Historical Final Notes

Loss of Banded Iron Formations (BIFs)

Reduction in BIFs due to increased atmospheric oxygen levels, leading to the formation of redbeds on land.

Chlorophyll and atmosphere

Chlorophyll in photosynthetic organisms produces oxygen, altering the Earth's atmosphere during the Great Oxygenation Event.

Heat flow and greenstone belts

Heat Flow of magma in the mantle led to early tectonics that formed the greenstone belts at subduction zones

Mesosaurus and Gondwanaland

Mesosaurus, a freshwater reptile, fossils in South America and Africa support the theory of Gondwanaland, indicating past continental connections.

Coccolithophores and the Cliffs of Dover

Coccolithophores contributed calcium carbonate to form the Cliffs of Dover.

Birds and dinosaurs

Birds evolved from theropod dinosaurs, sharing anatomical features like Archaeopteryx.

Glossopteris flora and plate tectonics

Distribution of Glossopteris flora supports the theory of plate tectonics and the supercontinent Gondwana.

Ring of Fire and subduction zones

Ring of Fire results from active subduction zones causing volcanic and seismic activity.

Ophiolite suite and subduction zones

Ophiolite suites represent uplifted oceanic crust and mantle in subduction zones.

Detrital uraninite and pyrite

Presence in ancient rocks indicates low oxygen levels in the early atmosphere during the Archean.

Neoteny and human evolution

Neoteny, retaining juvenile features into adulthood, may have influenced human evolution. led to traits such as a large brain and reduced facial projection, distinguishing modern humans from their ancestors.

Age of the Earth

Estimated at 4.54 billion years based on radiometric dating of meteorites, lunar rocks, and zircon crystals.

Anoxic atmosphere in the Archean

Evidence includes detrital uraninite, pyrite, and lack of redbeds, indicating low oxygen levels.

Abiotic origin of life

The Miller-Urey experiment demonstrated that organic molecules, such as amino acids, could be synthesized from inorganic precursors under conditions simulating early Earth. Meteorites containing amino acids and other organic compounds suggest that these building blocks of life could form in space and be delivered to Earth. Hydrothermal vent theories propose that life could have originated in the chemically rich environments of deep-sea vents, where energy and raw materials for life were abundant.

Rise of oxygen in Ediacaran time

Evidenced by redbeds, oxidized soils, and disappearance of BIFs. Additionally, biomarkers from Ediacaran rocks show an increase in organisms that require oxygen, reflecting higher oxygen levels in the environment.

Planets beyond the asteroid belt vs Within

The planets beyond the asteroid belt, known as Jovian or gas giants, are primarily composed of hydrogen and helium, have thick atmospheres, and lack solid surfaces. In contrast, the terrestrial planets inboard of the asteroid belt are rocky, have thinner atmospheres, and are composed mainly of silicate minerals and metals, due to their formation closer to the Sun where it was too warm for volatile compounds to condense.

Uniformitarianism

Geological processes occurring today have operated similarly throughout Earth's history.

Actualism

The present is the key to the past, understanding past geological events through modern processes.

Steno's three principles:

1. Principle of Superposition: In an undisturbed sequence of sedimentary rocks, each layer is older than the one above it and younger than the one below it.

2. Principle of Original Horizontality: Layers of sediment are originally deposited horizontally under the action of gravity.

3. Principle of Lateral Continuity: Layers of sediment initially extend laterally in all directions; they are continuous until they thin out or encounter a physical barrier.

-What differentiates the Phanerozoic from the pre-Cambrian?

Phanerozoic Eon is marked by abundant fossil records and complex life forms, including most major animal phyla, while the pre-Cambrian is characterized by primitive life forms and a scarcity of fossils.

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Sediments are deposited horizontally.

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Rock layers extend laterally until thinning or encountering a barrier.

Phanerozoic vs Cambrain

Phanerozoic has abundant fossils and complex life forms, while pre-Cambrian has primitive life and fewer fossils.

Oceanic vs Continental

Oceanic crust is thinner, denser basalt; continental crust is thicker, less dense granite.

Unconformities:

1. Angular Unconformity: Tilted or folded sedimentary rocks overlain by younger, more flat-lying strata.

2. Disconformity: A gap in the rock record between parallel layers of sedimentary rock.

3. Nonconformity: Sedimentary rocks overlying eroded igneous or metamorphic rocks.

Unique conditions for Archaebacteria

Thrive in extreme environments like high temperatures, salinity, and anaerobic conditions.

