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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3
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2answers
118 views

How abundant is high purity silica?

Silicon is often touted as the second most abundant element in the Earth's crust. However, this can be misleading when looking at the abundance of high purity silica needed for manufacturing ...
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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 ...
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1answer
471 views

Carbon's role in ocean acidification

This might seem like a basic question, but I'm a little confused about the effects on ocean acidification of different carbon compounds. I have heard that increased levels of carbon dioxide in the ...
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26 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 ...
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1answer
38 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 ...
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2answers
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Why does phosphate rock contain uranium?

I have been doing some research on the issue of phosphogypsum pollution. Phosphogypsum is a waste by-product formed with the "wet process" method of extraction of phosphoric acid out of ...
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1answer
113 views

Are there any sulphides, sulphates, carbonates that cannot be dissolved by aqua regia?

I was looking into these specific minerals: arsenopyrite, pyrite, chalcopyrite, barite, calcite, dolomite. I investigate issues with tellurides not showing expected gold concentrations. There is gold ...
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32 views

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?
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1answer
122 views

Do carbon dioxide hydrates exist in nature?

Do CO2 hydrates exist in nature? If so, how much carbon could they contain?
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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?...
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1answer
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How do hematite and magnetite form?

I want to understand the conditions under which hematite $\ce{Fe_2O_3}$ and magnetite $\ce{Fe_3O_4}$ form in nature. The linked Wikipedia articles explain various conditions under which they form, but ...
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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 ...
3
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1answer
34 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). ...
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How are Mauna Loa $\ce{CO2}$ monthly trends computed?

The problem I am trying to figure out how $\ce{CO2}$ concentration trends are computed in the data provided by the Earth Systems Research Laboratory Mauna Loa Observatory. The data contains monthly ...
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1answer
135 views

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 ...
11
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1answer
225 views

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 ...
13
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1answer
519 views

How is abundance of elements in the Earth's crust estimated?

In an quiz app I surprisingly learned that aluminium has a larger abundance then iron. When researching this on Wikipedia, I found this article, which also had the comment: Note that numbers are ...
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2answers
244 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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0answers
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Formation of Hematite on Mars via Perchlorates as an Oxidizer

Hematite on Mars is generally thought to have formed either in pools of water or from volcanic activity. A comment to the answer to the question: How do hematite and magnetite form? states that ...
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5answers
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What is the origin of the dominant atmospheric nitrogen content in Earth's atmosphere?

Comparing the atmospheric compositions of Earth with our nearest neighbours: As the table shows, the Earth's atmospheric nitrogen concentration is 78%, compared to 3.8% for Venus and 2.7% for Mars ...
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2answers
158 views

Relationship Between Ratio of Atmospheric Gases and Ocean Gases

A version of this question was posted in Chemistry SE and Worldbuilding SE but I've been told it wasn't appropriate to either SE. I was told to give this SE a chance. If you think it doesn't belong on ...
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1answer
79 views

Why is calcium so much more abundant in/on Earth's crust (and oceans) than it is elsewhere? (relatively speaking...)

Inside the entire Earth as a whole, and throughout our Solar System and galaxy, etc., magnesium is at least 14 times (or more) as common as calcium, atom-per-atom. But, on Earth's crust and oceans, ...
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2answers
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Calculating/estimating volatiles based on other representative samples

I am currently working on a set of geochemical data representing calc-alkaline igneous intrusions from central Canada. The samples were analyzed in ~2013-2014. These samples have been tested for LOI ...
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1answer
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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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Looking for a complete table of minerals for a database

I am building an open source spatial geochemical/geological observational database for mineral exploration. I need to fill the mineral lookup table. Where can I find a complete list of all minerals ...
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1answer
410 views

How much silicon is in the Earth's core, and how did it get there?

With some informal conversation with a peer of mine, he had suggested that there is evidence (which he couldn't find,but had remembered reading) that there was Silicon in the Earth's core. I referred ...
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603 views

Composition of Martian Crust

Does the composition of the crust of Mars roughly correspond to that of the crust of Earth. That is, is the elemental abundance in decreasing order silicon, oxygen, aluminum, etc.?
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98 views

How much does the gravitational and magnetic fields of a planet effect the chemistry in it?

It is known that the earth has a magnetic field and gravitational field around it, I wish to ask to what degree is the chemistry on the planet is influenced by these fields? How would the chemical ...
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1answer
45 views

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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2answers
99 views

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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2answers
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Is weathering of rock a primary means of $\text{CO}_2$ scrubbing on primordial Earth?

