Welcome to GEO 101 Introduction to...
Transcript of Welcome to GEO 101 Introduction to...
Welcome to GEO 101
Introduction to Geology
… so what is Geology?
… not just rocks!
Geology is ...study of Earth and planetary bodies
processes responsible for formationprocesses that modify
all areas of geology have either economic or environmental importance:
earth resourcestopography (study of landforms and processes responsible for their formation) natural hazards (floods, volcanism, earthquakes) waste disposal and pollution cleanupclimate change
mineralogy - petrology - geochemistry - volcanologystratigraphy - sedimentology - paleontologygeomorphology - surficial geology - hydrogeologystructural geology - tectonics - geochronologysolid-earth geophysics - rock mechanics
Geology is a physical science with many sub-areas of study or sub-disciplines:
environmental and groundwater use (environmental geology)oil and gas exploration and exploitation (petroleum geology)metal and non-metal mineral exploration and exploitation (economic geology)
Geology is also an applied science that interfaces with engineering and deals with:
... so what is the modern context in which we will
be examining Earth?
a system of various subsystems or related parts (atmosphere, hydrosphere, biosphere, and solid earth) interacting in organized fashion
The Dynamic Earth
LayersCrustMantle
upperlower
Outer coreInner core
du
ctileb
rittle
asthenosphere
lithosphere
initially homogeneous, but with cooling separated into distinct concentric layers:
Layer Thickness NatureInner core 1216 km solid iron-nickel alloyOuter core 2270 km liquid iron-nickel alloyMantle ~2885 km solid (Mg-rich silicates)
upper (shallow) - intermediate densitylower (deep) - high density
Crust ≤65 km solid (low to intermediate density silicates)
Oceanic Crust (5-10 km) - high density (Fe-Mg rich)Continental Crust (30-65 km) - low density (Fe-Mg poor)
igneous - formed by cooling and solidification of molten rock (magma)sedimentary - formed by precipitation from solution, compaction of plant and animal remains, or cementation of particles from pre-existing rocksmetamorphic - formed below surface under high temperatures and pressures from pre-existing rocks
solid Earth composed of rocks divided into three groups based on mode of formation:
different rock types related to each other by: rock cycle
Geologists interrelate Earth processes, rock
types and physical features through global
pattern of change described by what has
become known asPlate Tectonic Theory
Earth's brittle outer shell or lithosphere (crust and uppermost mantle) broken into
coherent pieces or plates that move slowly over the ductile asthenosphere
three major plate boundary types marked by earthquakes, volcanism, or both
plates move
apart from each
other with gap filled by molten
rock creating
new crust
divergent plate boundary
separation marked by long mountain ranges on ocean floors and deep linear
valleys (rift zones) on continents
Mid-AtlanticRidge
East PacificRise
IndianRidge
IndianRidge
Rio GrandeRift
East AfricaRift
convergent plate boundary plates move toward
one another and where crusts of adjacent plates have different
densities, denser plate is forced
down or subducted beneath other
plate convergence with oceanic crust subducted beneath lower density continental crust
plate convergence
with oceanic crust subducted beneath oceanic crust
plate convergence of continental crust against continental crust
marked by mountain belt or subduction zone with deep oceanic trench, volcanism
and inclined earthquake (Benioff) zone
plates slide past one another
transform plate boundary
crust neither created nor destroyed(earthquakes but no or extremely limited
volcanism)
Plate boundary CharacteristicsBoundary Topography Igneous Metamorphic Sedimentary Earthquakes
divergent-types
ocean MOR basalt hydrothermal deep ocean shallow
continent cont. rift basalt & rhyolite
low-T/low P coarse clastics
shallow
convergent-types
continent-continent
mountains granites high-T/low P regional
clastics shallow intermediate
deep
continent-ocean
volcanic arc & trench
andesite high-P/low T regional
clastics shallow intermediate
deep
ocean-ocean
volcanic arc & trench
andesite high-P/low T regional
clastics shallow intermediate
deep
transform-types
ocean very little none/limited basalt
none none shallow
continent very little none/limited basalt
none none shallow intermediate