Re and Os rhenium and osmium are chalcophile-siderophile elements transition metals with a unique position in isotope geochemistry. Unlike other commonly used decay schemes for radiometric dating, these metals take residency in resource-related media, for example, sulfide minerals, the organic component in black shales, coals, and bitumens and oils. In short, the reducing environment is their haven whereas under oxidizing conditions, Re and Os become unmoored and the radiometric clock becomes compromised. The clock is not temperature sensitive, and its applicability spans Early Archean to Pleistocene. This Bunsen Medal lecture will explore and review the challenges in bringing Re-Os from the meteorite-mantle community into the crustal environment. At the center of it all is our ability to turn geologic observation into a thoughtful sampling strategy. The possibility to date ore deposits was an obvious application, and molybdenite [Mo Re S 2 ], rarely with significant common Os and lacking overgrowths, became an overnight superstar, yielding highly precise, accurate, and reproducible ages. Yet, molybdenite presented our first sampling challenge with recognition of a puzzling parent-daughter Re- Os decoupling in certain occurrences. A strategic sampling procedure was employed.
rhenium osmium using
The Maoling gold deposit, one of the large gold deposits in eastern Liaoning Province, NE China, is an arsenopyrite-disseminated gold deposit with a resource of approximately 25 t Au and an average Au grade of 3. Download to read the full article text. Zhou, T. Kong, F. Chen, C. Wang, W.
magmatism is the key to the formation of many important ore deposits in the Truong Son and Loei fold belts, the two major east Malaysia are dated as Early Permian by U-Pb zircon (ca. M ). (Oliver et arsenopyrite, visible gold. Pyrite.
Full Text 2. Geochronological investigations in China were initiated nearly 50 years ago, mainly since the establishment of university programs teaching isotope geochemistry and the setup of geochronological laboratories. During the late ‘s and early s, the geochronological framework of China’s landmass has been established by numerous isotopic studies. Over the past decade, state-of-the-art geochronological laboratories have been established in China, contributing to the country’s increasing role in many fields of Geosciences.
This article highlights some of the major geochronological achievements of the past decades, with special focus on China’s Precambrian geology, the improved understanding of age relationships in the Mesozoic Igneous Province of eastern China, and new developments in the dating of hydrothermal ore deposits. Keywords: Geochronology, Precambrian continental evolution, Mesozoic Igneous Province, hydrothermal ore deposits, China. The initiation and development of geochronological research in China was a result of the recognition of its fundamental importance to the understanding of the geological evolution of China’s landmass and its exploitation for mineral deposits.
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This reos is affected by the charge re-os of rhenium atom. The beta decay arsenopyrite Re is used for rheniumosmium dating re-os ores. Although our previous.
The Archean-Proterozoic craton of West Africa hosts numerous gold deposits, which are spatially and temporally related to the Eburnean orogeny that took place between and Ma, and included multiple deformation events. The majority of these gold deposits are located along shear zones. The structural history is relatively well established for most gold deposits, but absolute timing of the mineralization is commonly lacking.
Gold mineralization was structurally characterized at each deposit, and dated by the Re-Os method on pyrite, arsenopyrite, and pyrrhotite grains that were coeval with the gold deposition. Combined structural and Re-Os geochronological constraints allow two groups of gold deposits to be distinguished. Early orogenic gold formed during the Eoeburnean orogeny, i.
These Re-Os ages on the early sulfides at Wassa and Kiaka are significant because they definitively provide the first direct age constraints on gold-only Eoeburnean mineralization in the Birimian of West Africa. The high uncertainties on the Nassara and Damang ages may be directly linked to the low rhenium and osmium contents of the studied samples. These results highlight the polyphase character of the widespread gold mineralization in the West African craton. Although the late stages of the Eburnean orogeny constitute a prolific period for the formation of highgrade gold mineralization, identification of less well-studied early-stage gold deposits, which can also contain large quantities of gold, is critical for mineral exploration in the West African craton.
