000129323 001__ 129323
000129323 005__ 20231215094308.0
000129323 0247_ $$2doi$$a10.1016/j.oregeorev.2018.07.024
000129323 0248_ $$2sideral$$a107692
000129323 037__ $$aART-2018-107692
000129323 041__ $$aeng
000129323 100__ $$aGonzález-Jiménez, J.M.
000129323 245__ $$aMetamorphic evolution of sulphide-rich chromitites from the Chernichevo ultramafic massif, SE Bulgaria
000129323 260__ $$c2018
000129323 5060_ $$aAccess copy available to the general public$$fUnrestricted
000129323 5203_ $$aThe upper mantle rocks of the metamorphosed ophiolite of Chernichevo, Rhodope Metamorphic Complex in southern Bulgaria, host small chromite ores with unusual mineralization of base-metal sulphides rich in platinum-group elements. Mineralogical and chemical data indicate that after their formation in the mantle the Chernichevo''s chromite ores were modified by the intrusion of an alkaline mafic melt, which resulted in the precipitation of a suite of metasomatic minerals (sulphides, calcite, apatite and ilmenite), accompanied by an increase in FeO, TiO2, Ga, Zn, Vn, Mn, and especially Ti and Fe2O3 contents in the chromite. The degree of chemical modification and abundance of metasomatic minerals are positively correlated and mark the extent of reaction of the chromitite with the intruding melt. Sulphide segregation promoted the concentration of high amounts of PGEs (up to 3661 ppb), particularly Pt and Pd, yielding chromite ores with a typical flat to positive-sloped chondrite-normalized pattern. Subsequently, the chromite ores were deformed and metamorphosed together with their host rocks at ultra-high pressure (UHP) (>2.5 GPa, >1200 °C) to be later retrograded under eclogite and finally hydrous amphibolite-facies conditions, giving rise to three microstructural types. Metamorphism of the most metasomatized (i.e., sulphide-rich) chromitites at temperatures >700 °C within the conditions of UHP and eclogite-facies resulted in the formation of (1) non-porous recrystallized chromite, consisting of a granoblastic microstructure made-up of coarse-grained blasts and finer-grained chromite neoblasts. In contrast, hydrous metamorphism on the less metasomatized (i.e., sulphide-poor) chromitite under the conditions of amphibolite-facies (ca. 482–483 °C) resulted in the formation of (2) partly altered chromite, characterized by unaltered cores surrounded by Fe2+-rich and Al-depleted porous chromite containing abundant clinochlore, and (3) porous chromite corresponding to a chromite that was entirely transformed by the metamorphic alteration to Fe2+-rich and Al-depleted porous chromite. During metamorphism magmatic Ni-Fe-Cu sulphides originally formed during the metasomatic event in the mantle were altered, resulting in a major leaching of Cu-rich sulphides, leading to significant remobilization of Pt and Pd.
000129323 536__ $$9info:eu-repo/grantAgreement/ES/MINECO/CGL2014-55949-R$$9info:eu-repo/grantAgreement/ES/MINECO/RYC-2015-17596
000129323 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/
000129323 590__ $$a3.387$$b2018
000129323 591__ $$aGEOLOGY$$b3 / 46 = 0.065$$c2018$$dQ1$$eT1
000129323 591__ $$aMINING & MINERAL PROCESSING$$b2 / 19 = 0.105$$c2018$$dQ1$$eT1
000129323 591__ $$aMINERALOGY$$b6 / 29 = 0.207$$c2018$$dQ1$$eT1
000129323 592__ $$a2.058$$b2018
000129323 593__ $$aEconomic Geology$$c2018$$dQ1
000129323 593__ $$aGeology$$c2018$$dQ1
000129323 593__ $$aGeochemistry and Petrology$$c2018$$dQ1
000129323 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000129323 700__ $$0(orcid)0000-0002-9615-9168$$aColás, V.
000129323 700__ $$aGervilla, F.
000129323 700__ $$aKerestedjian, T.N.
000129323 700__ $$aSergeeva, I.
000129323 700__ $$aCasado-González, A.
000129323 700__ $$0(orcid)0000-0002-0302-2737$$aFanlo, I.$$uUniversidad de Zaragoza
000129323 7102_ $$12000$$2120$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Cristalografía Mineralog.
000129323 773__ $$g101 (2018), 330-348$$pOre geol. rev.$$tORE GEOLOGY REVIEWS$$x0169-1368
000129323 8564_ $$s9033508$$uhttps://zaguan.unizar.es/record/129323/files/texto_completo.pdf$$yVersión publicada
000129323 8564_ $$s2462754$$uhttps://zaguan.unizar.es/record/129323/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000129323 909CO $$ooai:zaguan.unizar.es:129323$$particulos$$pdriver
000129323 951__ $$a2023-12-14-13:17:22
000129323 980__ $$aARTICLE