Geology Review Flashcards

Types of Geology

  • Physical, historical, environmental

Atom Structure

  • Neutron, proton

Chemical Bonding

  • Ionic vs. Covalent
  • Covalent bonds are stronger due to electron sharing, not transferring.

Rock Types

  • Igneous: Formed from magma.
  • Sedimentary: Formed on the surface.
  • Metamorphic: Formed by heat and pressure.

Age Dating

  • Relative vs. Absolute
  • Absolute age dating is more accurate.

Radioactivity

  • Isotope Definition: Atoms with the same number of protons but different numbers of neutrons (e.g., Carbon-12, Carbon-13).
  • Alpha, Beta, Gamma Decay
    • Three forms of radiation.
    • Gamma radiation is the most harmful as it can damage DNA.
  • Atomic Mass vs. Atomic Mass Number
    • Atomic Mass: Protons only.
    • Atomic Mass Number: Protons and neutrons.
  • Half-Life
    • The time it takes for half of a radioactive substance to decay.
  • Parent vs. Daughter
    • Parent material is highly radioactive and decays into the daughter material.
  • Uranium-238 vs. Carbon-14
    • Uranium-238 is better for dating very old rocks.
    • Carbon-14 is suitable for dating relatively young materials like Egyptian mummies.
    • Half-life of Carbon-14: 5,730 years.
    • Half-life of Uranium-238: 1,400,000,000 years.
  • Radioactivity is spontaneous; it occurs on its own.

Fossils

  • Definition: Remains of ancient organisms.
  • Modes of Preservation
    • Permineralization, carbonization, cast and mold
  • William Strata Smith
    • Principle of fossil succession and index fossils.
    • Father of historical geology.

Geologic Time Scale

  • Precambrian, Paleozoic, Mesozoic, Cenozoic Eras

Origin of the Universe and Earth

  • Universe began approximately 14 billion years ago.
  • Earth began approximately 4 billion years ago.

Early Atmosphere

  • The early atmosphere lacked oxygen.

Precambrian Time

  • Represents 87% of geologic time.

Supercontinents

  • Rodenia: First supercontinent.
  • Laurentia: North America.
  • Baltica: Russia.
  • Laurasia: Formed by the collision of Laurentia and Baltica.
  • Gondwana: Southern Pangaea.
  • Pangaea: Formed by the collision of Laurasia and Gondwana during the Late Permian period.

Continental Positions

  • Rodenia was located around the South Pole.
  • Laurentia was near the Equator in the early Cambrian period.

Formation Sequence

  • Laurentia + Baltica = Laurasia
  • Laurasia + Gondwana = Pangaea

Age of Life

  • Paleozoic: Age of invertebrates.
  • Mesozoic: Age of reptiles/dinosaurs.
  • Cenozoic: Age of mammals.

Fossilization

  • Requirements:
    • Hard parts.
    • Death in water.
    • Rapid burial.
    • Survival of chemical transformation (e.g., silicification, pyritization).
  • Preservation of entire skeletons is rare.

Classification of Organisms

  • Six Major Kingdoms: Animalia, Plantae, etc.
  • Binomial Nomenclature: Genus and species (e.g., Homo sapiens).
  • Cladogram: A diagram showing evolutionary relationships.
  • Monophyletic: Having one ancestor for all species.

Uniformitarianism and Actualism

  • Uniformitarianism: The father of all geology, James Hutton, proposed that Earth is very old and changes occur slowly over time.

Laws of Geology

  • Relative Age Dating Techniques
    • Superposition
    • Cross-cutting relationships
    • Lateral continuity
    • Original horizontality

Stratigraphy

  • Bedding Types: Planar and cross-bedding
  • Planar bedding is laid down flat.
  • Cross-bedding is not laid down flat.

Sedimentary Structures

  • Ripple marks: Appear like ripples.
  • Raindrop impressions: Impressions left by raindrops.

Colors of Sedimentary Rocks

  • Red: Desert/Eolian environments.
  • Black: Deep marine environments (except for the Devonian Chattanooga Shale).

Depositional Environments

  • Categories: Continental, transitional, and marine.
  • Subcategories: Eolian (wind), fluvial (river), lacustrine (lake).

Geologic Theories

  • Neptunism: Rocks formed underwater.
  • Catastrophism: Rocks formed violently.
  • Actualism: The principle used today.

Contacts and Unconformities

  • Contact: Separates two different types of rock.
  • Unconformities: Gaps or squiggly lines in the rock record.
  • Correlation: Comparing different stratigraphic columns.

Transgression and Regression

  • Transgression: Sea level rises (sand to limestone indicates deeper water).
  • Regression: Sea level falls (clay to silt to sand indicates shallower water).
  • Cratonic Sequence: A transgression followed by a regression.

Precambrian Eons

  • Hadean, Archean, Proterozoic

Shields and Cratons

  • Very old; from the beginning.

