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| 1 | The onset of deep recycling of supracrustal materials at the Paleo-Mesoarchean boundary显示文摘The recycling of supracrustal materials, and in particular hydrated rocks, has a profound impact on mantle composition and thus on the formation of continental crust, because water modifies the physical properties of lithological systems and the mechanisms of partial melting and fractional fractionation. On the modern Earth, plate tectonics offers an efficient mechanism for mass transport from the Earth’s surface to its interior, but how far this mechanism dates back in the Earth’s history is still uncertain. Here, we use zircon oxygen(O) isotopes to track recycling of supracrustal materials into the magma sources of early Archean igneous suites from the Kaapvaal Craton, southern Africa. The mean δ^(18)O values of zircon from TTG(tonalite–trondhjemite–granodiorite) rocks abruptly increase at the Paleo-Mesoarchean boundary(ca.3230 million years ago;Ma), from mantle zircon values of 5‰–6‰ to approaching 7.1‰, and this increase occurs in ≤3230 Ma rocks with elevated Dy/Yb ratios. The^(18)O enrichment is a unique signature of low-temperature water–rock interaction on the Earth’s surface. Because the later phase was emplaced into the same crustal level as the older one and TTG magmas would derive from melting processes in the garnet stability field(>40 km depth), we suggest that this evident shift in TTG zircon O isotopic compositions records the onset of recycling of the mafic oceanic crust that underwent seawater hydrothermal alteration at low temperature. The onset of the enhanced recycling of supracrustal materials may also have developed elsewhere in other Archean cratons and reflects a significant change in the tectonic realm during craton formation and stabilization, which may be important processes for the operation of plate tectonics on early Earth. | Xiaolei Wang Ming Tang Jeff Moyen Di Wang Alfred Kröner Chris Hawkesworth Xiaoping Xia Hangqiang Xie Carl Anhaeusser Axel Hofmann Junyong Li Linsen Li | 2022 | National Science Review2022，9，3： | 3 |
| 2 | 太古宙与现代的巨大差异:太古宙可能有板块构造吗?显示文摘太古宙出露的岩石(如TTG、科马提岩、绿岩带)大多与现代不同,故“将今论古”的思想不适合推演到太古宙,也不能把太古宙TTG对比为现今的埃达克岩。TTG与俯冲无关,也不是地壳加厚形成的,而可能是在停滞盖层构造背景下初始地壳内富钠玄武岩部分熔融形成的。地球演化是一个不断散热的过程,太古宙属于热球阶段,元古宙以后可能才进入冷球阶段。因此,太古宙可能主要表现为停滞盖层构造,元古宙以后可能才出现板块构造。板块热俯冲的可能性很小,只有当岩石圈足够冷且具有一定的刚性和浮力时,板块才可能俯冲;而查明板块构造的地质记录(如蛇绿岩、蓝片岩、混杂堆积、深海沉积等)才能知道板块构造启动的时间。 | 张旗 焦守涛 | 2021 | 地质通报2021，40，9： | 2 |
| 3 | Evidence for oxygenation of Fe-Mg oxides at mid-mantle conditions and the rise of deep oxygen显示文摘As the reaction product of subducted water and the iron core,FeO2 with more oxygen than hematite(Fe_(2)O_(3))has been recently recognized as an important component in the D'layer just above the Earth’s core-mantle boundary.Here,we report a new oxygen-excess phase(Mg,Fe)_(2)O_(3)+δ(0<δ<1,denoted as‘OE-phase’).It forms at pressures greater than 40 gigapascal when(Mg,Fe)-bearing hydrous materials are heated over 1500 kelvin.The OE-phase is fully recoverable to ambient conditions for ex situ investigation using transmission electron microscopy,which indicates that the OE-phase contains ferric iron(Fe^(3+))as in Fe_(2)O_(3) but holds excess oxygen through interactions between oxygen atoms.The new OE-phase provides strong evidence that H_(2)O has extraordinary oxidation power at high pressure.Unlike the formation of pyrite-type FeO_(2)H_(x) which usually requires saturated water,the OE-phase can be formed with under-saturated water at mid-mantle conditions,and is expected to be more ubiquitous at depths greater than 1000 km in the Earth’s mantle.The emergence of oxygen-excess reservoirs out of primordial or subducted(Mg,Fe)-bearing hydrous materials may revise our view on the deep-mantle redox chemistry. | Jin Liu Chenxu Wang Chaojia Lv Xiaowan Su Yijin Liu Ruilian Tang Jiuhua Chen Qingyang Hu Ho-Kwang Mao Wendy L.Mao | 2021 | National Science Review2021，8，4： | 2 |
| 4 | 高温高压法合成金刚石微区原位碳同位素及阴极发光特征显示文摘当前大量的研究集中在天然产出的金刚石上,而人工合成金刚石的研究往往容易被忽视。对人工合成金刚石进行详细的研究,结合已有天然金刚石的认知有利于揭示天然金刚石形成过程,有利于天然金刚石的鉴定。本研究综合利用显微镜、纳米离子探针、拉曼光谱、阴极发光等分析技术,对人工合成金刚石的晶体结构、包裹体、微区碳同位素、以及阴极发光图像等特征进行了详细的研究。研究揭示其阴极发光图像与天然宝石级金刚石有明显的区别,二次离子探针数据进一步表明其阴极发光图像的明暗差异与金刚石中微量元素氮的含量高低有关。 | 朱志勇 徐耀明 周巍 | 2020 | 地球学报2020，41，5： | 1 |
| 5 | 超深金刚石包裹体:对深部地幔物理化学环境的指示显示文摘超深金刚石及其包裹体是探究深部地幔组成及物理化学环境的重要样本。梳理了超深金刚石中新发现的典型矿物包裹体及其组合,并结合前人高精度原位分析、高温高压合成金刚石实验的研究成果,综述分析了超深金刚石矿物包裹体及其组合指示的深度范围、微量元素与温压条件之间的关系,超深地幔水的赋存矿物相、金属相以及强还原环境新认识,残留的俯冲洋壳可能是深部地幔水的重要储库,超深金刚石及其包裹体对深俯冲及深部碳循环的指示等研究进展。指出我国学者虽然在华北、扬子克拉通金刚石中也发现了指示超深来源的矿物包裹体,在超高压金刚石形成及蛇绿岩型金刚石成因研究方面获得了某些重要进展,但对超深金刚石包裹体的研究仍然有待深入。 | 郑昕雨 丘志力 邓小芹 马瑛 陆太进 | 2020 | 地球科学进展2020，35，5： | 1 |
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