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Questions tagged [geology]

The science comprising the study of the rocks Earth is composed of, and the processes by which they change. Some subfields of geology are petrology, mineralogy, and geophysics.

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What is this "hole" that blows sand into the air?

This video clip, "Strange Hole in the desert Blows Sand into the air in Saudi Arabia" (alternative link), shows a hole in the desert that erupts like a geyser, except with sand instead of water. It is apparently located in the Aljof area in the…
NVZ
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How has the relative ratio of igneous, sedimentary, and metamorphic rocks changed over Earth's history?

Has the relative ratio of sedimentary over igneous rocks increased, simply as a result of more and more of the Earth's rock being exposed to sedimentary processes? Or has it increased only for the first billion years of Earth's history, and stayed…
InquilineKea
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How did the Cliffs of Dover form flint in regular stripes?

The White Cliffs of Dover are mostly chalk but there are regularly spaced horizontal lines of flint. I understand how the chalk and flint layers are formed independently (from Wikipedia) but I haven't been able to find any information on why they…
John Leonard
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Extent of the Persian Gulf

Is there a consensus on when the Persian Gulf reached its modern day levels? So far the material I have read says the Persian Gulf attained its present levels around 4000 BCE, but I am not too sure. Any suggestions? Thanks.
Tyrone Smithers
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How long does one touch on a stalagmite/stalactite lasts?

There is a discussion about whether touching a stalagmite or a stalactite would stop it from growing or not: https://answers.yahoo.com/question/index?qid=20090629155053AAYFhCM . The results are that the oil on human body does prevent a stalagmite or…
krismath
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Why is Michigan Geology Circular?

Looking at maps of the geological layers in Michigan it looks like an onion starting in the center of the state. Why? Thinking of the recent glacial history of the state that would seem to have created streaks from glacial advance and retreat that…
QueueHammer
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Cause for round holes in stones

I picked up this stone form a beach on the south coast of England (lancing). How is it possible it has such round holes? Plenty of stones looked similar.
Nickpick
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Basalt sill - a contradiction in terms?

My textbook for a historical geography class mentions a couple of geological features it calls "basalt sills" (the sill of Rosh Pinah and one other). I'm a total newbie to geology, but the term basalt sill is confusing me. As best I can tell... 1.…
qianlong
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How are deposits of metals like tantalum located?

I am curious of how metal deposits are located in general, but to keep my question focused I wanted to just ask about tantalum for example. Are there people who traverse their own country drilling core samples here and there? What indicators would…
alec
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If I was to tunnel straight through a mountain, what kind of rock would I find?

I'm developing a semi-realistic game involving stereotypical dwarves digging into mountainsides and carving out grand caverns for themselves, similar to those in Moria or the Lonely Mountain from Tolkien's works. I'm attempting to research what kind…
Ross Taylor-Turner
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Determining hardness using teeth

So I know scratch tests are pretty common to quickly get an estimate of a rocks hardness. Also tooth enamel is a common material with a 5 on mohs scale. So far so good, but what shocked me is that I heard students on field trips actually use their…
Thomas Bosman
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How long could a steel artifact last?

Would man-made steel artifacts be able to be preserved like fossils for millions of years, or would corrosion make them dissipate? What about metals such as aluminum that don't corrode as easily?
john doe
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What is the motivation behind the choice of unglazed Porcelain as a Streak plate?

What characteristics does Porcelain possess that makes it a good choice for the Streak test? Additionally, are there any other materials that could also be used for designing a Streak plate?
vshlrnjth
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Pigments from earth

We're about to do lime wash on one of our heritage buildings. We decided to use ochre as pigment because it comes from earth. My boss says with any pigment that comes from earth, we don't need to worry about discoloration in lime mortar, which is…
user7836
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Why does gold and other metals conglomerate

When gold, or some other metals, such as copper, are found, they are often found in large nuggets. But, from what I understand, gold is produced in quite stochastic stellar processes. As such, shouldn't the distribution of gold and other elements be…
Terry Price
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