GEOL 1425 1st Edition Lecture 5Outline of Last Lecture I. Plate TectonicsII. Atomic particlesIII. mineralsOutline of Current Lecture I. Different types of rocksII. Rock cycleIII. Metals and oresCurrent Lecture- Definition of a rock: natural aggregate of minerals and/or other particles that are held together to form a solid material.- Sand and soil may make up rocks, but are classified as sediments.- Magma is liquid rock. Melted by extreme heat in mantle.- There are 3 rock families. They are based on the origins of the rocks.- Igneous-crystalized from melt/magma. Intrusive are hardened inside of the earth while extrusive are formed on the earth’s surface.- Sedimentary- rocks formed by sediments that are naturally cemented together from compression.- usually form layers. Also could be minerals precipitated from fluids like salt.- Metamorphic- sedimentary or igneous rock that has changed due to extreme pressure. - Lithification- process by which sedimentary rocks are cemented- Rocks are identified by texture, size, shape, arrangement of particles, and the minerals found in the rock.- Sedimentary rocks generally have loose material of sand and quartz grains. Grains are cemented together and do not interlock.- Intrusive igneous rocks tend to have large, uniform mineral grains and shapeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Extrusive igneous rocks tend to have small grains and large crystals b/c they cool rapidly so no time for minerals to enlarge.- Metamorphic rocks tend to have a flat and elongated mineral grain.- Rock cycle: ocean spreading causes new rocks to be formed while subduction zones pull under old rock to be formed again. Near the sides of ocean, erosion causes sediment build up and eventual sedimentary rocks. Volcanoes produce rocks.- Ore deposits associated with intrusive igneous rocks like gold veins. - At Bingham canyon, copper is diffused within the rocks so people mine the area. This is one of the largest man-made excavation sites.- 11 billion years ago- iron was heavily deposited in the ocean, then it evaporated into the atmosphere. Then it rained iron.- Coal and oil come from organic material under intense pressure.- If oil is really hot and not exposed to oxygen, it forms petroleum gas.- Placer deposits: heavy ore minerals (gold) transport by streams. Concentrate in sediment. - The magnetic field diverts solar winds which cause the northern
View Full Document