GEOL 1340 Lecture Notes - Lecture 26: Acasta Gneiss, Gneiss, Convergent Boundary

• School: University of Houston
• Department: Earth and Atmospheric Sciences
• Course: GEOL 1340
• Professor: Lytwyn Jennifer

Document Summary

3rd: most detailed, individual mountains, cliffs, valleys, hills: crustal formation, cratons and shields. Cratons rep. ancient crustal rocks that are deformed and met. Margin sediments, oceanic crust, and volcanic arcs in collision zones. Oceanic crust and volcanic arcs along other arcs microcontinents along convergent plate. Acasta gneiss (4 billion: oldest rocks. Suggests crusts not permanent until 4 billion. Zircons in acasta gneiss (4. 2: early protocontinents. Preserved in met gneiss complexes (>2. 5) on cratons: growth of continents. Plume activity, mantle convection and partial melting. Convergent boundaries sites of accretion: accretion. Ophiolites: pieces of ocean floor: geologic provinces na. Rocks older than 1 billion make craton. Rocks younger than 1 billion added later by accretion. 2 major supercontinent existed last billion years: supercontinent. Rodinia: 1 billion years and broke apart 600 million. Pangaea: 230 million years and broke apart 200. During late proterozoic: crustal deformation process.