中国大地构造基本特征及其发展的初步探讨

大地构造是地壳形变的结果,而地壳形变是在地壳形成的基础上发展起来的。地壳的形成主要表现为地质体的建造过程,包括地壳形成的地质时期中,不同温度和压力下所产生的沉积岩、岩浆岩和变质岩的类型、组合和相带的发展。地壳的形变主要表现为地质体的改造过程,包括各种岩层在形成过程之中或以后,经受内力和外力作用而产生的各种微观和宏观的结构变化,如流动、褶曲、破碎和断裂等。     

脉体充填的力学机制

我们把脉体充填的断裂构造的发生发展过程分为三个阶段:生成阶段、发展阶段和破坏阶段。第一阶段主要地是在水平的挤压应力作用下发生的,一般在(水)平面上形成两组剪性断裂和一组横向张性断裂,而在横剖面上则出现两组纵向压性断裂,有时还见一组张裂。这种立体空间形变特点反映在平面上构成“米”字型。此外,还有其他一些断裂。     

受断裂面性质控制的构造位移场的数学模拟

地质体有着十分复杂的结构和构造,因此,如何掌握地质体中各点的位移规律和应力分布规律,对工程地质研究,预测矿山边坡稳定性和地下工程稳定性,地震预测和预报以及地质构造形变的规律都是十分重要的。     

山东汶西凹陷边界断裂演化特征及其对沉积砂体的控制

在野外地质调查和室内资料处理的基础上,详细研究了鲁西地区汶西凹陷边界主干断裂的几何学、运动学特征,探讨了盆地边界主干断裂与旁侧低级构造的形变关系和形变规律,划分了构造形变期次,恢复了盆地自中生代以来的古构造应力场。分析了弧形边界主干断裂的控盆作用,认为不同地史时期边界断裂活动的不均衡性导致了盆内沉积砂体的发育在时间和空间上随沉降中心的迁移而发生变化,指出了边界弧形断裂与其横张断裂交汇部位为盆内古、今物源入口处,是砂体发育部位。      

现阶段地壳构造分区及其成因的初步探讨

近年来获得的大量地球物理资料以及地球深部构造作用的动力学条件的初步研究结果,提供了从构造力学观点考虑深部地质特征,进行地壳构造研究的一种新的可能。据此,我们拟在本文内对现阶段地壳构造分区问题做初步的探讨。地壳构造的分区应由其组成成分、结构和形变分析入手,进而结合对构造作用影响的深度和广度以及构造运动过程的分析进行探讨。     

福建何宝山金矿成因探讨

福建何宝山金矿的成矿地质条件在崇安—石城构造带,特别是中、南段金矿中具有广泛的代表性。本文从矿区宏观地质特征入手,结合成矿元素构造地球化学研究、氢氧硫同位素特征以及K-Ar年龄证据等。认为何宝山矿区金矿化主要经历了加里东期断裂变质-混合岩化作用和(印支晚期)—燕山早期构造动力作用两次叠加、富集成矿过程,前者是金富集成矿的“基础”,后者是形成具一定工业意义金矿体的“关键”。     

燕山地区中生代构造应力场特征

燕山地区现今的构造、地貌景观,是在漫长的地质历史时期,经历了长期、复杂的建造、改造过程而形成的。从沉积建造及构造形变特点来看,自元古宙至古生界,本区构造运动平缓,建造和改造的特点主要反映基底断裂的控制作用。中、新生代构造运动是燕山地区主要造山作用期,基本特征是强烈挤压形成线状褶皱及推覆构造系统。
中生代时期,本区构造形变显示水平应力作用的主导性,新生代时期,则以均衡代偿导致的隆升作用为主。本文侧重中生代构造应力场及变形挠度场的重塑,借以恢复本区中、新生代构造形变形成的力学过程及运动程式。      

