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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85 views

I found this stone with metal linings can someone identify it?

I am more curious about the metal on the surface (if it's even metal?) on this stone :) I don't really remember where I found it, probably at this beach of the Baltic Sea, but there is also a chance ...
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Rock ID: black rock found in Central Europe

I'm note sure if it's an anthracite, augite, jet (lignite) or something completely different. I don't know where exactly i found it because it's from my old rock collection. I would appreciate your ...
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Do earthquakes produce folds on rocks?

Earth rocks are frequently folded at surface. Folds in alternating layers of limestone and chert in Crete, Greece. Source: commons.wikimedia Are earthquakes the main mechanism ...
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Found a light brown rock with concentric circles on it. Is it a fossil? [closed]

I found the rock in the picture while visiting Pawnee National Grassland (Colorado, USA). The rock shows concentric circles on both sides. On one side these circles are very clear, on the other side ...
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Should I perform EOF analysis on an unevenly-spaced time series?

I have a dataset of sample concentrations of several ions/elements (Ca 2+, SO4 2-, K +, S, Ca, V, etc.) from an ice core which I am using to detect volcanic eruptions. The raw version of the dataset ...
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Is there limestone under the Oregon Coast Range?

I've found some diagrams of the Oregon Coast Range, but they are very basic. An friend said he thinks there is limestone deep underground, but my understanding of the formation of these mountains is ...
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Help to identify unusual rock please! [on hold]

Can someone please help to identify this rock? We are hoping it's a meteorite! About 3 x 2 inches, seems heavy for its size and very hard. Brownish/grey on the outside and smooth. It has a rust ...
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Are sand deserts the greatest natural convection heaters on Earth?

Ask any climate scientist the question: "Why are deserts so hot in the day time and so cold at night" and generally you will get the same answer, it’s all about the lack of moisture and latent heat ...
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How Can We Establish Precisely What Earth's Core is Made Of?

The consensus view is that that the Earths core is composed mainly of iron alloyed with about 10 percent nickel and traces of other heavy metals, but I have seen at least one account which says it is ...
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How is the difference in crust and mantle composition explained?

We know that the composition of the crust is SiAl and SiMa and the one of mantle is mostly ophiolites, but why? Which are the geological processes that make this difference exist?
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Rock ID: Found on South Downs in East Sussex UK

I found this slightly rude-shaped rock/stone on the South Downs in East Sussex, UK years ago. It was embedded in a chalky path and came out in the two pieces in the photo. It is heavy for its size (...
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How older is this snail shell possible could be?

Last weekend I was in Xınalıq(the village in Azerbaijan) and found this snail shell. I am wondering how old is this?
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Climate consequences of very large asteroids striking the Deep Ocean

For every asteroid or meteorite that hits dry land, two hit the sea. If a Manicouagan-sized asteroid struck the deep ocean (but not above a trench),how would the H2O vapour, chlorine, iodine bromine ...
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Green Rock Identification

This rock was found in the highlands of Scotland in the mountains.It is 2 1/2''x2 1/8''x 1'' it has a density of 2.95 leaves a clear streak weighs 130 grams and a hardness of 6 on Moh's scale.This ...
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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 ...
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Is this olivine? [on hold]

Could this small rock be olivine? It has got a rough feeling surface, and 'it's heavy. I found this in Wales 12 years ago.
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Pinkish rock with red 'veins'

I found this rock in Smithfield NC. It does scratch glass. A butter knife didn’t scratch it. When you hold it to a light it has an orange glow. It didn’t leave anything on porcelain.
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Is this rock Massive Epidote?

enter image description here This is a close up of outside of chipped off piece, and inside alsoI found this rock in Co. Donegal Ireland on a river bank buired under the dirt. It weighs 16.4lbs- 7....
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Peninsula vs Cape [closed]

I know that Peninsula is much larger than a cape, but is there a definite way to differentiate them? I.e. by area- if the total area is larger than 30 sqkm, any headland is classified as peninsula..
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Why can't we dig deeper?

I recently read on another SE site that there's a limitation on how deep we can dig into the earth. A Google search reveals that temperature is the problem. I quote from a Popular Mechanics article ...
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UK Mineral identification help [closed]

Can anyone help me identify these minerals please? I found them on a beach in northern England. The first has tiny angular crystals, some slightly pinkish maybe in certain lighting conditions but grey ...
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Can you please help me to identify this thing I found inside a rock in the Almanzora riverbed Spain

Can someone please help me identify this thing I found inside a rock in the Almanzora riverbed Spain
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Is there a widely accepted reason for the formation of tafoni?

Expansion of tafoni seems to be based on weathering (seems reasonable enough.) But what creates them in the first place? There are a number of explanations online (Wikipedia lists eight plausible ...
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Is sterescope still used to do cartography with orthophotography?

I used this tool at my degree a couple of lusters ago to do cartography with aerial orthophotos. We used it on cartography and geomorphology subjets. Source: gumtree.com The method consists ...
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what type of rock is this? blue/green and brown [closed]

I found this rock while up in the mountains and I have no idea what type of rock it is.
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Assessing graded bedding in metamorphosed pelitic sediments

I have the following image of metasedimentary outcrop from a Proterozoic continental rift-fill sequence: The middle layer has a pelitic composition and contains abundant cordierite porphyroblasts (...
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Is this a geode?

