When transported by magmas to the Earth's surface, diamond crystals underwent resorption, the intensity of which significantly differed in various kimberlite pipes. We experimentally simulated diamond resorption at different oxygen fugacities (fO₂) in ascending kimberlite magma enriched in CO₂ and H₂O. The experiments were carried out using specially prepared unaltered Group I kimberlite from the Udachnaya East pipe (Yakutia) and model carbonatite at 3.0 GPa, 1200–1400 °C, and fO₂ in a range of NNO–2 to NNO + 3.2 log units (where NNO is Ni-NiO buffer). Over the investigated range of conditions, resorption of octahedral diamond crystals is found to occur according to a single scenario. Negative trigons and shield-shaped laminae develop on the {111} faces and crystal edges are truncated by the surfaces of tetrahexahedroids. The rate of diamond resorption increases in all studied systems as fO₂ and temperature are raised. In this case, water-enriched melts are the most aggressive media in the investigated T–fO₂ interval. Among the most oxidized high-temperature melts, it is carbonatite melts depleted in SiO₂ that provide the maximum rate of diamond resorption. Furthermore, the rates of diamond resorption we obtained are an order of magnitude higher than those previously measured in silicate melts containing CO₂ and H₂O, at fO₂ values from the NNO buffer to NNO-2. Therefore, high oxygen fugacity, a temperature of ~1400 °C, and essentially carbonate composition of water-containing magma could provide a high intensity of diamond resorption at the mantle stage of magma ascent to the surface. Apparently, this process primarily influenced the formation of the appearance and preservation of natural diamond crystals in kimberlite pipes.

当通过岩浆运到地球表面时，钻石晶体会发生吸收，在各种金伯利岩管道中，其吸收强度明显不同。我们通过实验模拟了在富氧CO ₂和H ₂ O的上升金伯利岩岩浆中不同氧逸度（f O ₂）下的金刚石吸收。实验是使用Udachnaya East管道（雅库特（Yakutia））特制的未经改变的I组金伯利岩和模型碳酸盐岩进行的。在3.0 GPa，1200–1400°C和f O _2下在NNO-2到NNO + 3.2 log单位范围内（其中NNO是Ni-NiO缓冲液）。在研究的条件范围内，发现根据一种情况发生了八面体金刚石晶体的吸收。在{111}面上会出现负三角形和盾形薄片，并且晶体边缘被四面体的表面截断。在所有研究的系统中，随着f O ₂和温度的升高，金刚石的吸收速率均增加。在这种情况下，富含水的熔体是研究的T– f O ₂间隔中最具侵蚀性的介质。在氧化程度最高的高温熔体中，它是富含SiO _2的碳酸盐熔体提供最大的钻石吸收率。此外，我们获得的金刚石吸收速率比以前在含CO ₂和H ₂ O的硅酸盐熔体中测得的速率高一个数量级，从NNO缓冲液到NNO-2的f O ₂值为。因此，高氧逸度，约1400°C的温度以及基本上是含水岩浆的碳酸盐成分，可以在岩浆上升到地幔的地幔阶段提供高强度的金刚石吸收。显然，该过程主要影响金伯利岩管中天然钻石晶体的外观形成和保存。