scholarly journals Carbonate rocks epigenetic changes and their connection with chemical composition water of Upper Ordovician-Lower Devonian petroleum bearing area of the Chernyshev Ridge and eastern side of the Khoreyver Depression

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
I.I. Danshikova ◽  
◽  
T.V. Maydl ◽  
T.P. Mityusheva ◽  
◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carbonate Rocks ◽  
Lower Devonian ◽  
Epigenetic Changes ◽  
Upper Ordovician ◽  
Eastern Side ◽  
Chernyshev Ridge

Echinoderms of the Somerset Shale Member, Salem Limestone (Mississippian), in Indiana and Kentucky

1989 ◽  
Vol 63 (6) ◽  
pp. 900-912 ◽  
Author(s):  
Howard Randall Feldman
Keyword(s):  
Carbonate Rocks ◽  
Illinois Basin ◽  
Eastern Side ◽  
Number Of Species ◽  
Terrigenous Rocks

The Somerset Shale Member (Mississippian: Valmeyeran) is a discontinuous shale at the base of the Salem Limestone in southern Indiana and central Kentucky. It is the only significant terrigenous unit within a thick sequence of shoaling carbonates deposited on the eastern side of the Illinois Basin over the Borden Delta siltstones. The Somerset Shale contains a diverse echinoderm fauna of blastoids (five species), crinoids (20 species), and echinoids (two species). Most of the species are known only from the Somerset or from carbonate rocks directly above and below the Somerset Shale. There remains a small number of species previously known mostly from terrigenous rocks (the Borden Delta) below the carbonates. This demonstrates that at least some of the faunal differences between the Borden crinoids and those of the overlying carbonates are the result of paleoecologic factors. The Somerset Shale may mark a useful biostratigraphic boundary defined by last occurrences of the genera Barycrinus, Cyathocrinites, and Actinocrinites and the base of the range of Batocrinus. The species Batocrinus somersetensis n. sp., Dizygocrinus calvus n. sp., and Barycrinus punctus n. sp. are described.

Variation in the chemical composition of carbonate rocks of Russian platform

1957 ◽  
Vol 12 (3) ◽  
pp. 273-276 ◽  
Author(s):  
A.P. Vinogradov ◽  
A.B. Ronov ◽  
V.M. Ratynskii
Keyword(s):  
Chemical Composition ◽  
Carbonate Rocks ◽  
Russian Platform

scholarly journals Chrono-, litho- and conodont bio-stratigraphy of the Rauchkofel Boden Section (Upper Ordovician – Lower Devonian), Carnic Alps, Austria

2017 ◽  
Vol 50 (4) ◽  
pp. 445-469 ◽  
Author(s):  
Hans Peter Schönlaub ◽  
Carlo Corradini ◽  
Maria G. Corriga ◽  
Annalisa Ferretti
Keyword(s):  
Lower Devonian ◽  
Upper Ordovician ◽  
Carnic Alps

Optimization of Smart Water Chemical Composition for Carbonate Rocks Through Comparison of Active Cations Performance

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Malek Jalilian ◽  
Peyman Pourafshary ◽  
Behnam Sedaee Sola ◽  
Mosayyeb Kamari
Keyword(s):  
Chemical Composition ◽  
Oil Recovery ◽  
Carbonate Rocks ◽  
Low Cost ◽  
Recovery Phase ◽  
Ion Concentration ◽  
Water Flooding ◽  
Core Flooding ◽  
Smart Water ◽  
The Impact

Designing smart water (SW) by optimizing the chemical composition of injected brine is a promising low-cost technique that has been developed for both sandstone and carbonate reservoirs for several decades. In this study, the impact of SW flooding during tertiary oil recovery phase was investigated by core flooding analysis of pure limestone carbonate rocks. Increasing the sulfate ion concentration by using CaSO4 and MgSO4 of NaCl concentration and finally reducing the total salinity were the main manipulations performed to optimize SW. The main objective of this research is to compare active cations including Ca2+ and Mg2+ in the presence of sulfate ions (SO42−) with regard to their efficiency in the enhancement of oil production during SW flooding of carbonate cores. The results revealed a 14.5% increase in the recovery factor by CaSO4 proving its greater effectiveness compared to MgSO4, which led to an 11.5% production enhancement. It was also realized that low-salinity water flooding (LSWF) did not lead to a significant positive effect as it contributed less than 2% in the tertiary stage.

