Term
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Definition
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Term
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Definition
-The solar system formed ~5.0 BYA from a giant spinning cloud of gas and dust or a NEBULA
-Solar winds drove lighter elements and frozen gases outward into space
-Cold matter collected in eddies
-Particles began to accrete and form proto planets, then eventually planets |
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Term
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Definition
-Gravitational Contraction
-Bombardment of early earth by meteorites
-Radioactive decay |
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Term
| Gravitational Contraction |
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Definition
| The increased gravity of Earth, due to accretion, caused it to shrink in size which through friction produced great amounts of heat. Raised earths internal temperature to ~1500 |
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Term
| Rocky/Terrestrial Planets |
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Definition
-Mercury, Venus, Earth, Mars
-Composed of rock and metal
-Contain heavier elements
-Average Density 5.1-5.5 g/cm^3 |
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Term
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Definition
-Jupiter, Saturn, Uranus, Neptune
-Composed of lighter elements, H and He
-Average density 0.7-1.7 |
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Term
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Definition
-The orbit of planets around the Sun is on the same plane and in the same direction
-The rotation of most planets is the same direction
-The orbit and rotation of most moons about their planets are the same |
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Term
| Planetary Differentiation |
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Definition
| Shortly after the Earth accreted, the homogenous planet differentiated into layers based on density |
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Term
| Oldest Rocks and Minerals |
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Definition
-Oldest whole rock is 4.0 Ba
-Oldest mineral grains (detrital zircons) 4.2 Ba |
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Definition
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Term
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Definition
-The moon is believed to have formed when a proto planet collided with the Earth.
-Oldest moon rocks dated 4.4-4.5 Ba |
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Term
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Definition
| Aged 4.53-4.58 Ba also show age of the Solar System |
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Term
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Definition
-4.0-2.5 Ba
-Earths crust became stable enough that rocks were preserved
-Plate tectonics began
-Atmosphere became oxygenated |
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Term
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Definition
-Stable interior portion of continents
-Contain the oldest rocks |
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Term
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Definition
| The areas that are subject to mountain building (orogeny). They surround cratons |
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Term
| Cordilleran Orogenic Belt |
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Definition
| Runs from Alaska to Patagonia. Means backbone. |
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Term
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Definition
| A pile of sedimentary rocks that cover a craton |
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Term
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Definition
| The stable igneous and metamorphic rocks below the platform in a craton |
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Term
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Definition
Section of a craton that is exposed. Exposed precambrian rocks.
-Greenstone Belts
-Granite Gneiss Complexes |
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Term
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Definition
-Represent Archean ocean crust
-Composed of mafic rocks that have altered to chlorite
-Form at convergent boundaries (Back Arch Basins)
-Deformed turbidites
-Contain Pillow basalts |
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Term
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Definition
| A deposit representative of a turbidity current |
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Term
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Definition
| Sandstone with a high percentage of mud and other heterogeneous particles. Indicative of Islands |
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Term
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Definition
-Felsic
-Early remnants of continental crust
-Surround and intrude Greenstone Belts
-Form at convergent boundaries |
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Term
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Definition
| Areas that form behind some subduction zones where the crust is stretched and new basaltic crust is formed in the cracks left behind. |
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Term
| Greenstone Belt Preservation |
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Definition
-Closing of Back Arch Basins due to compression preserves Greenstone Belts
-Preservation is also due to the difference in plate tectonics in the past
-There where more subduction zones, and convection was more rapid |
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Term
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Definition
| Isotopic evidence for photosynthesis is evident 3.8 Bya |
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Term
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Definition
-Bacteria that photosynthesize
-Can live almost anywhere there is sunlight and moisture
-Can live alone or in colonies
-Filaments found in fossils 3.4-2.5 Bya |
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Term
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Definition
| Filamentous entangled microorganisms that form on top of sediments |
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Term
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Definition
Reefs formed by microbial mats that become lithified and grow upward
-Precipitate Calcium Carbonate
-The living part is on the surface
-Have a layered internal structure
-Form in hypersaline environments
-Verycommon from 3.0 Bya till end of the precambrian |
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Term
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Definition
Proteins-Amino Acids
DNA/RNA-Nucleic Acids |
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Term
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Definition
-Produced amino acids in labs
-Mixed CH4, NH4, O2, and N then added a spark (energy)
-Not accurate to early atmospheric conditions |
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Term
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Definition
-May have formed in deep ocean vents
-Amino Acids may have come from meteorites (have been found on them)
-Clay minerals have been hypothesized to have served as scaffolding or templates for assembling proteins
-No self replicating life has ever been produced in Laboratory |
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Term
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Definition
-Likely composed of H and He
-Solar winds likely blew those away because earths magnetic field had not yet formed |
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Term
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Definition
Likely composed of volcanic gasses (H, N, H2O, CO2)
-Outgassing due to differentiation |
