Abstract— The conditions of genesis of diamondiferous ultrabasic and basic rocks from xenoliths in kimberlite were studied by combining the data from analytical investigations of their mineral phases and experimental results of the study of melting relations in the diamond-forming mineral systems of the upper mantle. The compositions of minerals in some samples of metasomatized diamondiferous eclogite associated with diamond-free eclogite from kimberlite of the Udachnaya pipe (Yakutia) were studied for the first time. The new results obtained in addition to the literature data were applied for generalization of estimates of genetically important characteristics of the chemical compositions of garnets, Ca-clinopyroxenes, and omphacites from diamond-bearing peridotite, pyroxenite, and eclogite. As a result, it was found that quite “fresh” minerals of diamondiferous rocks have typomorphic differences from the same minerals of diamond-free upper-mantle rocks. At the same time, it is significant that the compositions of minerals from diamondiferous rocks and paragenetic inclusions in diamonds are identical. These peculiarities of mineralogy of diamondiferous rocks are genetically significant; based on the mantle–carbonatite theory of the origin of diamond and associated mineral phases, this provides support for the same physicochemical origin of diamonds, minerals of diamondiferous rocks, and paragenetic inclusions in diamonds. Finally, the following genetic conclusions are made. (1) Completely miscible silicate (±oxide)–carbonate melts with dissolved carbon are the parental medium in petrogenesis of diamondiferous ultrabasic and basic rocks. (2) The physicochemically consistent formation of diamondiferous rocks and paragenetic inclusions of peridotitic and eclogitic minerals in diamonds occurred in the common diamond-forming chambers/reservoirs of parental melts; diamond-free peridotite, pyroxenite, and eclogite were the host mantle rocks for such chambers. (3) The origin of continuous series of diamondiferous peridotite–pyroxenite–eclogite rocks is controlled by the fractional ultrabasic–basic evolution of parental melts with exhaustion of olivine and orthorhombic pyroxene via the peritectic reactions. (4) Ascending flows of kimberlite magmas destroyed the parental chambers and captured diamonds with inclusions, individual minerals, their intergrowths, diamondiferous ultrabasic and basic rocks; at the entrance and exit from the chambers, they captured differentiated diamond-free host rocks of the mantle as well. (5) With further ascent from the mantle to the Earth’s crust, the material of diamond-forming chambers and diamond-free mantle was mixed in convecting kimberlite magma and was transported from the mantle to cumulative crustal chambers. (6) Kimberlite magmas were gradually solidified in stationary cumulative chambers with the release of highly compressed fluids; with an increase of pressure up to the critical values, they intruded into the rocks of the roof and ejected kimberlite with xenoliths of diamondiferous and mantle rocks to the surface with the formation of explosion pipes.

中文翻译：

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金伯利岩上地幔捕虏体中含金刚石岩石的成因

摘要：结合金伯利岩捕虏体的含金刚石超基性和基性岩的成因条件，结合其矿相分析数据和上地幔金刚石形成矿物系统熔融关系研究的实验结果，研究了金伯利岩捕虏体中含金刚石超基性岩和基性岩的成因条件。首次研究了部分交代含金刚石榴辉岩样品中的矿物成分，这些样品与来自 Udachnaya 管（雅库特）金伯利岩的无金刚石榴辉岩伴生。除了文献数据外，获得的新结果还用于对含金刚石橄榄岩、辉石岩和榴辉岩中的石榴石、Ca-斜辉石和绿辉石的化学成分的遗传重要特征的估计进行概括。因此，研究发现，含金刚石岩石的相当“新鲜”的矿物与不含金刚石的上地幔岩石的相同矿物在类型形态上存在差异。同时，重要的是来自含金刚石岩石的矿物成分和金刚石中的共生包裹体是相同的。含金刚石岩石矿物学的这些特性具有遗传意义；基于金刚石和相关矿物相起源的地幔-碳酸岩理论，这为金刚石、含金刚石岩石的矿物和金刚石中的共生内含物的相同物理化学起源提供了支持。最后，得出以下遗传结论。(1) 具有溶解碳的完全混溶的硅酸盐（±氧化物）-碳酸盐熔体是含金刚石超基性岩和基性岩成岩的母质介质。(2) 含金刚石岩石的物理化学一致形成以及金刚石中橄榄岩和榴辉岩矿物的共生包裹体发生在母熔体的常见金刚石形成室/储层中；不含金刚石的橄榄岩、辉石岩和榴辉岩是此类室的主地幔岩石。(3) 连续系列含金刚石橄榄岩-辉石-榴辉岩岩石的成因受母熔体分次超基性-基性演化控制，橄榄石和斜方晶辉石通过包晶反应耗尽。(4) 金伯利岩浆上升流破坏了母室，捕获了含包裹体的金刚石、单个矿物、它们的共生体、含金刚石的超基性岩和基性岩；在房间的入口和出口处，他们还捕获了地幔中不同的不含金刚石的主岩。(5)随着地幔进一步上升到地壳，金刚石形成室和无金刚石地幔物质混合在对流金伯利岩浆中，从地幔输送到累积地壳室。(6) 金伯利岩浆在静止的堆积室中随着高度压缩流体的释放而逐渐凝固；随着压力增加到临界值，它们侵入顶板的岩石，并将金伯利岩与含金刚石和地幔岩石的捕虏体一起喷射到地表，形成爆炸管。金刚石形成室和无金刚石地幔的物质混合在对流金伯利岩浆中，并从地幔输送到累积的地壳室。(6) 金伯利岩浆在静止的堆积室中随着高度压缩流体的释放而逐渐凝固；随着压力增加到临界值，它们侵入顶板的岩石，并将金伯利岩与含金刚石和地幔岩石的捕虏体一起喷射到地表，形成爆炸管。形成金刚石的腔室和无金刚石地幔的物质混合在对流金伯利岩浆中，并从地幔输送到累积的地壳腔室。(6) 金伯利岩浆在静止的堆积室中随着高度压缩流体的释放而逐渐凝固；随着压力增加到临界值，它们侵入顶板的岩石，并将金伯利岩与含金刚石和地幔岩石的捕虏体一起喷射到地表，形成爆炸管。