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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10
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2answers
1k views

Undersea riverbeds?

On a meandering bit of research through Wikipedia, I was looking at the Google Maps location of Texas Tower 4. South-east of that location there is what looks like a river valley under the ocean. If ...
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1answer
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Mars maar craters explosive style formation gravitational effect

"Maars usually form when magma rises within a fissure and interacts with groundwater. If groundwater ceases to interact with magma at times during the eruption, continued magma ascent to the surface ...
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4answers
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What do the derivative or the integral of amplitude of a seismogram mean?

I'm doing a project in which I'm analyzing earthquake seismogram waves. I used a program to graph the exact amplitudes and how they changed over the course of a single earthquake. For the project I ...
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1answer
555 views

What is the natural replenishment rate of oil? [duplicate]

What is the natural replenishment rate of oil? Are extinction events connected with higher production?
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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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140 views

Online resources for geographical distribution of minerals

I'm trying to find the geographical distribution and availability of mineral Brannerite. Is there a resource online to know or query where a certain mineral is found? On the link page, they mention ...
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1answer
549 views

Dynamic cone penetrometer (DCP) results and correlation

I have been reading about DCP and watched a video of how it is done (the video is not in English). But there are something things that are still unclear and I would greatly appreciate some help and ...
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3answers
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When can taste be used to help identify rocks?

Taste can be used to distinguish halite (ordinary salt) from sylvite (which has some bitterness) and siltstone from mudstone (the latter has a creamy texture while the grains of the former can be felt)...
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1answer
151 views

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 ...
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2answers
480 views

What's it like inside a natural gas cavern on Earth?

I suppose natural gas underground caverns on Earth have substantial volume and gas is in gaseous form there. As such I wonder how it would look like inside such cavern (with artificial light of ...
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1answer
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Are coral cays and coral atolls just volcanic islands?

Are coral cays and coral atolls just a different type of volcanic island? When I hear: "volcanic island" I think at places like Moorea or Hawaii, but ultimately, coral cays and coral atolls lay their ...
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Width of strata in stratigraphic column

I am trying to understand whether there is one "standard" meaning of the width of represented strata in stratigraphic columns, but I can find nothing online or in my geology books. I notice that, ...
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1answer
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Icelandic rock I am trying to identify [closed]

This is a rock that I picked up from underneath a melted segment of Glacier in east Iceland. It is not unusually heavy or light for it's size. I can scratch the surface away with a penny. The ...
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1answer
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Hydrocarbon potential in Ganges Brahmaputra delta

According to Curray (1991): Total sediment thickness beneath the [Ganges–Brahmaputra delta] southeast of the hingezone exceeds 16 km... Considering a normal geothermal gradient and data for oil ...
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Why did people draw so many continuous squares in the sand on the beach at Cape Juby?

At Cape Juby, Morocco, we can see with Google Maps a rectangle of 3 km long, in which there is hundreds of little squares. What method was used to draw these squares on the sand? More importantly, why ...
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1answer
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How do I prepare for the International Earth Science Olympiad?

Recently I have been selected for the National Camp of INTERNATIONAL EARTH SCIENCE OLYMPIAD of my country. How do I prepare for it? Resources, books, etc. I know there are 4 parts- geology, ...
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6answers
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Is there a difference between rock and stone?

I couldn't find the definitions from either source: Geology Dictionary Glossary of Geologic Terms
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2answers
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Database of geological group or formation exposures?

Is there any sort of database that provides the locations of exposures of certain geologic groups or formations? I ask because I have read that halite occurs in the Michigan Basin, and specifically ...
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1answer
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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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1answer
528 views

What is the long term impact of large scale removal of material from subterraneal caches on the structural integrity of the soil?

For example, sinkholes can be human induced: New sinkholes have been correlated to land-use practices, especially from groundwater pumping and from construction and development practices. ...
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1answer
257 views

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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3answers
314 views

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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1answer
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How are spherulitic structures formed in basalt rock?

After having studied the thin sections of basalt under the microscope, I have come across many spherulitic structures occurring in clusters. How can this happen? Is it due to devitrification or is ...
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Why are alkali basalts found at rifting centres and on top of 'plumes', whereas MORBs are generally tholeiitic?

So I was essentially wondering why it was that the basalts on top of 'plumes' at 'hotspots' (sometimes called OIBs, ocean island basalts) and at continental rifting centres are enriched in alkaline ...
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1answer
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What lithologies are deemed most suitable for the storage of nuclear waste

I have visited storage- and test facilities that are within salt and clay (Opalinuston) lithologies. What are other lithologies that are considered for the storage of nuclear waste and what are their ...
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1answer
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Is angular momentum preserved in a gastropod fossil?

