TY - JOUR

T1 - About the Origin of Carbonado

AU - Afanasiev, Valentin

AU - Kovalevsky, Vladimir

AU - Yelisseyev, Alexander

AU - Mashkovtsev, Rudolf

AU - Gromilov, Sergey

AU - Ugapeva, Sargylana

AU - Barabash, Ekaterina

AU - Ivanova, Oksana

AU - Pavlushin, Anton

N1 - This work was supported by the state assignments of IGM SB RAS (No 122041400157-9), DPMGI SB RAS (FUFG-2024-0007), NIIC SB RAS (No 121031700313-8) and IG KarRC RAS (No 1022040400163-5).

PY - 2024/9

Y1 - 2024/9

N2 - Carbonado is a specific variety of diamonds, typical representatives of which are distributed in the diamond placers of Central Africa, Brazil, and Venezuela. Carbonado consists of the microcrystalline aggregates of diamonds, with inclusions of mineral matter. These aggregates appear as fragments that are rounded to varying degrees. Carbonado has been known for a long time, but its primary sources have not been found and its genesis remains unclear. We have substantiated the hypothesis that the most probable precursor of carbonado is shungite. Shungite is a specific form of non-crystalline, non-graphitic, fullerene-like carbon. Shungite rocks, currently known in Karelia (Russia), are natural microdispersed composite materials containing shungite—carbonaceous matter and mineral components of different compositions. The content of carbonaceous matter in shungite rocks is from less than 10% to 98%. The carbon isotopic composition of shungite is light ẟ13C from −25‰ to −40‰. The age of shungite rock is more than 2 billion years old, but earlier shungite was probably much more widespread. Known shungite rocks are more than 2 billion years old, but earlier shungite was probably much more widespread. Shungite rocks could recrystallize into diamond rock upon subduction to high pressure and temperature. The diamond rocks could then be exhumed to the Earth’s surface, where they could undergo disruption and reworking with formation of those very fragments that are known as “carbonado”. © 2024 by the authors.

AB - Carbonado is a specific variety of diamonds, typical representatives of which are distributed in the diamond placers of Central Africa, Brazil, and Venezuela. Carbonado consists of the microcrystalline aggregates of diamonds, with inclusions of mineral matter. These aggregates appear as fragments that are rounded to varying degrees. Carbonado has been known for a long time, but its primary sources have not been found and its genesis remains unclear. We have substantiated the hypothesis that the most probable precursor of carbonado is shungite. Shungite is a specific form of non-crystalline, non-graphitic, fullerene-like carbon. Shungite rocks, currently known in Karelia (Russia), are natural microdispersed composite materials containing shungite—carbonaceous matter and mineral components of different compositions. The content of carbonaceous matter in shungite rocks is from less than 10% to 98%. The carbon isotopic composition of shungite is light ẟ13C from −25‰ to −40‰. The age of shungite rock is more than 2 billion years old, but earlier shungite was probably much more widespread. Known shungite rocks are more than 2 billion years old, but earlier shungite was probably much more widespread. Shungite rocks could recrystallize into diamond rock upon subduction to high pressure and temperature. The diamond rocks could then be exhumed to the Earth’s surface, where they could undergo disruption and reworking with formation of those very fragments that are known as “carbonado”. © 2024 by the authors.

KW - carbonado

KW - diamond

KW - exhumation

KW - shungite

KW - subduction

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85205095582&origin=inward&txGid=7adde128c967fc476d882f6904e2adc2

UR - https://www.mendeley.com/catalogue/ae288247-e43d-3699-b72d-ab29862add30/

U2 - 10.3390/min14090927

DO - 10.3390/min14090927

M3 - Article

VL - 14

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 9

M1 - 927

ER -