Kimberlite explosion in New York

[Count Iblis]

http://www.users.muohio.edu/rakovajf/WTTW%20Kimberlite.pdf"

 

[mgb_phys]

I think you might mean kimberlite extrusion !
Unfortunately diamonds->kimberlite but kimberlite->diamonds

 

[Saul]

Kimberlites are interesting as there is no known geological mechanism to push or pull the kimberlite suddenly from a depth of 250 km to 150 km to the surface at 70 km/hr. Kimberlites are very focused abrupt events. Would not a force generated at great depths gradually push the kimberlite up through the mantel. What stops kimberlite from moving gradually to the surface as magma? (i.e. Think of forces balanced. Strength of the mantel that stops movement vs whatever force moves the kimberlite.)

Kimberlite eruptions are quite different than volcanos.

Why is the ancient carbon (diamond) found at great depths in the planet?

Kimberlites (The Oxford Companion to The Earth, page 577/578)

(kimberlite) … provides the deepest samples of the planet, because it has been erupted at high speed (roughly 70 km/hr as diamond is not stable above 150 km and will in the high heat revert in form back to carbon, if it does not move at 70 km/hr cooled by the entrapped expanding gas.) from depths in excess of 150 km (a region in which diamond is stable)

Diamondiferous kimberlite is known on all the continents, where is confined to the oldest shield segments, …

The eruptions range in age from early Precambrian to recent with a notable display in Cretaceous times in Africa and South America. No kimberlites have been recorded in the ocean basin.

From the detailed mineral chemistry it is possible to estimate the samples (Saul: Kimberlite) come from depths to about 250 km…

The ages of the diamonds are also interesting, because they are commonly much older than the host kimberlite, some, indeed, are as old as the oldest rocks on the Earth, showing that many, if not all were picked up by the kimberlite during its passage to the surface.