大别山榴辉岩的密度和波速及其对壳—幔循环的启示

测定了大别山地区榴辉岩和麻粒岩的密度和高温高压 (至 5 .0GPa和 130 0℃ )的纵波速度 (Vp)。超高压榴辉岩具有较高的密度和Vp 及较弱的各向异性。榴辉岩的压力系数为 0 .2 2～ 0 .33km/s·GPa ,超高压榴辉岩的温度系数为 - 3.41× 10 -4 km/s·℃。榴辉岩的密度和波速的分析表明 ,地幔深部的超高压榴辉岩形成后可能包含了两个过程 ,即一部分榴辉岩通过拆沉作用进入深部地幔 ,另一部分快速折返至地壳内或地表 ,榴辉岩的形成过程代表了壳幔物质循环。现今的大别山深部可能只存在少量榴辉岩。     

Three-Dimensional P-Wave Velocity Structure of the Crust of North China

Since the Xingtai (邢台) earthquake in 1966,China Earthquake Administration has carried out a survey campaign along more than thirty deep seismic sounding (DSS) profiles altogether about twenty thousand kilometers long in North China to study the velocity structure of the crust and the upper mantle in this region,and has obtained a great number of research findings. However,these researches have not provided a 3D velocity structure model of the crust of North China and cannot provide seismic evidence for the study of the deep tectonic characteristics of the crust of the whole region. Hence,based on the information from the published data of the DSS profiles,we have chosen 14 profiles to obtain a 3D velocity structure model of North China using the vectorization function of the GIS software (Arc/Info) and the Kriging data gridding method. With this velocity structure model,we have drawn the following conclusions: (1) The P-wave velocity of the uppermost crust of North China changes dramatically,exhibiting a complicated velocity structure in plane view. It can be divided into three velocity zones mainly trending towards north-west. In the research area,the lowest-velocity zones lie in the Haihe (海河) plain and Bohai (渤海) Bay. Although the geological structure of the sedimentary overburden in the study area is somewhat inherited by the upper crust,there are still several differences between them. (2) Generally,the P-wave velocity of the crust increases with depth in the study area,but there still exists local velocity reversion. In the east,low-velocity anomalies of the Haihe plain gradually disappear with increasing depth,and the Shanxi (山西) graben in the west is mainly characterized by relatively low velocity anomalies. Bounded by the Taihang (太行) Mountains,the eastern and western parts differ in structural trend of stratum above the crystalline basement. The structural trend of the Huanghuaihai (黄淮海) block in the east is mainly north-east,while that of the Shanxi block and the eastern edge of the Ordos block is mainly north-west. (3) According to the morphological features of Moho,the crust of the study area can be divided into six blocks. In the Shanxi block,Moho apppears like a nearly south-north trending depression belt with a large crustal thickness. In the southern edge of the Inner Mongolia block and the south of the Yanshan (燕山) block,the Moho exhibits a feature of fold belt,trending nearly towards east-west. In the eastern edge of the Ordos block,the structure of Moho is relatively complex,presenting a pattern of fold trending nearly towards north-west with alternating convexes and concaves. Beneath the Huanghuaihai block,the middle and northern parts of the North China rift zone,the Moho is the shallowest in the entire region,with alternating uplifts and depressions in its shape. For the anteclise zone in the west of Shandong (山东) Province,the Moho is discontinuous for the fault depression extending in the north-west direction along Zaozhuang (枣庄) -Qufu (曲阜).     

华北地区地壳P波三维速度结构

1968年邢台地震以后的30余年中, 中国地震局系统先后在大华北地区布置30余条、近20000km的人工地震宽角反射/折射深地震测深(DSS) 剖面, 用以研究地壳及上地幔顶部的速度结构, 取得了大量研究成果.但以往的研究明显的不足是未能形成华北区域性的地壳三维速度结构模型, 从大区域的角度为研究华北地区地壳深部构造特征提供地震学方面的依据.因此, 在现已发表的DSS剖面资料的基础上, 选择了14条测线的资料, 利用地理信息系统(ARC/INFO) 的“矢量化”功能, 以及克里格数据网格化技术构建华北区域性的地壳三维速度结构模型, 从而对华北研究区内地壳三维速度结构的特点得到如下认识: (1) 华北地区地壳表层P波速度变化幅度大, 平面结构较复杂, 大体上划分为相间排列、走向趋势以北西向为主的3个速度区.海河平原和渤海湾的低速带是研究区范围内速度最低的低速区.资料的情况说明, 研究区内沉积盖层的地质构造与上地壳构造之间虽有一定继承性, 但也存在较大差别. (2) 总体上看, 在华北研究区内地壳的P波速度随深度增大而增大, 但局部地区出现速度倒转的现象, 东区的海河平原低速异常逐渐消失, 而西区的山西地堑则以相对低速异常特征为主.区内地壳以太行山脉为界, 划分为东、西两区; 东部和西部, 结晶基底以上地层的构造方向不完全一致; 东部的黄淮海地块, 区域构造以北东向为主, 而西部包括山西地块和鄂尔多斯地块东缘, 其构造方向则以北西向为主. (3) 根据莫霍面的形态特征, 研究区地壳可大致划分为6个区块; 在山西地块范围内, 莫霍面呈近南北向的凹陷带, 地壳厚度大; 内蒙古地块南缘和燕山地块南部, 莫霍面表现出褶皱带的构造特征, 其延展趋势为近东西方向; 鄂尔多斯地块东缘, 莫霍面构造相对复杂, 呈近北西向凸、凹相伴的褶皱; 黄淮海地块(华北裂谷带中、北部) 为莫霍面隆坳区, 隆、坳相间排列, 构造较复杂, 但从整体上看, 这是全区莫霍面最浅的隆起区段; 鲁西台背斜主要为莫霍面断陷区, 其断陷带沿枣庄—曲阜一线向北西方向延伸.      

