1	Mountain Building
2	Building Mountains Orogenesis- “Birth of Mountains” Orogeny- Mountain-Building processes. Results in uplift Primarily caused by tectonic plate collisions Crustal thickening Compression of crust Produce large scale folding and thrust faulting
3	Factors for Mountain Belt Characteristics Intense deformation Compression that results in folding and faulting Isostasy Balance of lithosphere “floating” on the asthenosphere Results in mountain “roots” Weathering and erosion Erosion a factor in whether land will get higher or lower in elevation Weather or climate influences erosion
4	Characteristics of Mountains AGE Mountains higher in elevations are generally younger than lower mountains Craton: region of a continent that has been structurally stable for a long period of time Folding and faulting Folds open where deformation not very intense Tight, recumbent and overturned folds indicate more intense deformation Reverse faults are common Creates fold and thrust belts
5	Cross-Section of a typical Fold & Thrust Belt
6	Characteristics of Mountains Metamorphism and Plutons Regional metamorphic and plutonic rocks found in intensely deformed areas due to stress and high temperature conditions Normal faulting Result of vertical uplift and horizontal extension May form in the central, higher portion of mountain belts
7	Characteristics of Mountains Thickness and density of rocks Crust is thicker and younger under mountain belts Earthquakes Frequent earthquakes are found in geologically young, still active, mountain belts
8	Mountain building along convergent boundaries Subduction zone: continental-oceanic plate Partial melting, magma is created Accretionary wedge Examples: Andes and the Cascades
9	Mountain building along convergent boundaries Continental-continental collision Example: Himalayan Mountains Indian plate collided with Eurasian plate
10	The Himalaya, Orogenesis in Action Today Continental plate collides with Continental Plate Intense folding, thrusting and uplifting Creates enormous mountains Mt. Everest, 29, 028 ft.
11	Major North American Orogenies Laramide Orogeny, 40-80 million years ago (ma) Created modern southern Rocky Mountains
12	Major North American Orogenies Sierra Nevadan Orogeny, 130-160 ma Created Sierra Nevada Mountains of CA Further uplift caused when confining pressure of glaciers & overburden was removed, 18,000 years ago Alleghany Orogeny, 250-300 ma Last episode of uplift in the Appalachian Mts. Fold & Thrust Belt due to collision of e. NA continent during time of Pangaea Super-Continent
13	Cratons and Orogenic belts of North America
14	Mountain Belts of WA