I read somewhere that the reason Venus has a runaway greenhouse effect and Earth doesn't is because Venus failed to develop tectonic plates and instead formed a full tectonic plate enveloping the ...
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1answer
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Employment of Volcanologists and Petrologists

What industries or government departments hire volcanologists and igneous petrologists/geochemists in the United States?
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2answers
3k views

What exactly are enantiotropic and monotropic polymorphic transitions?

Recently, I've been studying the subject of polymorphism and met two important concepts, the monotropic and enantiotropic polymorphic transition types. However, I can't really seem to grasp the ...
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2answers
280 views

Where does molecular hydrogen in the atmosphere come from?

This figure from Wikipedia's Atmosphere of Earth shows a hydrogen fraction of 0.000055 percent by volume. Question: Where does molecular hydrogen in the atmosphere come from? Does this come directly ...
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2answers
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Are there any metal anomalies other than iridium in the K-Pg boundary?

The iridium anomaly marks the elevated concentration of iridium in sedimentary deposits of the Cretaceous-Paleogene boundary. The iridium is said to come from the impactor, which is supposed to have ...
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3answers
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Is the magma in one volcano different from the magma in every other volcano?

First off, a confession: I'm asking this question because of The Lord of the Rings. If you're not aware already, in the story, a magical ring can only be destroyed in a specific volcano. The reason ...
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1answer
229 views

Does Xenon really covalently bond to oxygen within quartz?

Wikipedia's Xenon; occurrence and production says Within the Solar System, the nucleon fraction of xenon is $\small\mathsf{1.56 \times 10^{-8}}$, for an abundance of approximately one part in 630 ...
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1answer
84 views

Relation between molecular mass and retention of a gas on a planet

An Introduction to Our Dynamic Planet under section 2.4 "The origins of the atmosphere and hydrosphere"(Page 80) says on the topic of gases escaping from our atmosphere as: Different gases ...
4
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1answer
58 views

Phosphate in the oceans, does it tend to bond with sodium?

Phosphate has a major role in biology and the biosphere. In its "abiotic" form, floating around in the oceans, lets say marine oceans to be specific, does it tend to be in the Na3PO4 form? ...
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4answers
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What was the first rock in the rock cycle?

I am an undergraduate student but I am a tutor at a High School, and one student asked me. Attempting to explain the rock cycle "if one rock turns into the other then which came first" my gut is ...
6
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2answers
453 views

Why doesn't the Earth's outer core dissolve into the mantle?

It is well accepted that the outer core is made out of liquid iron and nickel, and as everything else it should tend to reach chemical equilibrium with its surrounding. In particular, I would expect ...
4
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1answer
177 views

Why is the concentration of highly siderophile elements so uniform in the mantle?

The plot above is about the concentration of siderophile elements in the terrestrial mantle. From the logarithmic plot, we can deduce that the concentration of highly siderophile elements is quite ...
4
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1answer
110 views

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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1answer
192 views

Does the heating of the oceans due to greenhouse effect negate the acidification due to increased CO2 levels?

As I understand, the dissolving of carbon dioxide leads to increased acidification of the oceans, and thus increased atmospheric CO2 levels would lead to more dissolution in the oceans and thus ...
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1answer
3k views

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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2answers
581 views

Non-invasive techniques to find rock composition

If we had access to a totally new kind of rock (maybe a new meteorite), is it possible to tell what the rock is composed of without touching it / drilling into it? I'm thinking of something like ...
7
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1answer
532 views

Diamond at the core of Jupiter

Arthur C. Clarke, who correctly guessed there would be liquid water on Europa, posited a diamond core for Jupiter. Is this possible?
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2answers
122 views

Is there a risk with putting out smouldering underground coal reserves? [closed]

According to this Discovery News video about Centralia Pennsylvania and other underground coal fires, there are many smouldering underground coal reserves making the land above it uninhabitable to ...
4
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1answer
506 views

The effect of CO2 concentration on the pH of the ocean

I'm confused about how increased $\ce{CO2}$ concentration in the atmosphere affects the pH of the ocean. The increase in $\ce{CO2}$ concentration means the pH of the ocean will decrease (by several ...
3
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1answer
46 views

Is CO2 in the Pacific Ocean depleted or enriched in Carbon-13 compared to the Atlantic, and why?

Due to thermohaline circulation, the Pacific water is more 'aged' so there is a higher amount of total dissolved inorganic carbon (e.g. CO2) in the deep Pacific when compared to the Atlantic. However, ...

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