Questions tagged [geochemistry]

The science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems.

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What is a good definition for "lattice bound" and is iron within octahedral sites of illite considered lattice bound or interstitial?

The title pretty much says it all. I cannot find a satisfactory definition of "lattice bound", just a number of examples of it being used in literature. For example, in this paper about ...
Josiah's user avatar
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Likely air composition in cave only accessible from underwater?

I recently stumbled on the images of the Cosquer cave, located in France, famous for being a comparatively recently discovered as a Paleolithic decorated cave. The entrance to cave now is more than ...
Gnudiff's user avatar
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Does each volcano have a fingerprint?

Thinking about arc volcanism in a region, and there are two neighboring composite volcanoes 50 km apart from each other. Do you expect any differences about their products (lavas, pyroclastic deposits)...
Muharrem Yavuz's user avatar
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1 answer
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Does anyone know what the mineral of the year 2023 is?

I am collecting every mineral of the year since 2012, and I have not found anything on last year's mineral. Thank you.
Lalith_Aditya's user avatar
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1 answer
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Why don't most organisms use magnesium in their shells and bones if it is lighter and more common than calcium?

Magnesium is one of the most abundant elements in the Universe and on Earth.... So why is it not used in the forms of Magnesium Carbonate and Magnesium Phosphates (Hydroxyapatites, etc.) to make ...
Kurt Hikes's user avatar
5 votes
2 answers
167 views

Why are ionic bonds considered the "dominant" type in minerals?

I'm just starting out in geology and I keep reading that ionic bonds predominate among minerals. However, the majority of minerals are silicates and the silicate ion has covalent bonds, so they ...
vortek's user avatar
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What is the reason that some elastic constants are negative?

In this table of elastic constants, indices m = 1 and n = 4 result in negative values. What could the reason be?
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Estimation of rare earth elements in the SUAC complex

I am currently competing in a case study competition a part of which has asked us to estimate the amount of Nd, Pr, and Dy in the SUAC complex (Sung Valley Ultramafic-Alkaline-Carbonatite) in electric ...
Vijay Arvind's user avatar
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1 answer
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Interpretation of Phanerozoic CO2 levels graph

I used to talk with a family friend who often sent me links to Nobel Prize winners, claiming that climate change is a myth. Last week, we had a disagreement over a link referencing a Nobel Prize ...
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1 vote
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Co variance of isotopes in geochemical amplications

I recently heard that the d98Mo isotope is not different from the d238U isotope in redox processes e.g. in black shale events. But I can't find any evidence except the figure from Zhang et al. ...
Weiss's user avatar
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If the universe (and our galaxy) has about twice as many oxygen atoms as carbon ones, why does Earth have 300 times as many oxygen atoms as carbon?

A (relatively) recent 'Sky & Telescope' magazine feature story mentioned how little carbon the Earth has, and how some scientists' models predict we should somehow have even less.... So I looked ...
Kurt Hikes's user avatar
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Can $\ce{CaCO3}$ shells contribute to $\ce{CO2}$ emissions in volcanoes within subduction zones?

CaCO3 dissolves below the Carbonate Compensation Depth (CCD). However, this paper suggests that some CaCO3 can exist below the CCD. My question arises from a discussion in this answer. The question is ...
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1 vote
1 answer
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Is it possible that the rainbow sand dunes in Death Valley, California were formed by some massive mining in the ancient past? [closed]

I know there is a mainstream answer that thinks the rainbow sand dunes they be explained geologically... I just want to know if it's possible to form those colors and those dunes from mining? And if ...
American woman's user avatar
1 vote
1 answer
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Does granite and basalt behave differently in different atmospheric pressures?

We all know that the oxygen levels increase and decrease as well as the temperature, so I believe it's safe to assume atmospheric pressure changes as well... And since granite and basalt are formed ...
American woman's user avatar
5 votes
2 answers
199 views

Why does calcium occur together with felsic rocks and magnesium with mafic rocks if calcium is denser than magnesium?

Felsic rocks contain a lot of sodium, potassium and calcium (and a great deal of aluminum), while mafic rocks consist of a lot of magnesium with iron.... Why is this? Why is magnesium (z=12) in the ...
Kurt Hikes's user avatar
2 votes
2 answers
3k views

How do I convert an element measurement to oxides?

So, I did some measurements in ICP-OES and the results were given to me in elemets. However, I need to convert the results to oxides. After some googling I found out that I need to use simple ...
Ferreira's user avatar
45 votes
2 answers
12k views

Why is NaCl so hyper abundant in the ocean?

