Abstract Kimberlites are the surface manifestation of deeply-derived (>150 km) and rapidly ascended magmas. Fresh kimberlite rocks are exceptionally rare, as most of them are invariably modified by pervasive deuteric and/or post-magmatic fluids that overprint the original mineralogy. In this study, we examined fresh archetypal kimberlite from the Mark pipe (Lac de Gras, Canada), which is characterised by well-preserved olivine and groundmass minerals. The sequence of crystallisation of the parental melt and its major compositional features, including oxygen fugacity, were reconstructed using textural relationships between magmatic minerals, their zoning patterns and crystal/melt/fluid inclusions. Crystal and multiphase primary, pseudosecondary and secondary melt/fluid inclusions in olivine, Cr-diopside, spinel, perovskite, phlogopite/kinoshitalite, apatite and calcite preserve a record of different stages of kimberlite melt evolution. Melt/fluid inclusions are generally more depleted in silica and more enriched in alkalis (K, Na), alkali-earth (Ba, Sr) and halogens (Cl, F) relative to the whole-rock composition of the Mark kimberlite. These melt/fluid inclusion compositions, in combination with presence of elevated CaO (up to 1.73 wt%), in Mg-rich olivine rinds, crystallisation of groundmass kinoshitalite, carbonates (calcite, Sr-Ba-bearing) and alkali-enriched rims around apatite suggest that there was progressive enrichment in CO2, alkalis and halogens in the evolving parental melt. The Mark kimberlite groundmass is characterised by the following stages of in-situ crystallisation: (1) olivine rims around xenocrystic cores + Cr-spinel/TIMAC. (2) Mg-rich olivine rinds around olivine rims/cores + MUM-spinel (followed by pleonaste and Mg-magnetite) + monticellite (+ partial resorption of olivine, along with the formation of ferropericlase and CO2 as a result of decarbonation reactions) + perovskite + apatite. (3) Olivine outmost rinds, which are coeval with phlogopite/kinoshitalite + apatite + sulphides + carbonate (calcite, Ba-Sr-Na-bearing varieties). In addition, oxygen fugacity of the Mark kimberlite was constrained by olivine-chromite, perovskite and monticellite oxygen barometry and showed that the parental melt became progressively more oxidised in response to fractional crystallisation. (4) Deuteric (i.e. late-stage magmatic) and/or post-magmatic (i.e. external fluids) alteration of magmatic minerals (e.g., olivine, monticellite, ferropericlase) and crystallisation of mesostasis serpentine, K-bearing chlorite and brucite (i.e. replacement of ferropericlase). The absence of any alkali (Na, K) and halogen (F, Cl) rich groundmass minerals in the Mark kimberlite may be attributed to these elements becoming concentrated in the late-stage melt where they potentially formed unstable, water-soluble carbonates (such as those observed in melt inclusions). Consequently, these minerals were most likely removed from the groundmass by deuteric and/or post-magmatic alteration.

中文翻译：

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地壳中金伯利岩浆的演化：以马克金伯利岩（加拿大格拉斯湖）地块和矿物包裹体为例

摘要 金伯利岩是深层（>150 km）快速上升的岩浆的地表表现形式。新鲜的金伯利岩非常罕见，因为它们中的大多数总是被无处不在的氘和/或后岩浆流体所修饰，这些流体覆盖了原始矿物学。在这项研究中，我们检查了来自 Mark pipe（加拿大 Lac de Gras）的新鲜原型金伯利岩，其特征是保存完好的橄榄石和地块矿物。母体熔体的结晶顺序及其主要成分特征，包括氧逸度，是利用岩浆矿物、它们的分带模式和晶体/熔体/流体包裹体之间的结构关系重建的。橄榄石、铬透辉石、尖晶石、钙钛矿中的晶体和多相初级、伪次级和次级熔体/流体包裹体，金云母/kinoshitalite、磷灰石和方解石保存了金伯利岩熔体演化不同阶段的记录。相对于马克金伯利岩的全岩成分，熔体/流体包裹体通常更缺乏二氧化硅，更富含碱（K、Na）、碱土（Ba、Sr）和卤素（Cl、F）。这些熔体/流体夹杂物组合物与高 CaO（高达 1.73 wt%）的存在相结合，在富含镁的橄榄石外皮中，地块木菱镁矿结晶，碳酸盐（方解石，含 Sr-Ba）和周围富含碱的边缘磷灰石表明，在演化的母体熔体中，CO2、碱金属和卤素逐渐富集。Mark 金伯利岩地块的特征在于以下原位结晶阶段：(1) 异晶核周围的橄榄石边缘 + Cr-尖晶石/TIMAC。(2) 橄榄石边缘/核周围富含镁的橄榄石外皮 + MUM-尖晶石（其次是 pleonaste 和 Mg-磁铁矿）+ 蒙脱石（+ 橄榄石的部分吸收，以及由于脱碳反应形成的铁镁石和 CO2） + 钙钛矿 + 磷灰石。(3) 橄榄石最外皮，与金云母/kinoshitalite + 磷灰石 + 硫化物 + 碳酸盐（方解石，含 Ba-Sr-Na 的品种）同时期。此外，马克金伯利岩的氧逸度受到橄榄石-铬铁矿、钙钛矿和蒙脱石氧气压计的限制，并表明母体熔体随着分级结晶而逐渐氧化。(4) 岩浆矿物（如橄榄石、蒙脱石、亚铁镁石）和中间稳态蛇纹石、含钾绿泥石和水镁石的结晶（即亚铁镁石的替代品）。马克金伯利岩中不存在任何富含碱 (Na, K) 和卤素 (F, Cl) 的地块矿物可能是由于这些元素在熔体后期富集，在那里它们可能形成不稳定的水溶性碳酸盐（例如如在熔体夹杂物中观察到的那些）。因此，这些矿物很可能是通过氘代和/或后岩浆蚀变从地块中去除的。水溶性碳酸盐（如在熔体包裹体中观察到的那些）。因此，这些矿物很可能是通过氘代和/或后岩浆蚀变从地块中去除的。水溶性碳酸盐（如在熔体包裹体中观察到的那些）。因此，这些矿物很可能是通过氘代和/或后岩浆蚀变从地块中去除的。