Index Fossil criteria

1. Distinctive:

2. Globally widespread:

3. Abundant:

4. Limited to a particular geologic time:

5. Robust and preserves well:

Radiocarbon Dating limitation

Effective up to 50,000 years due to carbon-14 decay, unsuitable for dating older geological formations.

Horotely, Tachytely, Bradytely

Evolution at a standard rate (humans),

rapid change (angiosperms),

and slow change (horseshoe crabs), respectively.

Differentiation of Earth's interior

Denser materials sank to form the core, while lighter silicates rose to form the mantle and crust. Heat is transferred by radioactive decay.

Miller Experiment

The Miller Experiment demonstrated that organic molecules, such as amino acids, could form from inorganic precursors under prebiotic conditions, suggesting a possible pathway for the origin of life. Clay minerals can catalyze the formation of more complex organic molecules and provide surfaces for these molecules to assemble into primitive cells.

Meteorites and solar system composition

Reflect the original composition of the solar system and early processes.

Allopatric speciation

Population separation leads to genetic divergence and reproductive isolation. Due to physical or geographic barriers

Lagerstätten

Deposits with exceptional fossil preservation, providing insights into ancient life.

Allopatric vs Sympatric

Allopatric speciation occurs when populations are geographically separated, leading to speciation through physical isolation. Sympatric speciation happens within the same geographical area, often through genetic, behavioral, or ecological differences that reduce gene flow, such as polyploidy in plants or niche differentiation in animals.

Evolution of skeletons

(1) protection against ultraviolet radiation, allowing 

animals to move into shallower waters 

(2) prevent drying out in an intertidal environment (retain moisture)

(3) protection against predators

(4) Location to store minerals in body

(5) Place for muscle attachment to support larger body size

Flysch Phase

Deep-water, turbidite deposits formed in foreland basins during early orogeny stages.

Molasse Phase

Shallow-water and continental deposits, including conglomerates and sandstones, formed as the basin fills and orogeny wanes.

Paradoxides

Trilobite genus from western Europe found in Boston, indicating accretion of European landmass to North America. The Trilobite could not swim across the ocean. ESupporting evidecn of plate tectonics

Taconic Orogeny

Collisional orogeny from Laurentian subducting beneath the Taconic Island Arc during the Ordovician era. Forming a Proarc Foreland Basin, mostly flysch

Stromatolites

Sedimentary structures from microbial mats; Stromatoporoids:Body fossils from reef-building sponges.

Ostracoderms

Jawless fishes with bony armor, skin, and small mouths.

Sepkoski's Evolutionary Faunas

Cambrian, Paleozoic (trilobites, brachiopods, ammonites), Modern.

End Ordovician Mass Extinction

1) Major glaciation occurred during the end of the Ordovician period. This was likely caused by falling carbon dioxide levels in Earth's atmosphere. This eliminated most tropical and warm-water-adapted fauna.

2) When the glaciation period began to end and Earth's temperature warmed up, most cool-water-adapted fauna died off.

Michigan Basin

Contains evaporites in Silurian due to restricted circulation and high evaporation rates.

Eurypterids

Dominant predators in the Silurian.

Catskill Wedge

The Acadian Orogeny formed a clastic wedge deposited in a retro-arc foreland basin, which eroded towards the west.

The Acadian Orogeny formed a clastic wedge deposited in a retro-arc foreland basin, known as the Catskill Delta

Black Shale Deposits

(1) Deep sea deposits: dying of reefs, below photic zone and stagnant water

(2) Worldwide increase of salinity by evaporation condition 🡪 petroleum source

(3) Development of Forests (there now exists a lot more organic matter to contribute to creation of black shales)

Acadian Orogeny Basin

Retro-arc foreland basin formed during the Acadian Orogeny.

Collision between North America and Baltica

Devonian

White Mountains

Formed by igneous intrusions related to the Acadian Orogeny.

Antler Orogeny Basin

Proarc foreland basin formed on West Coast during the Antler Orogeny.

Devonian Reefs

Largest reefs in Earth's history formed during the Devonian period.

Dominant taxa Brachiopods

- Ordovician (Strophomenid),

Silurian (Pentamerid),

Devonian (Spiriferid),

Carboniferous (Productid).

Jaws Evolution

Evolved from gill bars in primitive fishes, with teeth derived from skin denticles.

Devonian Fish

Placoderms, Sharks, Ray-finned fish, lobe-finned fish.