南海东北部下地壳高速层的成因探讨

通过对南海北部大陆边缘地壳结构分析,指出南海东北部存在下地壳高速层,大致分布在112°E~120°E,19°N~22°N的陆坡和拉张程度大的陆架地区,呈NEE向延伸,在海底地震仪剖面上最大的厚度有8km,向南海海盆方向减薄。通过对比综合分析认为,高速层物质组成是底侵作用形成的熔岩垫,由于伸展作用,南海海底扩张（30Ma）前后底侵作用形成了熔岩垫,并促使南海北部大陆边缘地壳抬升,导致区域性抬升剥蚀。     

大陆下地壳麻粒岩的流变学研究进展

大险下地壳麻粒岩的流变学研究可以解释地壳变形、壳幔物质交换以及岩石圈深部动力学过程等科学问题.前人通过研究各矿物的显微构造变形特征与变形机制,运用广义混合流变律探讨多矿物复合岩石的流变性质,结合水与流体对岩石变形强度的弱化作用,阐明在大陆下地壳变形环境下复矿麻粒岩的塑性变形和韧性流变性质.目前人们致力于对天然变形岩石和...     

Seismic Velocity Structure and Composition of the Continental Crust of Eastern China

On the basis of a one-by-one latitude-longitude grid three-dimensional seismic velocity model, the crustal P-wave velocity structure in eastern China (105-125°E and 18-41°N) is obtained, and a set of geotherms for each grid is established for P-T correction on P-wave velocities. The average depths of sub-crustal layers and their average P-wave velocities of 18 tectonic units in eastern China are exhibited. Our result presents a 32-34 km thick crust beneath eastern China, which is thinner than previous studies, with an average velocity of 6.54 km/s, corresponding to a 5 kg/m3 variation in crustal mean density. The thicker upper but thinner middle and lower crust results in a lower average seismic velocity of eastern China. An intermediate crustal composition with a SiO2 content of 59.7 wt% has been estimated. However, there exists a significant lateral variation in the crustal structures among the tectonic units of eastern China. The structure and composition features of some regions in eastern China in     

塔里木盆地岩石高温高压下波速的实验研究及其地质意义

给出了塔里木盆地多种岩石样品在高温高压下弹性波纵波波速(Vp)的实验室测量结果。在最大压力为2 GPa,常温下样品的Vp范围从6．007-6．803 km·s-1时,最大值为安山质火山碎屑岩;当温度为600℃,Vp范围从 5．871-6．658 km·s-1时,其最大值是安山岩。结合地震转换波速度结构等资料,分析认为塔里木盆地地壳结构在大部分地区可三分:上地壳为花岗质变质岩为主;中地壳以花岗闪长岩为特征;下地壳是以安山玄武质成分为特征的岩层。     

高温高压下闪长岩的相变与纵波波速

利用脉冲透射-反射法,在YJ-3000 t高压装置弹性波速测量系统上,测量了0.6、1.0和2.0 GPa,最高1141℃条件下闪长岩的纵波波速(vp)。结果显示,高压下闪长岩的vp随温度升高首先缓慢降低,分别到769℃(0.6 GPa)、810℃(1.0 GPa)和925℃(2.0 GPa)后转而快速下降。实验产物观测显示,0.6 GPa下岩石在758℃时发生脱水熔融并有新生单斜辉石生成,1.0 GPa和2.0 GPa下,闪长岩分别在865℃和921℃的实验产物中出现熔体,新生矿物有单斜辉石和石榴子石。温度升高导致闪长岩中熔体含量增加,斜长石、角闪石和绿泥石等逐渐减少直至消失,单斜辉石和石榴子石呈先增加后减少趋势。探针分析显示,熔体含水量较高,且随温度升高熔体成分向基性方向演化。单斜辉石化学成分变化不明显,2.0 GPa下,随温度从1030℃升高到1138℃,新生石榴子石成分逐渐向钙铝榴石变化。vp变化和熔体含量关系表明,熔体含量增加导致了闪长岩在高温阶段波速的持续快速降低。     

