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标题：Petrogenesis of the Riacho do Icó Stock: evidence for Neoproterozoic slab melting during accretion tectonics in the Borborema Province?
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作者：Santos, Lauro Cézar Montefalco de Lira ; Lima, Haroldo Monteiro ; Lages, Geysson de Almeida 等
期刊名称：Brazilian Journal of Geology
印刷版ISSN：2317-4889
出版年度：2020
卷号：50
期号：2
页码：1-17
DOI：10.1590/2317-4889202020190127
出版社：Sociedade Brasileira de Geologia
摘要：One of the main characteristics of the Borborema Province in northeastern Brazil is the abundance of granitic domains. The Lagoa das Pedras plutonic-volcanic Complex record remnants of early to late Neoproterozoic primitive to highly evolved magmas. U-Pb SHRIMP determinations and whole-rock geochemistry on the granitic to granodioritic Riacho do Icó Stock, which is the largest plutonic body of this complex, were conducted. Zircon dating reveals that this body was intruded in the crust at 607 ± 3 Ma, whereas metamorphic overgrowths are coeval within uncertainty (600 ± 8 Ma). Geochemical characteristics of this stock suggest that it corresponds to Cordilleran-type magmas injected in the lithosphere above a subduction zone. Sr and Y contents in addition to MgO and SiO2 values are compatible with high-silica adakite-like magmas, interpreted as the result of slab melting in deep-seated regions. Based on the integration of this study and literature data, we suggest that the Riacho do Icó intrusion might be a dismembered part of a major continental magmatic arc described in the Central Subprovince of the Borborema Province, marking the onset of the accretionary stage of the Brasiliano orogeny.
关键词：Arc-related to syn-collisional magmatism; possible slab melting episode; accretion tectonics.
其他关键词：Arc-related to syn-collisional magmatism;possible slab melting episode;accretion tectonics