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Questions and Answers
What do sedimentary rocks primarily represent in regards to their formation?
What do sedimentary rocks primarily represent in regards to their formation?
Which type of weathering involves a change in the mineral composition of the rock?
Which type of weathering involves a change in the mineral composition of the rock?
What process describes how water freezing in rock cracks and expanding can lead to rock breakage?
What process describes how water freezing in rock cracks and expanding can lead to rock breakage?
What characterizes abrasion in the context of weathering?
What characterizes abrasion in the context of weathering?
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Which of the following statements about exfoliation is true?
Which of the following statements about exfoliation is true?
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Which statement is true regarding the chemical weathering of feldspar and quartz?
Which statement is true regarding the chemical weathering of feldspar and quartz?
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What does a clastic sedimentary rock rich in feldspar indicate about its formation?
What does a clastic sedimentary rock rich in feldspar indicate about its formation?
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How are clastic sedimentary rocks primarily classified?
How are clastic sedimentary rocks primarily classified?
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What does poorly sorted sediment suggest about its transport history?
What does poorly sorted sediment suggest about its transport history?
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What geological process is indicated by the presence of sedimentary rocks in New England?
What geological process is indicated by the presence of sedimentary rocks in New England?
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What geological feature is formed by water dripping from the roof of a limestone cave?
What geological feature is formed by water dripping from the roof of a limestone cave?
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What distinguishes sedimentary breccia from conglomerate?
What distinguishes sedimentary breccia from conglomerate?
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In what type of environment does tufa typically form?
In what type of environment does tufa typically form?
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What event is commonly represented by sedimentary breccia?
What event is commonly represented by sedimentary breccia?
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What characteristic of conglomerates indicates extensive transport before deposition?
What characteristic of conglomerates indicates extensive transport before deposition?
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Why are many stone walls in New England now deep in secondary growth forests?
Why are many stone walls in New England now deep in secondary growth forests?
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Which of the following describes the composition of conglomerates?
Which of the following describes the composition of conglomerates?
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What process leads to the formation of stalagmites in a cave?
What process leads to the formation of stalagmites in a cave?
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What was the duration of the global winter caused by Toba?
What was the duration of the global winter caused by Toba?
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Which inference can be made about the aftermath of the Toba eruption?
Which inference can be made about the aftermath of the Toba eruption?
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What is a caldera?
What is a caldera?
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Which region is noted for having the most volcanically active volcanoes in the U.S.?
Which region is noted for having the most volcanically active volcanoes in the U.S.?
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What makes Vesuvius and Phlegraean Fields particularly risky?
What makes Vesuvius and Phlegraean Fields particularly risky?
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Which volcano is noted as the most active in the Cascade Range?
Which volcano is noted as the most active in the Cascade Range?
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What issue do volcanic eruptions in Alaska primarily pose for aircraft?
What issue do volcanic eruptions in Alaska primarily pose for aircraft?
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How do volcanic activities differ between Hawaii and Alaska?
How do volcanic activities differ between Hawaii and Alaska?
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What phenomenon can occur due to a volcanic island experiencing a massive landslide?
What phenomenon can occur due to a volcanic island experiencing a massive landslide?
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What was one consequence of the eruption of Mt. Pinatubo in 1991?
What was one consequence of the eruption of Mt. Pinatubo in 1991?
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How many years did the cooling effect last after the eruption of Mt. Pinatubo?
How many years did the cooling effect last after the eruption of Mt. Pinatubo?
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What major climatic event occurred in 1816 as a result of the eruption of Mt. Tambora?
What major climatic event occurred in 1816 as a result of the eruption of Mt. Tambora?
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What was the estimated death toll from the effects of the 1815 eruption of Mt. Tambora?
What was the estimated death toll from the effects of the 1815 eruption of Mt. Tambora?
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What makes Mt. Rainier the most dangerous volcano in the Cascades?
What makes Mt. Rainier the most dangerous volcano in the Cascades?
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When did the last major eruption of Mt. Rainier occur?
When did the last major eruption of Mt. Rainier occur?
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How does the Long Valley Caldera's last major eruption compare to that of Yellowstone?
How does the Long Valley Caldera's last major eruption compare to that of Yellowstone?
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What type of eruptions have dominated the activity at the Long Valley Caldera in the last 5,000 years?
What type of eruptions have dominated the activity at the Long Valley Caldera in the last 5,000 years?
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What community reaction accompanied the increased volcanic activity near Mammoth Mountain in the 1980s?
What community reaction accompanied the increased volcanic activity near Mammoth Mountain in the 1980s?
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What phenomenon caused the underwater explosion in the Tonga island chain in January 2022?
What phenomenon caused the underwater explosion in the Tonga island chain in January 2022?
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What was the impact of the Tonga eruption heard as far away as Fairbanks, Alaska?
What was the impact of the Tonga eruption heard as far away as Fairbanks, Alaska?
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How did the 1980s activity around Mammoth Mountain manifest physically?
How did the 1980s activity around Mammoth Mountain manifest physically?
