GEOCHEMISTRY ARTICLES Archives

Rock-Eval Pyrolysis : A Technique in Petroleum Geology

1 Comment / GEO-ARTICLES, GEOCHEMISTRY ARTICLES, Petroleum/oil/gas/coal / opengeology

The Rock-Eval pyrolysis is a widely used geochemical technique in petroleum exploration and organic geochemistry. It provides valuable information on the quantity, type and thermal maturity of organic matter in sedimentary rocks, helping geologists asses hydrocarbon generation potential. Principles of Rock-Eval Pyrolysis Rock Eval pyrolysis involves heating a rock sample in an inert atmosphere and […]

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Gas Chromatography

GEO-ARTICLES, GEOCHEMISTRY ARTICLES, Petroleum/oil/gas/coal / opengeology

Gas Chromatography is a chromatographic technique used to separate volatile compounds and those which can vaporized by heat. If a mixture of compounds is analysed using GC system, each compound can be separated and quantified. It is useful and important because of following – Components of gas chromatography This is the overall main components of

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VPDB (Vienna – Peedee Belemnite) and Its Importance in Carbon Isotope Studies

GEO-ARTICLES, GEOCHEMISTRY ARTICLES / opengeology

Peedee Belemnite (PDB) is a well-known standard used in carbon and oxygen isotope studies. Originally derived from the fossilized remains of Belemnitella americana, a species of belemnite found in the Late Cretaceous peedee Formation in South Carolina, USA, PDB has played a crucial role in geochemistry, paleoclimatology and biogechemistry. Carbon Isotopes and PDB Carbon exists

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Role of H2O and CO2 in Silicate melt

GEO-ARTICLES, GEOCHEMISTRY ARTICLES, IGNEOUS PETROLOGY ARTICLES / opengeology

H2O and CO2 are the two most important components of fluids in the upper mantle and crust, and their solubilities in silicate melts control many processes like generation, migration, saturation and crystallization, exsolution of bubbles, polymerization and combinedly the volcanic eruption. Water (H2O) The hydrogen of the H2O molecule reacts with a bridging oxygen of

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Mantle Reservoirs

GEO-ARTICLES, GEOCHEMISTRY ARTICLES, IGNEOUS PETROLOGY ARTICLES / opengeology

As the amount of available data has multiplied over the past ten years, the number of apparently distinct reservoirs has risen from two (primitive and depleted mantle, respectively) to five (PREMA, Depleted, HIMU = high U/Pb and Two types of EM or enriched mantle reservoirs). The depleted reservoir produces “normal” (N-type) MORB probably more than

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Chemical Weathering and its type

GEO-ARTICLES, GEOCHEMISTRY ARTICLES, GEOMORPHOLOGY, SEDIMENTOLOGY ARTICLES / opengeology

Chemical weathering may be defined as the spontaneous and irreversible thermodynamic process that causes degradation of the mineral phases under the prevailing environmental conditions at the surface of the Earth. It is usually considered to be the solid/solution interactive process occurring in contact with the atmosphere. In other words chemical weathering may be defined as that set of processes

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X – Ray Fluorescence (XRF)

GEO-ARTICLES, GEOCHEMISTRY ARTICLES / opengeology

An X- ray fluorescence (XRF) spectrometer is an x ray instrument used for routine, relatively non-destructive chemical analysis of rocks, minerals, sediments and fluids. It works on wavelength-dispersive spectroscopic principles that are similar to an electron microprobe (EPMA). However, an XRF is used for bulk analysis of larger fractions of geological materials. The relative ease

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X-Ray Diffraction (XRD)

GEO-ARTICLES, GEOCHEMISTRY ARTICLES / opengeology

X- ray diffraction is a common technique that determine a sample’s composition or crystalline structure. For large crystals such it can be used to determine the structure of atoms within the sample. If crystal size is too small, it can determine composition, crystallinity, and phase purity. Bragg’s law reflection. The diffracted x-rays exhibit constructive interference

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Pathfinder elements of ore deposits (Geochemistry)

ECONOMIC GEOLOGY ARTICLES, GEO-ARTICLES, GEOCHEMISTRY ARTICLES / opengeology

Type of deposits Pathfinder element Gold- Silver vein type, Gold- Silver- Cobalt- Copper- Zinc and complex sulfide ores As W- Be- Zn- Mo- Cu- Pb- Skarns,Sn- Ba veins B Cu- Pb- Zn- Silver & Complex sulfide deposits Hg, Zn Ba- Ag vein deposit, Porphyry Cu Mn Wolframite- Tin contact metamorphic deposits Mo Porphyry Cu, Barium-

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