http://www.sciencedirect.com/science/article/pii/S167498711200148X

The Earth was born from a giant impact at 4.56 Ga. It is generally thought that the Earth subsequently cooled, and hence shrunk, over geologic time. However, if the Earth's convection was double-layered, there must have been a peak of expansion during uni-directional cooling. We computed the expansion-contraction effect using first principles mineral physics data. The result shows a radius about 120 km larger than that of the present Earth immediately after the consolidation of the magma-ocean on the surface, and subsequent shrinkage of about 110 km in radius within about 10 m.y., followed by gradual expansion of 11 km in radius due to radiogenic heating in the lower mantle in spite of cooling in the upper mantle in the Archean. This was due to double-layered convection in the Archean with final collapse of overturn with contraction of about 8 km in radius, presumably by the end of the Archean. Since then, the Earth has gradually cooled down to reduce its radius by around 12 km. Geologic evidence supports the late Archean mantle overturn ca. 2.6 Ga, such as the global distribution of super-liquidus flood basalts on nearly all cratonic fragments (>35 examples). If our inference is correct, the surface environment of the Earth must have undergone extensive volcanism and emergence of local landmasses, because of the thin ocean cover (3–5 km thickness). Global unconformity appeared in cratonic fragments with stromatolite back to 2.9 Ga with a peak at 2.6 Ga. The global magmatism brought extensive crustal melting to yield explosive felsic volcanism to transport volcanic ash into the stratosphere during the catastrophic mantle overturn. This event seems to be recorded by sulfur mass-independent fractionation (SMIF) at 2.6 Ga. During the mantle overturn, a number of mantle plumes penetrated into the upper mantle and caused local upward doming of by ca. 2–3 km which raised local landmasses above sea-level. The consequent increase of atmospheric oxygen enabled life evolution from prokaryotes to eukaryotes by 2.1 Ga, or even earlier in the Earth history.     

太赫兹频段雷达探测的冰云微物理参数反演算法模拟研究

在假设冰云粒子呈球形以及粒子谱服从对数正态分布的条件下,利用离散偶极子近似法(DDA),计算出太赫兹频段(220 GHz)冰云粒子的雷达反射率因子,及其与瑞利假设下雷达反射率因子的比值。忽略衰减和多次散射的影响,根据太赫兹波段冰云的雷达反射率因子,基于最优估计理论反演冰云的微物理参数,并验证该算法的可靠性。反演结果表明,当冰云粒子大小在设定的尺度范围内时,有效粒子半径(r_e)的反演误差小于4%,粒子谱宽(σ)的误差小于2.5%、粒子数密度(N_T)的误差小于1%,冰水含量(IWC)的误差小于5%。还分析了当N_T和σ为定值时,反演结果随粒子尺寸的变化情况,当冰云粒子尺寸在模拟计算设定的范围内时,r_e的反演误差小于0.04%,σ的反演误差小于0.02%,N_T的反演误差小于0.50%,IWC的反演误差小于0.08%,如果冰云粒子大小超出模拟计算设置的范围,反演误差随着r_e增加而增大。该结果证明了基于最优估计理论反演得到的冰云微物理参数与模拟设定值有良好的一致性,说明该方法可应用于太赫兹频段云雷达的冰云观测及云微物理参数的反演和研究。      

Experimental measurements of water content in crude oil emulsions by terahertz time-domain spectroscopy

We measured the water content （0.01% 0.25% w/w） in crude oil emulsions using terahertz time-domain spectroscopy （THz-TDS）. To improve the precision and range of the measurements, we used 1 and 10 mm thick quartz cells. The experiments were performed at 20 ℃ and the THz wave was transmitted vertically to the samples and detected on the other side. The experimental results suggest linear relation for the THz absorption coefficient and the water content of the crude oil emulsions in the observed range. The linear dependence facilitates high-precision measurements of the water content of crude oil. This suggests the potential of THz-TDS in determining the water concentration in crude oil and borehole fluid identification.     

