Academic Journal
Dolomite–magnesite formation and polymetallic mineralization in a rift-sag basin on the western margin of the Red Sea: Paleoenvironmental, hydrothermal, and tectonic implications
| العنوان: | Dolomite–magnesite formation and polymetallic mineralization in a rift-sag basin on the western margin of the Red Sea: Paleoenvironmental, hydrothermal, and tectonic implications |
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| المؤلفون: | Afify, A.M., Sanz Montero, M. Esther, González Acebrón, Laura |
| بيانات النشر: | SEPM (Society for Sedimentary Geology) |
| سنة النشر: | 2022 |
| المجموعة: | Universidad Complutense de Madrid (UCM): E-Prints Complutense |
| مصطلحات موضوعية: | 553.682(620), Mineralogía (Geología), 2506.11 Mineralogía |
| الوصف: | The present study gives new insight on the formation conditions of dolomite and magnesite in an early–middle Miocene succession related to a half-graben rift-sag basin on the western margin of the Red Sea. The studied Miocene succession comprises two units of siliciclastic–carbonate rocks separated by a magnesite bed. The succession is enriched with epigenetic–supergenetic polymetallic minerals, dominated by zinc-bearing ferromanganese oxides. These represent oxidized Mississippi Valley-type deposits (MVT) formed during uplifting in late Miocene–Pliocene time. Multistage dolomitization (four dolomite types: D1–D4) and magnesite authigenesis, enhanced by tectonic uplifting and faulting related to the Red Sea rifting, have been recorded. The first dolomite phase (D1) is pervasive early diagenetic dolomicrite (replacement type), which is dominant in the lower unit. Magnesite occurs as microcrystalline aggregates exclusive to the lower unit, where its authigenesis was after D1 and before D2. Occurrence of magnesite was mostly related to a restricted environment in a sag fault-bounded basin with shallow evaporative hypersaline conditions in coastal areas. D2 dolomite occurs in the lower and upper units as replacement and/or cement type of medium- to coarse-crystalline dolomite crystals. The three magnesium-rich carbonates (D1, magnesite and D2) are related to successive events of sea-level fall and rise in mesohaline and hypersaline conditions. Enrichment of magnesite and D2 dolomite with Na (up to 2.16 wt.%) and Sr (up to 1483 ppm) supports their formation under more saline evaporative conditions if compared with D1 dolomite which was formed in near-normal sea water or mesohaline fluids. The third and fourth dolomite phases (D3 and D4) are late diagenetic pore-filling coarsely crystalline and zoned, and restricted mainly to faulted areas associated with the polymetallic ore deposits. Elemental analyses of the four dolomite phases show different chemistries, i.e., non-ferroan dolomites (D1 and D2), alternation of ... |
| نوع الوثيقة: | article in journal/newspaper |
| وصف الملف: | application/pdf |
| اللغة: | English |
| تدمد: | 1527-1404 |
| Relation: | UCM-910404; https://doi.org/10.2110/jsr.2021.100; https://hdl.handle.net/20.500.14352/71380 |
| DOI: | 10.2110/jsr.2021.100 |
| الاتاحة: | https://hdl.handle.net/20.500.14352/71380 https://doi.org/10.2110/jsr.2021.100 |
| Rights: | restricted access |
| رقم الانضمام: | edsbas.43F50F87 |
| قاعدة البيانات: | BASE |
| تدمد: | 15271404 |
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| DOI: | 10.2110/jsr.2021.100 |