南极半岛别林斯高晋海天然气水合物成矿条件与成矿机理

位于南极半岛西侧的别林斯高晋海是南极附近海域天然气水合物成矿的远景区域。利用现有钻孔岩心样品、地震剖面、声波等资料,从气源、稳定域、构造输导及沉积储集等方面,分析了别林斯高晋海天然气水合物的形成条件,预测了天然气水合物成矿远景区,初步探讨了其形成机理,以期能为今后南极半岛区域的天然气水合物资源调查研究提供一定的科学参考依据。     

Gravitational collapse and equilibrium conditions of a toroidal vortex with thermal pressure

We found the equilibrium conditions for a self-gravitating toroidal vortex by taking thermal pressure into account. These conditions are shown to significantly differ from those for a disk or a sphere. The evolution of a thin vortex turns it into a compact vortex that loses mechanical stability for low masses at a polytropic index γ<4/3 but retains stability for sufficiently high masses and densities determined by the velocity circulation in the vortex.     

莺歌海盆地中央泥底辟带气田水地球化学特征及其油气地质意义

以莺歌海盆地东方区和乐东区气田水样品水化学常规分析为切入点,利用气田水矿化度、水型、钠氯系数(变质系数)、脱硫系数,氯镁系数等参数,深入分析了两区气田水地球化学特征及水化学组合参数特征,并判识对比了两区气藏封闭程度及其保存条件。在此基础上,结合莺歌海盆地天然气成藏地质条件,重点剖析了两区气田水分布规律及成因控制因素,探讨了两区气田水与天然气运聚成藏之间的成因联系。强调指出,两区气田水具有相似的形成演化特征,天然气保存条件好,但对比两区气田水的水化学组合参数,乐东区天然气保存条件稍差于东方区;东方区气田水以NaHCO3水型占绝对优势,其分布规律与断裂系统存在密切联系。该区水文地质开启程度差,气藏盖层封闭性好,有利于天然气富集成藏。乐东区气田水类型多样,成因复杂,天然气保存条件较好但相对东方区稍差。两区气田水具分区分块分布规律,莺歌海盆地泥底辟及其伴生热流体活动对气田水成因及分布规律与天然气运聚成藏等均具有重要控制作用和影响。     

Behavior of soil plugs in open‐ended model piles driven into sands

Calibration chamber tests were conducted on open‐ended model piles driven into dried siliceous sands with different soil conditions in order to clarify the effect of soil conditions on load transfer mechanism in the soil plug. The model pile used in the test series was devised so that the bearing capacity of an open‐ended pile could be measured as three components: outside shaft resistance, plug resistance, and tip resistance. Under the assumption that the unit shaft resistance due to pile‐soil plug interaction varies linearly near the pile tip, the plug resistance was estimated. The plug capacity, which was defined as the plug resistance at ultimate condition, is mainly dependent on the ambient lateral pressure and relative density. The length of wedged plug that transfers the load decreases with the decrease of relative density, but it is independent of the ambient pressure and penetration depth. Under several assumptions, the value of earth pressure coefficient in the soil plug can be calculated. It gradually reduces with increase in the longitudinal distance from the pile tip. At the bottom of the soil plug, it tends to decrease with increase in the penetration depth and relative density, and to increase with the increase of ambient pressure. This may be attributed to (1) the decrease of friction angle as a result of increase in the effective vertical stress, (2) the difference in the dilation degree of the soil plug during driving with ambient pressures, and (3) the difference in compaction degree of soil plug during driving with relative densities. Based on the test results, an empirical equation was suggested to compute the earth pressure coefficient to be used in the calculation of plug capacity using one‐dimensional analysis, and it produces proper plug capacities for all soil conditions.     

一座营钼矿床成矿控制条件及找矿标志

一座营钼矿床位于吉林省梅河口市一座营镇北东方向3.5 km处,经详查提交钼资源储量(332+333)15 204 t。笔者根据区域地质背景及矿床特征总结了矿床的控矿条件,认为志留系桃山组、华力西期、印支期侵入岩、北西向构造为主要控矿条件,并建立了找矿标志。     

利用示踪试验研究巨木地下河成库条件

示踪试验是客观认识地下河管道空间结构的有效手段之一,其成果可成为地下河开发利用的重要依据。通过对以食盐为示踪剂,以摩尔法为检测方法得出的巨木地下河出口水质中Cl#体积质量历时曲线的分析,认为该地下河具多支、网络状特点,系统内含水介质以管道、廊道、裂隙及溶潭的组合为特征,具有较强的调蓄能力,具备筑坝成库条件。     

赣北大湖塘矿田特大型钨矿床成矿条件及成矿模式探讨

文章收集了大湖塘矿田成矿信息资料,从成矿物源、成矿动力作用、成矿通道与赋存空间、成矿岩体化学特征、特别事件与成矿偏在性等方面,探讨了大湖塘矿田特大型矿床的形成条件和成矿模式。认为燕山早期多次岩浆侵入这一特别事件造就了大湖塘矿田巨大的成矿空间、丰富的成矿流体、多次聚集成矿;讨论了矿田围岩具有形成特大型矿床的成矿偏在性,得出特大型矿床主要是在燕山早期大规模岩浆活动和成矿大爆发这一特别事件与矿田特殊围岩的耦合机制下形成的。认为原大湖塘矿区具有形成特大型矿床的条件,有可能成为大湖塘矿田内又一个特大型钨多金属矿床。     

云南省禄劝县普福滑坡形成条件、发展趋势与防治对策

云南省禄劝县普福滑坡是我国典型灾难性滑坡之一,曾多次发生大规模滑动。本文回顾了普福滑坡的活动历史,分析了其形成条件。通过实地调查,结合由遥感多波段数据与DEM数据融合而成的三维影像图,指出普福滑坡实际上是一个滑坡(崩塌)→泥石流灾害链,且再次发生大规模滑动的可能性很大,影响范围覆盖烂泥沟两岸大面积区域。目前最经济有效的减灾措施包括搬迁避让、群测群防、监测预报、生态恢复和水土保持等。