断裂引起的应变量计算方法     

许顺山  Nieto-Samaniego  AF  Alaniz-Alvarez  SA 《地质力学学报》2008,14(4):320-327

本文介绍了断裂引起的应变量计算方法。断裂作用可导致连续应变和非连续应变。连续应变与断裂位移,断裂长度比值及断裂面上有效应力成正相关关系。影响非连续应变的因素有：断裂几何形态、断裂的旋转性、断裂规模。已经提出三种断裂旋转机制：刚性旋转,垂直剪切和斜向剪切。对于这三种机制,我们分别建立了断裂非连续应变的计算公式。这些公式与断裂的旋转角度和位移大小相关。刚性旋转时,断块内部没有任何塑性变形,因此地层的长度没有变化。它引起的非连续应变最小。垂直剪切作用使断块内地层变形,但水平方向的地层长度不变。推算的公式表明,对于相同的原始数据,它引起的非连续应变比刚性旋转机制引起的非连续应变大。斜向剪切也使断块内地层变形,但水平方向的长度也不变。在同等条件下,它引起的非连续应变比垂直剪切机制引起的非连续应变大。  相似文献   

A method to measure the isotopic (C) composition of dissolved organic carbon using a high temperature combustion instrument     

Susan Q. Lang  Marvin D. Lilley  John I. Hedges   《Marine Chemistry》2007,103(3-4):318-326

The stable isotopes of dissolved organic carbon (DOC) are a powerful tool for distinguishing sources and inputs of organic matter in aquatic systems. While several methods exist to perform these analyses, no labs routinely utilize a high temperature combustion (HTC) instrument. Advantages of HTC instruments include rapid analysis, small sample volumes and minimal sample preparation, making them the favored devices for most routine oceanic DOC concentration measurements. We developed a stable carbon DOC method based around an HTC system. This method has the benefit of a simple setup, requiring neither vacuum nor high pressures. The main drawback of the method is a significant blank, requiring careful accounting of all blank sources for accurate isotopic and concentration values. We present here a series of experiments to determine the magnitude, source and isotopic composition of the HTC blank. Over time, the blank is very stable at  20 ng of carbon with a δ¹³C of − 18.1‰ vs. VPDB. The similarity of the isotopic composition of the blank and seawater samples makes corrections relatively minor. The precision of the method was determined by oxidizing organic standards with a wide isotopic and concentration range (− 9‰ to − 39‰; 18 μM to 124 μM). Analysis of seawater samples demonstrates the accuracy for low concentration, high salinity samples. The overall error on the measurement is approximately ± 0.8‰.  相似文献   

煤岩变形破坏电磁辐射记忆效应实验研究   总被引：6，自引：1，他引：6       下载免费PDF全文

撒占友  何学秋  王恩元  于广明 《地球物理学报》2005,48(2):379-385

实验研究了原煤、型煤单轴压缩电磁辐射记忆效应特征、记忆内容及变化规律，探讨并分析了煤岩电磁辐射记忆效应机理.结果表明，煤岩变形破坏电磁辐射具有记忆先期最大应力、纵向应变、横向应变和体应变的能力，最直接的记忆内容是先期受到的应力、纵向应变和横向应变；当先期施加的应力水平大于70%～80%时，电磁辐射记忆能力迅速减弱，甚至根本失去记忆能力；煤岩损伤破坏过程的不可逆决定了电磁辐射过程的不可逆，电磁辐射过程的不可逆是煤岩变形破坏电磁辐射记忆效应的直接原因.煤岩电磁辐射记忆效应理论在地应力测试、巷道围岩不同应力区范围的确定及煤岩动力灾害预测等方面具有广阔的应用前景.  相似文献   

In situ measurement of dissolved chloride in high temperature hydrothermal fluids     

B.I. Larson  E.J. Olson  M.D. Lilley 《Geochimica et cosmochimica acta》2007,71(10):2510-2523

The ability to continuously monitor chemical properties of hydrothermal vent effluents for extended periods of time is essential to understanding dynamic processes responsible for the temporally variable nature of mid-ocean ridge hydrothermal systems. Although instruments do exist for some parameters, there has been no sensor capable of measuring the chloride concentration, an indicator of possible phase separation, on a real-time and long-term basis. In this article, we discuss the construction of a novel instrument which measures solution resistance as a proxy for chloride concentration. The sensor consists of four gold electrodes embedded in a cylindrical ZrO₂ ceramic housing. It has been successfully deployed in several high temperature vents at the Main Endeavour Field (MEF) on the Juan de Fuca ridge in the NE Pacific, and calibrated under simulated hydrothermal conditions ranging up to 380 °C and 300 bar. The in situ data clearly demonstrate a tidal influence on the effluent from some high temperature vents possibly relating to a subsurface mixing process involving non-seawater end-members. Non-tidal changes are used to constrain the sequence and type of controls operating on fluids circulating within the subsurface.  相似文献   

