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1.
差应力状态对岩石熔融程度的影响--以黑云母片麻岩的动、静态熔融对比实验为例 总被引：6，自引：2，他引：4
以河北省平山县阜平群的黑云片麻岩为实验样品,有差应力条件下的动态实验,围压10MPa,温度800℃条件下,施加相当于差应力为O～25MPa,且以每5MPa为间隔进行了天然块状岩石样品的动态熔融,在相同的围压条件下,温度由800～900℃每20℃为间隔,进行了无差应力条件下天然块状岩石的静态熔融实验,并进行了对比研究。结果表明,在相同温度条件下,岩石的熔融程度随着差应力的增加明显增高,当差应力达到25MPa时,800℃条件下岩石的熔融程度与900℃静态熔融条件下岩石的熔融程度相当。实验力学分析计算表明,动态实验中构造附加压力增加了围压,差应力每增加5MPa相当于1．67MPa的增压,其与静态实验中温度升高20℃的效果一样。该实验结果对研究岩石深熔作用的深度问题有一定的参考意义。 相似文献
2.
利用高温高压的实验分别对辉长岩进行差应力和温度与岩石熔融程度测试,并进一步分析讨论差应力和温度等岩石熔融程度的关系。动、静态的实验结论表明:(1)静态熔融条件下,岩石的熔融程度主要受温度的影响并且岩石熔融程度与温度呈正相关关系;(2)在保持一定温度不变的动态熔融条件下,岩石的熔融程度还与差应力呈正相关的关系;(3)差应力可以降低熔点,促使熔融提前发生并且使熔融强度增大;(4)差应力对岩石的熔融具有明显的控制作用;(5)以700℃为基准,差应力每增加5MPa其带来的影响与温度升高50℃的效果相当;(6)基性岩石的熔融对差应力的敏感程度最高。该实验结果还表明在研究岩石深熔作用时尤其是在构造作用较强烈地区要考虑差应力的影响因素。 相似文献
3.
差应力与岩石熔融性状关系的实验研究 总被引：1，自引：0，他引：1
为考察不同应力状态下岩石应变与岩石熔融作用的关系,利用英国Instron公司生产的电液伺服实验系统,配以围压和加温系统设计了动、静态不同条件下细粒闪长岩的对比熔融实验,力图找到差应力与岩石熔融程度及其熔体成分的关系。通过岩石动、静态熔融实验结果的对比得出：差应力的存在能够导致细粒闪长岩的熔融,随着差应力（应变速率）的增加,熔体的量增加,熔体成分向富Si、Al方向转变。 相似文献
4.
5.
辉长岩脆-塑性转化及其影响因素的高温高压实验研究 总被引：9，自引：1，他引：8
本文利用高温高压多功能三轴实验装置,以NaCl为固体围压传压介质,在围压为450MPa~800MPa,温度区间为600℃~1150℃和应变速率为1×10-4~3.125×10-6/s条件下,对攀枝花辉长岩进行了流变学实验研究。实验结果表明,辉长岩围压在450MPa~800MPa条件下,温度在600℃时为脆性变形,700℃~850℃时为半塑性流动,含微破裂,大于900℃时为塑性流动。辉长岩的脆-塑性转化温度为700℃~900℃,主要影响因素为温度、围压和应变速率,同时存在双相流变学问题。 相似文献
6.
利用Paterson气体介质高温高压流变仪对纯叶蛇纹岩在100~400MPa围压、25~700℃温度和10-5~1.5×10-6s-1应变速率下进行了三轴压缩变形实验。实验结果表明叶蛇纹石在低压条件下表现为脆性破裂,高压或脱水条件下表现为半脆性破裂。随着温度的增加,叶蛇纹石的强度显示逐渐降低的趋势;尤其在脱水条件下,温度的增加可导致叶蛇纹石强度大幅度地降低,而且此时预热时间对强度的影响比未发生脱水时更加显著。结合前人的研究并对比发现,围压在室温下的增加导致叶蛇纹岩强度增加;但在高温下围压的增加导致试样强度整体上降低,这很可能是试样内聚力的局部损失与韧性增强引起的。围压和温度的升高,以及断层面上流体的增加很可能会增加破裂面的韧性,从而减小摩擦系数。此外,叶蛇纹石并非以往人们所认为的那样具有极低的强度,其强度要比低温蛇纹石(如利蛇纹石和纤蛇纹石)的大得多,即便在高温(大约600℃)下差应力大于约600MPa和中-低温(≤400℃)下差应力大于约1000MPa时仍没有表现出明显屈服的迹象。在脱水条件下,蛇纹岩并没有发生脱水致脆,相反脱水使得试样的断裂行为变得更加温和些。因此,俯冲带蛇纹岩脱水更可能诱发其周围更加脆性的岩石发生地震而不是脱水的蛇纹岩本身发生地震。 相似文献
7.
