Petrogenesis of the Riacho do Icó Stock: evidence for Neoproterozoic slab melting during accretion tectonics in the Borborema Province?

Santos, Lauro Cézar Montefalco de Lira; Lima, Haroldo Monteiro; Lages, Geysson de Almeida; Caxito, Fabrício de Andrade; Neto, José Ferreira de Araújo; Guimarães, Ignez de Pinho

doi:10.1590/2317-4889202020190127

Cited by 9 publications

(2 citation statements)

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“…As pointed out by Santos et al (2020), the variety of structural markers in the Riacho do Icó stock makes it difficult to precisely track the processes that resulted in the intrusion emplacement. For instance, diapirism can be considered due to the near-ellipsoidal shape that imposed the deviation of supracrustal host rock foliation, whilst high-pitch downdip stretching lineation dips straight to the intrusion core (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Younger bodies related to this complex include Ediacaran granites representing the record of the Brasiliano Orogeny in the area, including the ca. 607 ± 3 Ma Riacho do Icó stock, recently interpreted as the result of oceanic slab melting (Santos et al, 2020). The second granitoid suite is located along the connection of the Patos shear zone with the Seridó metasedimentary belt, and consists of E-W to NE-SW elongated bodies of leucogranites that are spatially associated with the Espinho Branco and Santa Luzia migmatites (Archanjo et al, 2013;Viegas et al, 2013).…”

Section: Geological Settingmentioning

confidence: 99%

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Exploring the relationships between shear zones and granites: field and microstructural data for contrasting case studies of the Borborema Province (NE Brazil)

Santos

Viegas

2021

Geol. USP. Sér. Cient.

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We discuss meso- and microstructural features of granites closely related to strike-slip shear zones in the Borborema Province, NE Brazil. The Riacho do Icó stock is an en-cornue intrusion aged at ca. 607 Ma. Magmatic fabric is recorded in the core of the granite, whilst increasing deformation is marked by the development of mylonitic fabrics towards the Afogados da Ingazeira shear zone, including magmatic foliation and lineation rotation. Early recrystallization of quartz and K-feldspar crystals is widespread as a fabric with well-developed granoblastic polygonal textures and lobate subgrain boundaries, heterogeneously deformed lenses and ameboid quartz ribbons, typical of igneous rocks submitted to deformation in deep crustal levels. On the other hand, the Espinho Branco-Santa Luzia leucogranitic belt is hosted along the Patos Lineament, aged between the ca. 575 – 565 Ma interval. These rocks show discordant relationships with the host migmatites and the main deformational fabric is characterized by a dominant magmatic foliation that is locally overprinted by structures that are typical of solid-state flow. Quartz melt pockets and interstitial quartz grains filling fractures in feldspar clasts are common. Such characteristics are compatible with granites that were injected in the continental crust along planar anisotropies (i.e., shear zones) formed during the late-stage partial melting events that originated the migmatites of the area. The case studies are proxies in the understanding of different episodes of magma emplacement along shear zones in this part of West Gondwana.

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Section: Discussionmentioning

confidence: 99%