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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 white rock with large brown crystals?

Found this in a creek in the mountains of North Carolina.
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Rock ID: Geode, soft, dull black exterior with crystal inside, from Snæfellsnes, Iceland

My fiancée found this on a recent trip to Iceland, on Snæfellsnes peninsula - she spotted the sparkle of the crystals among the abundant black, grey, and dark red rocks. There is a roadside vista spot ...
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How does one create petroleum/crude oil for future generations?

I am a geological novice so maybe this is a wrong question. But the idea is to create a thought experiment. How does one "create" petroleum or crude oil for future generations? Is it enough to bury a ...
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Is it true that “[sand] grains in the Coconino Sandstone come from the Appalachian Mountains”?

The Creation Museum is a terrifying place for scientists of all stripes. One of their exhibits is the "Flood Geology" exhibit, which purports to explain how a flood of (literally) Biblical proportions ...
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Where can fluorite be found on Long Island, New York?

I'm interested in fluorite (Since Fluorine is my favorite element, and I wanted a sample of it, even if bonded, but I don't want to buy it; that would be no fun), and I'm curious if it can be found on ...
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Newton's estimate of the age of the Earth

I was reading many articles about estimates of the age of the Earth throughout the ages. I was dumbfounded when I read that Newton, arguably one of the greatest scientists ever to have ‘calculated’ ...
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368 views

How is/was continental drift monitored?

I am curious about current technology but I am particularly interested in what techniques were employed prior to the advent of satellite technology.
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434 views

In the oil field, when a vertical cylinder coring sample is taken, how is the core severed at the bottom and removed from the formation?

I would like to know how the core is cut off at the bottom of the drill. I also would like to know how the core is brought up to the surface without slipping out and falling back down.
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A circle shape in Madagascar

I was seeing Madagascar on Google Maps and accidentally i saw a circle shape near Bebao. Coordinates are 17.4317443°E and 44.644248°S. Please, to satisfy my curiosity, can you tell me why is this ...
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Why are there more intense earthquakes in Iran than in Iraq?

Why are there more intense earthquakes in Iran than in Iraq, if they are so close together? I often hear news items of earthquakes in Iran that are higher on the Richter Scale than those that happen ...
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Why are South African mountains short and flat?

I drove through South Africa from Cape Town to Mozambique and noticed that almost all heights and mountains were no higher than approx 200-400 meters and had a flat top, just like the iconic Table ...
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What causes such a narrow slit in a cliff? (see photo)

I have this photo as a background image and I often wonder how such a narrow, well-defined slit could be formed. Is it natural or man-made? If natural, what processes could have formed it? The rest of ...
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How to distinguish an explosion crater from an impact crater?

(How) Is it possible to tell the difference between a man made explosive crater and an impact crater?
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How old are Chile's fjords?

Do we have any knowledge about the age of Chile's fjords, more specifically, those found near the Northern Patagonian Ice Field? Is it reasonable to conclude that they were formed in Quaternary given ...
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How straight is the Kola superdeep borehole?

The legendary Kola superdeep borehole is about 12 km deep. To achieve such depth, a major difficulty is to make sure the borehole is vertical straight. Intuitively, when the borehole is deep enough, ...
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349 views

Mineral Rock Identification

Went out hiking after some heavy rains and came across an area that looked like broken glass sticking out from mud. On a closer look this is what we found. Not sure what it is and would like to know ...
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Will another big earthquake hit Kathmandu?

Recently, we got the news that the western part of Nepal may be hit by a larger earthquake than that of April 25, because it did release all of its energy. During the earthquake, only the eastern part ...
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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. ...
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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 ...
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Why is the elevation of the Iberian Peninsula so high?

The Iberian peninsula lies more than 600 m above sea level, on average, far above similar geological regions in western Europe. Even tectonically undeformed areas in the inner basins present a ...
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How do the swirls and veins in marble form in detail?

I am finding surprisingly little information about this. I imagine that the process is somewhat like foliation except because the particles that go into marble (to my knowledge) don't have any ...
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What is the rock I found on the Delaware river yesterday?

I spotted this large striped rock found on Delaware River. Note the fossil in the first picture. What kind of rock is this?
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What is the white coating “patina” we often see on deposited chalcedony/agate?

Me and some of my friends were wondering what exactly is the white coating we can see on chalcedony that has been deposited by a river during quartenary (and so the original material is damaged and ...
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Alpine schistosity

I often find the term Alpine schistosity (schistosité alpine in French, scistosità alpina in Italian) in texts about Alpine geology. Chronologically ordered phases of Alpine schistosity producing ...
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Rock ID: smooth, black, durable rock from Lake Ontario

What is this black rock? I found it beneath the waters of Lake Ontario near the shoreline, it is a dark greyish-black with small flecks of mineral deposits on it that are visible in the light. The ...
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The geology of local landscapes and small scale features

I'm learning geology to understand the processes behind the formation of my local landscape. I understand the processes behind big features, such as mountains. But I'm struggling to understand the ...
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Are trends in crossplots of compositional data from different analyses valid?

