Tectonic Evolution of an Early Precambrian High-Pressure Granulite Belt in the North China Craton

A large-scale high-pressure granulite belt (HPGB), more than 700 km long, is recognized within the metamorphic basement of the North China craton. In the regional tectonic framework, the Hengshan-Chengde HPGB is located in the central collision belt between the western block and eastern block, and represents the deep crustal structural level. The typical high-pressure granulite (HPG) outcrops are distributed in the Hengshan and Chengde areas. HPGs commonly occur as mafic xenoliths within ductile shear zones, and underwent multipile deformations. To the south, the Hengshan-Chengde HPGB is juxtaposed with the Wutai greenstone belt by several strike-slip shear zones. Preliminary isotopic age dating indicates that HPGs from North China were mainly generated at the end of the Neoarchaean, assocaited with tectonic assembly of the western and eastern blocks.

A Breakthrough in Pressure Generation by a Kawai-Type Multi-Anvil Apparatus with Tungsten Carbide Anvils

Expansion of the pressure range of Kawai-type multi-anvil presses (KMAPs) with tungsten carbide (WC) anvils is called for, especially in the field of Earth science. However, no significant progress in pressure generation has been made for 40 years. Our recent studies have expanded the pressure generation of a KMAP with WC anvils to 65 GPa, which is the world record for high-pressure generation in this device and is more than 2.5 times higher than conventional pressure generation. We have also successfully generated pressures of about 50 GPa at high temperatures. This work reviews our recently developed technology for high-pressure generation. High-pressure generation at room temperature and at high temperature was attained by integration of the following techniques:① a precisely aligned guideblock system,② a high degree of hardness of the second-stage anvils,③ tapering of the second-stage anvil faces,④ a high-pressure cell consisting of materials with a high bulk modulus, and ⑤ high thermal insulation of the furnace. Our high-pressure technology will facilitate investigation of the phase stability and physical properties of materials under the conditions of the upper part of the lower mantle, and will permit the synthesis and characterization of novel materials.

Investigation into high-pressure behavior of MnTiO_3:X-ray diffraction and Raman spectroscopy with diamond anvil cells

The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and lithium niobate type MnTiO3 reversibly transforms at room temperature to perovskite at 2.0 GPa. Bulk moduli （K300） of ilmenite, lithium niobate and perovskite are 174（4） GPa, 179 （8） GPa, and 208（5） GPa, respectively （at fixed first pressure derivative K＇ = 4）. The Griineisen parameter T has been estimated to be 1.28 for ilmenite and 1.75 for perovskite. In ilmenite phase, TiO6 octahedra become more regular with increasing pressure. In perovskite phase structural distortion increases with pressure increase.

In situ high-pressure nuclear magnetic resonance crystallography in one and two dimensions

Recent developments in in situ nuclear magnetic resonance(NMR)spectroscopy under extreme conditions have led to the observation of a wide variety of physical phenomena that are not accessible with standard high-pressure experimental probes.However,inherent di-or quadrupolar line broadening in diamond anvil cell(DAC)-based NMR experiments often limits detailed investigation of local atomic structures,especially if different phases or local environments coexist.Here,we describe our progress in the development of high-resolutionNMRexperiments in DACs using one-and two-dimensional homonuclear decoupling experiments at pressures up to the megabar regime.Using this technique,spectral resolutions of the order of 1 ppm and below have been achieved,enabling high-pressure structural analysis.Several examples are presented that demonstrate the wide applicability of this method for extreme conditions research.

Subsolidus Phase Relations in the System MgO-SiO_2-Cr-O and Thermodynamic Properties of Related Cr^(2+)-Containing End-members

