Researcher Qu W. Following molybdenite deposits, they innovatively produced standard substance for the Re-Os dating of Cu-Ni alkides and seafloor cobalt-rich crusts, which was certified as a national class 1 standard substance. After modifying the sample selection method, high-temperature sealed dissolution and testing analysis processes, they established the Re-Os isotopic analysis technique and dating method for pyrite, arsenopyrite, limestone, graphite, asphalt and other ultralow Re-Os content series samples. Their total procedure blank and testing precision are already the international leading level. This offers a new technical approach to the isotopic dating of sedimentary rocks, hydrocarbon source rocks and oil-gas pools. Re-Os isotopic testing. New understanding on the Premesozoic structures of the Alxa Massif. Jurassic multituberculate mammal was discovered in Liaoning, China for the first time. Re-Os isotopic analysis opened a new approach to dating sedimentary rocks Updated ,05,
Rhenium—osmium dating is a form of radiometric dating based on the beta decay of the isotope Re to Os. This normally occurs with a half-life of Rhenium—osmium dating is carried out by the isochron dating method.
(B) A sample containing fine-grained molybdenite as coatings on the surface of auriferous quartz veins and showing the results of Re-Os dating.
Re and Os are redox-sensitive and organophilic, and can be enriched in potential hydrocarbon source rocks, tar sands, crude oil, and bitumen. Re-Os geochronology of these organic-rich samples has the potential for direct dating the time frame of hydrocarbon formation, migration or charge within a petroleum system. Here, we review some major reported case studies on the Re-Os geochronology of oil and gas reservoirs over the last decade. Filling the above knowledge gaps requires a comprehensive academia-industry collaboration, which is critical step to accomplish a valuable application guide for the petroleum industry end-users on using the Re-Os isotope system to directly date petroleum systems.
N2 – Re and Os are redox-sensitive and organophilic, and can be enriched in potential hydrocarbon source rocks, tar sands, crude oil, and bitumen. AB – Re and Os are redox-sensitive and organophilic, and can be enriched in potential hydrocarbon source rocks, tar sands, crude oil, and bitumen.
Research (Crustal Re-Os Geochronology)
Official websites use. Share sensitive information only on official, secure websites. Re—Os geochronology of the lacustrine Green River Formation: Insights into direct depositional dating of lacustrine successions, Re—Os systematics and paleocontinental weathering Earth and Planetary Science Letters. By: Vivien M. Lacustrine sedimentary successions provide exceptionally high-resolution records of continental geological processes, responding to tectonic, climatic and magmatic influences.
Molybdenite Re-Os dating of Mo-Th-Nb-REE rich marbles: pre-Variscan processes in Moldanubian Variegated Group (Czech Republic).
Return Pre Home. The Re-Os isotope system, based on its unusual qualities, has been widely used on the dating and tracing in the geoscience and geochemistry. As a reflection of the international development of the Re-Os isotope geochemistry, Chinese geoscientists have also done a large quantity of work in this research field. In this paper we mainly describe the development of Re-Os isotope geochemistry in China based on the Chinese publications issued at home.
They presented their technique of Re-Os isotope geochronology of molybdenite as follows: Samples were dissolved and equilibrated with Re- and Os-enriched spikes by alkaline fusion. Separation of rhenium from matrix elements was effected by solvent extraction and cation exchange chromatography while osmium was distilled as OsO 4 from H 2 SO 4 -Ce SO 4 2 solution. All rhenium and osmium isotopic measurements were made on a VG plasma Quad facility.
In the determination of Re-Os isotopes for molybdenites by ICP-MS, for different solution and different condition of distillation, the chemical behavior of Os is different. This technique was also used to the Re-Os isotope geochronology of molybdenite together with the Carius tube digestion of samples Du et al. In addition, the Os-Os technique Gao et al. The yields of Os and Os depend on the neutron flow in the reactor and the Re contents of the sample being irradiated.
So the Os-Os age can be obtained from Os isotope ratios. The advantage of this method is that Os and Os double spikes can effectively compensate for the mass discrimination effects of ICP-MS, therefore the common correction practice for mass bias in the isotope dilution method with a single spike is unnecessary. In addition, the method enables one to reduce the determination error arising from instrumental instability.
