Classroom presentations to accompany Understanding Earth, 3rd edition prepared by Peter Copeland and William Dupré University of Houston Chapter 3 Rocks: Records of Geologic Processes
Three types of rocks Igneous Sedimentary Metamorphic Igneous rocks make up most of the earth sedimentary rocks make up most of the surface.
Major Rock Groups Fig. 3.1 IGNEOUSSEDIMENTARYMETAMORPHIC
Igneous Rocks Rocks formed from the cooling and consolidation of magma.
Fig. 3.2
Intrusive Granite
Fig. 3.2 Extrusive Basalt
Fig. 3.2 Intrusive Granite
Fig. 3.2 Extrusive Basalt
Rocks formed by the consolidation of fragments of previously existing rock or chemically precipitated from solution. Sedimentary Rocks
Fig. 3.3 From Weathering to Sedimentary Rock
Genesis of Sedimentary Rocks Physical weathering: reduction in size Chemical weathering: change in composition Transportation: –Solid particles... clastics by water, wind, ice –Ions in solution... chemical
Fig. 3.4 How common are sedimentary rocks?
Rocks whose original form has changed in the solid state due to increased temperature and/or pressure. Metamorphic rocks
Fig. 3.5 Where does Metamorphism occur? Regional Metamorphism
Fig. 3.5 Where does Metamorphism occur? Regional Metamorphism Contact Metamorphism
Outcrops Drilling Where we see rocks
Fig. 3.6 Outcrop
Fred Hirschmann Fig. 3.7
Russ Kinne/ Comstock Fig. 3.8
Carr Clifton Fig. 3.9
The Rock Cycle Fig. 3.10
The production and destruction of rocks is ultimately related to plate tectonics. Plate tectonics and the rock cycle
Fig. 3.11a Subduction at convergent plate boundaries causes partial melting to form magma and resulting igneous rocks.
Fig. 3.11b Magma rises from the mantle at divergent plate boundaries.
Fig. 3.11c Subsidence at rifted plate margin allows for the deposition, burial, and lithification of sediments.
Plate interiors are dominated by sedimentary processes, with some volcanism due to mantle “hot spots.” Fig. 3.11d
Convergence of plates causes deformation, uplift, and regional metamorphism. Fig. 3.11e