ANÁLISIS CINEMÁTICO Y DEFORMATIVO DE LOS METAGABROS DEL RÍO OLIVARES SECTOR NNW DE MANIZALES (CALDAS)
Published 2011-08-08
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Abstract
The Metagabbro of Rio Olivares (Toro et al., 2010), is a lithological unit located on the Río Olivares shore, NNWsector of the Manizales city. The primary minerals belonging to this unit are calcic plagioclase and clinopiroxene.This unit has ductile shear zones in which mylonites series are formed, brittle shear zones with development of rocks of the cataclasites series are superimposed to the previous one. In the mylonites there are pyroxene,and plagioclases porphyroclasts, with asimetrical tails that indicate dextral shear. Also, pseudotachylites veins are developed, that indicate paleo earthquakes. Plagioclases have microstructures of ductil deformation such asflexed twinned crystals, sweeping undulatory extinction, core–mantle structures and dynamic recrystalization by grain boundary migration. This mineral also has brittle microstructures such as microfractures, microfaultsand deformation twins. The clinopyroxenes show patches and sweeping undulatory extinction like ductilemicrostructures and microfractures as fragile microstructures. Mesoscopic and microscopic dextral movements and the shape of the shear zones indicate partitioning of the deformation. The above could be explained by adextral oblique collision of plates.
Key words: Manizales, metagabbros, deformation, pseudotachylites.
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References
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