南海NS90－103沉积物柱样沉积年代研究

本文结合浮游有孔虫氧同位素地层学和不平衡铀系测定沉积速率的方法来确立取自南沙海域的沉积物柱样（ＮＳ９０－１０３）的时间坐标、根据连续取样获得的δ（１８）Ｏ曲线可以将该柱划分为７个主要气候期次，底部（５５０ｃｍ）相当于氧同位素第７．４阶到第７．５阶之间，年龄约２３８ｋａ；而根据不平衡铀系的过量（２３０）Ｔｈ方法获得２．３ｃｍ／ｋａ的沉积速率，计算出底部年龄为２３９ｋａ；两个结果在误差范围内完全一致。     

制定综合技术对策提高地矿部门钻探生产效率

本文针对当前地矿部门岩心钻探生产形势和未来发展要求，简述了制定提高地矿部门岩心钻探生产效率的综合技术对策的必要性和意义，在明确的主导思想下，论述并提出了一套综合技术对策建议，供地矿部门岩心钻探管理决策人士参考。     

幔羽现象与地震电磁流体效应的可能联系——电磁流体效应和平面电流模型

综合分析了 2 0世纪 70年代以来发生在中国的 14个强震前地磁和地下流体参量动态图像的时空演化特征 ,发现强震前这些参量均呈现十分明显的异常图形。这些图像十分复杂 ,且随时间不断变化 ,并与孕震过程有某种时空规律性联系。 90年代地学家通过地震资料分析发现了幔羽现象。笔者设想核幔边界的幔羽磁流体物质上涌是地震电磁流体效应的一种可能成因。幔羽中的流体物质螺旋上涌至地壳的底部 ,并形成“蘑菇云”。流体在地壳中扩展或挤压 ,形成异常电流 ,可将其看作在孕震区地下 10 2 0km深处有一等效平面电流。再考虑到近地表的电磁环境———电离层电流体系的局部异常 ,计算了一个地下和电离层组成的等效平面电流模型在地面产生的磁场分布 ,结果与强震前地球磁场的零等变型异常动态图像较吻合。     

震电效应原理和初步实验结果

从电化学理论、薄膜效应以及浓差极化，解释了震电效应的基本原理.通过室内沙槽和岩芯标本实验，发现了震电信号，且在砂土上的震电信号比粘土上的大；含石油岩芯标本上的震电效应信号比含水岩芯标本上的强.通过室外实验，也已经测量到可信的震电效应信号，从而为石油测井继续研究提供了实验数据.     

Distribution of fault rocks in the fracture zone of the Nojima Fault at a depth of 1140 m: Observations from the Hirabayashi NIED drill core

Abstract Characteristics of deformation and alteration of the 1140 m deep fracture zone of the Nojima Fault are described based on mesoscopic (to the naked eye) and microscopic (by both optical and scanning electron microscopes) observations of the Hirabayashi National Research Institute for Earth Science and Disaster Prevention (NIED) drill core. Three types of fault rocks; that is, fault breccia, fault gouge and cataclasite, appear in the central part of the fault zone and two types of weakly deformed and/or altered rocks; that is, weakly deformed and altered granodiorite and altered granodiorite, are located in the outside of the central part of the fault zone (damaged zone). Cataclasite appears occasionally in the damaged zone. Six distinct, thin foliated fault gouge zones, which dip to the south-east, appear clearly in the very central part of the fracture zone. Slickenlines plunging to the north-east are observed on the surface of the newest gouge. Based on the observations of XZ thin sections, these slickenlines and the newest gouge have the same kinematics as the 1995 Hyogo-ken Nanbu earthquake (Kobe earthquake), which was dextral-reverse slip. Scanning electron microscopy observations of the freeze-dried fault gouge show that a large amount of void space is maintained locally, which might play an important role as a path for fluid migration and the existence of either heterogeneity of pore fluid pressure or strain localization.     

Dasuopu ice core record of atmospheric methane over the past 2000 years

The concentrations of CH₄ in the atmosphere over the past 2000 years have been deduced by extracting and analyzing the air in bubbles embedded in the Dasuopu ice core, Qing-hai-Tibetan Plateau. Upon analyzing 57 ice core samples we found that the concentration of CH₄ 200 years ago and earlier was 0.85 μ mol· mol^-1 or about 40% of present atmospheric CH₄ levels over Qinghai-Tibetan Plateau. A rapid and significant increase of atmospheric CH₄ started about 200–250 a ago. For a given age before 19th century, the Dasuopu CH₄ concentrations were about 15%-20% higher than those in Antarctic and Greenland references. It was also found that the Dasuopu CH₄ concentrations changed more frequently, and its fluctuations could reflect the temperature change sensitively.     

The effect of ferromagnetism on the equation of state of Fe3C studied by first-principles calculations

First-principles calculations have been used to determine the equation of state of Fe₃C in both its low-pressure magnetically ordered and high-pressure non-magnetically ordered states; at 0 K the ferromagnetic transition was found to occur at about 60 GPa. In the high pressure, non-magnetically ordered regime at 0 K the material may be described by a Birch-Murnaghan third-order equation of state with V₀=8.968(7) ų per atom, K₀=316.62(2) GPa and K′=4.30(2). At atmospheric pressure the ferromagnetic phase transition in Fe₃C occurs at ∼483 K; preliminary measurements of the thermal expansion by powder neutron diffraction show that this transition produces a large effect on thermoelastic properties. The volumetric thermal expansion coefficient in the paramagnetic phase was found to be 4.34×10⁻⁵ K⁻¹ at T∼550 K. By applying a thermal expansion correction to the calculated equation of state at 0 K, predicted values for the density and adiabatic incompressibility of this material at core pressures and temperatures were obtained. These results appear to be sufficiently different from seismological data so as to preclude Fe₃C as the major inner core-forming phase.