沁水盆地煤岩高温高压实验变形特征 总被引：1，自引：0，他引：1
对沁水盆地不同地区选取的5组煤岩样品进行高温高压变形实验,结果证实,在相同的实验条件下,(1)采自不同地区的煤岩强度在较低温压条件下表现出一致性,在较高温压条件下显现出差异性;(2)高煤级煤No.3煤样在某一温压条件下（100℃、100MPa）,应力应变强度都是最低的,为煤岩组分影响的结果。在不同的实验条件下, 煤岩在高温高压条件下（温压大于200℃、200MPa）,随着温度与围压增高,应力应变强度在降低,但这主要是温度影响的结果。在温压为100℃、100MPa和500℃、500MPa时,煤岩应力应变强度均很低,但却存在着本质的差别:前者产生的应力应变强度只有部分真实地代表了煤岩的强度（应变量ε<3％）,而持续的应力应变强度（应变量ε>3％）则是围压作用的结果;后者煤岩低应力应变强度显示出明显的韧性状态, 主要表现在温度对煤岩产生的影响。 相似文献
8.
高温高压下岩石部分熔融实验是模拟地球内部岩浆和岩石成因最常用的实验方法.但国内用岩石部分熔融实验进行这一类的研究并不多见.用天然块状岩石或岩石粉末的部分熔融无水实验,一般需在实验前将样品烘干处理.在前人的实验中,实验前样品烘干的温度和时间各不相同.Dunn(1994)在进行角闪岩相变质玄武岩的部分熔融实验时,样品在110℃下烘干时间超过2 h. 相似文献
9.
探讨差应力对熔体分布和成分演化的关系,利用细粒闪长岩进行高温高压条件下的岩石变形,主要包括静态熔融实验和有差应力参与的动态熔融2种类型。实验首先统计了熔体含量、确定了实验重要参数,然后分别描述了动、静态熔融实验后闪长岩的显微特征;并且通过对动、静态熔融实验结果熔体分布情况的对比,结合熔体成分电子探针数据进行分析。结果表明:在细粒闪长岩的部分熔融中,熔体在差应力的作用下沿一定的方向展布,并从差应力大的地方向差应力小的地方运移,差应力的作用使得高含水矿物(角闪石)先于熔点低的斜长石发生熔融,说明差应力促进了岩石的熔融,使得熔体成分向Si、Al等方向转化,即从基性向酸性转化。 相似文献
10.
以天然叶腊石为传压介质, 在温度800~100 0℃、围压0.6~1.0 GPa和应变速率10-4~10-5 s-1条件下, 对Maryland辉绿岩的脆性-塑性转化进行了实验研究.实验结果表明, 在10-4~10-5 s-1应变速率和固定围压1.0 GPa条件下, 当温度低于800℃时, 岩石变形为典型脆性破裂; 温度高于1000℃时岩石变形以准稳态蠕变为主; 温度在800~950℃之间, 岩石变形从脆性破裂向准塑性流动转化.温度变化对岩石脆-塑性转化影响敏感度高于压力变化对变形的敏感度.显微构造观察显示, 辉绿岩脆-塑性转化以稀疏弥漫状共轭塑性流动网络为特征. 相似文献
11.
高温下石灰岩和砂岩膨胀特性的试验研究 总被引：2，自引：0，他引：2
利用自行研制的高温岩石膨胀特性试验装置,对石灰岩和砂岩试件300～700 ℃高温过程中的膨胀特性进行试验研究。试验结果表明,升温过程中,石灰岩和砂岩的膨胀应力随温度的增加而增大,且砂岩膨胀速率比石灰岩大,刚到700 ℃时砂岩膨胀应力是石灰岩的2.45倍。升温过程中膨胀应力与温度曲线的拟合函数为2次抛物线,相关系数达0.94以上。恒温过程中,随时间延长2种岩石的膨胀应力缓慢增加,最后逐渐趋于稳定的数值。600 ℃高温后2种岩石膨胀均达到极限,但具体表现不同,700 ℃恒温结束时砂岩稳态膨胀应力是石灰岩的3.14倍。岩石热膨胀应力变化与其岩性、内部矿物分解、孔隙率变化、声速变化等有显著关系。 相似文献
12.