Subsolidus phase relations have been determined in the systems SiO2-Cr-O and MgO-SiO2-Cr-O in equilibrium with metallic Cr, at 1100 to 1500℃ and 0 to 2.88 GPa. The results show that there are no ternary phases in the SiO2-Cr-O system at these conditions, i.e., only the assemblage eskolaite-Cr-metal-quartz (or tridymite) is found. In the MgO-containing system, however, extensive substitution of Cr2+ for Mg is observed in (Mg, Cr2+)2SiO4 olivine, (Mg, Cr2+)2Si2O6 pyroxene, and (Mg, Cr2+)Cr2O4 spinel. Cr3+ levels in olivine and pyroxene are below detection limits. The pyroxene is orthohombic at XCrPx2+ < 0.2, monoclinic at higher XCrPx2+ . Thestructure of the spinels becomes tetragonally distorted at XCr2+Sp >0.2. The experimental datahave been fitted to a thermodynamic model, and the authors obtained the mixing parameter (W) of Mg-Cr2+ in olivine, pyroxene and spinel, and the relation between temperatures and free energies of formation for the end-members: Cr2+-olivine (Cr2SiO4), Cr2+-pyroxene (Cr2Si2O6) and Cr2+-spinel (Cr3O4).

波皮盖——一个保存完好的特大撞击构造,既是国家宝藏,也是世界地质遗址

最近一段时间,Popigai和impact diamond这两个词在地质界和宝石界都掀起了很大的反响,宝石界尤甚。事关这个被俄罗斯重新提起的Siberia撞击构造据说蕴含了可供人类开采3 000年的亿万克拉"金刚石"。此消息被各种媒体沸沸扬扬地"传播"着,形成各种效应。例如,有媒体在报道此消息时配上了大颗钻石毛坯的图片,使人遐想联翩,认为佩戴"鸽子蛋"钻石似乎已不再只是富人的梦想了。但是事实和"传说"明显不同,为了让珠宝业的同仁更清晰地了解这个撞击构造,我们选择德国-加拿大-俄罗斯组成的波皮盖联合考察队(IPEX 97)科学家早年撰写的一篇介绍波皮盖的科学文章进行了完整的翻译(翻译此文已征得原作者同意),以使珠宝界能更清晰和完整地认识这个"新发现",文章中提到的Diamond,我们用带引号的"金刚石"进行翻译,事实上这种撞击产物的定名至今还存在争议。

The effect of oxygen fugacity on ionic conductivity in olivine

The oxygen fugacity(f_(O2)) may affect the ionic conductivity of olivine under upper mantle conditions because Mg vacancies can be produced in the crystal structure by the oxidization of iron from Fe^(2+) to Fe3+. Here we investigated olivine ionic conductivity at 4 GPa, as a function of temperature, crystallographic orientation, and oxygen fugacity, corresponding to the topmost asthenospheric conditions. The results demonstrate that the ionic conductivity is insensitive to f_(O2) under relatively reduced conditions(f_(O2) below Re-ReO_(2) buffer), whereas it has a clear f_(O2)-dependence under relatively oxidized conditions(f_(O2) around the magnetite-hematite buffer). The ionic conduction in olivine may contribute significantly to the conductivity anomaly in the topmost asthenosphere especially at relatively oxidized conditions.

Aluminum solubility in bridgmanite up to 3000 K at the top lower mantle

The temperature dependence of the Al2O3 solubility in bridgmanite has been determined in the system MgSiO3–Al_(2)O_(3)at temperatures of 2750–3000 K under a constant pressure of 27 GPa using a multi-anvil apparatus.Bridgmanite becomes more aluminous with increasing temperatures.A LiNbO3-type phase with a pyrope composition(Mg_(3)Al_(2)Si_(3)O_(12))forms at 2850 K,which is regarded as to be transformed from bridgmanite upon decompression.This phase contains 30 mol%Al_(2)O_(3)at 3000 K.The MgSiO3 solubility in corundum also increases with temperatures,reaching 52 mol%at 3000 K.Molar volumes of the hypothetical Al_(2)O_(3)bridgmanite and MgSiO_(3)corundum are constrained to be 25.950.05 and 26.24±0.06 cm^(3)/mol,respectively,and interaction parameters of non-ideality for these two phases are 5.6±0.5 and 2.2±0.5 KJ/mol,respectively.The increases in Al^(2)O^(3)and MgSiO^(3)contents,respectively,in bridgmanite and corundum are caused by a larger entropy of Al_(2)O_(3)bridgmanite plus MgSiO_(3)corundum than that of MgSiO_(3)bridgmanite plus Al_(2)O_(3)corundum with temperature,in addition to the configuration entropy.Our study may help explain dynamics of the top lower mantle and constrain pressure and temperature conditions of shocked meteorites.

