A Mantle or Crustal Origin for Carbonado? Synthesis and Microanalytical Studies of Polycrystalline Diamond

EAR-0073862 Heaney/Vicenzi科学家将碳黑钻石描述为“所有钻石中最神秘的”。它们以豌豆大小的熔融钻石微晶黑色结核的形式出现，具有相对较大的空隙，可占总体积的15%以上。一些科学家提出了许多理论来解释它们的形成，其中一些如果被证明是真的，将极大地影响我们对地球历史和化学的看法。例如，一些科学家认为，碳碳化合物是由一颗巨大的陨石在太古代晚期撞击形成的，而另一些科学家则假设碳碳化合物是来自地球上地幔的一种奇异风格的钻石。我们打算通过将碳酸盐结构和矿物包裹体与在地球深处结晶的多晶钻石中的那些和陨石撞击进行比较来检验这些假设。此外，我们将进行最先进的成像和地球化学分析，以探索明确表明这些不寻常钻石的形成机制的指标。

EAR-0073862Heaney/VicenziScientists have described carbonados as "the most enigmatic of all diamonds." They occur as pea-sized black nodules of fused diamond crystallites with relatively large void spaces that can account for more than 15% of the total volume. Some scientists have proposed a host of theories to account for their formation, some of which would dramatically influence our perception of the history and chemistry of the Earth if proved true. For example, some scientists believe that carbonados formed by a single massive meteorite impact in the late Archean, whereas others postulate that carbonados are an exotic style of diamond from the Earth's upper mantle. We intend to test these hypotheses by comparing carbonado textures and mineral inclusions with those in polycrystalline diamonds that crystallized deep within the earth and by meteorite impact. In addition, we will perform state-of-the-art imaging and geochemical analyses to explore for indicators that will unambiguously demonstrate the formation mechanisms of these unusual diamonds.