Boletin de Geología
Print version ISSN 0120-0283
HINCAPIE JARAMILLO, Gustavo; TORO TORO, Luz Mary and OSSA MEZA, César Augusto. KINEMATIC ANALYSIS AND DEFORMATIVE OF THE METAGABBROS OF RIO OLIVARES NNW SECTOR OF MANIZALES (CALDAS). bol.geol. [online]. 2010, vol.32, n.2, pp. 85-92. ISSN 0120-0283.
The Metagabbro of Rio Olivares (Toro et al., 2010), is a lithological unit located on the Río Olivares shore, NNW sector 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 as flexed twinned crystals, sweeping undulatory extinction, core-mantle structures and dynamic recrystalization by grain boundary migration. This mineral also has brittle microstructures such as microfractures, microfaults and deformation twins. The clinopyroxenes show patches and sweeping undulatory extinction like ductile microstructures 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 a dextral oblique collision of plates.
Keywords : Manizales; metagabbros; deformation; pseudotachylites.