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WHAT IS OROGENY? Processes of mtn building. Distinctive patterns of deposition eugeocline, miogeocline Deformation Folding and thrust-faulting Metamorphism Intrusions: batholiths, etc Volcanic Activity. TYPES OF MOUNTAINS. Volcanic: Shield and composite
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WHAT IS OROGENY?Processes of mtn building Distinctive patterns of deposition eugeocline, miogeocline Deformation Folding and thrust-faulting Metamorphism Intrusions: batholiths, etc Volcanic Activity
TYPES OF MOUNTAINS • Volcanic: Shield and composite • Fault-block: normal faulting and tension • Folded: reverse faults and compression • Complex: mixture of most of the above
Mauna Loa in Background Kilaeua is Behind Mauna Loa Mauna Kea Shield volcano Hot Spot Basalt
Kilaeua Newest ground in The world Asthenosphere coming To the surface
Composite Volcano Mt Rainier Compressive forces Subduction zones Andesitic composition
Guagua Pichincha, Ecuador Quito in foreground Composite volcanoes explosive
Normal fault Footwall moves Up relative to Hanging wall FOOTWALL HANGING WALL Tension forces
Tilted fault-block range: Sierra Nevada from east, Steep side of block fault; Ansel Adams photo
Tilted Fault-block Sierra Nevada from west Side, low angle Yosemite valley the result Of glaciation on low-angle relief
Wasatch Range From Salt Lake City Typically fault- Block system
Alternating normal faults lead to a characteristic pattern called a Horst and Graben system. An area under tension will often have Multiple mountain ranges as a result.
Basin and range province: tilted fault-block mountains in Nevada. The results of a horst and graben system. Nevada is under tension Because of rising magma which is unzipping the system, all the way From Baja California Sierra Nevada and Wasatch Ranges part of this system
REVERSE FAULTS: Hanging wall moves up relative to footwall Result of compression: plates colliding Two types: low-angle or thrust faults, and high-angle reverse faults Individual layers can move 100’s of kilometers Alps are a great example
Thrust faults main cause Of folded mountains
ZAGROS MTS PERSIAN GULF Alternating Anticlines and Synclines
High-angle reverse faults Forms “Sawtooth Mtns” Flatirons classic example Sawtooth effect result of Differential erosion
SAWTOOTH RANGE, IDAHO Alice Lake White Cloud peak
COMPLEX MOUNTAINS Tend to have a little of Everything: volcanoes, Folds, thrust faults, normal faults ALPS HIMALAYAS