کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9535151 | 1356548 | 2005 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Reworking of Archaean and Palaeoproterozoic crust in the Mozambique belt of central Tanzania as documented by SHRIMP zircon geochronology
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
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![عکس صفحه اول مقاله: Reworking of Archaean and Palaeoproterozoic crust in the Mozambique belt of central Tanzania as documented by SHRIMP zircon geochronology Reworking of Archaean and Palaeoproterozoic crust in the Mozambique belt of central Tanzania as documented by SHRIMP zircon geochronology](/preview/png/9535151.png)
چکیده انگلیسی
New SHRIMP zircon ages for high-grade rocks from the Pan-African Mozambique belt (MB) of central Tanzania document reworking of Archaean-Palaeoproterozoic crust during the formation of this Neoproterozoic collisional orogen. Several gneisses and granulites from the Great Ruaha river area yielded late Archaean emplacement ages of 2575-2680Â Ma for their magmatic precursors. Core-rim relationships in some zircons revealed new zircon growth during relatively short episodes of granitoid magmatism. Metamorphic zircons, dated at 1925Â Ma, provide new evidence for high-grade metamorphism during formation of the Palaeoproterozoic Usagaran mobile belt. Metamorphic rims around magmatic cores in zircons extracted from granulite-facies garnet-amphibole bearing orthogneisses yielded an age of about 640Â Ma, which is interpreted to reflect the peak of Pan-African regional high-grade metamorphism. Resorbed zircons extracted from migmatitic orthogneisses show a wide range of apparently concordant results, varying between â500 and 700Â Ma. This wide range reflects HT/HP conditions during peak metamorphism as well as subsequent strong decompression (ITC cooling path). Our data suggest that the MB in Tanzania consists largely of Archaean crust north of the Great Ruaha river and of Palaeoproterozoic crust south of this river. Both the Archaean and Palaeoproterozoic domains were strongly reworked during the formation of the MB and experienced high-grade metamorphism at â¼640Â Ma. Our results imply that the Tanzania craton and Usagaran province originally extended much farther to the east and were structurally reworked, almost beyond recognition, during Pan-African ductile deformation and recrystallization.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of African Earth Sciences - Volume 43, Issue 4, November 2005, Pages 447-463
Journal: Journal of African Earth Sciences - Volume 43, Issue 4, November 2005, Pages 447-463
نویسندگان
Holger Sommer, Alfred Kröner, Christoph Hauzenberger, Sospeter Muhongo,