<p>Nowadays impact craters are of little significance. Back in the Hadean era of early planetary crust formation, bolide impacts were the defining process of planetary evolution.
As for diamonds, one might expect micro-diamonds to be formed in rare instances of carbon-rich impact craters. On the other hand, back in the days of early lunar exploration, some earth scientists expected abundant impact diamonds to be found on the moon's surface. They even tooled up a special laboratory to analyze diamonds brought back from the moon. Alas, none were found. </p>

CC BY-SA 3.0
2016-04-25T19:05:46.643Z
2016-04-25T19:05:46.643Z
Gordon Stanger
<p>It's worth noting that our planet was formed by "meteorite" impacts and that our own moon is the (geologically important) result of Mars smacking into our planet, but let's focus on impacts after, say, the Archaen. </p>

<p>If we lived on the moon, impact craters would pretty important to our geology. As it is, it's perhaps a lot more important to our biology than to our geology, though strictly by association. For one thing, every meteorite that has ever hit an ocean basin (almost %75 of the earth's surface) has been plowed into a subduction zone; that includes monsters over 100km in diameter. As for those whose erosional remnants can be found on continents, finding them isn't easy and interpreting their formation isn't without controversy. In fact, finding many of them is a matter of walking back specific meteorite-related minerals to a likely source and focusing there.</p>

<p>As for diamonds, their occurrence in impacts is rare and, economic importance, rarer still. From Charlie Murphy's paper, <a href="http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf" rel="nofollow noreferrer">Economic Mineral Deposits in Impact Structures</a>:
A Review </p>

<blockquote>
  <p>Diamonds generally occur in very small amounts in impact melt rocks.
  Grieve and Masaitis (1994) estimated an average concentration of about
  10 ppb.</p>
</blockquote>

<p>As for economically important placer occurrences of industrial-grade diamonds, their source is still controversial. Geochemistry may prove a kimberlite source for these diamonds....just like those in South Africa.</p>

<p><a href="https://i.sstatic.net/GLKJ2.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/GLKJ2.jpg" alt="enter image description here"></a></p>

<p>A little bit of lunar scenery, here on earth.</p>

CC BY-SA 3.0
2017-05-20T17:41:15.597Z
2017-06-03T11:16:57.173Z
2017-06-03T11:16:57.173Z
Knob Scratcher
<p>A useful article on impact structures and ore deposits is:</p>

<p>Economic Mineral Deposits in Impact Structures:
A Review </p>

<p><a href="http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf" rel="nofollow noreferrer">http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf</a></p>

CC BY-SA 3.0
2017-05-20T12:22:11.840Z
A summary of the paper you refer to would significantly improve your answer.
Fred
CC BY-SA 3.0
2017-05-19T16:13:08.610Z
2017-05-25T01:13:40.650Z
2017-05-25T01:13:40.650Z
charles murphy
<p><strong>Impact diamonds</strong></p>

<p>Yes, diamonds can form in meteorite impacts. For this several things need to happen:</p>

<ol>
<li>A meteorite of the correct size and velocity,</li>
<li>The stuff it hits needs to contain carbon.</li>
</ol>

<p>If you have a meteorite hitting granite or ocean you're not going to get any diamonds. It usually has to hit something that has biogenic carbon (let's say peat, coal, graphite). Even then, the diamonds will <a href="http://www.nature.com/ncomms/2016/160314/ncomms10970/full/ncomms10970.html" rel="noreferrer">form only</a> in a very specific distance from ground zero, because there is a specific relation between pressure and temperature that has to hold. Pressure has to be high enough to stabilise diamonds, it has to be hot enough to break the graphite carbon bonds, but not too hot to destabilise diamond. This is why it also depends on the size and velocity of the meteorite - only some will make these unique conditions happen. A notable case is the <a href="http://www.nature.com/articles/srep14702" rel="noreferrer">Popigai crater</a> in Russia (that has some <a href="http://dx.doi.org/10.1016/j.crte.2003.07.001" rel="noreferrer">weird</a> stuff in it). Another case is the stuff <a href="http://dx.doi.org/10.1016/j.pss.2013.05.003" rel="noreferrer">found</a> in the peat around the Tunguska event.</p>