Gilboa Forest

Earliest well-preserved forests, representing the earliest terrestrial tree ecosystems.

Tiktaalik

A transitional organism from fish to amphibians, serving as a missing link.

Alleghenian Orogeny

Collision Euramerica with Africa.

retro-arc foreland basin, mainly just consisted of molasse

Misiispian - Permian

Continued molasse deposition.

Coal Formation

• Compaction

• Removal of the water held within the peat between the plant fragments

• Ongoing compaction: removal of water from the intra-cellular structure of fossilized plants

• Heat and compaction: removal of molecular water

• Methanogenesis: production of methane which removes hydrogen, some carbon and some further oxygen (as water)

• Dehydrogenation: remove of hydroxyl groups from the cellulose and other plant molecules, resulting in the production of hydrogen-reduced coals.

Mississippian Sea Floor

Dominated by Crinoids and Blastoids= Echinodermata

Carboniferous Plants Environments

Wet environments - Ferns, Lycopsids; Spore Spreading Plants

Dry environments - Conifers, Gymnosperms, Canids, Seeded Ferns, Gilboa Forests, Tall Tress, Seed Spreading Plants

Insect Size in Carboniferous

Increased size due to higher oxygen levels in the atmosphere.

Permian Extinction

Caused 90-95% marine taxa extinction due to climate changes and volcanic eruptions.

Permian Floras

Euramerican flora

• Tropical climate

• Equatorial region 

Glossopteris flora 

• Southern Hemisphere (southern latitudes)

• Temperate climate

Siberian (Asian) flora

• Northern hemisphere (northern latitudes)

• Temperate climate

Permian Collision Causes

1. Climate Chage shut off ocean circulation and lead to anoxic water conditions

2. Siberian Trapps eruption of basaltic magma drove up CO2 and caused global climate change

Triassic Orogenies

Nevadan and Sonoma Orogenies on western margins of North and South America.

Triassic Ammonoids

Ceratitids

Placodonts Feeding Behavior

Ate hard-shelled fauna, evidenced by their tablet-shaped teeth.

Dinosaur Groups

Ornithischia Bird Hipped (Herbivores),

Saurischia Lizard Hipped (Herbivores and Carnivores).

Sloss Sea Level Sequences

1. Sauk Sequence: Cambrian to Early Ordovician.

2. Tippecanoe Sequence: Ordovician to Devonian.

3. Kaskaskia Sequence: Mississippian.

4. Absaroka Sequence: Carboniferous

Archaeopteryx

Bird-like dinosaur with feathers, wing-like features, and weak breastbone.

Bird Evolution

Birds evolved from Theropods.

Gastroliths

Stones ingested by animals to aid in digestion.

Ichthyosaurs Dominance

Dominant during the Jurassic period.

Rudist Bivalves

Built large reefs during the Cretaceous period. (unusual)

Cretaceous Extinction

Led to the extinction of non-avian dinosaurs, pterosaurs, ammonites, and marine reptiles.

Paleogene Predators

Mammals replaced raptorial dinosaurs as top land predators.

Isolation of Antarctica Effect

The major factor leading to the build-up of glaciers in Antarctica due to its separation from other continents.

What was the Great American Interchange?

North American Fauna Outcompeted South American fauna after the exchange across the Isthmus of Panama, causing the extinction of native South American fauna.

6 Evidence for Major Glaciation

1. Erratic Boulders

2. Glacial till and basin associated with glaciers 

3. Depression of Land, Hudson Bay

4. Glacial Scouring of low parts of mountain chains

5. Lowering of sea level: glacial expansion caused a drop

6. Migration of Specia across the Bering Strait on land corriors, Changing vegetation in response to climate change

Gorilla Distribution

The modern distribution of gorillas in Africa, mainly in central Africa, supports climate change during the late Neogene, as they were isolated due to the expansion of the Sahara during the last glaciation.

They could not expand after the end of glaciation due to competition with humans

Prairie Potholes

Depressions formed from buried blocks of ice, also known as kettles.

Mega-faunal Extinction Hypotheses:

1. Overkill hypothesis: Human hunting may have led to a mass extinction of large mammals such as American elephants and giant ground sloths.

2. Climate Change Hypothesis: Rapid shifts in climate (younger Dryas) influenced by glacial retreat lead to warming and fluxations. Grasslands changed to prairies.