高温高压下电解质溶液热力学性质的研究进展

高温高压下电解质溶液热力学性质的研究不仅对探讨地球内部流体的作用具有重要意义，而且在很多实际工业过程中也都有广泛应用。本综述了近10年来高温高压下电解质溶液热力学参数的实验测量和理论计算的进展，实验设备还有待进一步的改进和完善，以获得更高温度和压力下的数据，理论计算不仅有待于实验的发展，也与溶液的结构理论密切相关。     

SiO2 Solubility in Rutile at High Temperature and High Pressure

Silicon-bearing rutile has been found in chromitite from the Luobusa (罗布莎) ophiolite, Tibet. However, the extent of SiO2 solubility in rutile and the nature of its origin are still unclear. At high pressure, SiO2 takes a rutile structure with Si in 6-fold coordination. Thus, high pressures may enhance its solubility in rutile because of possible isovalent exchange in the oetabedral site. In this study, we report new experimental results on SiO2 solubility in rutile up to 23 GPa and 2 000 ℃. Starting materials were mixtures of powdered pure rutile and pure quartz, with compositions of (Ti0.5Si0.5)O2,(Ti0.93Si0.07)O2, and (Ti0.75Si0.25)O2. The mixtures were loaded into either platinum capsules (for a 10/5 assembly) or rhenium capsules (for an 8/3 assembly). The experiments were carried out using multi-anvil high-pressure apparatus with a rhenium resistance heater. Sample temperatures were measured with a W5%Re-W26%Re thermoeouple and were controlled within ±1 ℃ of the set temperature. TiO2-rich and SiO2-rich phases were produced in all the quenched samples. Microprobe analyses of the phases show that the solubility of SiO2 in rutile increases with increasing pressure, from 1.5 wt.% SiO2 at 10 GPa to 3.8 wt.% SiO2 at 23 GPa at a temperature of 1 800 ℃. The solubility also increases with increasing temperature from 0.5 wt.% SiO2 at 1 500 ℃ to 4.5 wt.% SiO2 at 2 000 ℃ at a pressure of 18 GPa. On the other hand, the solubility of TiO2 in coesite or stishovite is very limited, with an average of 0.6 wt.% TiO2 over the experimental P-T ranges. Temperature has a much larger effect on the solubility of SiO2 in rutile than pressure. At high pressure, the melting point of SiO2 is defmitely higher than that of TiO2 and the eutectic point moves towards SiO2 in the TiO2-SiO2 system. Lower oxygen fugacity decreases the solubility of SiO2 in rutile, whereas water has little effect on the solubility. Our experimental data are extremely useful for determining the depth of origin of the SiO2-bearing ruffle found in nature.     

下地壳麻粒岩包体波速测定及其地质意义

下地壳岩石的波速测定可以提供有关下地壳物质组成及物理性质的重要信息。但是，由于下地壳难于直接采样，因此常常利用目前出露地表的古老麻粒岩地体样品来代表下地壳，但所获结果常常与实际情况不符，由新生代玄武岩携带到地表的下地壳包体则为我们提供有关下地壳的直接信息。本文对采自河北汉诺坝武岩中的下地壳包体进行了密度和高温高压波速测定，下地壳由不同类型的麻粒岩相岩石组成。其密度和波速有较大的差异，因此所获波速不能直接与地震测深得到的下地壳波速进行对比，而需要进行波速的温度、压力校正，并进行具体的分析，本文得到下地壳包体的原地波速6.13-6.90km/s与该区地震资料得到的结果十分接近，并探讨了下地壳低速层的可能成因。     

Compressional Wave Velocities in Some Volcanic Rocks at Pressure up to 4.5 GPa

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃｏｍｐｒｅｓｓｉｏｎａｌｗａｖｅｖｅｌｏｃｉｔｙ（ｖｐ）ｉｎｒｏｃｋｍｅａｓｕｒｅｄａｔｈｉｇｈｐｒｅｓｓｕｒｅａｎｄｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｉｓｏｆｓｉｇｎｉｆｉｃａｎｔｉｍｐｏｒ－ｔａｎｃｅｔｏｅｌｕｃｉｄａ...     

