+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Metamorphism disturbs the Re-Os signatures of platinum-group minerals in ophiolite chromitites

, : Metamorphism disturbs the Re-Os signatures of platinum-group minerals in ophiolite chromitites. Geology 40(7): 659-662

The Os-isotope compositions of platinum-group minerals (PGMs) in ophiolite chromitites are commonly regarded as resistant to fluid-related processes, and have been used to track the evolution of Earth’s convecting mantle. However, we have found significant differences in 187Os/188Os between primary and secondary PGMs from metamorphosed ophiolite chromitites of the Dobromirtsi Ultramafic Massif, in the Central Rhodope Metamorphic Core Complex of southeastern Bulgaria. Primary (magmatic) PGMs hosted in unaltered chromite cores have 187Os/188Os from .1231 to .127, and 187Re/188Os ≤ .2.TMA and TRD model ages, calculated relative to the Enstatite Chondrite Reservoir, cluster around three main peaks: ca.3, .4, and .6 Ga. Secondary PGMs, produced by alteration of magmatic PGMs, have a wider range of variation (187Os/188Os = .1124–.1398, 187Re/188Os ≤ .24); these grains yield TMA and TRD model ages from –1.7 Ga up to 2.2 Ga. The larger range in 187Os/188Os in the secondary PGMs is interpreted as due to reactions between the primary PGMs and infiltrating metamorphic-hydrothermal fluids with a range of Os-isotope compositions. This redistribution of Os in PGMs during metamorphism has significant implications for the interpretation of both whole-rock and in situ Os-isotope data in mantle-derived rocks.


DOI: 10.1130/g33064.1

Other references

Neuhäuser, G., 1973: Cat-eye syndrome. Hippokrates 44(2): 199-200

Bos, J.E.; MacKinnon, S.N.; Patterson, A., 2005: Motion sickness symptoms in a ship motion simulator: effects of inside, outside, and no view. Introduction: Vehicle motion characteristics differ between air, road, and sea environments, both vestibularly and visually. Effects of vision on motion sickness have been studied before, though less systematically in a naval setting. It is hypoth...

Ma, X.; Liu, L.; Meng, J., 2017: MicroRNA-125b promotes neurons cell apoptosis and Tau phosphorylation in Alzheimer's disease. Alzheimer's disease (AD) is considered as one of the most common neural degenerative diseases in human. Although the continuous investigations about AD have been made in recent decades, the pathogenesis of this disease is still not definitely...

Klawans, H.L.; Goetz, C.; Westheimer, R., 1972: Pathophysiology of schizophrenia and the striatum. Diseases of the Nervous System 33(11): 711-719

Daniels, L., B.; Maisel, A., S., 2007: Natriureettic peptides. Natriuretic peptides (NPs) are released from the heart in response to pressure and volume overload. B-type natriuretic peptide (BNP) and N-terminal-proBNP have become important diagnostic tools for assessing patients who present acutely with dyspn...

Shreffler-Grant, J.; Weinert, C.; Nichols, E.; Ide, B., 2005: Complementary therapy use among older rural adults. Objective: Explore use, cost, and satisfaction with the quality and effectiveness of complementary therapy among older rural adults. Design: Descriptive survey. Sample: A random sample of 325 older adults from rural communities throughout Montana...

Brown, J.Belle.; Sangster, L.Michelle.; Ostbye, T.; Barnsley, J.M.; Mathews, M.; Ogilvie, G., 2002: Walk-in clinics: patient expectations and family physician availability. For over two decades, there has been controversy over the role and impact of walk-in clinics on primary health care. This study evaluates the providers' perspective on this topic. The purpose of this qualitative study was to explore the perce...

Anonymous, 1994: Charlotte, NC hospitals: lessons learned from airliner crash. Hospital Security and Safety Management 15(7): 8-10

Boquillon, M.B.ucrot, P., 1980: Effect of amount and mode of triglyceride administration on the absorption and the hydrolysis rats of rat native bile phosphatidylcholine. Reproduction nutrition developpement: 01309-1316

Bennett, K.J.; Probst, J.C.; Vyavaharkar, M.; Glover, S.H., 2012: Lower rehospitalization rates among rural Medicare beneficiaries with diabetes. We estimated the 3-day readmission rate of Medicare beneficiaries with diabetes, across levels of rurality.We merged the 25 Medicare Chronic Conditions 5% sample data with the 27 Area Resource File. The study population was delimited to those with...