47 votes
Accepted

Why is NaCl so hyper abundant in the ocean?

Fluoride salts tend to be not particularly soluble in water. Chloride salts are. The same goes for salts containing sodium versus those containing calcium. Sodium chloride is ridiculously easy to ...
  • 22.4k
41 votes

Why is NaCl so hyper abundant in the ocean?

Solubility. The question is quite chemical, in fact. Solubility works somewhat counter-intuitively: if two ions that are not soluble together are present in the solution, they find each other and form ...
  • 551
22 votes
Accepted

What was the first rock in the rock cycle?

which came first That's actually a very hard question. The most simple answer would indeed be igneous. Here's why: Sedimentary rocks (in the sense of rock cycle) comes from pre-existing igneous or ...
  • 22.8k
22 votes
Accepted

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

Let's start with the easy question: given our current known reserves of transuranic elements and again taking into account their decay products, where will the greatest uranium reserves be in, say, ...
  • 22.8k
20 votes
Accepted

Why does phosphate rock contain uranium?

To understand why sedimentary phosphate rocks (hereafter referred to as phosphorites) have elevated uranium contents we first need to understand what are they made of and why do they form in the first ...
  • 22.8k
16 votes

Is the magma in one volcano different from the magma in every other volcano?

In keeping with your Lord of the Rings inspiration, the first reference is from New Zealand, where the Lord of the Rings movies were made. There are three main types of magma that volcanoes currently ...
  • 23.1k
15 votes

What was the first rock in the rock cycle?

The Earth existed long before there were crustal rocks or a "rock cycle." The idea of the "rock cycle" has prerequisites to even be meaningful. These include: The existence of a crust (both a ...
  • 3,790
15 votes

Are fossil fuels really formed from fossils?

Let's look at this. A very large number of points for one question. First, the solar system. We do not see any hydrocarbons in the inner solar system (Mercury to Mars). This is because in this region ...
13 votes

Do lead 206 and other daughter isotopes occur naturally?

While lead 206 does occur naturally, unless a zircon (a zirconium silicate crystal) is contaminated with lead or has been around a long time, it will contain no lead. Zirconium, uranium, and thorium ...
  • 22.4k
12 votes

Is oxygen the most abundant element on Earth?

Both of them. The composition of the atmosphere, crust, mantle, core and bulk earth are all notably different. The atmosphere is composed of ~78% nitrogen and ~21% oxygen, with small amounts of ...
  • 2,211
12 votes
Accepted

Why don't iron meteorites on Mars rust or oxidize? Why are they shiny?

tl;dr: Compared to Earth, the atmosphere on Mars is very thin; in addition, it contains much less of oxygen and water (i.e., is very dry). It is much colder there. These conditions may slow down ...
11 votes
Accepted

Age of fossils found in rocks

Yes, there is some amount of circular reasoning in the statement: "geologist date rocks by the fossils they contain and date fossils by the rocks in which they are found". However, that statement ...
  • 22.8k
11 votes
Accepted

Diamond at the core of Jupiter

I would think this is questionable, though we don't have a definitive answer yet. We usually think Jupiter has a roughly solar composition, which according to the solar abundance measurments of ...
11 votes
Accepted

Non-invasive techniques to find rock composition

You are looking for a portable XRF. It does (almost) exactly what you said. It sends electromagnetic radiation to the rock (X-rays), which excites electrons in the atoms and when they bounce back ...
  • 22.8k
10 votes

Are there minerals which are not been found on earth but which are still possible to exist?

To answer the first part, there are many minerals on earth which do not involve silicate bonded structures. For instance, non-silicates (minerals of carbonates, sulfides, sulfates, phosphates, and ...
  • 101
10 votes

Would oceans regenerate if removed?

I'm ignorant of all the organic and inorganic chemical reactions that can destroy or create water, and the factors controlling them. But I can give a shot to the part of the question related to ...
  • 17.3k
9 votes

Why does Earth have abundant oxygen in the atmosphere?

This is only a partial answer as it doesn't explain why the excess of O2 stayed but one thing you have to appreciate is the fact that aerobic respiration appeared almost half a billion years after ...
  • 5,298
9 votes
Accepted

What are the cubic formations found inside Larimar gemstones?

Calcite and hematite may not be the the answer to my question Hematite is not the answer, but calcite is. The inclusions are not cubic, they are rhombohedral. This is precisely how calcite looks ...
  • 22.8k
9 votes

Do lead 206 and other daughter isotopes occur naturally?

The four stable isotopes of lead and their relative abundance on Earth are: 204Pb (1.4%), 206Pb (24.1%), 207Pb (22.1%) and 208Pb (52.4%). Lead-204 is a primordial nuclide and is not a radiogenic ...
  • 12.9k
9 votes

What oxidised the soil on Mars?

The red color of Mars is due to hematite presence, Fe3+2O3, in the martian soil and atmospheric dust. The size and concentration of the hematite particles present in a layer determines its color. ...
8 votes

What is the origin of the ocean's salt?

I'd like to add a bit to the existing answer and maybe break it down to several simple things: Chloride likes water. The chloride ion, Cl- really likes being in water. It's one of the most ...
  • 22.8k
8 votes
Accepted

What "g" would be needed to keep helium on Earth?

Atmospheric escape is the loss of planetary atmospheric gases to outer space. You'd never be able to contain ALL of any gas forever by gravity. Ultimately you end up in the rarefied atmosphere where ...
  • 511
8 votes
Accepted

Where can fluorite be found on Long Island, New York?

I do not know of fluorite being reported to occur on Long Island. If fluorite is found in NYC, the Natural History museum might have specimens. You might try contacting a mineralogy / mineral ...
8 votes

What is the difference between N-MORB, E-MORB and OIB?

The nomenclature is confusing and recent studies have shown that among mid-ocean ridge basalts (generally called MORBs) that normal mid-ocean ridge basalts (NMORB) should reflect the statistically ...
8 votes
Accepted

Is the iron on Earth's crust a leftover of the Iron catastrophe, or it was brought back by volcanoes?

Not all the iron sank to the core. Have a look at my answer to a previous question: https://earthscience.stackexchange.com/a/7076/725 Your question is similar, but coming the other way. You're ...
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8 votes

What kind of purple stone is this?

That's amethyst, a violet version of quartz See here
  • 744
8 votes

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

Not quite "rock vapour", but scientists do study gas-rock interactions. Some of that is used to understand processes forming in the moon. For example, this paper looked at volatile metals (...
  • 22.8k
7 votes

Magma resultant from group 1 and group 2 elements?

So let's break it down part by part: He sets forth that magma is not actually created from heat / pressure buildup, etc. There is not a single mechanism for magma formation in the Earth. Magma can ...
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