Feldspars albite twins

Experimental studies of alkali feldspars in Westerley granite with ordered microcline [63,64] and disordered sanidine [65-68] show that (010) [001] shp is active in both. Other dislocations derive from (010)[101] [Fig. 15(a)], (001) [110], and (121) [101] shp. In naturaUy deformed alkali feldspars, subgrain formation was observed, indicative of climb [357-360]. It has been suggested that shear-induced mechanical Albite and Pericline twinning in potassium feldspar may facilitate ordering [361] but this has been disputed [362]. Dislocations have no effect on diffusion in alkah feldspar [363]. 

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