Talk:Geothermal gradient

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The image: is currently in CMYK colorspace that many browsers (ie. Opera) are unable to display!

In addition the original image Geothermgradients.jpg is a BW line drawing. Would the creator of the original image please convert it to black-and-white paletted PNG image. See for additional information.

Thanks. Keep up the good work!

Geologician changed image to B&W .png file as requested above on 11/13/2007 —Preceding unsigned comment added by Geologician (talkcontribs) 14:49, 13 November 2007 (UTC)

Global average geothermal gradient[edit]

I am not a geologist (or natively English speaking), but...

The text says that the average geothermal gradient is 0.02º K/m. It would probably be good to mention that this number varies between 10º to 50º C/km (or 0.01º to 0.05º K/m).

Anomalies in the geothermal gradient is a way to chart deep structures of the crust.

(See fex: )

I do not know what is the current truth. IMHO better average number would be 0.025º K/m, or 0.03º K/m. It is classically teached that temperature rises 1ºC per 33m (which is roughly equal to 0.03º K/m).

Second thing:

It would be good to mention the geopressure gradient that always accompanies the geothermal gradient.


Wikipedia has a pressure gradient page ( but currently it focuses on the atmospheric one. Little rearranging perhaps?

Adiabatic heat gradient in solids

Later down in the article is mentioned an adiabatic heat gradient in the mantle which is said to be solid. So why wouldn't such a gradient exist in the crust then? Gravitational and adiabatic heat gradient is the same thing. Since horizontal stress in the crust can be negative or positive it can explain the fact that some boreholes become cooler with increasing depth. Heat gradient theories based on conduction can not explain this. Davidjonsson (talk) 20:20, 16 June 2009 (UTC)

I have changed the "22.1C/Km" to "about 25C/Km". I suspect that the 22.1 came from a imperial-metric conversion with too many significant figures and as the value varies with position a 3 significant figure number is not helpful. Mtpaley (talk) 00:53, 26 August 2012 (UTC)

WikiProject class rating[edit]

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:52, 10 November 2007 (UTC)

Temperatures at shallow depths[edit]

Should their be a subsection on this? —Preceding unsigned comment added by (talk) 18:17, 30 June 2009 (UTC)

Yes, there should. Shallow surface zones only a few meters deep contain both diurnal and annual variations important to several technologies including agriculture, civil engineering, geothermal heat pumps, etc. In addition, zone from 5 to 15 kilometer becomes hot enough to affect petroleum, and other, drilling tools. Mydogtrouble (talk) 03:30, 27 March 2010 (UTC)

I came to this listing hoping to find a chart showing how temperature decreases to whatever depth, and then begins to increase. Also, wondering what the average (isocline, thermocline not sure the definition) depth at which temperature remains constant year around.Flight Risk (talk) 22:26, 11 December 2011 (UTC)

Geothermal is awesome[edit]

I agree, but how the hell did you do that man, I can't even find it in the source code. (talk) 20:55, 14 October 2010 (UTC)

I have no idea, I just closed up the spare line at the top of the section and it disappeared. Mikenorton (talk) 21:14, 14 October 2010 (UTC)

Ocotober 26, 2011 WSJ resource, focus Indonesia[edit] (talk) 23:41, 26 October 2011 (UTC)

This might be better in Geothermal energy, or some place else. (talk) 03:26, 27 October 2011 (UTC)

Discovery of Geothermal Gradient[edit]

Is the claim in the article on Robert Were Fox correct? Should his discovery of Geothermal Gradient be noted in this article? Vernon White . . . Talk 10:26, 1 March 2012 (UTC)

Article is too Earth-centric[edit]

All terrestrial planets and terrestrial-like natural satellites have geothermal gradients, yet the definition used here apparently applies only to Earth. Mars, Mercury, Venus, Vesta, Titan, Ganymede, the Moon etc are all thought to have geothermal gradients under standard models although Earth has the only proven gradient. Therefore I have tagged the article so that information from these other planets can be included. --EvenGreenerFish (talk) 03:38, 30 April 2012 (UTC)

Perhaps it's because of the geo, which indicates earth. I'd suggest you start an article on planetary thermal gradients or some such, which could be linked to where appropriate here. Vsmith (talk) 09:30, 30 April 2012 (UTC)
Or simply add a section to the article re: planetary ... thermal gradients based on WP:RSs. Vsmith (talk) 09:37, 30 April 2012 (UTC)
I understand what geo means, but all the same, geology which uses the prefix has a general application, given that Planetary geology retains it (I mean without the geo, you're left simply with "ology" which doens't mean anything in this context). Attribution of the nomenclature is natural given that its only recently that other planets have been studied we don't have any new words for them, that does not mean however that they don't fall under the same definition. It makes sense to add another article but it also needs to be explained in the opening paragraph that the concept applies to almost all terrestrial planets (the prefix terra also paradoxically relates to Earth). --EvenGreenerFish (talk) 23:29, 30 April 2012 (UTC)
The terminology planetary geology always has bugged me -- I'd rather use planetology, but that's just a redirect. And I'll agree the planetary science folks have chosen to appropriate geo- to non-geo stuff despite logic and my objections :) (the moon landing happened in the middle of my undergrad geology studies). A separate article (with a link and blurb somewhere here) would be best in my view. I'm assuming there's plenty of sourced material to use. And it wouldn't have to be restricted to rocky bodies as I'm sure there exist thermal gradients w/in the gassy ones also. Vsmith (talk) 01:29, 1 May 2012 (UTC)

