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Questions tagged [geochemistry]

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

Geochemistry is the field that studies the chemical composition of natural systems. This includes rocks, water and air. The branch of cosmochemistry deals with extraterrestrial materials like meteorites or samples form other planets and moons.

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Why is hydrogen formation in serpentinisation an exothermic reaction?

In the process of serpentinisation, protons act as oxidising agents for ferrous ions, which results in the production of dihydrogen gas. How is that possible? Dihydrogen being a strong reductor, I woud expect this reaction spontaneously going the…
Chris D
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Marine and freshwater geochemistry

As rivers flow into the sea, rivers contain a high concentration of calcium and carbonates, and a low concentration of sodium and chlorine, and for marine water it is vice versa. How come?
Khaled El-kilany
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What is the difference between chalcophile and siderophile elements?

As it is described (W. M. White, Geochemistry): Siderophile elements have an affinity for a metallic liquid phase and chalcophile elements have an affinity for a sulfide liquid phase. What is the exact difference between them? It just…
marianess
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What are the formula weight and gram-formula unit (gfu)?

I'm reading Shaw's "Trace Elements in Magmas" and in his page 16 he writes the following: ...It is necessary to look at the relationship between $c_i$ and $x_i$, i.e. the weight and molar concentrations. In any phase of weight $W$ the weight of…
Gimelist
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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 obviously are everywhere, too. (Not to mention…
vortek
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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 wt%, but not H2O, CO2...etc. Historical…
Nancy
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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 reactions seen everyday on earth be different if the…
user21385
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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 semiconductor wafers. What purity level is required in…
gstudent
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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 to answer that?
Knight
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Why is sulfate reduction less important in freshwater sediments?

Is this due to increased salinity reducing sulfate concentration or the production of marsh gas converting sulfate to hydrogen sulfide or something else?
Jon
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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 1 year) is important and when it's best to do…
Weiss
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