Extensional Tectonic Framework of Post High and Ultrahigh Pressure Metamorphism in Dabieshan, China

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｔｕｄｙｏｆｈｉｇｈ－ｐｒｅｓｓｕｒｅ（ＨＰ）ａｎｄｕｌｔｒａｈｉｇｈ－ｐｒｅｓｓｕｒｅ（ＵＨＰ）ｍｅｔａｍｏｒｐｈｉｃｒｏｃｋｓｉｓｏｎｅｏｆｔｈｅｍａｊｏｒｈｏｔｔｏｐｉｃｓｉｎｔｈｅｓｏｌｉｄｅａｒｔｈｓｃｉｅｎ...     

Pressure State in Deep Crust and Formation Depth of UHP Metamorphic Rocks

INTRODUCTIONSincethediscoveryofeclogiteswithcoesiteanddia mondinclusionsrelatedtothecontinent continentcollision orogenyenvironment,theultrahigh pressuremetamorphism(UHPM )intheDabie Suluhasarousedgreatinterestinmanygeologists (Liouetal .,1994 ;Xuetal.,1992 ) .Experimentalstudieshaveprovedthatsuchmineralsasdia mond ,coesiteandomphaciteoccurredat 2 - 5GPa (andatthecorrespondingtemperatures) (Stevenetal.,1982 ;MirwaldandMasonne ,1980 ) .However,itdoesnotmeanthatthemetamorphicrockscanbe…     

高温高压离子交换法分离提取单一高纯稀土

本文研究了高温高压离子交换法分离稀土时,排代剂浓度、ＰＨ值、线性流速和柱温等因素对分离效果的影响,本方法在分离多元稀土富集和及稀土精料时,具有工艺简单、质量稳定、分离时间短、产品纯度高、成本低廉等特点,为单一高纯稀土生产开辟了一条新路。     

蛇纹石化碱性橄榄石玄武岩、水和氢氧化钠溶液的高温高压实验研究

蛇纹石化碱性橄榄石玄武岩、水和氢氧化钠溶液的高温高压实验研究宋茂双（中国科学院地球化学研究所，贵阳５５０００２）关键词高温高压碱性玄武岩Ｐ波速度熔融－结晶蛇纹石脱水温度作者测量了高温高压下蛇纹石化碱性橄榄玄武岩的Ｐ波速度、蛇纹石脱水温度和Ｈ２Ｏ及Ｎａ...     

秦岭造山带若干岩石高温高压脱水熔融的特征及其意义

对秦岭造山带和邻区块状岩石样品进行了高温（1 100~1 300 ℃）和高压（1.2~1.8 GPa）脱水熔融实验。通过对实验产物综合分析发现许多样品中出现了熔融玻璃和雏晶。玻璃代表的熔体成分为基性和中性,部分接近于超基性范围,熔体与原来岩石全岩成分比较,更偏基性。熔体出现的空间和成分都显示了局部熔融体系的特征,即含水矿物（角闪石或黑云母）和浅色矿物（石英或斜长石）控制了熔融的发生并且决定了熔体的成分。脱水熔融产生了比原岩更偏基性的熔体,这意味着熔融后残留部分将愈偏酸性。如果这种机制存在于大陆中-下地壳,将对探讨大陆地壳的结构和物质组成,解释某些地区的长英质中下地壳的成因等具有重要的意义。     

浅谈高温高压实验地球科学:方法和应用

在过去的二十多年间,高温高压实验地球科学研究得到了蓬勃发展,凭借其高度的灵活性和易于与其他分支学科相结合的优点,在很多不同的研究领域中都取得了令人瞩目的成果,并已发展成为国际地球科学的前沿领域和重要方向之一,同时也是固体地球科学最强有力研究手段之一。相比之下,国内的高温高压实验地球科学研究还显得相对比较薄弱,相关系统性的认识还有待增强。本文对高温高压实验研究的发展历程、方法原理、仪器设备以及在地球科学研究中的一些应用进行简单的介绍,旨在让更多的国内学者对这一领域有更深入的了解。     

高温高压下CO2在水中溶解度实验及理论模型

利用自行研制的高温高压反应釜,在不同温度、压力和矿化度条件下测试CO₂在地层水中的溶解度。实验结果表明:温度一定的条件下,CO₂在水中的溶解度随压力的增加而增加;压力一定的条件下,CO₂在水中溶解度的主要变化趋势为随温度的增加而降低,当温度大于100℃、压力在22 MPa左右时,CO₂在地层水中的溶解度将发生异常,出现低压(小于22 MPa)时随温度的增加而降低,高压(大于22 MPa)时随温度的增加而略微升高;在温度压力都一定的条件下,CO₂在水中的溶解度随矿化度的增加而降低。并且,在新测得的实验数据和已有的实验数据的基础上,通过修正PR-HV状态方程中的参数,建立了一个能够精确计算CO₂在水中溶解度的模型;并将该模型与其他模型对比。对比结果表明,该模型计算精度最高,平均相对误差仅为2.69%。