Origin of Diamonds and Their Host Xenoliths

尽管地幔的体积占地球体积的75%以上，但对其手部样本的研究相对较少。幸运的是，金伯利岩(钻石的来源岩石，以金伯利命名)，所以。AFR.)把珍贵的地幔样本带到地表。这些榴辉岩和橄榄岩包体(Gr.在很深的地方，金伯利岩中含有大量的外国岩石)，可能含有钻石。这些含钻石的包体，特别是榴辉岩，以及它们在地幔深处的钻石，是我们研究的主题。对于将含钻石岩石作为钻石形成条件的指标的可靠性存在一些争议，因为这些岩石可能经历了钻石后交代和/或部分熔融。钻石中的矿物包裹体被认为是地幔的原始样品，因为这些包裹体是从钻石形成后的地幔过程中分离出来的。似乎每一颗钻石都可以指示一套可能的不同的P-T-x形成条件，所有这些条件都可能不被宿主矿物学所代表。寄主榴辉岩可能只记录了钻石的最新居住地点，而不是其形成的原始条件。研究钻石及其包裹体的适当方式是在抛光表面上一起研究，包括复杂的微型仪器化学技术，再加上钻石的同位素分析，所有这些都是在钻石复杂的晶体生长模式的背景下进行的。建议对钻石中的包裹体进行一项全面的地球化学和岩石学研究，主要区别在于，钻石的生长历史和化学特征也将被记录下来，放在钻石的“地层”中。钻石将被用作地球地幔演化的记录器。为此，已经组建了一个拥有钻石成因大部分方面专业知识的国际科学家联盟。这构成了对钻石的岩石成因、其矿物包裹体及其宿主包体的第一个真正完整的研究。这种研究钻石、它们的包裹体和寄主包体的综合方法，将对了解钻石形成所需的地幔条件和地幔的演化作出重大贡献。

9909430TaylorThe mantle, although making up over 75% by volume of the Earth, remains relatively unstudied in hand sample. Fortunately, kimberlites (the source-rock of diamonds, named after Kimberley, So. Afr.) bring precious mantle samples to the surface. These eclogite and peridotite xenoliths (Gr. foreign rocks) were incorporated into the kimberlite at great depths and can contain diamonds. The origin of these diamond-bearing xenoliths, particularly eclogites, and their diamonds from deep within the mantle of the Earth is the subject of our research. There is some controversy over the reliability of diamond-bearing rocks as indicators of the conditions under which the diamonds formed, because these rocks may have been subjected to post-diamond metasomatism and/or partial melting. Mineral inclusions within diamonds are considered pristine samples of the mantle because these inclusions were isolated from post-diamond-formation mantle processes. It appears that each diamond can indicate a possible different set of P-T-x conditions for its formation, all of which may not be represented by the host mineralogy. The host eclogite may only record the most recent residence locale for the diamond and not the original conditions of its formation. The proper manner with which to study diamonds and their inclusions is together on polished surfaces, involving sophisticated micro-instrumental chemical techniques, coupled with isotopic analyses of the diamond, all within the context of the intricate crystal growth patterns of the diamonds. A comprehensive geochemical and petrologic study of inclusions within diamonds is proposed, with the key distinction that the growth-histories and chemical characteristics of the diamonds will also be documented, as placed within the 'stratigraphy' of the diamonds. Diamonds will be used as recorders of the evolution of the Earth's mantle. To this end, an international consortium of scientists has been assembled with expertise in most aspects of diamond genesis. This constitutes the first truly integrated study of the petrogenesis of diamonds, their mineral inclusions, and their host xenoliths. This integrated approach to the study of diamonds, their inclusions, and host xenoliths, will make a significant contribution to the knowledge of mantle conditions necessary for diamond formation and the evolution of the mantle