نتایج جستجو برای: diagenetic processes
تعداد نتایج: 529387 فیلتر نتایج به سال:
I\itrogen and carbon isotope ratios were studied in a stratified deposit of guano of ivlexican Free-tailed bats in Eagle Creek Cave. Arizona. U.S.A. Little diagenetic change was observed over the 25-year time span of the guano deposit. High aridity and reduced circulation of air in the cave are hypothesized to have slowed the normally rapid decomposition of the excreta and the subsequent escape...
This study presents a thorough analysis of the sedimentology, diagenesis, and sequence stratigraphy Middle Jurassic Samana Suk Formation in Hazara Basin northern Pakistan. Focusing on two sections, namely Mera Rehmat Por Miana, research aims to unravel complex geological processes within formation. The examination microfacies reveals nine distinct depositional textures, ranging from mudstone wa...
We have studied the REE distribution in shallow marine continental platform carbonates belonging to two late Neoproterozoic basins of India. Their REE abundance patterns normalized by chondrite display well defined W-type tetrad effect. Based on chondrite-normalized Gd/Ho, La/Nd ratios, the REE abundance patterns have been classified into three groups. (Y/Ho) and (Y/Dy) concentration ratios ref...
Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0.46 and 6.40 microg g(-1) with significant decrease in surficial sediment as a result of closing of two Hg-cell based chlor-alkali plants. Results of s...
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicate...
The reactivity of higher plant derived 3-oxy-triterpenoids to sunlight was investigated using a series of pure reference standards both under simulated and real solar exposure. The majority of the exposed compounds showed reactivity to light, particularly to simulated sunlight and among others generated seco-derivatives. While photochemical processes have been suggested for the formation of suc...
The elemental, molecular (lipid) and isotopic ( ) composition of organic matter in samples from the eutrophic lake, Rostherne Mere, U.K. were examined at high resolution in a single sediment core from a deep part of the lake. The distributions of lipids indicate an important contribution of allochthonous organic matter to the Rostherne sediments. However, increases in concentrations of unsatura...
Shahmirzad village is located on the southern parts of the Eastern Alborz Mountain Ranges. One of the sedimentary rock units that crops out in this area is Soltanieh Formation (Upper Precambrian Lower Cambrian). Thin section and oxygen isotope studies have been used in order to determine the petrological characteristics and the temperature of Soltanieh dolomites formation environment. E...
Source of Cement in the Great Oolite Reservoir, Storrington Oil Field, Weald Basin, South of England
The source of cement in oilfields is critical to the prediction of the distribution of cements in the reservoirs and also prediction of reservoir quality. The source of mineral forming cements has been determined for the Storrington oolitic carbonate reservoir (Middle Jurassic Great Oolite Formation, Weald Basin, onshore UK) using a combination of petrography, electron microscopy, fluid inclusi...
Massive Zn-Cu-Fe sulfide deposits at the Garon Lake Mine occur in three sulfide lenses in a group of metamorphosed rhyolite crystal tuffs, metasediments and basalts. The major ore minerals are sphalerite, chalcopyrite, pyrrhotite and pyrite. Minor associated silicates are actinolite, tremolite, chlorite, albite and quartz. Rounded detrital pyrite, magnetite and chert grains and diagenetic p...
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