GEOLOGY
SEDIMENTOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Poorly-sorted, angular grains, less than 15% matrix
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Poorly-sorted, rounded grains, more than 15% matrix
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Well-sorted, rounded grains, less than 15%Matrix
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Well-sorted, angular grains, less than 15%matrix
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Detailed explanation-1: -Sandstones are made of sand grains that have been cemented together. Like sandpaper, sandstones usually have a rough, granular texture, but to really identify a sandstone you have to peer closely at its surface and look for individual sand grains.
Detailed explanation-2: -Mature sandstones are clay-free, and the sand grains are subangular, but they are well sorted-that is, of nearly uniform particle size.
Detailed explanation-3: -Sandstones are first subdivided into two major textural groups, arenites and wackes.
Detailed explanation-4: -Wind-deposited sandstones therefore tend to be very well sorted. Meanwhile, the silt and clay that is blown away eventually lands somewhere to form a different (but also well sorted) rock called loess.