In the Northern hemisphere the rotation of the Earth determines a counter-clockwise spin on matter. Weather, ocean currents all are related in that spin. I wonder if my snail fossils preserve the ...
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1answer
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How much of a mountain is below the surface?

Is there some kind of math rule for how much does a mountain extend (depth) below the surface? I found an article like this http://www.livescience.com/6595-depth-himalayan-mountain-roots-revealed....
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1answer
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Is there geological evidence that the moon once collided with the Earth?

I've seen models in astronomy that show how the Earth-Moon system must have come together after a collision. However, I have not heard whether there is any actual physical evidence on Earth that ...
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1answer
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viable geothermal energy supply from exhausted fracked gas wells?

The UK legislator with primary responsibility for energy has claimed that exhausted fracked natural-gas wells will be suitable for re-use as a geothermal energy supply (not necessarily geothermal for ...
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1answer
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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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1answer
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How can scientists be confident of isotope ratios in past eras and varied locations, used for radiometric dating?

Radiometric dating relies on past isotope ratio predictions being very reliable. However, this is not necessarily so. For example, in Uranium forensics, 235U and 238U ratios are about the same for ...
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2answers
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Why are minerals found in “large” quantities and not scattered throughout the earth as individual atoms?

Heavier elements are created in stars. After stars die they scatter these heavier elements throughout the universe. These elements eventually gather to form planets. But why do we find "chunks" of ...
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1answer
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Measuring bed dip angle from contour lines, which lines to pick?

Measuring dip angle of a bed, I choose any 2 contour lines that cross the bed, and then project lines off and measure the angle (I'm assuming this is standard technique that doesn't require ...
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1answer
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Would it be wise to monitor real time human activity to anticipate earthquakes?

Documented strange behaviors of animals before an earthquake could invite us to believe that some of them anticipate tectonic activity. We also know that human complex organization makes it difficult ...
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1answer
805 views

What is this Cape Breton rock? [closed]

What is this rock? I found it in Cape Breton, Canada
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1answer
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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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1answer
803 views

What kind of coal did I find? [closed]

I found a piece of (what I believe is) coal, on Cape Cod last week. Its density is 1.43 grams per milliliter. With this information is it possible to know whether it's Anthracite, Bituminous or ...
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1answer
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How much fossil fuel came from the Carboniferous?

It is said that most of the fossil fuels in existence today (coal, oil, gas) came from the Carboniferous period. A unique set of circumstances lead to the creation of fossil fuels, which depends on ...
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1answer
219 views

How are the patterns in solid rock born

I took this photo on my vacation in Finland showing white stripes in the rock going different ways. How are these patterns born?
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How has the relative ratio of igneous, sedimentary, and metamorphic rocks changed over Earth's history? [duplicate]

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 ...
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2answers
253 views

How to determine how long ago a rock was broken?

I know that there are techniques that help scientists determine the age of a rock. But is it also possible to determine how long ago a rock was broken? For example, how could we date the formation of ...
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If all the sand in the Saharan Desert were to be removed, what would the remaining landscape look like? [closed]

Would it look like any other region of the planet?
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1answer
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Determining a rock age using volcanic ash layer

I wanted to know if volcanic ash deposits found in the geologic record are most useful in correlating the age of rock layers if the volcanic ash was distributed over a large area during a short period ...
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1answer
562 views

What's the geological period of the birth of the river Ganges?

Avatarana or Descent of the Ganges (extracted from Wikipedia): "In late May or early June every year, Hindus celebrate the avatarana or descent of the Ganges from heaven to earth." There are ...
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1answer
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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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1answer
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In what sense did the Oklo reactor “trap” its own nuclear waste?

A number of popular writings on the natural fission reactor at Oklo, Gabon (e.g. here) state that some of the energetic byproducts (krypton and xenon, presumably 85Kr and 133Xe) of the reactor were "...
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1answer
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How can I tell if a rock is really petrified wood?

I found a rock in the Mojave desert and it resembles a tree branch including what appears to be wood grain. Is there some test or observation that can be done at home to conclusively answer my ...
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1answer
160 views

Sediment layer chronology

In the new Cosmos series, Neil DeGrass Tyson in explaining different ways the age of the world has been determined, shows how sedimentary layers at the Grand Canyon are a fossil record of a lot of the ...
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1answer
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Why would a suite of related rocks have one anomalous sample?

I have a suite of rocks that have nearly identical major element chemistry, but a single sample has quite different trace element concentrations. All the rocks are trachydacites. I know the analysis ...
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1answer
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Is there any correlation between La Niña/El Niño and seismic activity?

I've read in the past that extreme precipitation levels may have an effect on seismic activity, and wondered if anyone has ever analysed the La Niña / El Niño cycles to see if there are any ...