Open AccessSan José de Guaviare Syenite, Colombia: Repeated Ediacaran intrusions in the northwestern Amazonian Craton
Author(s) -
Carolina Amaya López,
Marion Weber,
Mauricio Ibáñez Mejía,
Federico Alberto Cuadros Jiménez,
Jorge Julián Restrepo Álvarez,
Nilson Francisquini Botelho,
Mario Maya Sánchez,
Orlando Manuel Pérez Parra,
Carlos Ramírez Cárdenas
Publication year - 2021
Publication title -
boletín geológico
Language(s) - English
Resource type - Journals
ISSN - 2711-1318
DOI - 10.32685/0120-1425/bol.geol.48.1.2021.503
Subject(s) - geology , nepheline syenite , geochemistry , nepheline , igneous rock , craton , quartz , feldspar , rift , pluton , crust , petrology , tectonics , paleontology
The Neoproterozoic igneous rocks found in the municipality of San José del Guaviare include several isolated plutonic bodies that protrude from the Phanerozoic sedimentary cover in belts aligned NW-SE. Limited to the Guaviare department, these intrusions stretch from the La Lindosa mountain range to the corregimiento El Capricho. These plutonic bodies consist of nepheline syenites, nepheline monzosyenites, nepheline-bearing alkali-feldspar syenites, syenites, quartz-syenites, quartz-alkali-feldspar syenites, syenogranites, and quartz-rich granitoids, which have been grouped and termed the San José del Guaviare Syenite unit (SJGS).
The intrusion of the unit occurred in the Ediacaran (604 ± 7 Ma and 620.5 ± 7.5 Ma) by mantle-derived alkaline magmas formed in anorogenic settings, most likely in rift-like stretching zones. The silica-subsaturated magma may have reacted with host rocks at the crust level, producing some silica-saturated igneous rocks, such as syenogranites and quartz-syenites, which are found in the El Capricho and Cerritos bodies.