So just having issues with identification looks like a outer line of rock a bit transparent but the inside polished looks waxy other side of stone a bit more foggy but still blue visible Edit - ...
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What is this heavy green rock?

I found this grenish rock at a beach in Northwest Ireland called Inishcrone. It measures 45mmx35mmx22mm. It weighs 57 grams and has a density of 2.90. It is opaque, does not attract a magnet. It ...
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What is this heavy, dark grey and almost round rock?

I found this 'rock' on the beach in North West Washington State. It's almost perfectly round save for a few bumps, it's dark grey in colour, solid, feels smooth like any stone you'd find on the beach,...
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How much hydrogen can be extracted from the deep continental crust?

Far below the earth's surface, hydrogen gas is continuously produced through serpentinization. At least some fraction of this hydrogen remains trapped in the deep continental crust; indeed, Soviet ...
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What leads to formation of a nonassociative gas reservoir?

Why in some cases natural gas occurs in association with oil (associated gas) and in others there is no oil (nonassociated gas)? Is it because of the type of the rock? Or is it the pressure/...
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Can someone help ID this rock [on hold]

Found today in a creek in Indiana, has a geode look and the broken edge shows red opaque facades.
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Identification required, rock formation found whilst on holiday in Cephalonia, Greece white object embedded inside?

This rock was found in kephalonia Greece, on a beach in lassi. The rock is black in colour, smooth with thumb like prints, very metallic smell and very slightly magnetic. We took this rock to oxford ...
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Which ocean is going to be swallowed by the Supercontinent Cycle, Atlantic or Pacific?

The register shows several supercontinents have been formed on Earth's History: "The most recent supercontinent, Pangaea, formed about 300 million years ago (0.3 Ga). There are two different ...
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could a rhyolitic magma melt a ferromagnesian mineral like olivine?

if the temperature of a felsic magma is about 800-650 °C and olivine melting point oscillates between end members forsterite and fayalite near 1900-1200 °C, Does this mean that an olivine crystal in ...
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Can anyone help me identify this type of translucent green mineral? [closed]

This is the photo of the rock. I found it in the mountains in yemen, near rocks where a well was dug out. Its translucent green and It doesn't feel that heavy. I think it's some type of quartz.
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Why doesn't Earth absorb our carbon emissions?

If we look at the carbon cycle, we see that man-made carbon emission only account for a tiny fraction of all $\text{CO}_2$ emissions. However, we see a steady rise in atmospheric $\text{CO}_2$-levels....
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Is there a name for subduction boundaries at the North of Australia?

I know the ridge at the South of Australia is named Southeast Indian Ridge. I would like to know if there is a geological name for the three subduction branches that cross indonesian zone, at the ...
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What are the farthest Time Zone locations? [closed]

What place in the world has the farthest time zone? I heard it was Kiribati but then I found that Apia (Samoa) is further. So, is there anyplace that is the farthest in time than these two? What about ...
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How can I identify “tough” (mixed) granites?

I am trying to parse an old geologic description of stone suitable for use as road metal: Care must be taken to distinguish the difference between the hardness of a stone and its toughness......
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Can gemstones be cut into sheets? [closed]

TL;DR: Without lasers, electricity, or otherwise modern tools, could large transparent gems be sliced (like glass window)? So I’m world building. On this planet they have caves with enormous gemstone/...
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What is the basis for the Geologic Time Scale

The Geologic time scale was completed in the mid to late 1800s. What methods were used to date the various subdivisions?
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Is this Dragon Jasper?

Bought these rocks at a shop they were selling as Dragon Jasper,but when I density tested them they were 3.09 which I thought was a bit high for Jasper, and generally Dragon Jasper has Deep red veins, ...
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An oblique-square-prism crystal?

Does any mineral crystallize in the shape of an oblique square prism? If so, what crystal system (monoclinic, cubic, hexagonal, etc.) would such a mineral fall under?
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Is this an agate? [closed]

So I have found these in a creek there are some that look like this and I have broke them open and they were full of crystals these seem to small and I have tried cracking then and they wont budge I ...
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Did low $\small\sf{CO_2}$ levels affected Permo-Triassic mass extinction?

After answering this question: How did plants adapt to $\small\sf{CO_2}$ levels past 400k years? Why won't they do it again? I know Permo-Triassic mass extinction is associated to a catastrophic ...
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How Big Were the Siberian Traps ORIGINALLY?

252 million years ago, Siberia was subject to a mass series of flood basalt eruptions, creating a large igneous province called the Siberian Traps. Today, it measures 2.7 million square miles in area ...
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What is an isolated land area of one type of rock surrounded by land of a differing rock type called?

For example, if there were a large land area with exposed basalt, in the middle of which is a smaller isolated patch of Granite, what is that isolated patch called? I came across the single-word ...
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I found this rock on my property years ago and was curious what it was [closed]

What kind of rock is this? I found it on my property a long time ago and I can pinpoint exactly what. I was thinking red jasper maybe?