A Magnetometer Array Study Across Southern Victoria and Bass Strait Area, Australia     

F. E. M. Lilley 《Geophysical Journal International》1976,46(1):165-184

  相似文献   

A Magnetometer Array Study in Southern Australia     

D. I. Gough  M. W. McElhinny  F. E. M. Lilley 《Geophysical Journal International》1974,36(2):345-362

  相似文献   

Seeking a seafloor magnetic signal from the Antarctic circumpolar current     

F. E. M. Lilley  A. White  G. S. Heinson  K. Procko 《Geophysical Journal International》2004,157(1):175-186

  相似文献   

Electrical conductivity profiles and implications for the absence or presence of partial melting beneath central and southeast Australia     

F.E.M. Lilley  D.V. Woods  M.N. Sloane 《Physics of the Earth and Planetary Interiors》1981,25(4):419-428

A previous paper presented measurements by Australian magnetometer arrays of Earth response to the magnetic daily-variation source field, and interpreted these data by simple representative models of one-dimensional structure found by “forward model-fitting”. This paper now supplements the earlier interpretation by seeking to clarify the ranges of acceptable models which fit the data; that is, to demonstrate the extent of the non-uniqueness of the interpretation. Searches for models which fit the data have been carried out on both a systematic and a random basis, with similar results.The major conclusion of the earlier paper is confirmed; that there is a substantial difference in conductivity structure between central and southeast Australia. Beneath central Australia, the structure is consistent with a traditional continental geotherm and published laboratory measurements on the temperature dependence of the electrical conductivity of recognized upper-mantle crystalline olivine materials. Beneath southeast Australia, a higher conductivity by an order of magnitude in the depth range 200–300 km is most directly interpreted in terms of a small degree (perhaps 5%) of basalt melt.Such a partial-melt zone under southeast Australia is consistent with previous natural electromagnetic measurements for the area; has earlier and independently been indicated by a variety of seismic studies; and correlates with proposed thermal models which involve crustal intrusion from some sub-lithospheric magma source.  相似文献   

A magnetometer array study in northwest India     

F.E.M. Lilley  B.P. Singh  B.R. Arora  B.J. Srivastava  S.N. Prasad  M.N. Sloane 《Physics of the Earth and Planetary Interiors》1981,25(3):232-240

A magnetometer array study has been carried out in northwest India, from Rajasthan across the Indo-Gangetic Plain into the Himalayan foothills. Over the three months of operation, a wide variety of natural geomagnetic events has been recorded. The analysis of a simple substorm, polarized just west of north, shows a strong anomaly in the form of a reversal of the vertical component of the fluctuation, both in the Himalayan foothills and on the Ganga Plain.The magnetic fluctuations pattern observed is most directly interpreted in terms of a path of concentrated current flow in the Earth, striking across the Himalaya. It is evidently aligned with the Aravalli belt which outcrops further south, and may indicate that some geological structure in the sub-basement is of abnormally high electrical conductivity. The path of such a current concentration across the foothills raises the question whether some transverse structure in the Himalaya is not acting as a bridge to Peninsular India for current induced in the Tibetan plateau to the northeast.  相似文献   

Linear relationships in geomagnetic variation studies     

F.E.M. Lilley  D.J. Bennett 《Physics of the Earth and Planetary Interiors》1973,7(1):9-14

The linear properties of Maxwell's equations enable the primary and secondary fields of geomagnetic variations to be related together by an induction tensor. Variations of total field which are confined on or near a plane, as described first by Parkinson, can occur formally only under certain conditions on either the induction tensor (that it have a simple degeneracy), or on the primary variation field components (that they consistently obey the same linear relationship over all time). The second condition is implausible for typical transient variations observed on earth, and examination of the first condition demonstrates that for variations with no consistent correlation of the horizontal components, the existence of a well-determined Parkinson vector means that observed vertical variations are secondary fields, induced by observed horizontal variations. This conclusion has important implications for the theoretical explanation of the geomagnetic “coast effect”.That primary fields be spatially uniform is a tacit condition of much theoretical work on geomagnetic variations, though the condition can in fact be relaxed to require spatial uniformity of the primary fields just within some “induction region”. If however the primary fields are not uniform over the induction region a poor Parkinson-vector determination may result. This may be most noticeable at sites which have their induction regions greatly extended by a process such as current channelling.  相似文献