PECULIARITIES OF DISTRIBUTION AND COMPOSITION OF BETAFITE FROM DIFFERENT FORMATIONS OF THE ALDAN SHIELD (SAKHA-YAKUTIA)

2019 ◽  
pp. 8-15
Author(s):  
V. Guliy ◽  
I. Poberezhska ◽  
N. Bilyk
Keyword(s):  
Chemical Composition ◽  
Mineral Composition ◽  
Oxygen Isotopes ◽  
Carbonate Rocks ◽  
Aldan Shield ◽  
Mineralogical Composition ◽  
Significant Feature ◽  
Carbon And Oxygen Isotopes ◽  
Primary Composition ◽  
Geological Formations

Character of Nb and Ta distribution in the different geological formations of the Aldan Shield are given in this article. To get idea about betafite from different endogenic etalon formations the authors analyzed its well known locations in the pegmatites, skarns, carbonatites, metasomatites and late veins segregations. Geological setting and mineralogical composition of the apatite-bearing rocks from the Aldan Shield are described, and the most significant in scale metamorphosed carbonate and silicate varieties among them have been distinguished. Apatite mineralization in magnesium skarns and metasomatites is developed locally. Titanite and betafite are the main concentrators of Nb and Ta and apatite is typical accompanying mineral in the studied rocks. Betafite was detected in the pegmatite bodies from magnesium skarns and metasomatites of the Shield with irregular distribution within rocks rich and poor in apatite, but was not found in the most developed apatite-carbonate rocks which are regarded as ores of the Seligdar type, so it cannot be mineralogical indicator for this type of ores. Late carbonate generations are significantly enriched in light carbon and oxygen isotopes in contrast to positive δ13Ñ values in apatitecarbonate bodies of the Seligdar deposit and its family and the highest δ18Î values. We used these indicators to distinguish origin of the rocks with various carbonate generations, which have different amounts of betafite. Appearance of betafite is determined by primary composition of the initial rocks. Chemical composition of betafites from the skarns and metasomatites is similar, but with local variations. The most significant feature of the mineral composition is very low Ta content. Titanite is characterized by variable amounts of Nb and Ta in scale of sectors as well as within separate grains.

THE EFFECT OF VARIATIONS IN CHEMICAL COMPOSITION ON THE VELOCITY OF SEISMIC WAVES IN CARBONATE ROCKS

Geophysics ◽  
1953 ◽  
Vol 18 (1) ◽  
pp. 104-115 ◽  
Author(s):  
Carl Kisslinger
Keyword(s):  
Chemical Composition ◽  
Carbonate Rocks ◽  
Seismic Waves ◽  
Mineral Content ◽  
Magnesium Carbonate ◽  
Volume Replacement ◽  
Textural Characteristics ◽  
Local Porosity ◽  
Carbonate Material

The variations of velocity in limestones have not fallen into as definite a pattern as have those in sandstones and shales. Although it is conceded generally that textural characteristics are more important than mineral content in determining the velocity in sandstones and shales, the possibility that the concentration of magnesium carbonate may appreciably alter the velocity in a limestone is investigated. It is found that dolomitization can be expected to have an effect on the velocity, but that effect is not certain, in that it depends on the nature of the dolomitization process. A volume for volume replacement of calcite by dolomite tends to increase the velocity, but dolomitization giving rise to local porosity, whether the resulting interstices are empty or filled by non‐carbonate material, tends to decrease the velocity.

Isotope geochemistry of dissolved, precipitated, airborne, and fallout sulfur species associated with springs near Paige Mountain, Norman Range, N.W.T.

1982 ◽  
Vol 19 (7) ◽  
pp. 1395-1407 ◽  
Author(s):  
Robert O. van Everdingen ◽  
M. Asif Shakur ◽  
H. Roy Krouse
Keyword(s):  
Sulfate Reduction ◽  
Water Vapour ◽  
Carbonate Rocks ◽  
Isotope Fractionation ◽  
Lower Devonian ◽  
Isotope Geochemistry ◽  
Spring Water ◽  
Sulfate Radical ◽  
Sulfur Species ◽  
Rock Formation

δ34S values determined for dissolved sulfate in water discharged by sulfurous springs near Paige Mountain identify gypsum beds in the Lower Devonian Bear Rock Formation as the sulfate source, whereas relatively low δ18O values show that as much as 30% of the sulfate may have gone through a reduction–re-oxidation cycle. Reduced sulfur species in the spring water have negative δ34S values as a result of microbiological isotope fractionation during sulfate reduction; airborne sulfur species (H2S, SO2, H2SO4) and gypsum formed through reaction of H2SO4 fallout with exposed carbonate rocks show similar negative δ34S values. Negative δ18O values for the sulfate radical in H2SO4 fallout and in the alteration product indicate that more than half of the oxygen reacting with airborne H2S is derived from water vapour.

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