title: Nanodiamond finding in the hyblean shallow mantle xenoliths.
abstract: Most of Earth's diamonds are connected with deep-seated mantle rocks; however, in recent years, μm-sized diamonds have been found in shallower metamorphic rocks, and the process of shallow-seated diamond formation has become a hotly debated topic. Nanodiamonds occur mainly in chondrite meteorites associated with organic matter and water. They can be synthesized in the stability field of graphite from organic compounds under hydrothermal conditions. Similar physicochemical conditions occur in serpentinite-hosted hydrothermal systems. Herein, we report the first finding of nanodiamonds, primarily of 6 and 10 nm, in Hyblean asphaltene-bearing serpentinite xenoliths (Sicily, Italy). The discovery was made by electron microscopy observations coupled with Raman spectroscopy analyses. The finding reveals new aspects of carbon speciation and diamond formation in shallow crustal settings. Nanodiamonds can grow during the hydrothermal alteration of ultramafic rocks, as well as during the lithogenesis of sediments bearing organic matter.
authors.affiliation: LLC "ADAMANT" Skolkovo Participant, Harchenko 19-A-7H, St.Petersburg, 194100, Russia.
authors.forename: S K
authors.initials: SK
authors.lastname: Simakov
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kouchi
authors.affiliation: Lebedev Physics Institute, Russian Academy of Sciences, Leninsky pr. 53, Moscow, 119991, Russia.
authors.forename: N N
authors.initials: NN
authors.lastname: Mel'nik
authors.affiliation: Department of Biological, Geological and Environmental Sciences, University of Catania, Corso Italia Catania 55-I-95129 (Italy).
authors.forename: V
authors.initials: V
authors.lastname: Scribano
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hama
authors.affiliation: Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.affiliation: Research Division of JAPEX Earth Energy Frontier, Creative Research Institution, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.affiliation: Equipment Management Center, Open facility Division, Creative Research Institution, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yoshizawa