Weasel Words[edit]

There are several statements in this article that feel like weasel words.

"Because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher"

Is the ", scientists believe that early in Earth history, " part informative?

"Highly viscous or partially molten rock at temperatures between 650 to 1,200 °C (1,200 to 2,200 °F) is postulated to exist everywhere beneath the Earth's surface at depths of 80 to 100 kilometres"

"is postulated" implies that this is mere speculation.

Comments? Mtpaley (talk) 21:50, 4 December 2012 (UTC)

Geothermal v's groundsource.[edit]

Hi, This article states that ... Because heat is flowing through every square meter of land, it can be used for a source of energy for heating, air conditioning (HVAC) and ventilating systems using ground source heat pumps. In areas where modest heat flow is present, geothermal energy can be used for industrial applications that presently rely on fossil fuels.[10]

Which contradicts statements in articles about ground-source heat pump technology where it is observed that the heat energy used by such systems is in fact of solar origin.

Thanks for listening

Jonathan — Preceding unsigned comment added by Jonnyhugs (talkcontribs) 15:26, 6 January 2013 (UTC)

Consistency needed in using temperature units[edit]

In one sentence, a temperature is given in Fahrenheit and Celsius units but not Kelvin. In the very next sentence, a temperature is given in Kelvin and nothing else. This makes it hard to do an eyeball comparison of temperature when they are different units. Plus, it makes the article look sloppy when it switches units. The article should pick one unit and stick with it (talk) 16:06, 4 October 2013 (UTC)

Science errors there are[edit]

Some of the speculative content comes from ref 8 the rest are not publicly accessible "Heat released as abundant heavy metals (iron, nickel, copper) descended to the Earth's core." that article makes several obviously incorrect statements "gravitalional heat" might make an iota of sense if metal density is 8 and rock is 4 but Iron et al do not exist as metal but as minerals of rock density. The statement in that article that "most of the earth's heat is in the mantle" is contradicted by him stating the core's temperature and density (temp X density = heat content). "The mantle is mostly made up of high density minerals with high contents of atoms that have relatively small atomic radii such as magnesium (Mg), titanium (Ti), and calcium (Ca)." Again Magnesium and Iron(II) Silicates (Olivine) is the current beleived to be the primary Mantle forming mineral. Both are larger diameter atomic radii ions. Calcium and Potassium are even larger diameter atomic radii ions. Calcium (+2) and Thorium (+4) are interchangeable in rocks that they occur in e.g. Flouride, Phosphate rock, Granite to name a few. Ditto Uranium.

These only a few of the faulty and questionable references (not meeting Wiki guidelines) that permeate this article. See Abundance of the chemical elements(Solar System abundance and Earth's Crust abundance) and Wikipedia metal properties of individual elements.

  • Article fails to note that only the Earth and Jupiter emit more radiation (heat etc.) than they absorb from the Sun. This would improve perspective as other planets do not have this internal heating, migration of metals to the non-existent core, et al. The article implies a certain divine intervention in that it does not mention that Venus, Mercury, and Mars are exceptions to these theories?
  • Article fails to note that distribution of elements in the Earth's crust and the Solar system as a whole is significantly different. The elements lacking in the crust (Nickel, Chromium, Platinum, Thorium, etc. and including Carbon and Sulfur)are Ferrophilic or "Carbide forming" elements (used to alloy with Iron in various steels). The metals that are common on Crust/Lithosphere versus Solar System abundance are Ferrophobic metals (rejected by the core) like Calcium and Magnesium. The assumption of an Iron-Nickel core is partly based on Nickel and Iron depletion in the crust.
  • The above information noted in article on Late Heavy Bombardment in (notes all metals migrate to core, including radioactive ones, but crust enriched in heavy elements by meteorites.)
  • Caveats that composition of Mantle and Core are proposed and not verifiable.
  • And the release of huge quantities of Water Vapor, Carbon Dioxide, and Sulfur Dioxide during vulcanism, c.f. Deccan traps, would tend to lower Earth's internal heat. Current Mantle theories don't account for these gases origin (core-mantle interaction?). Kimberlite article notes origin in upper mantle?

Shjacks45 (talk) 07:25, 11 October 2013 (UTC)