Electronic Resource
Co-occurrence of compositionally variable chromitites in the Sabzevar ophiolite, NE Iran
| العنوان: | Co-occurrence of compositionally variable chromitites in the Sabzevar ophiolite, NE Iran |
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| المؤلفون: | Eslami, A, Grieco, G, Bussolesi, M, Ichiyama, Y, Lenaz, D, Skogby, H, Kutyrev, A, Cavallo, A, Khedr, M, Eslami, Alireza, Grieco, Giovanni, Bussolesi, Micol, Ichiyama, Yuji, Lenaz, Davide, Skogby, Henrik, Kutyrev, Anton V., Cavallo, Alessandro, Khedr, Mohamed Zaki |
| بيانات النشر: | Elsevier BV country:NL 2023 |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | The Sabzevar ophiolite belt consists of a series of thrust-bound massifs that widen in extent to ∼150 km in NE Iran. The Kuh-Siah harzburgite-dunite massif in the central sector of this belt hosts abundant discontinuous pod-like chromitite deposits. These deposits are characterized by spinels with contrasting and variable compositions, but without any microtextural differences. The chromian spinel in these chromitite bodies displays a wide range of Cr-number (Cr/(Cr + Al)) atomic ratio from 0.50 to 0.77, and reveals a co-occurrence of Al-rich and Cr-rich chromitites within a single ophiolitic massif. Despite these chemical differences, primary spinels from both the high-Al and high-Cr chromitites have similar TiO2 contents, indicating that they formed in a single tectono-magmatic setting. Both high-Al and high-Cr chromitite samples display low to moderate total platinum group element (PGE) abundances (85–537 ppb). Solid phases hosted by Cr-spinel grains in chromitites and their host dunites can be divided into three categories: platinum group minerals (PGM), base-metal minerals (BMM), and silicates. Euhedral quadrangular and round-shaped silicate inclusions consisting of clinopyroxene, orthopyroxene, Na-bearing phlogopite, serpentine and chlorite, are sporadically scattered in the Cr-spinel grains. These inclusions are mainly single crystals and rarely occur as polyphase assemblages. The BMM are mainly euhedral Ni- and Cu-rich sulfides with rare occurrence of pentlandite. The most widespread PGM are crystals of the laurite-erlichmanite series with subordinate malanite, braggite and BM-PGE-rich sulfides. Textural relationships reflect that the PGM are of magmatic origin. The BMM, on the other hand, formed during both magmatic and post-magmatic processes. The occurrence of low-temperature inclusions within Cr-spinel and ferrian Cr-spinel, comprising tremolite, chlorite and serpentine, are interpreted as post-magmatic entrapments of already-formed silicate phases at th |
| مصطلحات الفهرس: | Chromitite, Cr-spinel, Ophiolite, Platinum-group element, Sabzevar, Solid inclusion, GEO/09 - GEORISORSE MINERARIE E APPLICAZIONI MINERALOGICO-PETROGRAFICHE PER L'AMBIENTE E I BENI CULTURALI, info:eu-repo/semantics/article |
| URL: | info:eu-repo/semantics/altIdentifier/wos/WOS:001092007000001 volume:446-447 issue:June 2023 journal:LITHOS |
| الاتاحة: | Open access content. Open access content info:eu-repo/semantics/embargoedAccess |
| ملاحظة: | STAMPA English |
| Other Numbers: | ITBAO oai:boa.unimib.it:10281/405755 10.1016/j.lithos.2023.107133 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85150858620 1376787941 |
| المصدر المساهم: | BICOCCA OPEN ARCH From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1376787941 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |