Examinando por Materia "Complejo Cajamarca"

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    Ítem
    Caracterización de las rocas metamórficas localizadas entre el alto de Boquerón y el corregimiento de Palmitas, Antioquia
    (Universidad EAFIT, 2022) Londoño Amaya, Daniela; Aristizábal Aristizábal, Valentina; Bustamante Londoño, Camilo
    The tectonic evolution of Colombia is marked by collision, subduction and obduction events that developed between the Paleozoic and Cenozoic. These events were building what is now the western margin of the Northern Andes. The continuous tectonic dynamism of this western region has resulted in compositional, geochemical and petrographic changes in the metamorphic rocks that outcrop in the Central Cordillera of Colombia. The main objective of this research is to characterize the metamorphic rocks that outcrop between the Alto de Boquerón and Palmitas, between kilometer 22 to 27 of the San Jerónimo - Medellín road, which are part of the Ayurá - Montebello Group, and that present geochemical, geochronological, petrographic and structural characteristics of high complexity and great importance in the construction of the regional geological framework of the country.
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    Ítem
    Protolith and metamorphic conditions of the metapelites from the Rio Claro Region (Antioquia Departament)
    (Universidad EAFIT, 2021) Madrid Restrepo, Diana Carolina; Bustamante Londoño, Camilo
    The Cajamarca Complex is distributed along the Central Cordillera of Colombia, its formation is attributed to a Permian subduction zone, volcanic arc magmatism, opening and closing of basins and accretion of terrenes. The 16 samples studied in this research crop out near Rio Claro in the department of Antioquia. The analyzes were made with 7 metasedimentary, 2 metabasic belonging to the Cajamarca Complex and 7 pegmatites related to the magmatism of the Antioquia Batholith. Detailed petrography of the samples was performed and did total rock geochemistry for metamorphic rocks for analysis of major and trace elements. This study focuses on discussing the tectonic environment of protolith formation based on tectonic discrimination diagrams and P-T conditions for metamorphism, based on mineralogical reactions. In the N-MORB analysis it shows an enrichment in the LILE and a depleting in the HFSE, in the same way an inverse relationship is observed of the rare earth elements (REE) normalized with the primitive mantle. The metasedimentary rocks are mainly formed by quartz, muscovite, biotite, graphite, Andalusite and as accessory minerals titanite and zircon; the metabasics are composed of epidote, actinolite, chlorite, hornblende, and plagioclase. The P-T conditions yields a pressure of 6 to 4 kbar and a temperature that did not exceed 550 ° C. This represents a metamorphic gradient of medium pressure and medium temperature indicating a passage through the green schist to epidote-amphibolite facies which is linked to a Barrovian type metamorphism. This type of regional metamorphism led toward a depth approximately of 20 km. In this work it is suggested that the formation of the sedimentary protolith is in the accretion wedge of a subduction zone, unlike the igneous protolith that would be part of the formation of the crust. oceanic; this differs from what Blanco-Quintero et al. (2014) proposes south of the Cajamarca Complex. This oceanic crust would later subduct to the paleo western margin of South America; where the metamorphic event would finally be generated.