论岩体力学模型

岩体力学是研究现状的地质体受力条件改变时产生变形、破坏及其力学性质形成规律的科学。地质体与一般材料不同,由于其成因和经历的历史过程不同,致使其成分、结构及其形成条件不同。故现状的地质体当受力条件改变时,其力学作用,即变形和破坏机理亦不同。在进行岩体力学研究时,必须清楚地看到这一点。当前岩体力学研究成效不大的重要原因之一,就是没有注意地质体这一特点,在进行岩体力学研究时,不加分析地把地质体一律做为连续介质力学模型处理,显然是不合适的。     

“板内形变与晚期成藏”出版

为纪念孙肇才先生从事石油地质工作50周年,以“板内形变与晚期成藏”为书名的孙肇才石油地质论文集2003年由地质出版社出版。全书精选了孙先生的论著24篇,分“基础地质”(3篇)、“中国含油气盆地综述”(3篇)、“典型含油气盆地分析”(10篇)和“在中外咨询会议上的发言”(8篇)4部分。书末附有孙先生学术论著和报告目录。全书共332页,约53万字。书中论述了中国含油气盆地的构造格局、成因机制、石油地质特征和油气远景。     

浙江高岭土矿床中氢氧同位素的研究

浙江省是我国高岭土矿的产地之一,矿床主要集中于浙南火山岩地区。浙南地区广泛分布中生代的中酸性火山碎屑岩、熔岩及浅成侵入岩,构造断裂发育,气候温暖湿润,具有风化或热液作用形成高岭土矿床的有利地质条件。     

The Maximum Effective Moment Criterion （MEMC） and Its Implications in Structural Geology

1 Introduction A high-level generalization of structures in the earth crust has been given by Ramsay (1980): low-angle thrusts in the brittle upper crust and high-angle reverse shear zones in the ductile middle-lower crust are formed in contractional regimes; high-angle normal faults in the brittle upper crust and low-angle normal shear zones in the ductile middle- lower crust are formed in extensional regimes. The formation of low-angle thrusts and high-angle normal faults in brittle domains …     

Deformation Localization-A Review on the Maximum- Effective-Moment (MEM) Criterion

The essential difference in the formation of conjugate shear zones in brittle and ductile deformation is that the intersection angle between brittle conjugate faults in the contractional quadrants is acute(usually ~60°) whereas the angle between conjugate ductile shear zones is obtuse(usually 110°). The Mohr-Coulomb failure criterion, an experimentally validated empirical relationship, is commonly applied for interpreting the stress directions based on the orientation of the brittle shear fractures. However, the Mohr-Coulomb failure criterion fails to explain the formation of the low-angle normal fault, high-angle reverse fault, and the conjugate strike-slip fault with an obtuse angle in the σ1 direction. Although it is ten years since the Maximum-Effective-Moment(MEM) criterion was first proposed, and increasingly solid evidence in support of it has been obtained from both observed examples in nature and laboratory experiments, it is not yet a commonly accepted model to use to interpret these antiMohr-Coulomb features that are widely observed in the natural world. The deformational behavior of rock depends on its intrinsic mechanical properties and external factors such as applied stresses, strain rates, and temperature conditions related to crustal depths. The occurrence of conjugate shear features with obtuse angles of ~110° in the contractional direction on different scales and at different crustal levels are consistent with the prediction of the MEM criterion, therefore ~110° is a reliable indicator for deformation localization that occurred at medium-low strain rates at any crustal levels. Since the strain–rate is variable through time in nature, brittle, ductile, and plastic features may appear within the same rock.     