Why is sodium chloride far and away the most abundant salt dissolved in ocean water? Its two constituent ions do have a very high frequency in the crust of the earth, but they are far from the most ...
Fraser Orr's user avatar
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Reason for finding low boron levels in clayey soil with high organic matter?

I've read from various University Extension sites (e.g., here and here) that boron levels would be deficient in sandy soils with low organic matter. This would suggest that boron levels would be ...
theforestecologist's user avatar
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Causes of high calcium levels in sandy alluvial soils

When soil calcium is high: High levels of soil calcium may be expected when there is substantial calcium carbonate bedrock from which the soil has weathered. Calcium levels can be high in agricultural ...
theforestecologist's user avatar
2 votes
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Searching for Geochemical Threshold for PTE's of Spain

Where can I find a table with the geochemical threshold for potentially toxic elements in the soils of Spain? I only have seen a decree with organic compounds for Spain.
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Why does decreasing surface alkalinity increase surface pCO2?

According to Takahashi et al. (1993), pCO2 (partial pressure of CO2) in the surface ocean changes due to 4 surface variables: temperature, salinity, total carbon (dissolved inorganic carbon, DIC) and ...
earthyguy's user avatar
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Under which conditions would you see the MOST lake effect precipitation?

It's well known that the Great Lakes produce large amounts of precipitation in the Fall. When cold polar air moves over the lakes it causes large amounts of relatively warm moist air to rise, ...
user3501561's user avatar
4 votes
2 answers
235 views

Why is there gold in the earth's crust?

I would naively assume that when the earth was formed and still molten, all the heavy stuff such as gold would have sunk to the centre, so almost nothing would remain in the earth's crust where humans ...
David Bailey's user avatar
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11 votes
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What oxidised the soil on Mars?

What exactly was it in the ancient Martian atmosphere that made it red? Was it water, molecular oxygen or something else?
Andykins 's user avatar
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Help me find a certain type of crystallographic notation

I was looking through wikipedia a few weeks ago while half asleep, reading articles about rocks and their chemical compositions. I then came across a certain crystallographic notation which I had not ...
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2 votes
1 answer
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Why is silver found mainly in lead

Apparently according to the Parkes Process silver is 3000 times more soluble in zinc than in lead. So why is it that most silver is obtained from galena? Edit: “ Silver mainly occurs as a contaminant ...
Liam Clink's user avatar
2 votes
0 answers
26 views

Calculate original volatile content of a degassed mineral

A lunar apatite sample has a relatively low OH content of 5 ppm, but a an elevated D𝛿 of 11,000‰ (vs. SMOW). Assuming that water had an original figure of around -100‰ or so, how do I estimate the ...
Andy's user avatar
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1 answer
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Is experience abroad important for your career?

I'm just finishing my Bachelor's degree in Geochemistry at a German university and will soon start my Master's degree, but I've been wondering for a few weeks whether a stay abroad (1 semester or even ...
Weiss's user avatar
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1 vote
1 answer
379 views

What does fugacity mean in the context of geology?

I am reading about water in the Lunar mantle, however it mentions fugacity a lot. What does it mean in this context?
Andy's user avatar
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3 votes
2 answers
103 views

Where is basalt in the Goldich dissolution series?

In relation to this experiment: https://www.remineralize.org/rem_publications/action-of-microorganisms-in-basalt-powder/ It is said that applying basalt rock dust to soil can improve soil fertility ...
Dave Kirkby's user avatar
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0 answers
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Kinetic or equilibrium fractionation from 2H and 18O in evaporation and condensation?

Is the isotope fractionation that occurs during evaporation of surface water equilibrium fractionation or kinetic fractionation? I mean, evaporation can be described by Rayleigh fractionation, but I ...
Weiss's user avatar
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What chemical or physical parameters altered during the usage of buffered versus unbuffered extractant for leachability of a soil or sediment?

Toxicity characteristic leaching procedure (TCLP) is an extraction method to simulate a soil or sediment leaching. The method employed two extraction fluids - one is a buffered solution of acetic acid ...
làntèrn's user avatar
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Is this kind of sediment location sampling on river acceptable?

Yesterday, we performed a sediment sampling along both sides of a river. On various research papers, it seems that they always made it successfully to perform the sampling at both left and right side ...
làntèrn's user avatar
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6 votes
1 answer
687 views

Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?

