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North Dakota State University *
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Geology
Date
Dec 6, 2023
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docx
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Uploaded by HighnessRavenMaster978
1. The Archean Eon
What is the hypothesis for the origin of the moon in early Earth's history?
The Moon formed during a collision between the Earth and another small planet, about the size of Mars. The debris from this impact collected in an orbit around Earth to form the Moon.
What is the origin of gasses in the atmosphere and water?
The gases came from volcanic eruptions and comets. Nitrogen, carbon dioxide, hydrogen, and water vapor, or water in gas form, were in the first atmosphere.
What is partial melting and how was it involved in the formation of the oldest continents?
Partial melting is the transformation of some fraction of the mass of solid rock into a liquid as a result of decompression, heat input, or the addition of a flux. The resulting liquid is called magma and becomes lava if it erupts from a volcano. Multiple volcanic eruptions built islands and made what are the continents today.
When in time did plate tectonics begin?
2.8 Billion years ago.
What are prokaryotes and stromatolites? What do they indicate about life in early Earth's history?
Prokaryotes are all single-celled organisms that lack membrane-enclosed nuclei and organelles. Stromatolites are microbial reefs created by cyanobacteria. They indicate that it is very simple. They did not need oxygen telling us that there wasn't oxygen.
What are banded iron formations? What do they indicate about oxygen in early Earth's history?
Banded iron formations occur when oxygen from the air is attached to metals and
rusts them. They indicated an increase in oxygen in the air.
2. The Proterozoic Eon
What are cyanobacteria and eukaryotes? When do they appear in the rock record?
Cyanobacteria are microscopic bacteria that live in all types of water bodies. Eukaryotes are any cell or organism that possesses a clearly defined nucleus. They appeared 2.1 billion years ago.
How did eukaryotes evolve from prokaryotes?
Through endosymbiosis.
What are metazoans? When do they appear in the rock record?
Metazoans are the first animals. They appeared 900 million years ago.
What are Ediacaran animals and why they are significant? When do they appear in
the rock record?
Ediacaran animals are the first marine creatures, and they’re significant because they’re the first soft-bodied creatures. They appeared 635 to 541 million years ago.
What are orogens, cratons, and provinces? How were they involved in the formation of Laurentia?
Orogens are mountain-building areas. Cratons are original pieces of the
continent and the first pieces of Earth's continental crust. They are involved by starting with cratons then different orogenies occur and form Laurentia.
What is the difference between Laurentia and Rodinia?
Laurentia was/is North America, and Rodinia was the first supercontinent.
3. Snowball Earth
When in geologic time did the Sturtian and Marinoan Snowball Earth events (a.k.a., global glaciations) occur?
Sturtian occurred 720 to 710 million years ago and Marinoan occurred 660 to 635
million years ago.
How long did each global glaciation last?
10 to 25 million years.
What rock types were deposited during Snowball Earth events?
Volcanic rocks and glacial sediments.
What rock types were deposited in oceans after the end of each Snowball Earth event?
Not a fuckin clue tbh…
Describe the “Faint Young Sun” hypothesis and the ice-albedo feedback hypothesis in terms of how each may have contributed to the runaway cooling of the Earth, eventually leading to a Snowball Earth event.
The Sun was fainter when the Earth was young, but the climate was generally at least as warm as today. Warmer temperatures melt persistent ice masses in high elevations and upper latitudes. Ice reflects some of the solar energy into space because it is highly reflective. The ice reflected too much, causing the Earth to cool rapidly as it was not receiving enough heat from the sun.
What role did greenhouse gasses such as carbon dioxide (CO2) play in Snowball Earth events?
The lack of greenhouse gasses would have made the global climate colder, creating larger areas of ice and snow. A great amount of greenhouse gases would have caused the ice to melt, making the global climate warmer, and bringing the Earth out of a snowball effect.
How did carbon dioxide concentrations in the atmosphere change during Snowball Earth events?
When the carbon dioxide levels in the atmosphere surged, it created a global greenhouse that melted away much of the ice. This began because volcanoes spewed gas into the atmosphere.
What are cap carbonate rocks? What do they signify about the end of Snowball Earth events?
Cap carbonates are a special type of laminated carbonate rocks (limestone and/or dolostone) associated with glacial deposits during Snowball Earth. They sharply overly (“cap”) unsorted glacial sediments called tillites.
Why is it unlikely that a Snowball Earth event would happen again in Earth history?
Snowball earth is unlikely to reoccur without a major redistribution of the continents.