峰峰矿区通二井田煤镜质组有限应变特征及其应用

利用MPV—COMPACT型显微光度计对峰峰矿区通二井田煤镜质组反射率进行较系统的测试,发现井田内煤 3个光轴体主轴互相垂直,最大反射率轴倾角多数集中在 68°～69°之间,倾伏向有 3个方向,即近 280°、近 90°和近 180°。测区内煤的镜质组反射率椭球体的变形特征属于拉长型应变和压扁型应变。该井田煤镜质组反射率椭球体有限应变特征分析结果表明在煤系地层中,煤的最大镜质组反射率的方位除与区域构造应力场的作用有关外,还与其所处的局部构造位置有关。在断层附近,反射率Ro_max和Ro_min的差值随着距断层的距离增加而减小,且在断层面的两盘发生突变。这一特征有助于煤矿井下构造的预测。     

结构面力学性质的定量鉴定

变形带力学性质的鉴定是地质力学研究中的先行基础步骤.近来出现一些新的概念和方法,可用以定量表征变形带的力学性质.天然变形带通常是一般剪切作用的产物,是纯剪切(共轴缩短或伸展)和简单剪切的组合.为了定量说明两者间的相对贡献,提出了运动学涡度(W_k)这一物理量,并简单地定义为cos υ.υ是主变形面内两特征方向间的夹角.纯剪切的υ=90°,W_k=0;简单剪切的υ=0°,W_k=1.一般剪切的υ介于0°和90°之间,W_k为0到1.运动学涡度符号的正负分别代表变形带的减薄和增厚.υ可通过极摩尔圆法求出.主压应力(σ₁)方向与W_k的关系为W_k=sin2ξ.ξ是σ₁与变形带法线间的夹角.因此,可用以确定变形带的W_k和力学性质.根据最大有效力矩准则,韧性变形带与主压应力(σ₁)方向间的夹角为55°,可用以确定古应力轴的方向,并可能确定变形时差应力的大小.      

一种常见的岩体结构——板裂结构及其力学模型

岩体结构观念的提出对岩体工程地质和岩体力学的研究具有重要意义。岩体结构类型划分方案已经提出了许多,已有的岩体结构划分原则主要是岩体破碎程度。谷德振、孙玉科等曾提出过岩体结构基本单元是:结构面和结构体。1977年底谷德振教授曾提出过,碎碎带应作为一种岩体结构单元问题,没有引起人们的重视。     

侧向挤压下粘土破裂实验及其地质含义

长期以来,许多学者(Chang,1984,1950;张文佑、钟嘉猷,1965;Tschlenko,1967)用粘土、松散材料或岩石做变形试验,研究破裂的形成和发展的特点,并与野外观察到的节理或破裂进行对比,取得了很大进展。诸如材料变形初期出现的吕德氏线、破裂的共轭性与褶皱构造的空间展布规律性、破裂形成过程从剪切开始到张性破裂完成(张文佑等,1983,1975),以及根据破裂的产出探讨区域构造应力场,从全球性断裂组系追溯岩石圈动力学和地壳运动力源等等。     

Structure and Fluid Transportation Performance of Faults in the Changxing-Feixianguan Formation,Xuanhan County,Northeastern Sichuan Basin

On the basis of field observations, microscopic thin-sections and laboratory data analysis of ten faults in Xuanhan County area, northeastern Sichuan Basin, central China, the internal and megascopic structures and tectonite development characteristics are mainly controlled by the geomechanical quality in brittle formation of the Changxing-Feixianguan Formation. The fluid transportation performance difference between the faults formed by different geomechanics or different structural parts of the same fault are controlled by the mcgascopic structure and tectonite development characteristics. For instance, the extension fault structure consists of a tectonite breccia zone and an extension fracture zone. Good fluid transportation performance zones are the extension fracture zone adjacent to the tectonite breccia zone and the breccia zone formed at the early evolutionary stage. The typical compression fault structure consists of a boulder-clay zone or zones of grinding gravel rock, compression foliation, tectonite lens, and dense fracture development. The dense fracture development zone is the best fluid transporting area at a certain scale of the compression fault, and then the lens, grinding gravel rock zone and compression foliation zones are the worst areas for hydrocarbon migration. The typical tensor-shear fault with a certain scale can be divided into boulder-clay or grinding gravel rock zones of the fault, as well as a pinnate fractures zone and a derivative fractures zone. The grinding gravel rock zone is the worst one for fluid transportation. Because of the fracture mesh connectivity and better penetration ability, the pinnate fractures zone provides the dominant pathway for hydrocarbon vertical migration along the tensor-shear fault.     

