Earth Sciences 1022A/B Lecture 20: Earth Science Lecture March 24 2016
Document Summary
Ore if mined for profit: non-metallic are industrial minerals. Magmatic: heavy crystals like chromite and magnetite can settle in cooling pluton. Lightest minerals with rare elements crystallize in pegmatite dykes. Sedimentary: banded iron formation including magnetite, hematite and chert formed by bacteria in precambrian seas when the atmosphere lacked oxygen, placer deposits formed by running water concentrating heavy minerals. Metamorphism: contact metamorphism and associated igneous activity cooked rocks including limestone that became skarns rich in zinc, lead, copper and gold. Weathering: by hydrolysis of silicate minerals in the tropics. Concentrated insoluble aluminum as an oxide that is shipped to canada to extract the aluminum. Aggregate and stone: crushed stone, sand and gravel used for concrete and asphalt. Stone used in building facing, walkways and countertops. Industrial minerals: diamonds minded in canada from abrasives and gems. Form in the deepest roots of old mountain belts then picked up by rising bodies of kimberlite magma from asthenosphere.