GEOL 101 Chapter 7

24 July 2022
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question
If all the particles in a detrital sedimentary rock are nearly the same size, it is _________.
answer
Very well-sorted
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A smooth grain like a cigar is ___________ and shows ____________.
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Well-rounded; low sphericity
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Wind-blown sand deposits would most likely be __________ and _____________.
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Very well-sorted; well-rounded
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Which of the following correlate to transport distance?
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Grain size and rounding
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A conglomerate is poorly sorted with well-rounded grains. This rock was likely formed in what depositional environment?
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Mountain stream
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Rock salt is an example of a(n) __________, deposited by saturation and precipitation in evaporating water.
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Evaporite
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What mineral is the major component of rock salt?
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Halite
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From what you learned in the video, compare the Pleistocene climate to present-day climate of the western United States.
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The Pleistocene was wetter and cooler relative to present-day climate.
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Name the progression of coal types with increased heat and pressure from burial.
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Peat, lignite, bituminous, anthracite
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Abundant plant material accumulating in a swampy environment with ___________ is required for peat to form.
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Low oxygen levels
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What coal is soft, black in color, and produces soot upon handling?
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Bituminous
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How is anthracite produced from bituminous coal?
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Metamorphism
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In the United States, the most common type of coal is ________ and the largest producing state is __________.
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Sub-bituminous; Wyoming
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Working in field, you find a rock that contains rounded fragments that are greater than 2 mm in diameter. What would you call this rock?
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Conglomerate
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The geologic laboratory where you work received a sample for analysis that is composed of calcite that includes many microscopic fossils of marine organisms and reacts with acid. What name would identify this rock?
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Chalk
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Which structure is common in sedimentary rock?
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All of the selections are correct.
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What property of detrital sedimentary rocks can be indicative of the energy of sediment transport?
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Grain size
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For a detrital sedimentary rock that contains mudcracks, you could be confident that the environment in which it formed was __________.
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Alternately wet and dry
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In your field area you find a quartz sandstone unit with cross-bedding in it that is on the order of 2 m high. In what environment would you deduce this rock formed?
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Sand dunes
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In another field area you find a detrital sedimentary rock that contains particles larger than 264 mm that are angular and surrounded by finer-grained particles. In what environment might you think these sediments were deposited?
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Glacial Moraine
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Which of the following defines depositional environment?
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An area where sediment was deposited under certain conditions in Earth's past.
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What is a delta?
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A triangular landform created where a stream enters a body of water and deposits sediment.
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Other than sand dunes in a desert environment, where else would you expect to find well-rounded and sorted sand deposits?
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Beach
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Describe the distribution of sedimentary deposits you would expect to find on a delta.
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Sand in channels, mud on floodplain
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The same formation changes laterally from layered evaporites to mudcracked sandstone to conglomerate. Using the facies concept, which of the following is an accurate interpretation?
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Shallow lake, shoreline, mountain front setting
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What is the sequence of sediments you would pass over if you were to walk from the shoreline and then swim in the offshore direction?
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Sand, clay, carbonate
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Which of the following is a reason that limestone is formed in a relatively offshore position?
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The lack of sediment derived from land.
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By what process do ooids form?
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Layers of CaCO3 are precipitated out of seawater and coat grains.
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Neighboring sedimentary facies generally show __________.
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A gradational relationship