廊固凹陷沙四晚期构造应力场模拟及低级序断层预测

在了解区域构造背景、分析断层活动特征及构造演化特征的基础上,对廊固凹陷沙四晚期构造应力场进行数值模拟,并对低级序断层发育进行预测。研究结果表明,研究区在沙四晚期活动的主要断层包括大兴断层、半截河断层等6条,牛北斜坡构造带与河西务构造带在该时期隆起明显,综合分析可知该时期最小主应力方向为SE144°—NW324°;低级序断层发育受最小主应力、剪应力等的影响,最小主应力和最大主应力与最小主应力的差值控制断层的优势发育区,平面剪应力控制断层走向,该区主要发育北北东—北东走向的断层;剖面剪应力在大部分区域为左旋,表明断层视倾向以北西向为主。     

Solution transfer syn-S2: an inferred means of deriving fault fill in the lake Moondarra area, Mt. Isa, Queensland, Australia, based on oxygen isotope results

Many of the faults within the Lake Moondarra area cropout as wide zones which are filled with massive or fibrous milky quartz. Additionally, a variety of rock fragments from the surrounding metasediments are present in the fault zones. The second regional slaty cleavage, S₂, is locally observed through the quartz and country rock fragments within some of the zones, indicating that these fault fills originated pre- or early syn-S₂. The absence of the first regional slaty cleavage, S₁, suggests that the fault fills developed post or late syn-S₁. Evidence supporting an early syn-S₂ timing for the development of these fills is provided by the results of oxygen isotope analysis carried out on quartz specimens collected from the faults and also by the nature of the quartz. Specimens of quartz taken from the various fault zones have δ¹⁸O values between 12.4 and 14.5‰. This suggests that metamorphic water isotopically equilibrated with connate formation water was the aqueous fluid which transported the silica. δ¹⁸O values for the silica in the quartz-rich, sometimes dolomitic, metasediments of the Mount Isa and Haslingden Groups within the Lake Moondarra area are similar to the quartz within the fault fills. The lack of any metamorphic event between the first and second deformation, together with the sometimes fibrous nature of the fault-filling material with fibres parallel to the mineral elongation in S₂ (i.e. L₂²), suggests that the quartz in the faults was derived syntectonically at grain to grain contacts in the metasediments within the Lake Moondarra area, early in the development of S₂. The quartz is believed to have moved by the process of solution transfer to the faults as they underwent dilation during D₂. Subsequently the quartz was precipitated as a result of a chemical potential gradient.     

The relationship of porosity and angle of repose to mixture proportions in assemblages of different sized materials

Rotating drum experiments on the repose angles of mixtures of glass spheres have shown that φ_r (angle of shear) is strongly influenced by the proportions of the mixture. It was found that φ_r reached a peak value for the minimum porosity mixture; where the pore spaces between the large particles were just filled with small material; which was attributed to increased dilatation on the shear plane during avalanching. The geomorphic significance of these observations, in terms of slope development, is discussed. Secondly, the results of the experiments showed that, although more constant than φ_i (limiting angle of repose), φ_r was subject to some variation. Thus φ_r, as measured in a rotating drum, is not a true constant and can not be exactly analogous to φ'_cv (angle of internal sliding friction at constant volume) as measured in a shearbox test—as has been previously suggested. It is tentatively suggested that at least some of the variability in φ_r is attributable to the magnitude of the immediately preceding value of φ_i, in that an unusually high value of φ_i, favours a lower value of φ_r due to the greater amount of kinetic energy released on failure.