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Coupled deep-mantle carbon-water cycle: Evidence from lower-mantle diamonds.

ABSTRACT: Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H₂O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200-500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle silicates. Our work presents strong evidence for coupled recycling of water and carbon in the deep mantle based on natural samples.

SUBMITTER: Wang W

PROVIDER: S-EPMC8454732 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

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Coupled deep-mantle carbon-water cycle: Evidence from lower-mantle diamonds.

Wang Wenzhong W Tschauner Oliver O Huang Shichun S Wu Zhongqing Z Meng Yufei Y Bechtel Hans H Mao Ho-Kwang HK

Innovation (Cambridge (Mass.)) 20210504 2

Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H<sub>2</sub>O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200-500 K below ...[more]

PMID: 34557764

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