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Term
| Detrital Pyrite and Uraninite |
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Definition
-Unstable on earths surface, degrade rapidly if exposed to O2
-If O2 were present in past atmospheres, these would not have survived
-Disappear around 2.5 bya |
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Term
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Definition
-Altering bands of Hematite, an iron rich mineral, and Chert, a quartz mineral
-Proterozoic
-Marine sediments, formed in oceans
-97% of iron ore in US comes from BIFs
-Indicative of a time when O2 levels began to rise |
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Term
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Definition
-Sandstone and shale beds that are red due to the presence of iron oxide
-terrestrial deposits, common in rivers |
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Term
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Definition
-2.5-542mya
-Atmosphere rich in O2
-First eukaryotic and multicellular organisms
-first large continent assembled
-First ice age
-Mature siliciclastic sediments accumulate
-Limestone beds become widespread |
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Term
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Definition
-One of the first large continents, assembled by a series of collisions
-Contained much of what is now North America, Greenland and Scotland |
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Term
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Definition
-Supercontinent formed in the mid-Proterozoic when Laurentia collided with other large continents
-Means "Motherland" russian |
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Term
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Definition
-First eukaryotes, single celled, comparible to modern eukaryotes,
-Eukaryotes reproduce sexually and hav a nucleus
~1.6 Bya |
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Term
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Definition
Organelles such as mitochondria and chloroplasts were once bacteria that took up residence in other cells
-Symbiotic Relationship
-Organelles have cytoplasm and their own DNA
-DNA of mito and plast resemble that of Bacteria |
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Term
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Definition
Fossils found in australia of soft bodied organisms, believed to indicate a period of rapid climate change at the end of the Proterozoic
-Evolved in isolation, in melt pools on snowball earth |
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Term
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Definition
-Sun was weaker during the Precambrian
-Evidence of 2 glaciated periods, 2.4 BYa and 700-600 MYa(snowball Earth) |
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Term
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Definition
| Rivers of ice that flow by their own weight |
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Term
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Definition
| Poorly sorted sediment that is left behind by receding glaciers |
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Definition
| Glacial till that has become lithified |
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Term
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Definition
| Sediment carried by icebergs, and deposited elsewhere |
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Term
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Definition
700-600 MYa when the earth was entirely glaciated
-Suns luminosity was 90% of its current value
-Lower greenhouse effect
-Rodinia was situated on the equator, which increased earths albedo
-Increased chemical weathering due to the large continent drew down more CO2
-Ended by volcanic eruptions that delivered enough CO2 to swing earth out of ice age
-Shown by glacial tillites and dropstones followed by limestones |
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Term
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Definition
542-251 MYa
-Rodinia breaks up then reforms as Pangea
-Sea level was much higher
-Life in the oceans diversifies and land is colonized |
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Term
Epeiric Sea
(Epicontinental Sea) |
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Definition
Seas on top of continental crust
-usually very shallow
-Yellow sea (china) Hudson Bay (canada) |
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Term
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Definition
-NA craton has been covered by epeiric seas 6 times during the Phanerozoic Eon
-Shoreline transgressed
-Deeper water facies deposited on shallower water facies
-Observed 6 transgressive sequences recording sea level rise separated by unconformities |
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Term
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Definition
| A landward shift of shoreline due to sea level rise |
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Definition
| A layer of Limestone on top of mudstone on top of sandstone records transgressions |
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Term
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Definition
| Can occur because the level of the sea bed is changed by relative accumulation or by sediment compaction or by fault movement |
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Term
| Global (Eustatic) Sea Level Change |
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Definition
-The volume of water stored in oceans changes
-The capacity of the ocean basins changes
-Rising at 3.5 mm/yr.
-Warming of oceans can cause water to expand |
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Term
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Definition
Chemical weathering of silicate minerals such as feldspars scrub CO2 out of the atmosphere
-Weathering produces bicarbonate ion which is transported to and stored in the ocean |
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Term
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Definition
| Rising coastlines near convergent boundaries can cause local regression of sea level (Alaska) |
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Term
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Definition
| Land sinking due to tectonics or oil extraction causes transgression (Galveston, TX) |
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Term
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Definition
-Around 535 mya variety of fossils diversifies rapidly
-Almost all phyla of invertebrates appear
-Hard and Soft bodied animals preserved |
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Term
| Cambrian Explosion Explanations |
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Definition
1. Increased O2 levels (not likely)
2. The expansion of habitats due to transgression
3. Advent of predation |
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Term
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Definition
-organisms produce minerals to harden their bodies
-Began at the end of the proterozoic |
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Term
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Definition
-(Strange Shrimp) Early predator found in Burgess Shale
-Got as big as 1 meter
-Preyed on trilobites |
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Term
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Definition
-Most likely explanation of the Cambrian Explosion
-Lead to development of external skeletons and improved locomotion
-Accelerated the pace of evolution |
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Definition
-Discovered in 1909 by Charles Walcott in BC
-Mid-Cambrian in age
-Contains unusual assemblage of soft bodied organisms
-Preserved by a piece of reef that collapsed and was buried in mud in deep O2 deficient waters |
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