Upper Limit for Rheological Strength of Crust in Continental Subduction Zone： Constraints Imposed by Laboratory Experiments 总被引：2，自引：0，他引：2
Zhou Yongsheng State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing China Zhong Dalai Institute of Geology Geophysics Chinese Academy of Sciences Beijing China He Changrong State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing China 《中国地质大学学报(英文版)》2004,15(2):167-174
The transitional pressure of quartz-coesite under the differential stress and highly-strained conditions is far from the pressure of the stable field under the static pressure. Therefore, the effect of the differential stress should be considered when the depth of petrogenesis is estimated about ultrahigh pressure metamorphic (UHPM) rocks. The rheological strength of typical ultrahigh pressure rocks in continental subduction zone was derived from the results of the laboratory experiments. The results indicate the following three points. (1) The rheological strength of gabbro, similar to that of eclogite, is smaller than that of clinopyroxenite on the same condition. (2) The calculated strength of rocks (gabbro, eclogite and clinopyroxenite) related to UHPM decreases by nearly one order of magnitude with the temperature rising by 100 ℃ in the range between 600 and 900 ℃. The calculated strength is far greater than the faulting strength of rocks at 600 ℃, and is in several hundred to more than one thousand mega-pascals at 700-800 ℃, which suggests that those rocks are located in the brittle deformation region at 600 ℃, but are in the semi-brittle to plastic deformation region at 700-800 ℃. Obviously, the 700 ℃ is a brittle-plastic transition boundary. (3) The calculated rheological strength in the localized deformation zone on a higher strain rate condition (1.6×10-12 s-l) is 2-5 times more than that in the distributed deformation zone on a lower strain rate condition (1.6×10-14 s-1). The average rheological stress (1 600 MPa) at the strain rate of 10-12 s-1 stands for the ultimate differential stress of UHPM rocks in the semi-brittle flow field, and the average rheological stress (550-950 MPa) at the strain rate of l0-14 -10-13 s-l stands for the ultimate differential stress of UHPM rocks in the plastic flow field, suggesting that the depth for the formation of UHPM rocks is more than 20-60 km below the depth estimated under static pressure condition due to the effect of the differential stress. 相似文献
13.
A. Tarantola L. W. Diamond H. Stünitz A. Thust M. Pec 《Contributions to Mineralogy and Petrology》2012,164(3):537-550
Extraction of useful geochemical, petrologic and structural information from deformed fluid inclusions is still a challenge in rocks displaying moderate plastic strain. In order to better understand the inclusion modifications induced by deviatoric stresses, six deformation experiments were performed with a Griggs piston-cylinder apparatus. Natural NaCl–H2O inclusions in an oriented quartz crystal were subjected to differential stresses of 250–470 MPa at 700–900 °C and at 700–1,000 MPa confining pressure. Independently of the strain rate and of the crystallographic orientation of the quartz, the inclusions became dismembered and flattened within a crystallographic cleavage plane subperpendicular to σ 1. The neonate (newly formed) inclusions that result from dismemberment have densities that tend towards equilibrium with P fluid = σ 1 at T shearing. These results permit ambiguities in earlier deformation experiments on CO2–H2O–NaCl to be resolved. The results of the two studies converge, indicating that density changes in neonate inclusions are promoted by high differential stresses, long periods at high P and high T, and fluid compositions that maximize quartz solubility. Neonates spawned from large precursor inclusions show greater changes in density that those spawned from small precursors. These findings support the proposal that deformed fluid inclusions can serve as monitors of both the orientation and magnitude of deviatoric stresses during low-strain, ductile deformation of quartz-bearing rocks. 相似文献
14.
