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

黑金刚石的地幔或地壳起源？

• 批准号: 0073862
• 负责人: Peter Heaney
• 金额: $ 7.25万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-15 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0073862&HistoricalAwards=false
• 关键词: Mantle; Crustal; Origin; Carbonado; Synthesis

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.

Heaney/Vicenzi科学家将碳钻描述为“所有钻石中最神秘的。“它们以豌豆大小的黑色熔融金刚石微晶体结节的形式出现，具有相对较大的空隙空间，可以占总体积的15%以上。 一些科学家提出了一系列理论来解释它们的形成，其中一些理论如果被证明是正确的，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，碳酸岩是在太古代晚期由一颗巨大的陨石撞击形成的，而另一些科学家则认为碳酸岩是来自地球上地幔的一种奇异的钻石。 我们打算测试这些假设，通过比较碳质纹理和矿物包裹体与那些在地球深处结晶的多晶金刚石和陨石撞击。 此外，我们将进行最先进的成像和地球化学分析，以探索能够明确证明这些不寻常钻石形成机制的指标。