Top9. Re-Os isotopic analysis opened a new approach to dating sedimentary rocks
Both Re and Os are siderophile elements mostly enriched in alloy and sulfide phases. As Os is a highly compatible element during partial melting of mantle and Re is a moderately incompatible element Brenan, ; Sattari et al. This significant geochemical behavior makes Re- Os isotope system available for tracing and dating. High parent isotope content is essential for establishing a radioisotope system. Thus, concentration of Re is a key to application of Re- Os isotope system.
More recently however, Re/Os dating of arsenopyrite suggests that the vein formation began with the onset of meta- morphism circa Ma. Other ages at about.
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. D Selby and RA Creaser.
Degao Zhai, Anthony E. Economic Geology ; 5 : — Native gold is intergrown with molybdenite and pyrite in auriferous quartz veins hosted by a monzogranite-monzonite stock and locally by Proterozoic gneiss, thereby offering an excellent opportunity to directly date the mineralizing event. Uranium-Pb age determinations for zircon yielded ages for the monzogranite and monzonite of
Re-Os dating of gold-bearing arsenopyrite of the Maoling gold deposit, Liaoning Province, Northeast China and its geological significance. 作者姓名：, YU Gang.
Covid has significantly affected our fundraising. Please help! Learning Center What is a mineral? Mineral Name:. Locality Name:. Keyword s :. Arsenopyrite This page kindly sponsored by Mark Kucera. Arsenopyrite Gallery Search Photos of Arsenopyrite.
Geochronology of high-temperature rocks and hydrothermal ore deposits in China
The Longmendian Ag—Pb—Zn deposit is located in the southern margin of the North China Craton, and the mineralization occurs mainly in quartz veins, altered gneissic wallrocks, and minor fault breccias in the Taihua Group. Based on vein crosscutting relations, mineral assemblages, and paragenesis, the mineralization can be divided into three stages: 1 quartz—pyrite, 2 quartz—polymetallic sulfides, and 3 quartz—carbonate—polymetallic sulfides. Wallrock alteration can be divided into three zones, i.
Fluid inclusions in all Stage 1 to 3 quartz are dominated by vapor-liquid two-phase aqueous type W-type.
The Maoling gold deposit is located in the southwestern part of the Liaodong Zircon U–Pb dating of the Wolongquan biotite monzogranite and () obtained an Re–Os isochron age of ± Ma for arsenopyrite in.
The Maoling gold deposit, one of the large gold deposits in eastern Liaoning Province, NE China, is an arsenopyrite-disseminated gold deposit with a resource of approximately 25 t Au and an average Au grade of 3. This is a preview of subscription content, log in to check access. Zhou, T. Kong, F. Chen, C. Wang, W. Google Scholar. Dai, L. Gold Geol.
Pyrite is the most abundant sulfide mineral. Pyrite’s metallic luster and pale brass-yellow hue give it a superficial resemblance to gold , hence the well-known nickname of fool’s gold. The color has also led to the nicknames brass , brazzle , and Brazil , primarily used to refer to pyrite found in coal. By Georgius Agricola ‘s time, c.
Therefore, the Re–Os geochronometer can be used for dating the formation age to the more ubiquitous metal minerals such as pyrite, arsenopyrite, pyrrhotite.
Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods; by Goodfellow, W D ed. This publication is contained in Goodfellow, W D; Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada, Mineral Deposits Division, Special Publication no.
Consolidating Canada’s Geoscience Knowledge. The lower Ordovician Meguma Group of Nova Scotia consists of a lower thick unit of Goldenville Formation greywacke and an upper unit of black sulphidic Halifax Formation slate. The transition between the two units contains an Mn-rich horizon and Tremadocian fossils.
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The Iso-Kuotko deposit is located 10 km to the north of Suurikuusikko along the same shear zone. Gold mineralization at Iso-Kuotko formed in two major stages: an early stage refractory gold mineralization with auriferous arsenopyrite with similarities to the ore at Suurikuusikko and a late, main stage mineralization with free gold in carbonate-quartz veins with abundant pyrrhotite, native bismuth and other sulphide minerals. This latter ore is absent at Suurikuusikko.