<p>However, calling the material that forms "diamond" does not say much about what it's actually like. In some cases, it's not even proper diamond, but rather a carbon polymorph called <a href="http://www.mindat.org/min-2431.html" rel="noreferrer">lonsdaleite</a>, which is some kind of "hexagonal diamond" which has lower hardness than real diamond. Impact diamonds are also usually not pretty, so they're not suitable as gemstones in jewelry. If anything, they're useful as industrial diamonds. The thing is, that making industrial diamonds synthetically is much easier than digging them up from these locations. So, the answer is no. The economical significance of meteorite impact craters in relation to diamond formation is negligible.</p>

<p>Pretty diamonds usually form in Earth's mantle and are brought up to the surface in volcanic eruptions. They are mined from volcanic pipes such as kimberlites, and even though some of them are named like they're impact craters (like the <a href="http://www.craterofdiamondsstatepark.com/" rel="noreferrer">Crater of Diamonds State Park</a>) they are not actually impact craters.</p>

<p><strong>Other stuff</strong></p>

<p>There is one notable occurrence of an impact crater that did cause economic mineralisation of something: the Sudbury Igneous Complex, or the Sudbury Basic, in Canada. In here, a meteorite impact caused melting of the crust and the formation of a nickel deposit. Currently, nickel, copper and some noble metals are mined from there. Even though it has been known for more than 100 years, only in the past 30 years or so the impact origin of it has been fully accepted.</p>

CC BY-SA 3.0
2017-05-20T16:59:18.680Z
Graphite is hardly a "biogenic" form of carbon. From geology.com: "Graphite is a naturally-occurring form of crystalline carbon. It is a native element mineral found in metamorphic and igneous rocks." In fact, impact diamonds associated with igneous rocks can be traced to graphite found in host granites.
Knob Scratcher
CC BY-SA 3.0
2017-05-21T02:06:49.913Z
@KnobScratcher graphite occurs in coal, obviously biogenic. Graphite in metamorphic rocks formed by reduction of sedimentary biogenic organic compounds. Got a reference for graphite in host granites? Igneous forms of carbon are extremely rare in granite, and igneous graphite is unheard of AFAIK.
Gimelist
CC BY-SA 3.0
2017-06-18T18:42:02.460Z
Saying that "graphite is a biogenic form of carbon" is like saying marble is a biogenic form of calcium carbonate. As for where to find graphite, it is sometimes associated with lightly metamorphosed coal deposits, but only then as a crappy, amorphous form with limited commercial use. In fact, economically important  crystalline graphite occurences are linked to hydrothermal veins, but more generally to high grade metamorphics whose carbon sources are carbonates (likely of a biogenic origin). Plenty of on-line references for that including a passing mention in...
Knob Scratcher
CC BY-SA 3.0
2017-06-18T18:42:21.437Z
...Charles Murphy's link at the bottom of this page. But maybe you'd like a basic primer on graphite: Graphite Deposit Types, Their Origin, and Economic Significance
1 British Columbia Geological Survey, Ministry of Energy and Mines, Victoria, BC, V8W 9N3
2 School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, V8P 5C2
3 Geological Survey of Canada, Pacifi c Division, Sidney, BC, V8L 4B2