Breathing Enable the Magnetic Properties of Erythrocytes （Hem Fe） Oxygen, Cells and Carbondioxide

To prove that magnetic characteristics （MC） of participants in breathing are crucial in respiration; to explain the impact of Earth＇s magnetic field （EMF）, cosmic radiation （CR） and MC of cells on evolution and respiration; to show MC of cells, i.e. development of cytoplasm and membrane of nucleus and cell; to explain crossing over; to show in detail the impact of EMF on cell division; to explain the exchange of oxygen and carbon dioxide in the lungs and cells MC; to explain how the nervous system works as a regulator of respiration. Studying the literature about ceil, respiration and the role of nervous system in breathing; linking natural EMF, CR and MC of cells with evolution and respiration. Every cell has MC. They are very important in every cell metabolism. Crossing over provides polymorphism, enabled by EMF. Crucial factor in cell division is EMF. Electrical pulses （action potentials） are generated by CR. Breathing is enabled by MC of oxygen, carbon dioxide, hemoglobin and cells. MC enables respiration. EMF, CR and MC of cells are crucial factors in evolution processes generally. EMF is the initiator of cell division. Micro electrical pulses from central nervous system are regulators of respiration. Conductivity of micro electrical pulses in the body is fast-electronic and slow-ion （chemical）.

Cause of Autoimmune Diseases： Anomalous Magnetic Fielads

The aim of this work is to prove the AMF （anomalous magnetic fields） from the environment cause of AID （autoimmune diseases）. The therapeutic possibilities of natural EMF （Earth＇s magnetic field） is pointed out and how to act to prevent AID is determined. Authors indicate in which magnetic fields the IS （immune system） defends the body. They also explain why, in medical literature, risk factors are mistakenly declared pathogens of AID. The magnetic fields intensity in 20 peoples＇ beds, suffering from Type 1 diabetes, was measured with proton magnetometer （accuracy of 100 nT）. The measurement results are presented on sketches, patients were transferred to the natural EMF, medical condition was monitored, and AID function IS ethiopathology was studied. The correlation between AMF and organ location where AID occurred was determined by measuring. The cells of an organism, formed in natural EMF, are in magnetic balance. When an intruder enters the body, magnetic balance disappears and leukocytes with its MF （magnetic forces） destroy intruders. In the AMF, cells get enlarged MF without magnetic balance, causing IS with its MF to attack own cells, resulting AID. When an intruder enters a tissue, tissue cells and cells of intruders gain enhanced MF. IS with its MF destroys intruders. In the literature （The China Study by T. Colin Campbell）, the food is presented as cause of number of diseases. It was found what led to such a misinterpretation. It has been proven that causes of mentioned diseases are only AMF, which can be located in any organ, and with Type 1 diabetes its spread to the whole body with strongest intensity on pancreas. AMF give tissue cells reinforced MF without magnetic balance causing IS to deplete own tissues, resulting AID. IS works perfectly without AMF and risk factors are only a consequence of AMF.

尖晶石CoAl_2O_4中阳离子分布的温度依赖性

本文通过X射线粉末衍射数据的Rietveld结构精化法,确定了经过750～1200℃淬火的合成尖晶石CoAl_2O_4样品的阳离子分布。其反生参数X随温度750—1200℃相应地从0.11平滑增加到0.25(±0.005),并可用带有α_(Co-Al)=45.3±0.5,β=-18.3±1.2kJ/mol的一般热力学模型描述。其β项与 O’Neill和Navrotsky(1984)提出的2—3价型尖晶石的数据(-20kJ/mol)相吻合,而CoAl_2O_4尖晶石性能相似于大多数氧化物尖晶石,显示出阳离子分布的温度依赖性。既然,Co^(2+)和 Fe^(2+)通常显示相似的高温晶体化学行为,本次研究结果强调了与近来关于FeAl_2O_4中阳离子分布的温度依赖性的研究结果不一致的性质,它们不能很好地用一般的热力学模型所描述。CoAl_2O_4中阳离子的再有序化速率在低温(700℃)下定性地相似于另一些铝酸盐尖晶石;但FeAl_2O_4是例外;由于内部的“Fe^(3+)/空穴”存在,FeAl_2O_4的阳离子再有序化速率更快。FeAl_2O_4的明显异常特性可能是由于高速动力学的人工合成所致。

