Renewal: Mineral Physics Studies under the Pressure-Temperature Conditions of Earth's Deep Lower Mantle

研究人员认为，他们在地球深部地幔和铁核之间的极端压力-温度条件下发现了一个巨大的氧气库。 水库由以前未知的铁超氧化物组成，这些铁超氧化物可能会突然释放出过量的氧气。 在本项目中，研究小组将进一步探索不同类型的铁超氧化物，爆炸性氧气释放的条件以及氧气爆发的后果。 这些零星的喷发提供了一种新的统一机制，可以回答地球46亿年历史中发生的看似无关的过去事件的问题，并塑造了现在的地球。 空气中的氧气从何而来？ 是什么导致了大规模的灭绝，导致了恐龙的灭绝和哺乳动物的出现？ 是什么推动力促使所有大陆合并成一个超级大陆，后来又将超级大陆分开形成单独的大陆？ 研究者最近发现的具有黄铁矿型Pa 3结构的高P-T铁超氧化物FeO_2和FeO_2H_x，预示着下地幔深部矿物物理和地球动力学的潜在范式变化。 该团队建议进一步研究超氧化物的高P-T矿物物理性质，包括将其他主要成分如MgO 2，AlO 2和SiO2掺入Pa 3铁超氧化物中，其与硅酸盐桥镁石和后钙钛矿的相互作用，其电子和磁自旋状态以及铁和氧的价态。除了Pa 3之外，该团队还将寻找其他稳定的结构类型，用于具有明显Fe氧化态3+的基于铁的超氧化物，并确定它们的弹性波速度，以与地球深部的地震观测进行比较。 该团队先前的研究表明，在核幔边界存在大量富氧斑块。这项研究将调查这种巨型氧气库的亚稳定性，以及当储存的氧气被释放时的后果，特别是由此产生的超级板块构造的地球动力学，这可能解释超级大陆合并和断裂的起源。

The investigators believe they have discovered a giant oxygen reservoir at the extreme pressure-temperature conditions between the Earth's deep mantle and iron core. The reservoir consists of previously unknown iron superoxides which could suddenly release its excessive oxygen. In the present project, the team will further explore the different types of iron superoxides, the conditions for the explosive oxygen release, and the consequences of oxygen eruptions. The sporadic eruptions provide a new, unified mechanism for answering questions on a list of seemingly unrelated past events that occurred during Earth's 4.6 billion years history and shaped the present living planet. Where did the oxygen in the air come from? What caused the mass extinctions that killed the dinosaurs and ushered in the mammals? What was the driving force that pushed all continents to merge into a single supercontinent, and later pulled the supercontinent apart to form individual continents? From understanding the Earth's Past and Present, we may gain insights into the Earth's Future.The investigator's recent discovery of high P-T iron superoxides, FeO2 and FeO2Hx with the pyrite-type Pa3 structure has suggested potential paradigm changes in mineral physics and geodynamics of the deep lower mantle. The team proposes to further investigate the high P-T mineral physics properties of the superoxides, including the incorporation of other major components such as MgO2, AlO2 and SiO2 into the Pa3 iron superoxide, its interactions with silicate bridgmanite and post-perovskite, its electronic and magnetic spin states, and its valence states of iron and oxygen. The team will search for other stable structural types in addition to Pa3 for firon-based superoxides with the apparent Fe oxidation state 3+, and determine their elastic wave velocities for comparison for comparison with seismic observations in the deep Earth. The team's previous research suggested the existence of a massive amount of oxygen-rich patches at the core-mantle boundary. This research will investigate the metastability of such giant oxygen reservoirs, and the consequences when the stored oxygen is released, particularly the resulting geodynamics of the super plate tectonics that may explain the origin of merging and rifting of supercontinents.