GEOLOGICAL PRINCIPLES
Nature of
matter
Elements
& atoms
92
naturally occurring elements
structure
of atoms and the nucleus
isotopes -
stable and unstable
Combining
atoms - compounds and atomic bonding (briefly) ionic, covalent
Atomic
structure of gases, liquids, solids
Difference
between these
amorphous
versus crystalline solids
Minerals & Rocks
"Naturally
occurring, crystalline solid with a definite (not necessarily fixed) chemical
composition"
Distinction
between minerals sensu stricto and mineraloids
Silicates
atomic
structure of silicates; silica tetrahedron
single
twin
ring
chain
sheet
framework
other
mineral groups
oxide,
hydroxide, sulfides, carbonates, phosphates etc.
Crystallization
of minerals:
from
melt, from solution, in a living cell, recrystallization from previous minerals
Rocks
as aggregates of minerals
Nature
and origin of rocks: igneous, sedimentary, metamorphic
Igneous
Magma; volcanic and plutonic rocks; accompanying fluids
Sedimentary
Clastic(detrital) sst etc.
Chemical: evaporites, some limestones
Biogenic
(biochemical) : limestone, cherts,
coal
Metamorphic
Contact; Regional
Geologic time
Stratigraphy
telling
geological time in sedimentary
rocks
superposition
unconformities
use
of fossils
the
Geological time
scale (eras, periods, epochs etc)
Isotopic
(radioactive) age determination of
measuring
geologic time in years in igneous and metamorphic rocks
isotopes,
radiactive decay, parent and daughter elements, half-lives
Methods
Rubidium
Strontium 87Rb -> 87Sr half-life
47, 000 millionyears
Potassium
Argon 40 K
-> 40Ar half
life 1300 million years
Uranium
Lead Complex
Results
of dating
The
age of rocks and of the Earth
Overview of the Earth:
Whole
Earth
size,
internal structure
and composition
Lithosphere
and crust
structure
and composition
DYNAMICS OF THE LITHOSPHERE: plate tectonics
Plate
tectonics; ( link 1, link2)
basic
ideas
Plate
boundaries:
divergent
(spreading): sea floor spreading; formation of oceans
convergent
(subduction): trenches, subduction, volcanoes
transcurrent(transform):
Origin
of igneous rocks at plate boundaries and within plates
association
of igneous provinces with plate boundaries; hot spots; pressure release
(divergent and hot spots) & water (convergent)
Continental
drift: Continental break up and rifting; continents as
passive riders on plates; breakup of Pangea
Mountain
building:
closure
of ocean;
obduction
of ophiolites (ancient ocean);
folding
and faulting;
thickening
of continental crust and uplift
Surface processes
Weathering
–
process
of breakdown of bedrock
chemical: oxidation, hydrolysis
(silicates to clay minerals)
regolith
and soil formation
mechanical
Regolith
and soil
Erosion
-
removal
of regolith and soil
agents
of erosion (denudation) - gravity,
running water , ice and wind
Agents
of erosion:
Gravity:
landslides etc
Water: rivers, drainage basins; ability of running
water to carry particles of sediment. point bar deposits, deltas
Ice: present day glaciers; past glaciations and
interglacials; glacial sediments
Wind:
importance in deserts & coastal areaes; dunes; loess