Origin of pegmatites and fluids at Ponta Negra (RJ, Brazil) during late- to post-collisional stages of the Gondwana Assembly
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- 作者：Everton Marques Bongioloa ; ebongiolo@geologia.ufrj.br" class="auth_mail" title="E-mail the corresponding author ; Christophe Renacb ; Patricia d'Almeida de Toledo Pizac ; Renata da Silva Schmitta ; André ; Sampaio Mexiasd
- 关键词：Pegmatite ; Brasiliano Orogeny ; Post-collisional ; Stable isotopes ; Fluid inclusions ; Cabo Frio Tectonic Domain
- 刊名：Lithos
- 出版年：2016
- 出版时间：January 2016
- 年：2016
- 卷：240-243
- 期：Complete
- 页码：259-275
- 全文大小：3205 K
文摘
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Temperatures of pegmatite dikes (280-720 °C) are lower than those previously estimated for the metamorphic peak (740 °C).
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Composition of fluids in equilibrium with pegmatite dikes consists of magmatic and metamorphic components.
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The Ponta Negra pegmatites originated by partial melting of the metasedimentary Palmital succession.
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The minimum pressures for the emplacement of pegmatites are equivalent to 1.7 and 3.5 km, which correspond to the exhumation of the orogen.
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The 454 ± 5 Ma U–Pb (zircon) age obtained on the Cajú syenogranite extends the time interval for the Gondwana assembly collapse magmatism in the region.