Structural Geology of Peridotite and Rheology of the Uppermost Mantle

Abstract

The earth consists of crust, mantle and core. The crust is the earth's surface component, upon which we live. Situated below the crust, the mantle is the dominant component consisting of the earth, making up 80 %. The rheology of the mantle is the key to understanding the working of our mother planet. Peridotite, which is derived from the uppermost mantle, preserves structures and textures that contain information on flow stress and strain (e.g., foliation, lineation and grain size), while the crystal-preferred orientations of minerals (i.e., fabric) reveal the nature of kinematic movement within the mantle. The mantle section of the Oman ophiolite is the largest section of oceanic lithosphere exposed at the earth surface. Extensive structural mapping of these rocks has been conducted throughout the Oman mountain range to unravel mantle processes associated with the generation of oceanic lithosphere. Research in this area demonstrated that the formation of oceanic mantle lithosphere at a fast-spreading ridge involves active mantle flow associated with a mantle diapir.