This answer to What is the nature of "rock vapor" in this description of the formation of the Moon? explains what "rock vapor" is and how scientists use the concept to understand ...
uhoh's user avatar
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4 votes
1 answer
203 views

How did hydrogen make its way into proto-Earth?

Background I read (what I could understand of) this article in which authors Yuan and Steinle-Neumann "...use advanced quantum mechanical simulations on silicate and metallic melts showing that ...
g s's user avatar
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10 votes
3 answers
2k views

Taking into account the decay products of transuranic elements, are the world's uranium reserves growing or shrinking?

I was talking to a friend of mine who is an environmentalist like me but not a big fan of nuclear power and she told me it was not a good option in the long run because of the decay of uranium. Of ...
ablon's user avatar
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2 votes
0 answers
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How should we deal with geochemical anomalies in stream sediment?

We know that geochemical anomalies in stream sediment usually distributed along the drainage. Therefore, when we use stream sediment as the sampling medium and found an anomaly, we should trace the ...
tunar's user avatar
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3 votes
1 answer
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Reconstructing lake level from organic and magnetic sediment data

I would like to understand why any of the following conditions in a layer of a lacustrine sediment core appear to imply that the lake level was low at the relevant time: low C/N ratio low δ13C low ...
qr597's user avatar
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3 votes
1 answer
309 views

What are the compressive strengths of goethite and magnetite?

I am attempting to determine what the compressive strengths are of the minerals goethite and magnetite. None of the research I did has proven to be fruitful. What I have found: multiple studies ...
KEY_ABRADE's user avatar
2 votes
2 answers
205 views

What is the role of trace elements in magmatic crystallization?

I understand that trace element behavior in a system depends on whether they are compatible or not. But , if that question is asked in an examination , what could be the points that one should write ...
Knight's user avatar
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5 votes
0 answers
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Carbon emission from estuaries

I've heard that estuaries like Chesapeake Bay produce a lot of methane during anoxic conditions. Is there a chance of these estuaries emitting significant amounts of CH4 in the future (because of the ...
Victor1995's user avatar
5 votes
0 answers
42 views

Can geochemical anomalies of stream sediment samples be used directly for mapping targets?

We know that geochemical dispersion in stream sediment is much widespread, facilitating discovering mineral targets in a regional scale. However, we also know that there should be discrepancy in space ...
tunar's user avatar
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1 vote
0 answers
96 views

convert mol/m2 to μg/m3 [duplicate]

Sentinel-5P satellite provides high-resolution data products on concentration levels for several atmospheric trace gases (NO2, SO2, O3, and others), which are measured in mol/m2 within the total or ...
Md.Rased Hasan Sojib's user avatar
4 votes
1 answer
42 views

Why were Fe-oxides not usually used for finding skarn Fe ore deposits in geochemical exploration?

I found that Fe-oxides were usually not used for vectoring Fe mineral deposits of skarn type in geochemical exploration. As an indicator element, the common practice told us Fe-oxides should be the ...
tunar's user avatar
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4 votes
0 answers
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What is the electrical conductivity of a liquid Komatiite?

I am searching for previous work that has determined the electrical conductivity range for komatiites at the surface. Does anyone have some values or references?
thehungrygraduate's user avatar
8 votes
2 answers
2k views

Do lead 206 and other daughter isotopes occur naturally?

I am reading studies about the age of the earth and U-238 to Pb-206 comes up a lot. My question is: In meteorites, or really anywhere, is lead 206 natural or does it always come from radioactive decay?...
Beans's user avatar
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6 votes
1 answer
316 views

Do carbon dioxide hydrates exist in nature?

Do CO2 hydrates exist in nature? If so, how much carbon could they contain?
Victor1995's user avatar
5 votes
0 answers
52 views

Artifical Ore Genesis?

From my understanding, the formation of ores can be reduced to a simple three-step process of the removal of minerals from a source via some mechanism, the transportation of these minerals, and ...
zachery moïse's user avatar
3 votes
1 answer
38 views

Spatially-explicit global database of parent rock chemistry?

As the title suggests, I am looking for the most reliable database(s) of parent-or bedrock chemistry, e.g. the concentration of nitrogen, phosphorus and some other metals (basically plant nutrients). ...
y chung's user avatar
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-2 votes
2 answers
374 views

How are we going to handle oxygen shortage problem arising due to massive usage of current fossil fuel combustion and future Hydrogen fuel cell tech?

This question is being redirected from the Chemistry Stack Exchange community. The current corona pandemic has created a situation where in order to save lives, there is a huge huge requirement for ...
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