Lü Guxian 《中国地质大学学报(英文版)》2004,15(2):162-166
An experimental study of the confining pressure, i.e. additional hydrostatic pressure initiated by the tectonic force is presented. The experimental progress is that the σ1 is gradually increasing from 0 in a limiting movement (ε1=0) in the σ1 direction and the speed rate of the accelerating load is 0.4 MPa*s-1 in the lateral and level directions. When σ2=σ3<200 MPa, Δσl is nearly lacking, Δσl is increasing at a high speed only when the horizontal force reaches 250-380 MPa, and Δσl almost ceases to increase at the level force of 380 MPa. It is calculated that the tectonic force can produce the confining pressure which is gradually increasing with σ2=σ3 before it reaches 380 MPa in an experiment. It is supposed that the horizontal force is almost all transformed into the confining pressure with the increase of the creep deformation of rocks. 相似文献
15.
热液金刚石压腔 (HDAC)在地质上的应用及甲烷水合物合成实验研究 总被引：16，自引：4，他引：12
热液金刚石压腔 (HDAC)是 2 0世纪末发展起来的一种高温高压及低温高压实验技术。它可在 - 180～ 12 0 0℃ ,10 0～ 10 0 0 0MPa水热体系进行实验 ,并具直观实验全过程的特点。文中首次运用HDAC在水体系中对哀牢山花岗岩进行了熔融实验 ,在显微镜下观察到花岗岩熔融过程 ,其初熔温度为 712 88～ 714 87℃ ,压力为 2 2 5MPa ,熔融温度为 759 54～76 0 0 0℃ ,压力为 30 0MPa。重点介绍了国外运用HDAC进行冰的高压相、水体系中伟晶岩矿物溶解、可燃有机岩、石油及岩石热解、高压下矿物包裹体均一温度测定及甲烷水合物合成实验研究新成果。甲烷水合物在永久冻土带及大陆坡、海底高原、海底沉积物等地质环境广泛分布 ,储量大 ,可成为 2 1世纪人类使用的新能源。目前世界主要国家的科学家除致力于该资源勘探外 ,还运用不同方法进行甲烷水合物的合成研究 ,以了解其形成条件及性质。开发和应用甲烷水合物具有重大意义 ,为促进我国此项工作开展 ,文中作了重点介绍。 相似文献
16.
The brittle failure behavior of an over-consolidated clay shale (Opalinus Clay) in undrained rapid triaxial compression was
studied. The confining stress levels were chosen to simulate the range of confining stresses relevant for underground excavations
at the Mont Terri Underground Research Laboratory, and to investigate the transition from axial splitting failure to macroscopic
shear failure. Micro-crack initiation was observed throughout the confining stress range utilized in this study at a differential
stress of 2.1 MPa on average, which indicates that friction was not mobilized at this stage of brittle failure. The rupture
stress was dependent on confinement indicating friction mobilization during the brittle failure process. With increasing confinement
net volumetric strain decreased suggesting that dilation was suppressed, which is possibly related to a change in the failure
mode. At confining stress levels ≤0.5 MPa specimen rupture was associated with axial splitting. With increasing confinement,
transition to a macroscopic shearing mode was observed. Multi-stage triaxial tests consistently showed lower strengths than
single-stage tests, demonstrating cumulative damage in the specimens. Both the Mohr–Coulomb and Hoek–Brown failure criteria
could not satisfactorily fit the data over the entire confining stress range. A bi-linear or S-shaped failure criterion was
found to satisfactorily fit the test data over the entire confinement range studied. 相似文献
17.
Influence of Loading Rate on Deformability and Compressive Strength of Three Thai Sandstones 总被引：1，自引：0，他引：1
Uniaxial and triaxial compressive strength tests have been performed using a polyaxial load frame to assess the influence
of loading rate on the strength and deformability of three Thai sandstones. The applied axial stresses are controlled at constant
rates of 0.001, 0.01, 0.1, 1.0 and 10 MPa/s. The confining pressures are maintained constant at 0, 3, 7 and 12 MPa. The sandstone
strengths and elastic moduli tend to increase exponentially with the loading rates. The effects seem to be independent of
the confining pressures. An empirical loading rate dependent formulation of both deformability and shear strength is developed
for the elastic and isotropic rocks. It is based on the assumption of constant distortional strain energy of the rock at failure
under a given mean normal stress. The proposed multiaxial criterion well describes the sandstone strengths within the range
of the loading rates used here. It seems reasonable that the derived loading rate dependent equations for deformability and
shear strength are transferable to similar brittle isotropic intact rocks. 相似文献