Earth Sciences 1070A/B Lecture Notes - Lecture 8: Convergent Boundary, Global Positioning System, Strike And Dip
18 Jan 2017
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Document Summary
Tectonic forces = crustal deformation: create mountains, shift islands, move rocks past rock on fault line. Analyze orientation of folds and faults can reconstruct original tectonic setting and sequence. Deformation - changes in orientation and location of rock: proximal to plate margins (segments of lithosphere move relative to one another) Stress amount of force applied to given area: stress = rock deformation, strain visible result of stress, equal stress = strata undeformed, differential stress = strata deformed. Tensional stress stress pulling apart rock: occurs at divergent plates, where stress = rifting perpendicular max tensional stress. Elongate perpendicular to direction of greatest stress. Differential stress = minerals align perpendicular to direction of greatest stress. Shear stress differential stress forces rock to move past each other: different when shallow, near surface environment and at great depths, shallow rocks closely spaced parallel surfaces. Foliation, microfaults, bedding planes: depth high temps and pressure rocks deformed by solid-state flow (plastically)
