geo exam 1

• A mineral is an inorganic solid substance composed of one or more elements and a specific crystal structure
• orthoclase is made of potassium
• plagioclase is made of sodium and calcium
• hornblende is made of iron and magnesium
• pyroxene is made of iron and magnesium
• quartz is SiO2
• Calcite is CaCO3
• according to bowens reaction:

  • quartz, muscovite, and feldspar, crystallize last
  • olivine and pyroxene crystallize first
• a rock is made up of minerals and is a solid aggregate
• larger crystals cool slowly and take more time. small crystals cool quick and need less time
• granite: greater than 10% quartz, orthoclase rich with few dark minerals
• basalt: less than 10% quartz, plagioclase rich with 50-90% dark minerals
• peridotite is dark colored
• igneous rock is the densest, basalt and gabbro are more dense with less quartz (oceanic)
• • gravel is >2 mm with highest flow of velocity
  • sand is middle velocity
  • mud has lowest flow of velocity with smallest particles
• Sedimentation occurs when loose particles are cemented together or chemically precipitated from water, they accumulate in depositional environments
• • limestone: >50% calcite, shell fragments precipitated together
  • chert: glass and shells of plankton
• • coal: oxygen poor swamps
  • halite/gypsum: arid, hydrologically restricted basin
  • sandstone: deserts, riverbeds, or coastal areas
  • chert: cold, deep ocean or lake
  • mudstone: tidal flats, deep lakes, calm water
  • limestone: calm water
• fossiliferous limestone: shell fragments cemented together
• stromatolites: mound shaped formed from cyanobacteria
• the asthenosphere is part of the mantle
• • divergent plates are basaltic
  • oceanic-continental convergent are granitic/andesetic
• • Rifts have extensional stress
  • convergent plates are compressional stress
• • mid ocean ridges (divergent) are normal faults
  • convergent boundaries are reverse faults or folds
  • transform are strike slip
• • continental crust: granite, diorite
  • oceanic crust: basalt, gabbro
  • mantle: silicates
• the lithosphere is where the tectonic plates are
• mesosphere is the lower mantle
• asthenosphere is a low velocity zone that allows for movement of plates
• lithosphere is the crust and upper most mantle (tectonic plates), tectonic plates sit on top of asthenosphere
• large scale circulation is driven by thermal convection
• plate tectonics is large scale motion of earths segmented lithosphere
• • divergent: separate through extensional stress, rifts break up continents (mid ocean ridge)
  • convergent: subduction of one plate under another (mountains)
  • transform: strike slip motion (san andres fault)
• hot rock rises, cold rock sinks, moving towards thermal homogeneity
• gravity sliding, slab pull, and slab suction are mechanisms that drive thermal plates