Here's the link: http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/Papers/Documents/P2015-3/19%20Simandl.pdf
Knob Scratcher
CC BY-SA 3.0
2017-06-18T21:11:01.057Z
@KnobScratcher marble is indeed (originally) biogenic calcium carbonate. As you say, the graphite in metamorphic rocks is eventually sourced from biogenic carbonates. The rest is semantic. I'm still interested in evidence to support your claim of igneous graphite in granites.
Gimelist
CC BY-SA 3.0
2017-06-18T23:57:43.267Z
Graphite-bearing peraluminous dacites from the
Erlend volcanic complex, Faeroe-Shetland Basin,
North Atlantic : http://www.minersoc.org/pages/Archive-MM/Volume_61/61-405-175.pdf
Knob Scratcher
CC BY-SA 3.0
2017-06-18T23:58:24.860Z
Graphite-bearing ignimbrites and granites at Croydon
Queensland, and their relationship to gold minerlaization: https://d28rz98at9flks.cloudfront.net/90242/ResearchNews_08_p001.pdf
,
Knob Scratcher
CC BY-SA 3.0
2017-06-18T23:58:49.467Z
Geochemistry and Rb-Sr age of graphite-bearing granitoids in the southeast of the Main Sayan Fault: https://www.researchgate.net/publication/267229013_Geochemistry_and_Rb-Sr_age_of_graphite-bearing_granitoids_in_the_southeast_of_the_Main_Sayan_Fault
Knob Scratcher
CC BY-SA 3.0
2017-06-18T23:59:24.300Z
NEW UNIQUE “GRAPHITE IN GRANITE” PROJECT: http://www.metallicaminerals.com.au/wp-content/uploads/2016/09/graphite_in_granite_project.pdf
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:00:10.563Z
Tourmaline granite of the Kumdykol graphite-diamond deposit: https://link.springer.com/article/10.1134/S1028334X10120184
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:00:35.717Z
GEOCHEMISTRY AND Rb-Sr AGE OF GRAPHITE-BEARING GRANITOIDS IN THE SOUTHEAST OF THE MAIN SAYAN FAULT: http://www.academia.edu/24766854/GEOCHEMISTRY_AND_Rb-Sr_AGE_OF_GRAPHITE-BEARING_GRANITOIDS_IN_THE_SOUTHEAST_OF_THE_MAIN_SAYAN_FAULT
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:01:19.397Z
Tourmaline Granite of the Kumdykol Graphite–Diamond Deposit: http://www.readcube.com/articles/10.1134/S1028334X10120184
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:02:03.397Z
Origin of coexisting wustite, MgFe and REE phosphate minerals in graphite-bearing fluorapatite from the Rumburk granite: https://www.schweizerbart.de/papers/ejm/detail/22/75246/Origin_of_coexisting_wustite_MgFe_and_REE_phosphate_minerals_in_graphite_bearing_fluorapatite_from_the_Rumburk_granite?l=FR
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:06:20.133Z
Carbon isotopes of graphite: Implications on fluid history: http://www.sciencedirect.com/science/article/pii/S1674987111001083
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:09:13.153Z
Sr-Nd-Hf isotopic characteristics of
late Paleoproterozoic A-type granite,
South Korea : implication on the
Paleoproterozoic orogeny: https://whiteiron.org/uploads/conferences/27/abstracts/finalPDFs/2017001578-20170322070952.pdf
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:12:39.313Z
GRAPHITE IN ONTARIO: http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/IMR020/IMR020.pdf
Knob Scratcher
CC BY-SA 3.0
2017-06-19T00:14:43.133Z
The red-brown biotite in this graphite- and garnet-bearing granite has high titanium and low Fe3+ content. This patch of biotite shows a range of pleochroic colors caused by different crystal orientations.: https://minerva.union.edu/hollochk/c_petrology/ig_minerals.html
Knob Scratcher
CC BY-SA 3.0
2017-06-19T02:53:47.570Z
@KnobScratcher all of these only prove my point. They are interpreted (in the case where they are) as xenoliths, restite after anatexis or graphite introduced hydrothermally at a later stage. None of these are primary igneous graphite that crystallised from the silicate magma.
Gimelist
CC BY-SA 3.0
2017-06-19T05:33:59.660Z
Your point was that: "If you have a meteorite hitting granite or ocean you're not going to get any diamonds. It usually has to hit something that has biogenic carbon". In which case, I've given you references citing many important occurrences of graphite-bearing granite, including an impact-related occurrence where diamonds are believed to have been produced: http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf. Perhaps you think ALL carbon is biogenic? Is that your point too?
Knob Scratcher
CC BY-SA 3.0
2017-06-19T07:04:46.380Z
In that context, you are correct. It doesn't matter what's the source of the carbon as long as it's there. Now reading your first comment, I noticed that you didn't claim the the graphite is igneous. Accept my apologies.
Gimelist
CC BY-SA 3.0
2016-04-27T22:36:48.447Z
2016-04-27T22:36:48.447Z
Gimelist
<p>What is the economic importance of large meteorite impact craters with a diameter over 100 m? Can they form diamonds or produce other economic deposits? </p>

