GL101 Chapter Notes - Chapter 13: Continental Crust, Accretionary Wedge, Mantle Plume
Document Summary
Isostasy: continents stand higher than ocean basins. Lithosphere thins and cracks to form rift valleys, these then collapse downward, forming a step-like appearance: accompanying volcanism contributes to high relief. Passive margins: precursors to convergent margins: passive continental margins - not a plate boundary but part of the same plate as the adjoining oceanic crust, tectonically quiet, a thick wedge of sediments accumulate, causing margin to sink. Mountains in convergent margin settings: the process of establishing a new gravitational equilibrium is called isostatic adjustment, explains why many mountain belts stand high above surface, mountain belts that stand high above the surface have deep crustal roots. Simple subduction: andean and aleutian type mountain building: andean type. Convergence of an oceanic plate and a plate whose leading edge contains continental crust; exemplified by the andes mountains. Results in subduction zone, volcanic arc and compressional tectonic features.
