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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24 views

Stratigraphy of limestone applied to the Great Pyramid of Giza

The Great Pyramid of Giza is made from blocks of limestone quarried from the Giza plateau. The pyramid is composed up of about 200 layers, with individual blocks varying in thickness from 20 to 60 ...
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How to read stratigraphy data?

I have a list of geological data. The data is for 3 variables: member, level and L+/- These variables correspond to a particular position on a stratigraphic column/chart. I would like help with ...
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How can the 'crystal cleavage' of apatite have a four-digit number?

On Wikipedia's page for apatite, the crystal cleavage is listed as [0001] or [0101], which I assume are Miller indices.... But how can there be four numbers/digits instead of two, like there usually ...
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How do you infer what a cross section might look like below sea level?

Here is a schematic of a cross section which should represent an anticline: https://postimg.cc/4HcmmZ26 Below sea level, I have inferred what the units might look like with the dashed lines. As I have ...
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What is the best way to split strike and dip data on the image provided into “domains” in order to interpret folding on a stereonet?

Link to the original image: https://postimg.cc/v4bRqxxR I believe this image represents two folds which are overturned and plunging. I would like to analyse these folds on a stereonet, but I am unsure ...
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Ages of chemical elements [duplicate]

how can we assume the creation age of the current chemical elements and the age of non-existent elements of 8-10 rows of the periodic table? how to estimate the time of creation of new elements in ...
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Why is Earth's density gradient a step-function, rather than smooth?

Why is the density of particles in Earth's atmosphere above surface-level so much less than ground and below? Why, instead, isn't Earth simply a ball of swirling gasses / liquids, which become ...
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Are metals and other elements in every continent?

I originally thought that you can only find certain things like iron, copper, and other things in certain places in the world and deep in mines but I saw in a few YouTube videos that you can find iron ...
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Are Fluvial and River Terraces the same?

I study about fluvial terraces. However, resources related to this topic are limited. When I searched fluvial terraces in geomorphology books, I cannot find anything, but I find river terraces. My ...
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1answer
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What happens when a mid-ocean ridge sub-ducts underneath continental crust?

I'm aware that oceanic crust always sub-ducts to continental crust, but surely the geologic forces pushing the ridge apart in the first place isn't just going to turn off, right? Any answers would be ...
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Question Concerning Meteorite Ejecta Travel

I was researching more into the studies done by Kjaer and his team ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6235527/ ) concerning the hypothesis about the Younger Dryas impact crater named ...
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Identifying thrust faults on a geologic map

I am not able to upload the map as the file is too large, but I have a map which states there is an over thrust fault. It has two ticks on it indicating downthrow to the NE. The downthrow is pointing ...
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Is it a Lake, Cove, Tidal Creek or a Spring?

We are very confused by this water body. This is called "Carolina Lake" however other suggests that it is not a Lake but a cove. Other say it is a tidal creek for it is influenced by tide. ...
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How would one go about drawing the contour lines for this map in order to draw the cross section?

Good Day. We Received this map as practice for our Geology university module and I have no idea how to draw the strike lines where the different heights intersect the different rock types in order to ...
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Structural geology

Map 4 shows two dykes that have been offset by a vertical fault. In different coloured pencils, draw strike lines on each dyke. (a) On a blank sheet of paper, use the strike lines that you have drawn ...
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Will the sea get saltier forever?

The sea wasn't always salty. It's been getting saltier over millions of years as minerals dissolve. Is there a natural limit to this process, or the will the sea keep getting saltier forever? Is there ...
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1answer
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How are tall cays formed?

From reading about Cays on Wikipedia it seems they are formed from coral reefs covered with sand or gravel. There are however some cays scattered around the world which are hundreds of feet off of ...
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SC7 and SC10 Lithology Classifications

I am looking for the full names of the lithology classifications SC7 and SC10. According to the FAO's guidelines for soil description SC3 e.g. refers to silt-, mud-, claystone. What do SC7 and SC10 ...
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Does science suggest Venus would resume plate tectonics if surface water were somehow reintroduced and rotation sped up? [closed]

Assume that we're talking about a terraformed Venus with an Earth-like atmosphere so no risk of the water simply boiling away before being allowed to permeate the lithosphere. Does this meet the ...
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1answer
52 views

How did Mount Evans become a mountain?

Multiple websites state that the mountain, which is in Colorado, was formed by an intrusion of magma about 1.4 billion years ago, forming a batholith. On the other hand, the rocky mountains are said ...
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1answer
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What is this red glassy rock [closed]

I found rocks looking like this in my backyard but cant get to know what they are or how to find out. Below are pictures I don’t know if there’s more info I should mention. If there’s anything please ...
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How many years does it take for rivers to form?

I've looked this up as best as I could and couldn't find a clear answer. I've seen for example articles on the age of several rivers as being the oldest ones, but nothing regarding the opposite. Could ...
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1answer
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How are Quaternary alluvial deposits differentiated in subglacial latitudes?

The USGS maps of coastal California label alluvial deposits as Qyf and Qof — the “younger” and “older” fans of coarse sediments. But in areas of the earth that never saw Quaternary glaciation (like ...
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Why REE concentration in a melt due to fractional melting is less than in a melt of same source rock due to batch melting?

I plotted this ree data for batch melting and fractional melting for the same source. From the plot we can see that the melt due to fractional melting is more depleted in REE than the melt due to ...
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1answer
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Will California become a subduction zone in the distant future

California is one of the few places in the world that lie on a transform fault. My question is why considering the fact that North American Plate is moving westward shouldn't California be a ...
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Is it possible for Mexico to have a magnitude 9 earthquake?