CC BY-SA 3.0
2016-04-24T22:04:17.630Z
The geological importance of meteorite impact craters is too broad to be covered by an answer here. About diamond formation, are you asking if diamonds can form in impacts or are you asking if the diamonds that are currently mined come from impact craters? Please clarify your question.
Gimelist
CC BY-SA 3.0
2016-04-25T15:31:39.380Z
I mean the heat and pressure that result from impact could produce diamond or not. If not is there any othere conmical potintial for it.??
Liath Fahad
CC BY-SA 3.0
2016-04-27T12:49:47.143Z
Voting to close as too broad. However, I think there's a valid question about the connection (if any) between metrorite impact and diamond formation. You could ask that question :-)
Semidiurnal Simon
<geology><economic-geology><meteorite><diamond>
Importance of meteorite impact craters in geology?
Liath Fahad
# Importance of meteorite impact craters in geology?

(Asked by: username_0 on 2016-04-24)

What is the economic importance of large meteorite impact craters with a diameter over 100 m? Can they form diamonds or produce other economic deposits?

**Tags:** geology, economic-geology, meteorite, diamond

> **Comments:**
> **username_1**: The geological importance of meteorite impact craters is too broad to be covered by an answer here. About diamond formation, are you asking if diamonds can form in impacts or are you asking if the diamonds that are currently mined come from impact craters? Please clarify your question.  
> **username_0**: I mean the heat and pressure that result from impact could produce diamond or not. If not is there any othere conmical potintial for it.??  
> **username_2**: Voting to close as too broad. However, I think there's a valid question about the connection (if any) between metrorite impact and diamond formation. You could ask that question :-)  

---

## 4 answers

### Answer by username_1 on 2016-04-27. Score: 5 | Accepted answer

**Impact diamonds**

Yes, diamonds can form in meteorite impacts. For this several things need to happen:

1. A meteorite of the correct size and velocity,
2. The stuff it hits needs to contain carbon.

If you have a meteorite hitting granite or ocean you're not going to get any diamonds. It usually has to hit something that has biogenic carbon (let's say peat, coal, graphite). Even then, the diamonds will [form only](http://www.nature.com/ncomms/2016/160314/ncomms10970/full/ncomms10970.html) in a very specific distance from ground zero, because there is a specific relation between pressure and temperature that has to hold. Pressure has to be high enough to stabilise diamonds, it has to be hot enough to break the graphite carbon bonds, but not too hot to destabilise diamond. This is why it also depends on the size and velocity of the meteorite - only some will make these unique conditions happen. A notable case is the [Popigai crater](http://www.nature.com/articles/srep14702) in Russia (that has some [weird](http://dx.doi.org/10.1016/j.crte.2003.07.001) stuff in it). Another case is the stuff [found](http://dx.doi.org/10.1016/j.pss.2013.05.003) in the peat around the Tunguska event.

However, calling the material that forms "diamond" does not say much about what it's actually like. In some cases, it's not even proper diamond, but rather a carbon polymorph called [lonsdaleite](http://www.mindat.org/min-2431.html), which is some kind of "hexagonal diamond" which has lower hardness than real diamond. Impact diamonds are also usually not pretty, so they're not suitable as gemstones in jewelry. If anything, they're useful as industrial diamonds. The thing is, that making industrial diamonds synthetically is much easier than digging them up from these locations. So, the answer is no. The economical significance of meteorite impact craters in relation to diamond formation is negligible.

Pretty diamonds usually form in Earth's mantle and are brought up to the surface in volcanic eruptions. They are mined from volcanic pipes such as kimberlites, and even though some of them are named like they're impact craters (like the [Crater of Diamonds State Park](http://www.craterofdiamondsstatepark.com/)) they are not actually impact craters.