Some geochemistry papers that I have read contain crossplots of compositional components that resulted from different analyses of a rock sample. For example, one is the percent volume of TiO2 versus ...
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Recreating the rock cycle

I want to recreate the rock cycle using some item that can behave as a rock. The purpose of this is to get a point across to my students about how really there is a reason why the rock cycle is called ...
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How is geological time divided into units?

Earth's history is divided into eons, which are divided into eras, which are divided into periods etc. Consecutive time units differ in their geology and/or fossil species. But what events are the ...
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What is the global distribution of oil filled geodes?

In a general 40 mile radius of Keokuk, Iowa many sedimentary geodes can be found. They are abundant in the Warsaw Formation with the type section at Geode Glenn in Warsaw, Illinois. In one specific ...
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What is the average color of dirt?

Where I live the soil is red. Is there a map or chart where you can see the average color of the dirt according to geographical location? What would the color be if all of the dirt on Earth was ...
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Which Earth minerals would Moon colonists miss the most?

In my science-based novel, Moon colonists need to return to Earth to collect some rare or absent mineral(s) Ideally, something they could derive from seawater. Which minerals might they be...?
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Simulating the earths crust

I would like to create a computer simulation which would fold two plane-ish surfaces into two crumpled-ish surfaces. This in order to simulate the earths crust movement and collisions resulting in ...
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1answer
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How can a non-geologist identify a rock? [closed]

I found a rock on a beach in north-east Evia, Greece. Half is light gray, and half is dark gray. There are white (or very light gray) thin lines that form swirls throughout, crossing the light/dark ...
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Round structure in southern United States

Assuming here might be someone who knows something about this, I wanted to ask what is behind this round structure I have spotted today on Google Earth: There seems to be a large (~200 km), nearly ...
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Rock identification and features

The rock is approximately 12cm in length and from what I can tell this is a sedimentary rock and is a conglomerate. I'd say it was from a high energy environment due to the round gravels. This is all ...
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Are old geophysics textbooks useful?

I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from ...
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Interpreting a geological map

I have a homework question that I'm stuck on, I have attempted interpreting this map but am not sure if I have to correct interpretation. What is the youngest/oldest rock in the geological ...
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344 views

Uranium Deposits in the Ocean?

I was wondering whether there are any uranium deposits in the ocean floor, or in the rock walls of the continental shelf, etc. I was hoping to have some deep sea uranium deposits accessible from the ...
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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 ...
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Himalayas are currently rising. What will be the highest point they can reach?

Himalayas are currently rising about 5 mm/year. What will be the highest point they can reach?
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What kind of data is best shown in a rose diagram?

I am looking for some geological data where presenting it in a rose diagram is desirable. I don't really know what kind of data is suitable. Any suggestion of data — preferably from the field of ...
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What caused this waterfall to have rounded formations?

This is at Bua Tong Waterfalls in Chiang Mai, Thailand. Tried to find scientific information about this waterfall, but google turns up only travellers' vague guesses, suggesting calcium carbonate ...
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Why are the mountains predominately grey or dark brown?

Observing many photos of mountains one can assume that most of the mountains are grey or brown. See also the mountain article at Wikipedia. There are however several ways a mountain can form, which ...
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In an Earth-like planet with no history of carbon-based life forms, would there be limestone?

The extent of my understanding of limestone is about what Wikipedia says at the very top of the page: Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such ...
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Please help me Identify this rock

I am not an avid collector but I found a rock that was really out of place and have had it for 40 years now. So...basically, it's about time to figure this out. I found it in a field on the east side ...
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1answer
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Volcanoes in the Alps and Himalayas and the subduction of Tethys Sea

Geologist have theorized that the Tethys Sea subducted under Eurasian plates. But where are the volcanoes that would have resulted due to this? Where are the volcanoes in the Alps and the Himalayas?
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Why do ooids not grow larger than 0.5 mm?

I know ooids form in high energy water, by rolling and building layers around a nucleation site, but I don't understand what limits their size. What keeps these such a regular, small size?
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What kind of rock is this (from UK)?

What kind of rock is this? It was found in Threemilestone, near Truro in Cornwall, UK. The rock has a hardness of over 5.5, as a knife doesn't scratch most parts of it. It is 10cm across the top, ...
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Could the Grand Canyon be flooded by the ocean if it got deep enough?

The Colorado River has been carving the Grand Canyon for a few million years now, such that the canyon floor is around 6000 feet lower in elevation than the surrounding area, at about 2400 feet above ...