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.