This oblong, relatively small, 'I-type' pluton, which yielded a preliminary U-Pb emplacement age on zircon of 420 [+ or -] 5 Ma (Fyffe and Bevier 1992), contains a penetrative, northeast-trending, cataclastic
fabric defined by aligned augen of plagioclase and potassium feldspar set in a granulated quartz matrix.
The shear zones that generally cut across the strata are typical cataclastic
strike slip in character showing distinct asymmetric kinematic indicators of reidel assemblages (Marwar, 1989).
The ores mainly comprise cataclastic
, idiomorphic or hypidiomorphic granular, and gric textures.
The zones of cataclastic
rocks of the strike cataclastic
zone are oriented in the north-south direction and to the north-north-west and south-south-east; and are occupied with the crushed adjacent rocks with graphite and tectonic breccia.
The previous K/Ar methods used three decades ago are not considered reliable since isotopic content is very susceptible to changes by hydrothermal events which are evident in the zone, and are also susceptible to be changed due to tectonism such as shearing and cataclastic
events which we have documented in the petrographic analysis.
Locally, the Osa Melange is strongly tectonized and displays deformation of blocks (Rio Tigre) or even cataclastic
rocks of the San Gabriel Faults--An expression of deformation at deeper crustal levels in the San Andreas Fault Zone.
A series of NE-SW-striking shear and cataclastic
fault zones are located in a belt between the largest Wiborg and Riga plutons.
Occurrence: In hydrothermal assemblages in vugs in cataclastic
and mineralized dolomite carbonatite.
The mineralised bodies occur in pipes and pockets with complex shapes, with the main zone occurring within a wedge of terrigenous rocks in the upper cataclastic
The Bear Showing at the west end of Sharpe Lake, formerly mapped as an older meta-conglomerate and tonalite assemblage, has been recognized and redefined as a younger felsic intrusive bounded on both sides by cataclastic
bifurcations of the SWFZ.
The older faults, involving granodiorite dykes, show a fabric defined by foliated cataclastic
rocks and quartz veins and give rise to the retrogradation of the granodiorite to chlorite-muscovite assemblages.