**Other stuff**

There is one notable occurrence of an impact crater that did cause economic mineralisation of something: the Sudbury Igneous Complex, or the Sudbury Basic, in Canada. In here, a meteorite impact caused melting of the crust and the formation of a nickel deposit. Currently, nickel, copper and some noble metals are mined from there. Even though it has been known for more than 100 years, only in the past 30 years or so the impact origin of it has been fully accepted.

> **Comments:**
> **username_4**: Graphite is hardly a "biogenic" form of carbon. From geology.com: "Graphite is a naturally-occurring form of crystalline carbon. It is a native element mineral found in metamorphic and igneous rocks." In fact, impact diamonds associated with igneous rocks can be traced to graphite found in host granites.  
> **username_1**: @username_4 graphite occurs in coal, obviously biogenic. Graphite in metamorphic rocks formed by reduction of sedimentary biogenic organic compounds. Got a reference for graphite in host granites? Igneous forms of carbon are extremely rare in granite, and igneous graphite is unheard of AFAIK.  
> **username_4**: Saying that "graphite is a biogenic form of carbon" is like saying marble is a biogenic form of calcium carbonate. As for where to find graphite, it is sometimes associated with lightly metamorphosed coal deposits, but only then as a crappy, amorphous form with limited commercial use. In fact, economically important  crystalline graphite occurences are linked to hydrothermal veins, but more generally to high grade metamorphics whose carbon sources are carbonates (likely of a biogenic origin). Plenty of on-line references for that including a passing mention in...  
> **username_4**: ...username_5's link at the bottom of this page. But maybe you'd like a basic primer on graphite: Graphite Deposit Types, Their Origin, and Economic Significance 1 British Columbia Geological Survey, Ministry of Energy and Mines, Victoria, BC, V8W 9N3 2 School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, V8P 5C2 3 Geological Survey of Canada, Pacifi c Division, Sidney, BC, V8L 4B2  Here's the link: http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/Papers/Documents/P2015-3/19%20Simandl.pdf  
> **username_1**: @username_4 marble is indeed (originally) biogenic calcium carbonate. As you say, the graphite in metamorphic rocks is eventually sourced from biogenic carbonates. The rest is semantic. I'm still interested in evidence to support your claim of igneous graphite in granites.  
> **username_4**: Graphite-bearing peraluminous dacites from the Erlend volcanic complex, Faeroe-Shetland Basin, North Atlantic : http://www.minersoc.org/pages/Archive-MM/Volume_61/61-405-175.pdf  
> **username_4**: Graphite-bearing ignimbrites and granites at Croydon Queensland, and their relationship to gold minerlaization: https://d28rz98at9flks.cloudfront.net/90242/ResearchNews_08_p001.pdf ,  
> **username_4**: Geochemistry and Rb-Sr age of graphite-bearing granitoids in the southeast of the Main Sayan Fault: https://www.researchgate.net/publication/267229013_Geochemistry_and_Rb-Sr_age_of_graphite-bearing_granitoids_in_the_southeast_of_the_Main_Sayan_Fault  
> **username_4**: NEW UNIQUE “GRAPHITE IN GRANITE” PROJECT: http://www.metallicaminerals.com.au/wp-content/uploads/2016/09/graphite_in_granite_project.pdf  
> **username_4**: Tourmaline granite of the Kumdykol graphite-diamond deposit: https://link.springer.com/article/10.1134/S1028334X10120184  
> **username_4**: GEOCHEMISTRY AND Rb-Sr AGE OF GRAPHITE-BEARING GRANITOIDS IN THE SOUTHEAST OF THE MAIN SAYAN FAULT: http://www.academia.edu/24766854/GEOCHEMISTRY_AND_Rb-Sr_AGE_OF_GRAPHITE-BEARING_GRANITOIDS_IN_THE_SOUTHEAST_OF_THE_MAIN_SAYAN_FAULT  
> **username_4**: Tourmaline Granite of the Kumdykol Graphite–Diamond Deposit: http://www.readcube.com/articles/10.1134/S1028334X10120184  
> **username_4**: Origin of coexisting wustite, MgFe and REE phosphate minerals in graphite-bearing fluorapatite from the Rumburk granite: https://www.schweizerbart.de/papers/ejm/detail/22/75246/Origin_of_coexisting_wustite_MgFe_and_REE_phosphate_minerals_in_graphite_bearing_fluorapatite_from_the_Rumburk_granite?l=FR  
> **username_4**: Carbon isotopes of graphite: Implications on fluid history: http://www.sciencedirect.com/science/article/pii/S1674987111001083  
> **username_4**: Sr-Nd-Hf isotopic characteristics of late Paleoproterozoic A-type granite, South Korea : implication on the Paleoproterozoic orogeny: https://whiteiron.org/uploads/conferences/27/abstracts/finalPDFs/2017001578-20170322070952.pdf  
> **username_4**: GRAPHITE IN ONTARIO: http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/IMR020/IMR020.pdf  
> **username_4**: The red-brown biotite in this graphite- and garnet-bearing granite has high titanium and low Fe3+ content. This patch of biotite shows a range of pleochroic colors caused by different crystal orientations.: https://minerva.union.edu/hollochk/c_petrology/ig_minerals.html  
> **username_1**: @username_4 all of these only prove my point. They are interpreted (in the case where they are) as xenoliths, restite after anatexis or graphite introduced hydrothermally at a later stage. None of these are primary igneous graphite that crystallised from the silicate magma.  
> **username_4**: Your point was that: "If you have a meteorite hitting granite or ocean you're not going to get any diamonds. It usually has to hit something that has biogenic carbon". In which case, I've given you references citing many important occurrences of graphite-bearing granite, including an impact-related occurrence where diamonds are believed to have been produced: http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf. Perhaps you think ALL carbon is biogenic? Is that your point too?  
> **username_1**: In that context, you are correct. It doesn't matter what's the source of the carbon as long as it's there. Now reading your first comment, I noticed that you didn't claim the the graphite is igneous. Accept my apologies.  