4. Paleozoic Tectonics
What properties of the rock record distinguish the Paleozoic from the previous interval of geologic time?
We began to see animals appear in the rock record. A mass oxygenation event occurred with rifts signifying that showing creatures are beginning to need oxygen.
What is orogeny? How many occurred during the Paleozoic?
An orogeny is a mountain-building event. 3 occurred during the Paleozoic. Taconic first, then Acadian, then Alleghenian. What are transgression and regression? How many occurred during the Paleozoic? List them in order.
Transgression occurs when the shoreline migrates landwards. Regression occurs
when the shoreline migrates oceanwards. 6 occurred during the Paleozoic. Sauk first, then Tippecanoe, then Kaskaskia, then Absaroka, then Zuni, then Tejas.
How do changes in seafloor spreading rates affect global sea levels?
The cooler crust is old and dense, so it sinks, creating more space in the ocean, and lowering the sea level. The new crust is hotter, causing it to be less dense, which causes it to rise, creating less space in the ocean, and rising the sea level.
What types of rocks represent orogenies? What types of stones represent transgressions and regressions?
Volcanic (forming of volcanoes) & Metamorphic rocks (squeezing and crashing of
rocks). Rocks include limestone, shale, and sandstone.
Which parts of North America were first inundated during Paleozoic transgressions? Which parts were inundated last?
The first part of the flooding was the coastlines which are closer to the water level, and the last part of the flooding was the higher elevated land areas.
Which parts of North America were underwater for the most extended amount of time during Paleozoic transgressions? Which were underwater for the least amount of time?
Coasts (low elevations) get flooded first, which means the higher elevations are going to be underwater for the least amount of time.
What rock types formed during the Paleozoic orogenies, the Taconic, Acadian, Antler, and Alleghenian? Where are these rocks found today?
Alleghenian and they are found on the Eastern side of America.
What rock types formed during the Sauk, Tippecanoe, and Kaskaskia transgressions? Where are these rocks found today?
During the later transgressions, more carbonate types of rocks formed and we had more marine life present. They are found at low elevation points.
5. Paleozoic Marine Life
What are invertebrates and vertebrates?
Vertebrates are creatures that have spines, and invertebrates are creatures that don’t.
What is the Cambrian explosion? How long did it last and what geological and biological factors contributed to it?
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The Cambrian explosion was when life was blooming and Earth was becoming diverse with animals. It lasted approximately 10 million years. The end of Snowball Earth caused warmer temperatures, the sea level rose, and more space for things to live and grow was found. What are arthropods? Why were they so successful during the Paleozoic?
Arthropods are bugs, and they were so successful because their bodies are extremely adaptable to their environments.
What types of arthropods lived on land during the Paleozoic? How did they adapt to life on land (recall the Origins of Life video)?
Trilobites mainly, and adapted well because they have hard exoskeletons.
What are examples of filter feeders that appeared during the Cambrian?
Cnidarians and Brachiopods.
What are the first vertebrates/chordates to appear during the Cambrian? Agnathians.
What was the first jawless and jawed fish to appear during the Paleozoic?
Jawless includes Ostracoderms and Conodonts. Jawed includes Plackderms.
What is a lobe-finned fish and how is it related to amphibians that appeared later?
Lobe-finned fish had strong fins and were capable of land travel if necessary. They ended up evolving to land creatures.
What types of environmental stress may have prompted fish to adapt to life on land?
Possible environmental stress includes new predators moving into the area or aquatic habitats drying up.
6. Paleozoic Terrestrial Life and Extinctions
How did labyrinthodonts adapt to life on land? Why were they important to subsequent life on land?
They laid their eggs in the water but traveled and lived mainly on land. They paved the way for new reptile evolutions by slowly letting their eggs hatch on land.
What were the first reptiles on land and when did they appear?
They first appeared during the Carboniferous (Mississippi) time period.
What are therapsids and when did they appear?
They are mammal-like reptiles and they developed around the Permian.
When did the first plants appear on land?
Plants first appeared during the Ordovician but did not become very prominent until later on.
What conditions of the Mississippian and Pennsylvanian favored the evolution of trees?
The environment was very warm and contained extensive amounts of carbon dioxide.
What marks the end of the Paleozoic?
The Permian mass extinction event.
What fraction of species were lost at the end of the Permian/Paleozoic?
65% of terrestrial, 96% of marine, and 35% of insects.
What caused the Permian extinction?
Large amounts of volcanism caused large amounts of carbon dioxide and the ocean was depleting / extremely warming the earth