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Study Notes
Western Interior Seaway
- Spanning the Mesozoic Era (250 to 65 million years ago)
- Coprolites are fossilized animal dung
- Gastroliths are stomach stones (rocks animals swallow to aid digestion)
Coprolites and Gastroliths
- Coprolites: Fossilized animal dung
- Gastroliths: Stomach stones used by some animals to grind food
Casts and Molds
- Cast: Forms when a body cavity fills with sediment, which hardens, preserving the body shape after the body is destroyed
- Mold: The inverse of a cast, a hardened sediment around a body that later decays, leaving a vacant space (mold) of the original body shape
Flattened Molds
- Often called impressions
- Flattened molds are usually called impressions
The Ediacara Fauna
- Approximately 600 million years old
- Represents early multicellular organisms
- One of the world's important fossil deposits is the Burgess Shale (found in the Canadian Rockies)
- Preserves a diverse community of marine animals buried in a rapid mudslide-like event.
Pikaia
- Earliest known Chordate (phylum to which humans belong)
- Possesses a nerve cord
Amber
- Fossilized tree sap or resin
- Represents ancient forests
Additional Information from Tree Rings
- Each ring represents a year of tree growth
- Closely spaced rings indicate slower growth (e.g., due to drought)
- Wider gaps between rings indicate faster growth (e.g., favourable climactic conditions)
- Ash layers help date a tree's death which can provide a volcanic eruption date
Stromatolites
- Mushroom-cloud shaped cemented sediment mounds
- Can reach a meter in height
- Composed of thin layers of sediment cemented together by organic material
- Date back to 3.5 billion years ago
- Modern Stromatolites are common in hypersaline (very salty) water
Hydraulic Fracturing ("Fracking")
- Involves pumping high-pressure fluid into the ground to crack rocks and release oil and gas
- The sand keeps the cracks open, allowing oil/gas to flow to the well.
- Natural gas is more cost efficient, cleaner, and produces more energy than burning coal, but has potential environmental issues like contaminating water.
Sedimentary Structures
- Ripples: Symmetrical or asymmetrical patterns on sedimentary layers, usually formed by flow in a single direction
- Cross beds: Created by sloping movement
- Mud cracks: Formed in wet sediment, commonly in swamps, drying out.
Oxbow Lakes
- Extreme stream meanders cut off during a rapid flow event
- A stream creates a new channel
Coal Formation
- Coal forms from remains of ancient swamp plants that undergo conversion over millions of years
- Coal is the worst fuel choice environmentally (produces the most CO2) compared to natural gas
Chert
- Composition of silica (SiO2), usually quartz
- Represents deep marine deposits
Other Marine Deposits
- Agate: Forms in concentric rings within hollow spaces in chert
- Chalk: Microscopic coccolithophorids (a type of single celled algae) are the primary component, made of limestone
- Coquina: Broken pieces of larger CaCO3 shells (visible without a microscope); closer to shore
- Travertine: Limestone not formed from organisms, usually in caves from precipitation of calcite
Sedimentary Breccia
- Composed of angular fragments, poorly sorted, but mostly sharp-edged fragments
Sedimentary Conglomerate
- Composed of rounded fragments of all different sizes, very poorly sorted, and mostly rounded
- Indicates significant transport before deposition
Sedimentary Rocks
- Form 75% of the Earth's surface
- In areas like New England, the upper sedimentary layers are largely removed by glaciers leaving the underlying igneous and metamorphic rocks exposed.
Weathering
- Chemical weathering: Dominant in warmer, wetter climates
- Physical weathering: Dominant in colder, drier climates
- Frost wedging: Water in cracks expands as it freezes, causing rocks to break apart
- Abrasion: Rocks that are moved by water, ice, or wind, will wear away other rocks they contact.
Exfoliation
- Rocks expand as weight is removed by erosion, causing them to crack and break away like the layers of an onion. Also caused by thermal expansion/contraction
Volcanic Eruptions
- Timing between eruptions can predict size and type
- Earthquakes become more frequent and shallower before a large eruption
- Subduction zones and hot spots are the two types of volcanoes where eruption can be significant
- Yellowstone region experiences regular earthquakes but it's not necessarily a clear indication of imminent eruptions.
- Mt. Toba in Indonesia erupted 73,000 years ago and caused a global winter that lasted 6 to 10 years.
- The eruptions at Mt. Pinatubo, in the Philippines 1991, and the earlier eruption of a remote Alaskan volcano in 1912, are the only eruptions of the 20th and 21st centuries to have been large enough to cause measurable drop in global temperatures.
Other Information
- The region around Mammoth Mountain experienced increased seismic activity in the 1980s, raising concerns but not immediately leading to eruptions.
- The eruption in Tonga in 2022 caused a major underwater explosion, creating tsunamis; this is one way volcanoes can generate tsunamis.
- Tsunamis can also be generated by landslides in volcanic regions.
- Large volcanic eruptions can cause a significant drop in global temperatures (short-term) and harm to populations (long-term) by impacting agriculture.
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Description
Test your knowledge of sedimentary rock formation and the processes of weathering. This quiz covers key concepts such as clastic sedimentary rocks, types of weathering, and geological features. Challenge yourself with questions on the characteristics and classifications of sedimentary rocks.
