EARTH SCIENCE EXAM 3

Principle of Uniformitarianism

“the present is the key to the pass”

Presented by James Hutton

geological processes observed today operated similarly in the past.

• Geologic time

Time the earth has formed

4.6 billion years ago

• Relative age

Tells which rocks are older or younger

Wont tell how old

o Principles used to determine relative age

Cross cutting, superposition and og horizontally

• Geologic column/stratigraphic column

Diagram of sequence of rock layers

• Fossil record/fossil succession

Fossil record: collection of all known fossils, shows how the earth has changed over time

Fossil Succession: different kinds of ways fossils appear in rocks

• Isotopic (radiometric/numeric) dating

Used to find the actual age of rocks

o What does it tell us?

How old rocks are

o Types of rocks that can be numerically (radiometrically) dated

Igneous and Metamorphic

o Half-life

Time it takes a element to break down

o Isotopic dating techniques

Carbon 14 dating, Uranium lead, Potassium Argon

• Age of Earth

4.6 billion years

• Formation of continental crust

Formed from magma and the tectonic plate process

Thicker, less dense and is older than the oceanic crust

o When?

4.6 billion years ago

• Early life

Started in ocean, single cell organism

o First single-celled organisms

Appeared 3.4 billion years ago

prokaryotes

o Stromatolites

layered structured from cyan bacteria

o Fossilized bacteria

preserved remains of ancient bacteria

• Great Oxygenation Event

Atmospheric oxygen level increases

Ocean became more saturated with oxygen and precipitated iron oxide

o When was the great oxidation event?

2.4 - 1.8 GA

• Cretaceous Period

Warming climate, Atlantic ocean formed and India was moving towards Asia

Types of animals becoming extinct?

Non- avian Dinos, Marine reptiles

Types of animals emerging?

Mammals, birds, insects and marine life

Temperatures?

Warm

Effects of rising sea levels

Cover of continents

Continental collisions

Two tectonic plates collide

• Hydrocarbons (what are they?)

Chain/ ring like structures of carbon and hydrogen atoms

Natural gas, Oil and tar

Hydrocarbon source rocks

Formation begins when organic debris settle with clay

heat and pressure turns them into clay

Higher temps turns into oil and gas/ seeps upward

Hydrocarbon reserves

forms in rocks with high porosity and permeability

Porosity and permeability

Porosity: % of empty space

Permeability: liquid flow through rocks

Conventional hydrocarbon reserves (those that can be pumped with relative ease)

Oil and natural gas that can be extracted using traditional methods

Hydrocarbon traps

geological structures that stops oil and gas from escaping the surface

Anticline trap, fault trap, salt-dome trap, stratigraphic trap

Anticline trap: rocks fold upward into arch trap

Fault trap: movement along the fault line

Salt- dome trap: salt rises

Stratigraphic trap: Change in rock/ not by folding or layers

Unconventional hydrocarbon reserves

Oil and gas can'‘t flow easily needs special extraction methods

▪ Oil shale, tight oil/gas, tar sands

Oil shale: solid organic matter, must be heated for oil extraction

Tar sands: sand, clay and water heated or diluted to extracted oil

Tight oil/gas: low permeability rocks, fracking to extract oil

Coal

remains of plants

Formation of coal

Forms from organic materials that die and fall into water with low oxygen content

Nuclear Energy

energy released in atoms during fission

Renewable energy

comes from natural sources

Geothermal energy, hydroelectric energy, wind power, solar energy

Geothermal energy: harnessing the earth internal hear

Hydroelectric energy: use of flowing water to generate electrical

Wind power: use of wind to make power

Solar power: use of sun rays to produce heat and energy

Mineral resources

Natural substance used for industry, construction or energy

Metallic, non-metallic and energy materials

Metallic mineral resources

Iron, copper, gold

Ore minerals

Iron, copper and aluminum

Formation of ore deposits

When minerals concentrate

• Magmatic deposits, hydrothermal deposits, seafloor massive sulfide

Magmatic deposits: forms from cooling magma

Hydrothermal: from hot, metal- moves through rocks

Seafloor: from underwater thermal vents

secondary enrichment, sedimentary deposits, placer deposits,

residual deposits

Extraction techniques (strip mining, underground mining)

Nonmetallic mineral resources

Generation of relief and associated processes

Landforms – definition/examples

Hydrologic Cycle – Define

Reservoirs and relative amounts stored in each

Mass Wasting

Types and characteristics (from slides)

Factors that increase/decrease risk of mass wasting

• Unconformities,

gap in the geologic record represented by a period of time nor represented by strata, called a hiatus

Nonconformities

younger sedimentary rocks over older igneous and metamorphic rocks

Disconformities

Beds below and above the gap in time and they are parallel 

Hadean Eon

4.54 - 4.0 GA

The earth accumulated from smaller planetesimals

Archean Eon

4.0 - 2.5 GA

Ocean formed, Atmosphere became primarily nitrogen
▪ Plate tectonics began.
▪ Continental crust appeared.
▪ Early life appeared

Proterzonic Eon

2.5 Ga to 541 Ma
▪ Great oxygenation
event (2.4 Ga)
▪ Banded iron
formations (BIF)
▪ Formation of large
continents
• Rodinia
• Pannotia
▪ Eukaryotes developed.
▪ Snowball Earth

Phanerozoic

541 Ma to present
▪ Shell fossils abundant
▪ Increased oxygen in the
atmosphere
▪ Subdivided into eras
• Paleozoic: 541–252 Ma
• Mesozoic: 252–66 Ma
• Cenozoic: 66 Ma–present