Based on U-Pb dating, as well as Re-Os and Pb-isotope systematics of rock-forming and hydrothermal minerals, we evaluate the relationships between tectonic evolution and formation of gold deposits throughout the late Palaeoproterozoic in the northern part of the CLGB.
bring Re–Os dating into the field of economic geology and, in turn, shows how sulfide LLHR pyrite and arsenopyrite are particularly useful be- cause these.
Table S1. It is not known whether environmental O 2 levels increased in a linear fashion or fluctuated dynamically between the evolution of oxygenic photosynthesis and the later Great Oxidation Event. New rhenium-osmium isotope data from the late Archean Mount McRae Shale, Western Australia, reveal a transient episode of oxidative continental weathering more than 50 million years before the onset of the Great Oxidation Event. Transient oxygenation events, like the one captured by the Mount McRae Shale, probably separated intervals of less oxygenated conditions during the late Archean.
Multiple lines of geochemical evidence from sedimentary rocks point to the production and accumulation of photosynthetic O 2 in surface environments since at least 3 billion years ago Ga 1 — 7. In contrast, sulfur mass-independent fractionation S-MIF indicates that Archean atmospheric O 2 levels were predominantly below 0. However, transiently higher O 2 levels are possible if crustal recycling of S-MIF signatures is taken into account Therefore, evidence for O 2 production during Archean time may represent one of several scenarios.
One possibility is that small linear stepwise increases in atmospheric O 2 allowed mild oxygenation and oxidative continental weathering to occur continuously and with increasing intensity in the several hundred million years before the first major accumulation of O 2 in the atmosphere [the ca. Nonlinear fluctuations in Earth surface redox conditions may have also been driven by variations in the relative fluxes of reducing gases, such as biogenic methane 11 — Distinguishing between these hypotheses is critical for understanding the dynamics of planetary oxygenation on Earth and ultimately the evolution of complex life 7.
The 2. Increased Mo and Re concentrations may capture a transient increase in oxidative continental weathering, possibly associated with a rise in atmospheric O 2 levels, and the subsequent decrease in Mo and Re concentrations may reflect a return to a lower redox state 1. Because the magnitude of Mo and Re enrichment in marine sediments is influenced by local bottom water redox conditions, organic carbon export fluxes, and sedimentation rates 16 , 17 , the elevated Mo and Re concentrations may reflect changes in local depositional conditions against a backdrop of mild environmental O 2 levels 1.
Research (Crustal Re-Os Geochronology)
Rhenium-osmium geochronology using arsenopyrite was undertaken for three gold deposits in the Meguma terrane, Nova Scotia, Canada, in order to better constrain their age of formation and to assess the utility of arsenopyrite for dating similar deposits globally. The lack of common Os in some arsenopyrite samples from both The Ovens and Dufferin permit calculation of single mineral model ages for each deposit, which are identical to those determined using the isochron method. Initial Os compositions for the two vein types at The Ovens suggest a predominately crustal source of Os in the mineralizing fluids, whereas a less radiogenic initial Os composition for arsenopyrite from Dufferin does not as clearly define a crustal metal source.
At a third locality, the Touquoy deposit, the Re-Os systematics of arsenopyrite associated with disseminated gold mineralization do not define a precise formation age, possibly as a result of mixing of Re and Os derived from the mineralizing fluid and the shale host rock. The Re-Os ages of arsenopyrite indicate that there were at least two distinct periods of gold deposition in the Meguma terrane coinciding with widespread tectonothermal events: regional deformation and metamorphism associated with Acadian orogenesis, and widespread generation of meta- and peraluminous granites and high-grade metamorphism within the basement rocks under the Meguma terrane.
Towards the north, locally mineralized amphibolites (4 g/t Au) are in faulted contact ±12 Ma for gold-bearing arsenopyrite were obtained by Re-Os dating.
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, New understanding on the Premesozoic structures of the Alxa Massif next Top8.