On the Formation of K-Feldspar Augens - An Example from the Central Crystallines of the Bhutan Himalaya

Abstract

Mesoscopic and microscopic studies on the K-feldspar augens of Thimphu augengneiss of Bhutan suggests microshearing followed by a rotational mechanism. Megacrysts of K-feldspar are often broken into smaller segments by ductile shear faulting, followed by a combination of simple shear and flattening deformation giving rise to the augens.