کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6431467 1635167 2013 24 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Geochemistry and zircon geochronology of the Archean granite suites of the Rio Maria granite-greenstone terrane, Carajás Province, Brazil
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Geochemistry and zircon geochronology of the Archean granite suites of the Rio Maria granite-greenstone terrane, Carajás Province, Brazil
چکیده انگلیسی

The Archean granites exposed in the Mesorchean Rio Maria granite-greenstone terrane (RMGGT), southeastern Amazonian craton can be divided into three groups on the basis of petrographic and geochemical data. (1) Potassic leucogranites (Xinguara and Mata Surrão granites), composed dominantly of biotite monzogranites that have high SiO2, K2O, and Rb contents and show fractionated REE patterns with moderate to pronounced negative Eu anomalies. These granites share many features with the low-Ca granite group of the Yilgarn craton and CA2-type of Archean calc-alkaline granites. These granites result from the partial melting of rocks similar to the older TTG of the RMGGT. (2) Leucogranodiorite-granite group (Guarantã suite, Grotão granodiorite, and similar rocks), which is composed of Ba- and Sr-rich rocks which display fractionated REE patterns without significant Eu anomalies and show geochemical affinity with the high-Ca granite group or Transitional TTG of the Yilgarn craton and the CA1-type of Archean calc-alkaline granites. These rocks appear to have been originated from mixing between a Ba- and Sr-enriched granite magma and trondhjemitic liquids or alternatively product of interaction between fluids enriched in K, Sr, and Ba, derived from a metasomatized mantle with older TTG rocks. (3) Amphibole-biotite monzogranites (Rancho de Deus granite) associated with sanukitoid suites. These granites were probably generated by fractional crystallization and differentiation of sanukitoid magmas enriched in Ba and Sr.The emplacement of the granites of the RMGGT occurred during the Mesoarchean (2.87-2.86 Ga). They are approximately coeval with the sanukitoid suites (∼2.87 Ga) and post-dated the main timing of TTG suites formation (2.98-2.92 Ga). The crust of Rio Maria was probably still quite warm at the time when the granite magmas were produced. In these conditions, the underplating in the lower crust of large volumes of sanukitoid magmas may have also contributed with heat inducing the partial melting of crustal protoliths and opening the possibility of complex interactions between different kinds of magmas.

Highlights► The granites from Rio Maria terrane have Mesoarchean ages (∼2.87 Ga). ► The Potassic leucogranites show affinity with low-Ca granite from Yilgarn craton. ► The Leucogranodiorite-granites are similar to the Transitional TTGs from Yilgarn craton. ► Amphibole-biotite monzogranites are associated with sanukitoid suites from Rio Maria Terrane.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of South American Earth Sciences - Volume 42, March 2013, Pages 103-126
نویسندگان
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