20.500.12556/RUL-180921 Decoding metamorphic nanodiamonds formation through their internal structures Metamorphic diamonds offer insights into Earth's evolution, modulating the global carbon cycle through subduction into the mantle and exhumation. However, the formation and internal structure of minute diamonds remain poorly understood. Here, we study the internal structures of diamond-bearing inclusions from the Eastern Alps using state-of-the-art analytical techniques. Atomically resolved images revealed intricate structures, including well-faceted monocrystalline diamonds, complex nanocrystalline clusters of intergrown diamond and graphite and amorphous matter. Associated fluids contain CO$_2$, CH$_4$ and H$_2$O, indicating formation from C–O–H fluids. The proposed model of C–O–H fluid behaviour suggests monocrystalline diamond precipitation at the onset of retrograde metamorphism. Amorphous layers formed through interaction between the trapped fluid and the host garnet during the further exhumation. When the fluid reached the P–T conditions of the transition zone between the diamond and graphite stability fields, polycrystalline clusters formed. For the first time, we can see a detailed record of metamorphic fluids evolution, preserved in the internal structures of microsized diamond inclusions. amorphous matter C–O–H fluids metamorphic diamonds Raman spectroscopy TEM true false true Angleški jezik Ni določen Članek v reviji 2026-03-19 14:04:30 2026-03-19 14:04:31 2026-03-22 04:11:38 0000-00-00 00:00:00 2026 0 0 Str. 226–245 iss. 3 Vol. 44 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 55 0263-4929 10.1111/jmg.70032 263396611 Journal_Metamorphic_Geology_-_2026_-_Sotelsek_-_Decoding_Metamorphic_Nanodiamonds_Formation_Through_Their_Internal.pdf Journal_Metamorphic_Geology_-_2026_-_Sotelsek_-_Decoding_Metamorphic_Nanodiamonds_Formation_Through_Their_Internal.pdf 1 E476BC9420EF674CDEAD01363DF3BDA6 e3465dc487ee8ab4a2b615581e433e6b39d1e4b7c4f28237f80959da927c5685 58fc7d3f-2394-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=230899 https://onlinelibrary.wiley.com/doi/10.1111/jmg.70032 0 3a29300a-2394-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=230898 Naravoslovnotehniška fakulteta 0 0 0