GEOL 11 - LE 1 REVIEWER - common for geology to

deal with both

Introduction to Geology small-scale and
large-scale features
What is Geology? - Differences in scale
- “Gē”: Earth + “logia” study could have
- Study of the earth, form, structure, consequences such as
composition and history hazards
- First used in publications by Jean - Indicate scale, whether
André Deluc and Horace-Bénédict de small or large
Saussure, but only became well ➢ Micro vs macro
received in the Encyclopédié (1751) by - Observed under a
Denis Diderot petrographic
microscope
Geology as a Discipline ➢ Local vs regional
● Relevance of time ● Complexity of replicating natural
- Geology deals a lot with time systems & phenomena in the
- If we squeeze in all of Earth’s laboratory
history in 24 hours, humans - Many phenomena cannot be
have only been around for 17 replicated in the laboratory
seconds - Modeling large-scale
- Geologic time scale phenomena using accessible
objects and controlled analogs
- Analogs can often encounter
minor problems or inaccuracies
due to the complexity of natural
phenomena
- Indeter Tectonic model of
Tapponier explains the current
regional tectonics and relative
position of India, mainland
Eurasia, and neighboring plates,
using an indenting block analog
- Models, simulations
➢ Remote sensing data to
map alteration zones
➢ Magnetic data to
identify possible
porphyry targets
➢ Gravity data to
delineate possible faults
➔ To determine
crustal
thickness
➢ Geochemical data to
● Issue of scale determine the
➢ Small vs large provenance and
tectonic setting of
clastic rocks
 ➢ Seismic data to - Remains unchanged in between
delineate deformation these periods of upheavals
features within the - Widely accepted by theologians
Manila trench region in the early 1800s since it is
similar with biblical events (e.g.
Divisions of Geology Noah’s ark)
● Physical Geology ● Uniformitarianism
- Earth’s composition and - Proposed by James Hutton in
processes the 18th century
- Mineralogy, Petrology - The Earth is continuously
- Geomorphology, Structural modified by geology processes
Geology, Tectonics, Volcanology that have always operated (at
- Geochemistry, Geophysics, different rates)
Seismology - James Hutton (1726-1797)
- Marine Geology, Planetary Father of Modern Geology
Geology - “The present is the key to the
● Historical geology past”
- Origin of Earth, origin of life, - Popularized by Charles Lyell
and changes in Earth through (1797-1875) in his book,
time Principles of Geology
- Layered rock records and fossils - The Earth has been around for
- Geochronology a very long time, as opposed to
- Paleontology, Stratigraphy the bible
● Applied and Inter/Multi-disciplinary - Examples of things that took a
- To solve human problems long time: continental drift,
influenced by geological India’s collision with Eurasia,
factors Baguio’s uplift to its present
- DRRM, Engg. Geology, Envi. configuration, the formation of
Geology, Geological and the Philippine archipelago
Geophysical Hazards,
Paleoclimatology, Quaternary Advances in Geological Research
Geology ● Developments in field methods,
- Energy Resources, laboratory, techniques, and equipment
Economic/Ming Geology, (hardware & software)
Hydrogeology, Petroleum ● Developments in experimental and
Geology numerical/quantitative modeling
- Biogeosciences, Forensic ● Advances in technology
Geology, Geoarchaeology, ● Availability of datasets and
Medical Geology, Remote remote-sensing data
Sensing and GIS ● UAVs in Geosciences
● Robot Geologists
Early schools of thought in Geology
● Catastrophism
- Proposed by Baron Georges The Universe and the Earth
Cuvier in the 16th century
- Catastrophes are the agents of Big Bang Theory
change that alter physical - Universe began as a hot and infinitely
features of the Earth dense point
 - 13.7 billion years ago, this singularity ● Terrestrial planets evolved their
exploded secondary (Venus and Mars) and
tertiary (Earth) atmospheres
Nebular Hypothesis
● A cloud of dust and gas (composed of
75% Hydrogen, 24% Helium) became
unstable. Gravity pulled the dust and Size and shape of the Earth
gas to the center of the cloud → ● Shape: oblate spheroid
spherical shape - because equatorial and polar radii are
● Size of cloud decreased in size → not equal
collapsing cloud increased its rate of ● Equatorial radius: 6378 km
rotation. This is based on “the ● Polar radius: 6357 km
conservation of angular momentum” ● Volume: 1,083,206,916,846 km^2
● Increased rotation caused change in ● Density: 5.53 g/cm^2
shape, flattened at the rotational poles ● Total surface area: 509,600,000 km^2
thus, becoming disk shaped. Rotating ● Area of land: 148,326,000 km^2
disk became the “solar nebula” ● Area of water: 361,740,000 km^2
● As cloud collapsed, gravitational energy ● Age: 4.5 to 4.6 B yrs
released, heating the central portion of
the nebula forming a protosun Internal structure and composition
● Condensation was occurring within the - Variations due to density sorting
disk surrounding the sun. Because of - Layers formed as Earth became molten
varying temperatures at different mass
distances from the sun, different - Densest material, containing iron and
materials condensed at different nickel, settled in the core
locations - Less dense material, containing
● Closer to the center → High temp, Iron iron-rich materials, rose to surface
and Silicates form (C.H.I.S.) forming crust
● Farther from the center → LOw temp,
Hydrogen, Water, and low temp How were the layes within the Earth
condensates form (F.LO.H.W) discovered?
● Collisions between condensed particles - Geophysics
caused planetesimals → planets and - Seismic waves
moons. Violent process of formations is - Andrija Mohorovicic
evident by cratered surfaces of Mercury ➢ Seismograms from
and our Moon. shallow-focus earthquakes had
● Heat generated by impacts and by 2 sets of P-waves and S-waves
radioactive decay of elements resulted ➢ Used info from velocity to
in molten planets calculate depth of the Moho
● Evolving star at the center passed discontinuity
through a T-Tauri star at which it
released bursts of energy. These bursts Layers of the Earth
swept light element (e.g. hydrogen from ● Crust - ~3-70 km thick
outer to inner solar system where it is ➢ Oceanic - basaltic, Si Mg,
swept up by distant jovian planets denser
● Young protosun hot enough to ignite ➢ Continental - granitic, Si Al,
hydrogen in its core. Thermonuclear less dense
reactions in the core is what ● Mohorovicic discontinuity
distinguishes a sun from a protosun
 ● Mantle - ~2900 km deep; rich in ● Fossils
perovskite ● Rock types and structures - same rocks
➢ Upper mantle - ultramafic rock, on landmass on opposite sides of a
peridotite body of water
● Gutenberg discontinuity ● Paleoclimates evident - glacier and coal
● Core - iron-rich, 3486 km radius deposits
➢ Outer core - convection of
conducting liquid includes a Seafloor Spreading
magnetic field; 2270 km thick; - Introduced by Harry Hess (1960s)
liquid Fe and Ni -
● Lehmann discontinuity
➢ Inner core - solid Fe and Ni,
1216 km radius

Mechanical layers
● Lithosphere
- Crust and uppermost mantle
- ~100-250 km thick
- Plates
- rigid
● Asthenosphere
- Upper mantle
- Ductile
● Mesosphere
- Rest of the mantle
- Rigid

Large scale features

● Wilson cycle - opening and closing of
an ocean basin

Isostasy
● Airy model
- Have roots
- Depth and root are proportional
● Pratt model
- Higher elevation, lower density

Tectonics
Continental Drift
- Alfred Wegener “The Origin of
Continents and Oceans:
- Pangaea
Evidences:
● Jigsaw puzzle