Geog 312 -- Geography of Landforms -- Study Guide 1
Davis -- Fall 1998
The following is an outline of the lectures:
Introduction -- The Science of Geomorphology
W. M. Davis's Structure, Process, & Stage/Time
Geomorphic Scales
Endogenic vs. Exogenic processes
Megageomorphology & Endogenic Processes
Earth Structure
Internal Structure -- core/mantle/crust: density, composition; oceanic vs. cont. crust
Asthenosphere vs. Lithosphere
Isostasy -- Airy & Pratt
The Continents
The Lithosphere
Continental Drift & Plate Tectonics
The Theory of Continental Drift -- Wegener & various lines of evidence
Sea Floor Spreading -- paleomag, ocean cores/dating, concept of spreading centers
The Plate Tectonics Paradigm
Divergent Plate Boundaries -- spreading centers, ridges, mafic rocks, volcanism
Convergent Plate bdys -- oceanic\oceanic; oceanic\cont; cont\cont; subduction, collision, sutures, relationship to volcanism
Shear Plate bdys -- transform faults, San Andreas
General Conclusions - What does Plate Tectonics Explain?
Impact of Successive Plate Tectonic Events -- old collisions, old continents
Major Continental Features
Trailing Edge -- sedimentary rock cycle, metamorphism upon burial
Leading Edge -- sed, meta, & igneous rx; volcanism/plutonism; subduction; accretionary prism
Sub-Continental Megageomorphic Features
Residuals of previous plate tectonic events -- old suture zones, mountain ranges
Rift Zones
Mountain Ranges & Mountain-Building:
Orogeny (Cordilleran & Cont. Collision) & Epeirogeny
Why are mountains higher? -- Uplift Processes
Cause of Uplift
Isostatic Equilibrium -- glacio- and sedimento-isostatic rebound
Brief Introduction to Tectonism -- bed, stratum, bedding plane, fold, fault, joint
Volcanism
Products of volcanism
lava -- aa, pahoehoe, blocky
pyroclastics or tephra -- ash, lapilli/cinder, blocks, bombs, tuff
volatiles -- water vapor, CO2, sulfur gases, fumaroles, solfataras, geysers/hot springs
Mixtures -- other flows -- nuees ardente, lahar
Igneous Rocks of lava & tephra -- minerals, basaltic vs. rhyolitic magma -- physical properties; basalt/gabbro, andesite/diorite, dacite/granodiorite, rhyolite/granite
Landforms produced by volcanoes
Flood Basalts -- effusive
Central Vent (pipe) Eruptions and Volcanic Cones
Shield Volcanoes -- effusive
Tephra Cones
Composite Cone or Stratovolcano
Plug Dome
Craters & Calderas -- morphometry (3x)
Plutonism : Intrusive Igneous Activity
Rock Types (see above)
Intrusive Forms -- sills, dikes, laccoliths, batholiths
Sedimentary Rocks:
(origin, type of sediments, mineralogy of rock or cement, resistance to weathering)
compaction, recrystallization, dissolution, replacement, authigenesis, cementation
clastic: conglomerate, sandstone, siltstone, mudstone, shale
chemical (& biogenic): rock salt; gypsum; carbonates: limestone & dolomite; chert-flint-jasper; coal
Metamorphic Rocks: (origin, original rock, resistance to weathering): slate, schist, gneiss, marble, quartzite
Weathering
An Exogenic processes
Chemical Weathering
Solution
Hydration
Hydrolysis
Carbonation
Oxidation
Products of Chemical Weathering
Mechanical weathering
Unloading/Dilatation/Exfoliation
Thermal expansion/contraction
Freeze/thaw
Crystal growth in voids
Hydration shattering/expansion weathering
Root Growth
Weathering and its Effects on Landforms
Structure -- fissility, massive rx, granular rx, case hardening, tafoni
Process
Time -- rate of weathering