Accretionary Tectonics

  • Land is added on.
  • Greenstone belts and granite-nice complexes were common in the Precambrian.
  • Pillow basalt forms when lava cools underwater.

Life Requirements

  • Oxygen, nitrogen, hydrogen, sun

Stromatolites

  • Living things made of algae.
  • Present during the Archean and abundant in the Proterozoic.

Proterozoic Events

  • Water present, clouds, rain.
  • Banded Iron Formations (BIFs) indicate an early atmosphere.

Early Paleozoic Cratonic Sequences

  • Tippecanoe, Kaskaskia, Absaroka

Orogenies

  • Taconic: Subduction.
  • Acadian: Baltica collided with Laurentia, forming Laurasia.
  • Allegheny: Africa collided, forming the Appalachian Mountains and Pangaea.

Continental Margins

  • Passive: Few earthquakes or volcanoes.
  • Active: Many earthquakes and volcanoes.

Late Paleozoic Events

  • Pangaea formed in the Permian period.
  • Chattanooga Shale: Devonian, black, shallow marine.
  • Cyclothems: Repeating patterns of sea-level rise and fall during the Pennsylvanian period (sandstone, shale, limestone).
  • Vaporites formed in the Permian.
  • Ancestral Rockies: Formed when Africa collided, causing Precambrian rock to uplift.
  • Brevard Zone: Suture zone between Africa and North America.

Paleozoic Life

  • Archaeocyanathids: Cup within a cup; good index fossils for the Lower Cambrian but went extinct in the Middle Cambrian.
  • Sponges: Phylum Porifera.
  • Trilobites: Three lobes.
  • Brachiopods: Two valves, bilaterally symmetrical through the valves.
  • Ostracoderms: Early fish.
  • Corals: Phylum Cnidaria (polyp).
  • Rhizoids: Little creatures living in an apartment complex; lacy bryozoan.
  • Graptolites: Found in the Chattanooga Shale via carbonization.
  • Conodonts: Mystery animal; look like teeth.
  • Acanthodians: Early fish.
  • Placoderms: Armored fish.
  • Ammonites: Coiled or straight with ammonitic sutures.
  • Eurypterids: Sea scorpions.
  • Lycopods: Type of plant.
  • Crinoids: Sea lilies with a crown.

Mesozoic World

  • Breakup of Pangaea: Northern Pangaea broke from Southern Pangaea. Then Gondwana broke up, followed by Australia separating from Antarctica and South America from Africa.
  • Zuni Cratonic Sequence: Highstand in the Cretaceous period.
  • Western Interior Seaway: Divided America into two halves.
  • Laramide Orogeny: Produced many mountains in the West.
  • Mesozoic Formations: Navajo Sandstone, Morrison Formation, Coon Creek Formation.
  • Coon Creek Formation: Found in Tennessee.
  • Morrison Formation: Famous for dinosaurs.
  • Navajo Sandstone: Cross-bedded red sandstone.
  • Climate in the Permian: Very dry.
  • Angiosperms: Flowering plants that made their first appearance.

Mesozoic Life

  • Two Types of Dinosaurs: Saurischian (lizard-hip) and Ornithischian (bird-hip).
  • Mammals: Small during the age of dinosaurs.
  • Scleractinians: Reef-building corals.
  • Coccolithophores: Made of chalk.
  • Diatoms: Made of quartz.
  • Pterosaurs: Flying reptiles.

Cenozoic World

  • Notable Places: John Day Fossil Beds, Badlands of South Dakota.
  • Alpine-Himalayan Orogeny: Formation of the Himalayas.
  • Flood Basalts: Miocene in Washington and Oregon.
  • Rio Grande Rift: Formed during the Cenozoic.
  • Farallon Plate: Subducted; only Juan de Fuca Plate remains.
  • Isostasy: The rise of land after the removal of weight (e.g., melting glaciers).

Quaternary Period

  • Last Ice Age: Pleistocene Epoch.
  • Lewis Agassiz: Studied glaciers and erratics (large rocks in unexpected locations).
  • Ice Advance and Retreat: Occurred four times.
  • Bering Strait Land Bridge: Formed during the Pleistocene due to lower sea levels.
  • Pluvial Lakes: Wetter climate leading to lakes (e.g., Lake Bonneville, now Great Salt Lake).

Cenozoic Life

  • Flourishing: Coccolithophores, foraminifera, corals, echinoids.
  • Marsupials and Placentals: Types of mammals.
  • Isthmus of Panama: Formed in the Pliocene; led to extinction of South American mammals.
  • Mammoths and Mastodons: Extinct mammals.

Primates and Humans

  • Australopithecus: Genus of Lucy.
  • Characteristics: Binocular vision, opposable thumb, canine incisor teeth, bipedalism.
  • Out of Africa: Theory of human origin.
  • Homo Habilis: Early human species.
  • Homo Erectus: Stood upright.
  • Cro-Magnon: Cave painters.