ERS120H5 Lecture Notes - Convergent Boundary
Document Summary
Brittle: temperature low, pressure low, time (deformation rate) fast, composition strong. Ductile: temperature high, pressure high, time (deformation rate) slow, composition weak. Upper crust = brittle, below temperatures are high enough allows rocks to flow and therefore become ductile therefore brittle ductile transition. Rock deformation principle features: fractures (joints, faults fracture with movement around it, folds, foliation (cleavage) brittle ductile. Thrust faults: shortening, compression squeeze rocks, older rocks on younger rocks, repeated section. What causes thrust faults: compression: occurs at convergent plate boundaries, strain: shortening, thickening. Normal faults: extension, lengthening, tension, younger rocks on older rocks, missing section. Strike-slip faults: shearing, occur at transform plate boundaries. Rock deformation: strain : shear, horizontal shear stress is parallel to a strike slip fault. Anticline (like an ant hill) oldest rocks in the core, and younger rocks on the outside. Syncline (like a sink) youngest rocks in the core.
