Electronic Resource
Geology and geochronology of the Archean plutonic rocks in the northeast Democratic Republic of Congo
| العنوان: | Geology and geochronology of the Archean plutonic rocks in the northeast Democratic Republic of Congo |
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| المؤلفون: | Turnbull, Rose E., Allibone, A.H., Matheys, F., Fanning, Christopher Mark, Kasereka, E., Kabete, J., McNaughton, Neal, Mwandale, E., Holliday, J. |
| المصدر: | Precambrian Research |
| بيانات النشر: | Elsevier 2021 |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | Here we report the first regional-scale study of Archean plutonic rocks from 50,000 km of the northeast Democratic Republic of Congo (DRC). We include 50 new U-Pb zircon Sensitive High-Resolution Ion MicroProbe (SHRIMP) ages supported by petrographic and whole rock geochemical data from a further ~400 samples, and 39 additional U-Pb zircon ages reported by Kabete et al. (submitted) and Bird (2016). Felsic-intermediate magmatism across the northeast DRC occurred from ~ 3200 to 2530 Ma. Plutonism before ~ 2670 Ma is restricted to the West Nile Gneiss in eastern and northern-most DRC, whereas plutonism across the remainder of the northeast DRC initiated between 2670 and 2640 Ma. Two Neoproterozoic granite plutons ~ 1000–950 Ma are also present within the West Nile Gneiss. Magmatism between ~ 2670 and 2530 Ma marks the principal period of crustal growth in the northeast DRC. Felsic-intermediate plutonism between ~ 2670 and 2600 Ma included two suites of magnesian, calc-alkaline rocks, (1) a sodic-calcic suite with high Sr/Y ratios (>40) comparable with tonalite-trondhjemite-granodiorite (TTG) suites in other Archean terranes, and (2) a calc-alkaline to high-K suite of granitoids with low Sr/Y ratios (<40) and lower Na and Al contents, comparable with “low-Ca” granites in the Yilgarn Craton. In contrast, most granitoids emplaced between ~ 2600 and 2530 Ma have ferroan, high-K calc-alkaline compositions, and are enriched in high field strength (HFSE) and rare Earth elements (REE). Although the HFSE-elevated granitoids are comparable with Closepet-type, and “mafic granites” in other Neoarchean terranes, their volume within the northeast DRC appears unprecedented. Before ~ 2600 Ma partial melting of hydrous metabasalts at depths > 40 km is inferred to have produced the high Sr/Y magnesian granitoids, whereas the low Sr/Y magnesian granitoids were derived from melting-assimilation-storage-hybridization (MASH) processes in the overlying low-mid crust during the same period. T |
| مصطلحات الفهرس: | Crustal growth, SHRIMP U-Pb zircon dating, Democratic Republic of Congo, Neoarchean, HFSE-elevated granite, Journal article |
| URL: | |
| الاتاحة: | Open access content. Open access content © 2021 Elsevier B.V. |
| ملاحظة: | en_AU |
| Other Numbers: | AUANP oai:openresearch-repository.anu.edu.au:1885/276230 0301-9268 1397766513 |
| المصدر المساهم: | AUSTRALIAN NAT UNIV - PRINT REPOSITORY From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1397766513 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |