Hai ◽  
◽  
...  
Keyword(s):  
Organic Matter ◽  
Distinctive Feature ◽  
Sedimentary Rocks ◽  
Crystalline Basement ◽  
Source Rocks ◽  
Sedimentary Sequences ◽  
Geochemical Study ◽  
The World ◽  
Sedimentary Source ◽  
Hydrocarbon Distribution

This article presents the results of a geochemical study of oil on the Vietnam shelf (Cuu Long basin), including those in the crystalline basement. The Bach Ho field oils in the basement have a hydrocarbon distribution that is no different than oil of numerous accumulations in Oligocene and Miocene sedimentary sequences. Similar to the organic origin oils of the world, oils from the Bach Ho field lack regular isoprenanes С12 and С17 and cheilanthanes (tri-cyclic terpanes) С22 and С27. A distinctive feature of these oils is a large amount of cheilanthanes С19-С29, and large neo-adiantane to adiantane and hopanes to steranes ratios. All these parameters indicate a large bacterial contribution in the generation of these oils. Studies have shown the similarity between oil biomarker parameters and the organic matter of sedimentary rocks, which supports the organic nature of the oils in the basement fields on the Vietnam shelf. It is shown that the hydrocarbon accumulations in the basement complexes of the Cuu Long basin are in a secondary occurrence, and their origin was the organic matter of the sedimentary source rocks.

scholarly journals Small-scaled lateral variations of an organic-rich formation in a ramp-type depositional environment (the Late Jurassic of the Boulonnais, France): impact of the clastic supply

2017 ◽  
Vol 188 (5) ◽  
pp. 31 ◽  
Author(s):  
Ebraheem Hatem ◽  
Nicolas Tribovillard ◽  
Olivier Averbuch ◽  
Viviane Bout-Roumazeilles ◽  
Alain Trentesaux ◽  
...  
Keyword(s):  
Organic Matter ◽  
Distribution Patterns ◽  
Mineral Particle ◽  
Iron Sulfides ◽  
Reactive Iron ◽  
Geochemical Study ◽  
Oxygenation Level ◽  
Depth Increase ◽  
Sulfide Ions

We studied a potential petroleum source rock deposited in a clastic-dominated ramp environment: the Argiles de Châtillon Formation (Kimmeridgian-Tithonian, Boulonnais area, northern France). The formation was deposited along a proximal-distal gradient on this ramp affected by synsedimentary fault movements. A sedimentological, mineralogical and geochemical study was conducted to decipher the distribution patterns of sedimentary parameters along such a depth increase over the ramp. It comes out that smectite distribution unexpectedly mimics the lateral depth evolution despite the good floatability of the mineral. It is also observed that the Argiles de Châtillon could accumulate noticeable amounts of organic matter in spite of paleoenvironmental conditions that were not specifically prone to organic matter preservation and burial (sedimentation rate, mineral particle grain size, productivity, oxygenation level…). Conversely, reactive iron, when being present in limited abundance, must have allowed sulfide ions to react with organic molecules instead of forming iron sulfides, which fostered organic matter preservation and accumulation. This protecting role of organic sulfide incorporation (additional to other favorable factors) cannot exist if reactive iron is relatively abundant. Lastly, our results (still fragmentary) suggest that smectite minerals could carry reactive iron, which would have occasionally hampered organic-matter preservation.

scholarly journals Permian petroleum system of Lena-Anabar trough - lithological-geochemical studies (at an example of well Ust’-olenek 2370)

2016 ◽  
pp. 71-81
Author(s):  
E. A. Bakay ◽  
M. E. Smirnova ◽  
N. I. Korobova ◽  
D. V. Nadezhkin
Keyword(s):  
Organic Matter ◽  
Source Rocks ◽  
Petroleum Potential ◽  
Marine Organic Matter ◽  
Geochemical Study ◽  
Study Results ◽  
Core Descriptions ◽  
Geochemical Studies ◽  
First Time ◽  
Sand Bodies

Lithofacies of different genesis were determined within the Permian sequence, basing on analysis of core descriptions. The best reservoirs are associated with deltaic sand bodies. Permian source rocks with marine organic matter were distinguished. Initial organic matter parameters were estimated, initial good-excellent petroleum potential was suggested. Lithological-geochemical study results for core samples from one of the northern wells of Laptev Sea coast are published for the first time.

scholarly journals Geological solutions concluded by petroleum geochemical data in Western Greece

2013 ◽  
Vol 47 (4) ◽  
pp. 2131
Author(s):  
N. Rigakis ◽  
V. Karakitsios ◽  
F. Marnelis ◽  
Sp. Sotiropoulos
Keyword(s):  
Organic Matter ◽  
Correlation Study ◽  
Petroleum Exploration ◽  
Geochemical Data ◽  
Geochemical Study ◽  
Oil Generation ◽  
Hydrocarbon Sources ◽  
Two Parameters ◽  
Paleogeothermal Gradient ◽  
Western Greece

A detailed petroleum geochemical study has been performed in the previous years in the Western Greece. Several source rock horizons have been identified, the oil window has been calculated for the most significant sub-basins and the oil correlation study has distinguished the different oil groups of the area, generated from different hydrocarbon sources. These results are very significant and useful for the oil exploration. But, further to these, some more geochemical observations can also be very important on solving some geological problems of the area.- A major problem is the deposition and preservation of the organic matter in the Western Greece.- The dolomitization in relation with the oil generation is also an issue.- Another issue is the calculation of the eroded overburden formations thickness.- The Paleogeothermal gradient determination is also very important.The last two parameters are absolutely necessary for organic matter maturity calculations.The study of all the above parameters completes the geochemical study of the Western Greece, and in relation with other geological studies can provide solutions in the petroleum exploration of the area.

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