   
   

   
   

Overkill hypothesis

Suggests that human hunting led to the mass extinction of large mammals like American elephants and giant ground sloths.

Climate Change Hypothesis:

Proposes that rapid climate shifts, influenced by glacial retreat, led to warming and fluctuations, changing grasslands to prairies during the Holocene.

Cyclothem

 During Transgression, witness deposition of marginal marine sediment on top of nonmarine deposits that is capped with marine sediments. During Regression, the sequence is reversed.

Valley - Coal

Transgression - Sandy Shale, Marine limestone,

Peak Offshore Shale

Regression Marine Limestone, Sandy Shale, Non-marine sediments

Valley- coal

Pattern: Coal, Sandy Shale, MArine Limestone, Offshore Shale, Marine Limestone, Sandy Shale, non-marine sandstone, Coal

Oldest Reptile

Carboniferous

evidence is there for a cool climate in the Lower Permian?

• Permo-Carboniferous glacial deposits on all Gondwanan continents (no tillites in northern continents)

• Archaeocyathids in clasts from Antarctica (Archaeocyathids not known in Africa)

  Glacial expansions and fossilized trees at high altitudes.

  
  
  

two separate pulses of extinction at the end of Permian?

1. Climate change shuts off ocean circulation and leat to anoxic water conditions. Killed off many marine taxa.

2. Siberian Trapps Eruption of baltic magma dove up CO2 and caused global cooling and sulfate release > lowering Oxygen

three major lagerstatten in the Cambrian and what important types of fossils do they preserve?

1. Burgess Shale (Canada): Preserves a diverse array of soft-bodied organisms, providing insight into early complex life.

2. Chengjiang (China): Contains well-preserved early arthropods, sponges, and other soft-bodied creatures.

3. Green River Formation: Fossil Palm Trees

What are biomeres?

intervals in the fossil record marked by abrupt changes in the dominant groups of marine organisms,

usually associated with extinction events.

 Wopmay Orogeny? When did it occur? What does it tell us about the size of continental landmasses at this time?

Proterozoic Eon

is one of the earliest well-documented orogenic events,

providing evidence of ancient plate tectonic processes.

It indicates the existence of sizable continental landmasses and supports the theory that plate tectonics operated in the Proterozoic.

Eukaryotes using diagrams

 a proto-eukaryotic cell engulfed aerobic bacteria, leading to the formation of mitochondria.

Later, similar events with cyanobacteria gave rise to chloroplasts in photosynthetic eukaryotes.

These endosymbiotic events led to complex cellular structures and the diversity of eukaryotic life.

significance of complex trace fossils in the preCambrian Belt Group

 indicate the presence of multicellular, motile organisms before the Cambrian Explosion.

These fossils provide evidence of early animal life and complex behaviors, such as burrowing, suggesting the evolutionary experimentation

Ediacaran fauna

earliest known complex multicellular life forms, dating back to about 635-541 million years ago.

provide crucial insights into the pre-Cambrian biota and the early evolution of complex life,

showcasing a variety of unique body plans and ecological strategies

bilateral symmetry

Sepkoski’s three evolutionary faunas

1. Cambrian Fauna, 

2.  Paleozoic Fauna - including taxa such as trilobites, brachiopods, and ammonites

3. Modern Fauna

   
   
   

major changes occur in the terrestrial environment during the Devonian?

1. Plants begin to grow on land

2. Rooted plants keep soil intact

3. Tall tree and forest ecosystems begin to form

4. Plants become food for the expansion of land dweller fauna

List and explain the differences between the major orogenies the formed the Appalachian Mountains.

1. Taconic – peripheral foreland basin, Ordovician. Destruction of the Ordovician-Cambrian carbonate platform and development of a peripheral foreland basin with a flysch and molasse deposition. No Collision (collides with island arc, but not a continent).

   
   
   

   2. Acadian – retro-arc foreland basin, Devonian. Destruction of the Siberian-Devonian carbonate platform and development of a foreland basin with a flysch and molasse deposition. Collision Laurentia with Baltica and North America with Avalonia.

   
   
   

   3. Alleghenian – retro-arc foreland basin, mainly just consisted of molasse (above sea level when depositing sediment), Pennsylvanian – Permian. Continued molasse deposition. Collision Euramerica with Africa.

   
   
   

 Evidence is there for aridity during the early Jurassic in North America?

Large salt deposits dating from the Jurassic represent areas of high aridity,

Ichthyosaurs dominant?

Jurassic