Geochronology and Isotopes
America; West of Shetlands oilfields. Selby’s research has developed a unique geochemical toolbox using rhenium, osmium, platinum and palladium that constrain more accurate geological models leading to better reserve predictions. The toolbox provides previously unavailable geological time constraints and source identification of resources e.
This work has resulted in major advancements in the direct isotopic dating of crustal sulfide minerals, petroleum source-rocks, and natural hydrocarbons, using Re-.
Development of Re-Os geochronology for crustal matrices has been ongoing since in the laboratory. This work has resulted in major advancements in the direct isotopic dating of crustal sulfide minerals, petroleum source-rocks, and natural hydrocarbons, using Re-Os isotopes. For sulfide minerals, Re-Os geochronology has direct application to the timing and duration of hydrothermal ore deposit formation.
Some key papers include:. Systematic work, aimed at further evaluating the utility, robustness and cross-calibration of the Re-Os geochronometer to other dating methods, has also been a key research theme. Using Re-Os isotopes to determine the deposition age of petroleum source-rock formation organic-rich shales is a major research theme, both in terms of technical development and application.
This method has been applied to better understand the origins of global Oceanic Anoxic Events OAEs , the timing of shale deposition and correlation in Precambrian sedimentary basins and this rise of oxygen on Earth. Re-Os isotopes in natural hydrocarbons is the third major research theme of the laboratory, again approaching this new field from both a systematic evaluation and application perspective.
Re-Os isotopes natural hydrocarbons are directly related to source-rock Re-Os isotope character and in some cases Re-Os geochronology of hydrocarbons is possible. Research Crustal Re-Os Geochronology Development of Re-Os geochronology for crustal matrices has been ongoing since in the laboratory.
Extending In-Situ Dating to New Geochronometers: Pb-Pb, Sm-Nd, Re-Os, and LuHf
Over the years, Chemostrat has expanded the services on offer to now include more advanced isotopic techniques that so far have been used only in academia. The information presented below briefly outlines how Chemostrat is utilising two of these techniques, i. Re and Os become concentrated in the organic, hydrogenous fraction of organic rich shales, thus the time when the shale was deposited can be dated.
Extending In-Situ Dating to New Geochronometers: Pb-Pb, Sm-Nd, Re-Os, and LuHf. Metadata Updated: July 17, Goals This proposed work will extend.
Rhenium—osmium dating , method of determining the age of the important ore mineral molybdenite; the method is based upon the radioactive decay of rhenium to osmium The rhenium—osmium ratio in most minerals is too low to be of general use as a dating technique, but molybdenite molybdenum disulfide, MoS 2 has a very high ratio of rhenium to osmium; and workers have found that the osmium in molybdenite is practically pure radiogenic osmium Ores as old as 3,,, years and as young as 38,, years have been dated this way.
Rhenium—osmium dating. Info Print Cite. Submit Feedback. Thank you for your feedback. The Editors of Encyclopaedia Britannica Encyclopaedia Britannica’s editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree See Article History. Read More on This Topic. The decay scheme in which rhenium is transformed to osmium shows promise as a means of studying mantle—crust evolution and the evolution
Rhenium-osmium dating method
While whole-rock peridotite Re-Os isotopic signatures are the core of such investigations, the Re-Os dating of individual peridotite minerals—base metal sulfides BMS and platinum group minerals PGM —that are the main hosts for Re and Os in the mantle peridotites came into play two decades ago. This is, however, not a rule of thumb as clear evidence of crust-mantle age decoupling also exist.
As such, they are the mantle equivalents of crustal zircons. Abrajano, T. Sulfide petrology of the critical zone of the Acoje massif.
The Re-Os model ages for the molybdenites range between and Ma and apparently correspond to the early stages of metamorphism connected with pre-Variscan rift-related tectono-metamorphic events, which affected and recrystallized sedimentary CLM material rich in Mo-Th-Nb-REE. There is no geological evidence for the participation of fluids mobilized from host rocks in the formation of the CLM. Because the Re-Os chronometer in molybdenite is demonstrably stable through later Variscan facies metamorphism, the molybdenite chronometer has not been affected by subsequent thermal overprints associated with the Variscan orogeny.
Atencio D. Mineralogist 48, — Bingen B. Earth Planet. Earth Sci. Czech Geol. Craig J.