Everyone has heard of the Cascadia Subduction Zone and the potential threat it poses. However, I have heard nothing about The Cocos Subduction Zone, even though it caused a devastating earthquake over ...
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What formed this rock slide formation near Hyndman Peak Idaho (photos)?

While hiking Hyndman Peak in Idaho a couple weeks ago we noticed a rock slide that appeared to be formed by a glacier, however it was on the west side of the mountain. It was also strange that the ...
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How much role does radioactivity play in making Earth geologically active [duplicate]

A hot molten core is important for making the Earth geologically active. I believe most of the heat is from the time of the planet formation, and the high pressures due to everything pushing down to ...
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Megaspherulite growth

I have been fascinated by photos of these for a while, and I would like to ask how megaspherulites grow so large, when spherulites are normally quite small? I also noticed that all papers about the ...
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Is there a way to convert from Dip direction to Strike direction?

I have some set of recorded data in dip direction/dip format. I wish to transform then to strike/dip. I am currently having a hard time imagining how to convert from dip direction to strike direction. ...
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1answer
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regarding four-way closure in structural geology

I am a little bit confused on the two concepts in structural geology, i.e., what is the relationship of anticline and four-way closure. My understanding is that anticline belongs to four-way closure. ...
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Urgent, Please help, where can I find worldwide standards of manganese mining?

Hi everybody who sees this post, I need urgent help for finding all official world wide standarts of the manganese mining. Problem is that, many houses has been damaged in my village with manganese ...
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Crustal age global map

I've been searching for a map depicting the age of each part of the crust for a long time. I'm not a geologist but I'm a physicist so I would like to know about the most up-to-date and accurate ...
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3answers
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Book recommendation for 7 year old

By some poorly understood series of events, I have managed to convince my 7 year old daughter that she wants to be a geologist when she's older. Of course I'm aware that this likely won't be the case, ...
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Looking for videos/GIFs of petrification/permineralization

Do you know of any good animations, videos, or GIFs of petrification/permineralization? For some students verbal and written explanations don’t work, they don't always visualize well. So it’d be ...
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What is the scientific reason for Falgu river being subterranean?

According to wikipedia "The Phalgu or Falgu, a river that flows past Gaya, India in the Indian state of Bihar, is a sacred river for Hindus and Buddhists. Lord Vishnu's Temple Vishnupad Mandir is ...
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Using Enhanced Rock Weathering in the Sahel Region of Africa

A recent Guardian article "Spreading rock dust on fields could remove vast amounts of CO2 from air" has gotten some attention in the nongovernmental and UN organizations working in the Sahel ...
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How does uplift lead to onlapping?

I read in a paper that: Interpretation of 2-D seismic lines shows the lower to middle Patchawarra Formation onlapping onto paleostructural highs at approximately 270 Ma and again at 273 Ma, ...
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Principal component analysis (PCA) and normalization of radiometric data?

I did some experiments with airborne radiometric data in a region in southern Brazil and I would like to know your suggestion about the following topic: I tried to classify high, medium and low ...
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What kind of soil is being worked in this video? [closed]

I have recently stumbled across this video on Youtube, where quite a magnificient building is carved into the soil with simple tools like a shovel and hoe. The location is somewhere in South America, ...
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1answer
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Pressure Increase in stone and in water

Why does the pressure increase only by 0,3-0,4bar per km in stone but 1bar per 10m in water while stone has the higher density?
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What is the most expensive project related to Earth's geology and/or to engineering geology on the Earth? [closed]

Costs related to space exploration are well documented. However, what about the costs of Earth projects like dam/mines/tunnels? What has been the most expensive projects? I know that nuclear power ...
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Why is Cambrian denoted with such a weird symbol?

I find Ꞓ such an odd-looking symbol. What's the historical significance, etc, of that symbol? Latin letter C with bar My understanding is, C was the Carboniferous, K for Cretaceous... why not ...
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What do scientists mean when they say the Earth formed 4.56 billion years ago? [duplicate]

Does that mean that the Earth gained the classification of a planet that long ago rather than some other celestial body? How did they determine that this happened that long ago? How discrete is the ...
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What local formation am I drilling?

I'm having a water well drilled on my property. The drilling crew has been working since Wednesday. They are using an airlift rig with a 6in bore. They are at 300ft and only have 4gpm. I would really ...
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1answer
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What would a rock thin section look like without any polarizers?

I'm interested in knowing what features can still be discerned. I've been struggling find any image of a thin section of a rock under a regular light microscope, or a petrographic microscope with the ...
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What was the Earth's continent's positions 10000 years ago, or 11700 years ago, AKA when the late Pleistocene epoch was coming to an end?

In many articles online, geologists and geographers have described and depicted the theorized locations of all our continental plates with great detail and illustration, providing pictures, time-lapse ...
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Are the precious metals (silver, gold, platinum) present everywhere throughout the Earth's crust at least in the trace quantities?

Do some rocks, soils, sands or waters exist that contain fewer than one atom of gold per cubic meter or tonne of their mass?
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Geo-Spherical shape of Earth

I know that the best possible approximation of the shape of earth is an oblate sphere. But people also call it as geo-spherical shape of the Earth. What is the meaning of geospherical shape? Does this ...
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How do you choose appropriate parameters for a lowpass filter when filtering a Bouguer anomaly?

I am trying to filter my Bouguer anomaly data to remove the short wavelength features. I have created a lowpass filter to achieve this, but I am wondering how I can more objectively choose my cutoff ...

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