Textural Relations of Lamprophyric Mafic Microgranular Enclaves and Petrological Implications for the Genesis of Potassic Syenitic Magmas: the example of Piquiri Syenite, southern Brazil
Textural Relations of Lamprophyric Mafic Microgranular Enclaves and Petrological Implications for the Genesis of Potassic Syenitic Magmas: the example of Piquiri Syenite, southern Brazil
| dc.contributor | en-US | |
| dc.contributor | pt-BR | |
| dc.creator | CID, JORGE PLÁ | |
| dc.creator | NARDI, LAURO VALENTIM STOLL | |
| dc.creator | GISBERT, PERE ENRIQUE | |
| dc.date | 2002-12-31 | |
| dc.date.accessioned | 2018-11-07T21:59:30Z | |
| dc.date.available | 2018-11-07T21:59:30Z | |
| dc.identifier | https://seer.ufrgs.br/PesquisasemGeociencias/article/view/19602 | |
| dc.identifier | 10.22456/1807-9806.19602 | |
| dc.identifier.uri | http://repositorioslatinoamericanos.uchile.cl/handle/2250/2192353 | |
| dc.description | The Neoproterozoic Piquiri Syenite exhibits a large amount of mafic microgranular enclaves (MME) with elliptical-shape and millimeter to centimeter-size dimensions. These enclaves were originated by co-mingling of minettetype lamprophyre and potassic syenite magmas, producing the typical textural features of quenched magmas. They show elongated crystals of diopside and Mg-biotite, and acicular apatite. Early crystallized phases are represented by the same minerals, which occur as phenocrysts (diopside + Mg-biotite) and euhedral smaller crystals (apatite). The textural relationship and the identification of mineral phases as K-clinopyroxene and pyrope in the MME, suggest that mingling started at mantle conditions, when lamprophyric and syenitic magmas were near crystal-free and close to liquidus temperatures. The absence of syenite xenocrysts and chilled-margins in MME, are consistent with the high temperature of co-mingling. Alkali feldspar laths that poikilitically enclose quenched phases, represent late-magmatic mineral phase. The Piquiri Syenite MME represent a quite rare example of co-mingling between lamprophyre and intermediate magmas, and represents important evidence for the genesis of potassic silica-saturated magmas at mantle conditions. | en-US |
| dc.description | The Neoproterozoic Piquiri Syenite exhibits a large amount of mafic microgranular enclaves (MME) with elliptical-shape and millimeter to centimeter-size dimensions. These enclaves were originated by co-mingling of minettetype lamprophyre and potassic syenite magmas, producing the typical textural features of quenched magmas. They show elongated crystals of diopside and Mg-biotite, and acicular apatite. Early crystallized phases are represented by the same minerals, which occur as phenocrysts (diopside + Mg-biotite) and euhedral smaller crystals (apatite). The textural relationship and the identification of mineral phases as K-clinopyroxene and pyrope in the MME, suggest that mingling started at mantle conditions, when lamprophyric and syenitic magmas were near crystal-free and close to liquidus temperatures. The absence of syenite xenocrysts and chilled-margins in MME, are consistent with the high temperature of co-mingling. Alkali feldspar laths that poikilitically enclose quenched phases, represent late-magmatic mineral phase. The Piquiri Syenite MME represent a quite rare example of co-mingling between lamprophyre and intermediate magmas, and represents important evidence for the genesis of potassic silica-saturated magmas at mantle conditions. | pt-BR |
| dc.format | application/pdf | |
| dc.language | por | |
| dc.publisher | Instituto de Geociências /Universidade Federal do Rio Grande do Sul | pt-BR |
| dc.relation | https://seer.ufrgs.br/PesquisasemGeociencias/article/view/19602/pdf | |
| dc.source | Pesquisas em Geociências; v. 29, n. 2 (2002): Pesquisas em Geociências; 21-30 | pt-BR |
| dc.source | 1807-9806 | |
| dc.source | 1518-2398 | |
| dc.subject | en-US | |
| dc.subject | lamprophyres, mafic microgranular enclaves, syenite, mingling. | en-US |
| dc.subject | Geociências;Geologia;Geografia;Geodésia;Paleontologia;Engenharia Cartográfica | pt-BR |
| dc.subject | lamprophyres; mafic microgranular enclaves; syenite; mingling. | pt-BR |
| dc.subject | Geociências | pt-BR |
| dc.title | Textural Relations of Lamprophyric Mafic Microgranular Enclaves and Petrological Implications for the Genesis of Potassic Syenitic Magmas: the example of Piquiri Syenite, southern Brazil | en-US |
| dc.title | Textural Relations of Lamprophyric Mafic Microgranular Enclaves and Petrological Implications for the Genesis of Potassic Syenitic Magmas: the example of Piquiri Syenite, southern Brazil | pt-BR |
| dc.type | Artículos de revistas | |
| dc.type | Artículos de revistas | |
| dc.coverage | Rio Grande do Sul;Brasil | pt-BR |
| dc.coverage | pt-BR | |
| dc.coverage | pt-BR |