Natural End Member Samples of Pyrope and Grossular:A Cathodoluminescence-Microscopy and-Spectra Case Study

Garnet is one of the most significant minerals in metamorphic rocks, that provides key information on prograde, peak-metamorphic and retrograde parts of the pressure-temperature （PT） path. Such results require a detailed knowledge of its different growth domains. For iron-poor compositions, the cathodoluminescence （CL） microscopy is an important and often overlooked method and allows to identify the internal structures of all garnet grains in one thin section within only a few seconds. The advantage of the CL-microscope is to deliver low magnification images in true color, not only of garnet but also, for instance, of other rock forming silicates, carbonates, sulfates, etc., of metamorphic, but also of sedimentary and magmatic origin, using polished thin sections. Internal structures of grossular from Mexico and pyrope from the Italian Alps were characterized and visualized by CL-microscopy. The different growth domains were additionally studied using CL-spectra and electron microprobe （EMP） analysis. Grossular shows a patchy zonation in its core while in mantle and rim zones oscillatory zoning is observed. It contains zones of anomalous birefringence, zones of orange and bluish luminescence and zones lacking luminescence. Different but low amounts of the activator elements Mn2＋ and Eu2＋ are responsible for the orange and bluish luminescent domains. Pyrope is also characterized by oscillatory growth zones, shows a dull luminescent core with a change of crystal morphology during growth, and displays an increase of brightness from core towards rim--the outermost rim, however, is lacking luminescence. The different luminescent zones are characterized by different amounts of Dy3＋, Tb3＋, Sm3＋ and Sm2＋ as activator elements. Because of slow diffusion rates of activators such as the REEs Sm, Dy and Tb, it can be still possible to visualize possible prograde and/or peak pressure stage growth domains of garnet, even if later high temperature events may have homogenized the major element profiles. Such domains may help to identify respective assemblages of mineral inclusions, and hence these results can represent an integral part of a detailed PT path. Thus the CL-information can be used as an important pathfinder prior to supplementary investigations, as for instance EMP, ion probe, mineral or fluid inclusion studies.

Chemical diffusion and oxygen exchange of LaNi_(0.4)Fe_(0.6)O_(3-δ)ceramics

Oxygen surface exchange and oxygen chemical diffusion coefficients of LaNi_(0.4)Fe_(0.6)O_(3-δ)ceramics are determined via conductivity relaxation method after stepwise change of temperature in the range of 700-950℃in air and Ar/O2 gas flow at oxygen partial pressures(p_(o2))of 4 Pa,18 Pa,37 Pa,47 Pa and 59 Pa.The highest conductivity(about 160 S·cm^(-1))is found at 950℃in air.No oxygen exchange(δ=0)below 700℃is observed in the investigated p_(o2) range.The oxygen exchange coefficients determined in reduction mode are higher than those determined in oxidation mode.This is explained by clusterization of oxygen vacancies on the surface of the sample investigated in oxidation mode.The opposite tendency is found for chemical diffusion coefficients.Unlike surface,the oxygen vacancies of the volume region are probably not clustered and have predetermined the higher oxygen diffusion mobility of the sample treated in oxidation mode.

High-pressure, High-temperature Synthesis and Properties of the Monoclinic Phase of Y2O3

The monoclinic phase of Y2O3（B-RES） has been synthesized using a Kawai-type multi-anvil apparatus under 20 GPa at 1800℃. Samples of the cubic Y2O3（C-RES） and monoclinic Y2O3 phases were characterized by synchrotron radiation X-ray diffraction, X-ray absorption near edge structure and Raman spectroscopy. Crystal structures of the cubic and monoclinic phases have been examined using Rietveld refinement of the X-ray diffraction data. The cubic-to-monoclinic transition of Y2O3 was reconstructive and irreversible. The X-ray diffraction results were further confirmed by simulation of the X-ray absorption spectra.