内蒙古阿拉善盟二道岭矿区太西煤地质成因浅析

太西无烟煤是内蒙古自治区重点出口创汇产品。以其特有的煤质成为独特的煤化工产品,其成因也有一定的特殊性,现浅析其地质成因,作为煤炭资源探采的参考。     

中条山涑水杂岩的同位素年代学研究及其地质意义

中条山是中国重要的铜多金属成矿带,拥有著名的晚太古代“变斑岩型”铜矿峪大型铜矿床和元古代“层控型”胡家峪-篦子沟铜矿床,近年来又在中条山西南段的涑水杂岩中发现以变基性火山岩（斜长角闪岩）为容矿岩石的桃花洞铜矿。为了弄清楚该铜矿的形成时代及其成矿地质背景,利用电感耦合等离子质谱（LA-MC-ICP—MS）方法对桃花洞铜矿容矿围岩涑水杂岩中的寨子-西姚灰色片麻岩、斜长角闪岩及二长花岗岩进行了同位素年代学研究。结果表明：寨子-西姚灰色片麻岩、斜长角闪岩脉和二长花岗岩中锆石的岩浆结晶年龄分别为（2625±11）、（2592±16）、（2548±15）Ma;岩石中古老继承性锆石的年龄分别为（2790±15）、（2773±24）、（2782±34）Ma;三种不同成生顺序的岩石中均有大于2700Ma的锆石存在,且年龄相当接近;中条山地区涑水杂岩可能最初形成于太古代。涑水杂岩作为与成矿关系密切的容矿围岩,其成岩时代可以间接指示成矿时代,由此得出赋存在变基性火山岩层中的古火山含矿原岩建造型铜矿有可能是中国最古老的铜矿之一。     

断裂在斜坡区油聚集中的作用——以松辽盆地太东地区葡萄花油层为例

为研究断裂在太东地区葡萄花油层中的作用,利用地震和钻井资料,在油藏解剖基础上,分析太东地区断裂发育及分布、油藏类型及分布和断裂在油聚集中的作用.结果表明:太东地区发育71条断裂,走向以北北东、近南北和北北西向为主,剖面上呈似花状组合,平面上呈5条密集带分布.油藏类型以断层—岩性和断块油藏为主,剖面上油层由上至下逐渐减少,平面上由东至西含油面积逐渐减少.断裂对油藏的形成与分布的控制作用表现在:北北东和近南北向断裂遮挡为油气聚集提供圈闭;反向断裂较顺向断裂更有利于油气聚集成藏;断裂侧向封闭性控制油气聚集程度.     

云南牟定大民太铜镍矿床的矿化结构及产状模式

大民太铜镍矿为小岩体型铜镍硫化物矿床。文章以对含矿岩体和矿体的大比例尺地质编录和综合地质研究为基础,进行了矿化精细结构分析和矿体产状模式构建,并提出了大民太基性-超基性岩体具备一定的成矿条件,铜和镍都具有向深部变富的趋势。     

云南省者太地区金锑矿找矿预测-来自水系沉积物测量的证据

云南者太地区位于开远-丘北金成矿带东缘,该区及其周边已发现卡林型金矿和木利式锑矿床（点）20余处,具有良好的金、锑矿找矿前景。本文以1:5万水系沉积物测量19种元素含量数据为基础,统计分析了水系沉积物地球化学参数、元素相关性、成矿有利度系数等指标,总结了元素组合、富集贫化规律及其与地质背景、地质构造与成矿作用的关系。区内主要富集元素为Au、Sb、As、Bi、Cd,主要高分异元素为Au、Sb、As、Cd,且具有较高的成矿有利度系数。结果显示,Au元素异常严格受近东西向构造带、北西向构造带、北东向构造带,以及二叠系-三叠系不纯碳酸盐岩、硅质岩、细碎屑岩等因素控制;而Sb元素异常与近东西向构造带、台盆相沉积环境、泥盆系硅化灰岩（硅化碎屑岩等）有着密切联系。依据水系沉积物异常特征和成矿地质条件,圈定综合异常7处,划分出3个找矿远景区,指出了区内今后的找矿方向。     

我国早前寒武纪地层研究的主要新进展

1996年以来我国早前寒武纪地层研究的新进展主要包括以下五个方面的内容 :1)古太古代陈台沟表壳岩的发现 ;2 )五台群时代研究的新进展 ;3)阜平群、涑水杂岩和达肯大坂岩群的解体和重组 ;4 )根据新的年龄数据 ,叠布斯格岩群、双山子岩群、界河口岩群、吕梁岩群、熊耳群、龙首山岩群和宿松群的时代进一步得到了肯定或做了重要的修正 ;5 )美岱召岩群、官都岩群、寻乌岩群、连云山岩群和苍溪群等古元古代地层单位的建立。     

胶东群新议

太古代胶东群主要是由ＴＴＧ花岗质片麻岩组成。近期区调研究发现真正的变质表壳岩系仅在其中呈包体出现,据岩性特征胶东岩群可分为苗家岩组、郭格庄岩组,时代为晚太古代