“不协调伸展”作用下裂陷盆地断层的形成演化模式

应用"不协调伸展"的目标砂箱模拟实验成果和新的脆性断裂力学模型——"不协调性准则",分析了裂陷盆地断层形成和演化的控制影响因素,建立了裂陷盆地断裂系统形成和演化的新模式——"不协调伸展"模式。该模式显示:"不协调伸展"的递进变形过程是导致裂陷盆地断裂系统的复杂性的根本原因,实质是不同方向、性质和规模的基底先存构造(主要是先存断裂)的活动性方面存在差异,导致所控制形成的断层在走向、形成的先后次序、规模等方面存在差异,从而形成复杂的断层组合;"不协调伸展"模式是裂陷盆地断裂系统形成和演化的基本型式,复杂的断裂系统可以在方向不变的区域伸展构造作用下在递进变形过程中逐渐形成;裂陷盆地断裂系统虽然比较复杂,但断层的形成和演化是有序的,分布是有规律的,可以通过"不协调性准则"加以分析和预测。     

Potential Tsunami Hazard Associated with the Kerepehi Fault,Firth of Thames,New Zealand

Geophysical data have identified four submarine segments of the Kerepehi Fault, roughly bisecting a back-arc rift (Hauraki Rift). These segments have been traced through the shallow waters of the Firth of Thames, which lies at the southern end of the Hauraki Gulf, New Zealand. No historical or paleotsunami data are available to assess the tsunami hazard of these fault segments.Analysis of the fault geometry, combined with paleoseismic data for three further terrestrial segments of the Fault, suggest Most Credible Earthquake (MCE) moment magnitudes of 6.5–7.1. Due to the presence of thick deposits of soft sediment, and thesemi-confined nature of the Firth, the MCE events are considered capable of generating tsunami or tsunami-like waves. Two numerical models (finite element and finite difference), and an empirical method proposed by Abe (1995), were used to predict maximum tsunami wave heights. The numerical models also modelled the tsunami propagation.The MCE events were found not to represent a major threat to the large metropolitan centre of Auckland City (New Zealand's largest population centre). However, the waves were a threat to small coastal communities around the Firth, including the township of Thames, and 35,000 ha of low-lying land along the southern shores of the Firth of Thames.The Abe method was found to provide a quick and useful method of assessing the regional tsunami height. However, for sources in water depths < 25 m the Abe method predicted heights 2–4 times larger than the numerical models. Since the numerical models were not intended for simulating tsunami generation in such shallow water, the Abe results are probably a good guide to the maximum wave heights.     

黑龙江省新生代火山岩构造环境与地震活动

黑龙江省是中国新生代火山岩广泛分布的地区之一。通过对该省新生代火山岩构造环境的分析指出，本省西部火山岩区为大陆板内裂谷环境，地慢上隆、底辟是裂谷形成火山与地震活动的主要原因，而东部火山岩区火山与地震活动的动力则主要来自西太平洋板块对欧亚板块的俯冲作用。     

吉林省地体构造的基本特征

吉林省地体构造的一个显著特征是在早古生代以前，伊舒断裂两侧分属两个不同的大地构造单元，西侧的构造环境与华北大陆板块北缘相似，为受古蒙古洋作用的早生代活动陆缘，东侧为长白山一张广才岭地体添加带（也称联合地体（省内包括吉林－延边古生代增生褶皱带及辽吉台块。其中辽吉台块于新元古代到早寒纪位于赤道附的，以后沿巨型拆离面逐渐北移，于二叠纪末沿辉发河－古洞河拼贴带，与吉林一延边古生代陆缘增生褶皱带拼贴到一起。     

裂谷盆地的断层封闭类型

对油气运移和聚集而言，裂谷盆地的断层可分为断面封闭型和生封闭型两大类；断面封闭型以以断面（或断裂带）本身作为遮挡体或通道；岩性封闭型断层依靠对盘财层遮挡或提供通道，根据断层的封闭能力，每大类还可分为完全封闭型、不完全封闭型和开启型３亚类、磊断层以断面封闭型为主；小断层大断层在浅层的分支断层都为生封闭型，但者的油气分布特所不同，一盘为基岩的断层较在盖层内的断层能力低，断层活动有利于油气运移。     

阿尔泰大型-超大型矿床富集区地壳演化

通过构造、岩浆、变质、成矿等地质作用及其时空演化规律的对比分析,以及物探重力、航磁及遥感信息的综合研究,认为古生代阿尔泰富蕴地幔热柱成因的三联点裂谷形成与演化———“手风琴式”开合,是阿尔泰大型- 超大型矿床富集区形成与演化的根本原因。地幔热柱热地幔物质大规模上涌和横向扩张,产生三联点裂谷系统,导致古大陆解体,形成阿尔泰“洋岛型”蛇绿岩、阿尔泰型花岗岩、花岗岩化、高温低压变质带和主要大型- 超大型矿床;地幔热柱活动停止或间息,导致三联点裂谷系统发生A 型俯冲而封闭造山,形成三叉式陆间造山带和同造山花岗岩、     

A model for the three-dimensional evolution of continental rift basins,north-east Africa

Large areas of north-east Africa were dominated by regional extension in the Late Phanerozoic. Widespread rifting occurred in the Late Jurassic, with regional extension culminating in the Cretaceous and resulting in the greatest areal extent and degree of interconnection of the west, central and north African rift systems. Basin reactivation continued in the Paleocene and Eocene and new rifts probably formed in the Red Sea and western Kenya. In the Oligocene and Early Miocene, rifts in Kenya, Ethiopia and the Red Sea linked and expanded to form the new east African rift system.This complex history of rifting resulted in failed rift basins with low to high strain geometries, a range of associated volcanism and varying degrees of interaction with older structures. One system, the Red Sea rift, has partially attained active seafloor spreading. From a comparison of these basins, a general model of three-dimensional rift evolution is proposed. Asymmetrical crustal geometries dominated the early phases of these basins, accompanied by low angle normal faulting that has been observed at least locally in outcrop. As rifting progressed, the original fault and basin forms were modified to produce larger, more through-going structures. Some basins were abandoned, others experienced reversals in regional dip and, in general, extension and subsidence became focused along narrower zones near the rift axes. The final transition to oceanic spreading was accomplished in the Red Sea by a change to high angle, planar normal faulting and diffuse dike injection, followed by the organization of an axial magma chamber.     

雷琼第四纪火山活动的新认识

本文根据７６个岩石样品的年龄和１０７个钻孔剖面的对比，认为本区第四纪火山活动可分为６期，并具有以喷溢为主，多旋回，从海相向陆相转变的，文中以较多的岩石学证据论证了岩浆源地和火山构造环境，同时从板块构造观点论述了雷琼裂谷的发育阶段和火山活动兴衰过程。     

伊舒地堑的构造-沉积演化及其聚油条件

伊舒地堑早第三纪盆地的结构、充填形式和充填序列以及区域构造格局表明,它属于我国东北部(东部)新生代裂谷系中的一部分,其发育级别低于辽河裂谷盆地带,而优于佳伊地堑北段,为一初始裂谷盆地。该盆地经历了裂谷前隆升剥蚀(晚白垩—古新世)、张裂深陷(始新世)、充填淤积(渐新世)和后期改造(早第三纪末)四个阶段的演化。与我国东部其它新生代裂谷盆地的演化近同时同步。地堑中5000多米厚的早第三纪陆相沉积物具有良好的生储油条件。同时地堑的构造-沉积演化决定了所形成的油气藏具有个体多而细小的特点,在有利的油气聚集区形成复式油田。