---

### Answer by username_3 on 2016-04-25. Score: 2

Nowadays impact craters are of little significance. Back in the Hadean era of early planetary crust formation, bolide impacts were the defining process of planetary evolution.
As for diamonds, one might expect micro-diamonds to be formed in rare instances of carbon-rich impact craters. On the other hand, back in the days of early lunar exploration, some earth scientists expected abundant impact diamonds to be found on the moon's surface. They even tooled up a special laboratory to analyze diamonds brought back from the moon. Alas, none were found.


---

### Answer by username_4 on 2017-05-20. Score: 1

It's worth noting that our planet was formed by "meteorite" impacts and that our own moon is the (geologically important) result of Mars smacking into our planet, but let's focus on impacts after, say, the Archaen.

If we lived on the moon, impact craters would pretty important to our geology. As it is, it's perhaps a lot more important to our biology than to our geology, though strictly by association. For one thing, every meteorite that has ever hit an ocean basin (almost %75 of the earth's surface) has been plowed into a subduction zone; that includes monsters over 100km in diameter. As for those whose erosional remnants can be found on continents, finding them isn't easy and interpreting their formation isn't without controversy. In fact, finding many of them is a matter of walking back specific meteorite-related minerals to a likely source and focusing there.

As for diamonds, their occurrence in impacts is rare and, economic importance, rarer still. From Charlie username_5's paper, [Economic Mineral Deposits in Impact Structures](http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf):
A Review

> Diamonds generally occur in very small amounts in impact melt rocks.
> Grieve and Masaitis (1994) estimated an average concentration of about
> 10 ppb.

As for economically important placer occurrences of industrial-grade diamonds, their source is still controversial. Geochemistry may prove a kimberlite source for these diamonds....just like those in South Africa.

[![enter image description here](https://i.sstatic.net/GLKJ2.jpg)](https://i.sstatic.net/GLKJ2.jpg)

A little bit of lunar scenery, here on earth.


---

### Answer by username_5 on 2017-05-19. Score: 0

A useful article on impact structures and ore deposits is:

Economic Mineral Deposits in Impact Structures:
A Review

<http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf>

> **Comments:**
> **username_6**: A summary of the paper you refer to would significantly improve your answer.  

---

