新元古代扬子—华夏陆块拼合带：来自华南重磁异常的启示

扬子和华夏两大陆块是构成华南大陆的最基本单元, 但它们的拼合带位置（尤其是西延位置）是人们长期争论的焦点。本文以国家专项“深部探测技术与实验研究”探测得到的深反射地震剖面以及华南大陆的地质资料为约束, 对重、 磁异常作地壳构造融合解译, 追踪扬子—华夏陆块拼合带。由于华南大陆广泛发育具有剩磁多期、 多类的火山—侵入岩, 本文将磁异常换算为受剩磁影响小的解析信号作构造解译, 减小剩磁造成的地质解释偏差。研究认为, 扬子与华夏两陆块的拼合带东界为鹰潭—萍乡—衡阳—贺州—北海一线, 而西界为宜昌—张家界—铜仁—都匀—百色一线, 鹰潭以东和以北的拼合带位置因为受大规模岩浆岩的干扰而不清。     

Study on Strength Influence Mechanism of Fiber-Reinforced Expansive Soil Using Jute

This study was undertaken to research the effects of jute fiber content, fiber length, water content and dry density of reinforced and unreinforced soil on the strength influence mechanism by implementing a series of laboratory tests and analysis. The most efficient fiber reinforcement effects was achieved by means of adding jute fiber with content of 0.6 % and length of 6 mm into expansive soil specimen prepared at maximum dry density and optimum moisture content. The cohesion of reinforced specimens increased first with increasing fiber content and fiber length and then decreased with further increase in fiber content and fiber length. The internal friction angle of reinforced specimens were not affected significantly by fiber content and fiber length. Higher water content reduces the fiber reinforcement effects by means of acting as lubricant in the interface of fiber and soil particles. Fiber reinforcement effects is more prominent for specimens prepared at higher dry density by increasing the effective contact area of fiber/soil. The application prospect of soil reinforcement using natural fiber is impeded by the hydrophilic nature and biodegradability of natural fiber, thus, studies on using chemical additive to do surface treatment for natural fiber are needed to improve the interfacial interaction of fiber/soil so as to widen the application of natural fiber.     

伊犁盆地侏罗系水西沟群层序地层学研究

伊犁盆地侏罗系水西沟群是一套在基本一致的构造应力和沉积环境下形成的含煤碎屑岩建造,但在这套地层的中部(三工河组)出现了岩性、颜色的突变,并且对应的测井曲线也出现明显的突坎现象。笔者运用层序地层学的观点,从年代地层、岩性、体系域、沉积韵律以及测井曲线解释等5方面对这一现象进行了分析,认为该群中部存在一不整合面(或层序界面),并尝试对水西沟群层序地层进行重新划分。     

Experimental research on horizontal bearing behavior of caisson-pile composite foundationEI北大核心CSCD

In this study, four groups of different types of bridge foundation model are tested to research the horizontal bearing behavior of caisson-pile composite foundation in lab based on the Qiongzhou Strait bridge project. The Q-s curve and horizontal ultimate bearing capacity of these four groups of foundations in sandy soil layer are obtained. Pile bending moment and shear force of pile shaft are analyzed in detail. At the same time, the load sharing ratio of caisson and piles is discussed. The results show that the horizontal ultimate bearing capacities of a single caisson foundation are increased by 1.2 times, 1.6 times and 2 times respectively with adding skirts, steel pipe pile, or steel pipe pile and the skirt. The maximum bending moment point is in the middle of the pile shaft, i.e. at about 0.5 m under the mud surface. The horizontal load is borne mainly by the upper caisson foundation and soil layers above the middle upper part of pile. The maximum shear force is found at the joint of pile top of steel pipe and caisson pile, where the reinforcement measures should be taken in practical engineering. The research achievements could provide a better reference for design or construction of caisson-pile composite foundation.     

吉林延边地区浅成热液金(铜)矿床的~(40)Ar/~(39)Ar激光探针测年与成矿时代讨论

延边地区是中国东北部陆缘浅成热液金铜矿床发育的地区之一,广泛发育着浅成热液金矿床、中温热液金(铜)矿床和中深成中高温热液富金铜矿床(类斑岩型);富金铜矿床的成矿时代发生在105～102 Ma,为了进一步确定浅成热液金矿床与中深成中高温热液富金铜矿床的成矿动力学背景,采用流体包裹体的~(40)Ar/~(39)Ar激光探针定年法,对该区典型浅成热液金矿床进行了精细的年代学测定,获得刺猬沟金矿床、五星山金矿床和杜荒岭金矿床的脉石矿物石英流体包裹体的~(40)Ar/~(39)Ar等时线年龄分别为(141±7)Ma、(123±7)Ma和(107±6)Ma,其中刺猬沟金矿床((141±7)Ma)和五星山金矿床((123±7)Ma)的脉石矿物石英流体包裹体含有过剩放射性成因~(40)Ar,而杜荒岭金矿床((107±6)Ma)的脉石矿物石英流体包裹体几乎不含或含极少量过剩放射性成因~(40)Ar。结合最新获得的相关地质体的精细年代学成果,认定该区浅成热液金矿床成矿作用均发生在早白垩世晚期,或发生在早白垩世晚期火山喷发、浅成岩浆就位之后,其形成环境与富金铜矿床一致,为古太平洋板块向亚洲大陆正北向俯冲转入Izanagi-Farallon板块西向俯冲的构造转换期。     

豫西嵩县前范岭石英脉型钼矿床地质特征及辉钼矿Re-Os同位素年龄

位于熊耳山-外方山地区的前范岭钼矿是东秦岭地区新近发现的石英脉型钼矿床之一。赋矿围岩为古元古界熊耳群安山质火山岩类。矿体主要以含辉钼矿石英脉产出,矿石类型以石英脉型为主。金属矿物以辉钼矿和黄铁矿为主,脉石矿物以石英为主,其次为方解石、萤石等。围岩蚀变类型有硅化、钾长石化、青磐岩化等。对6件辉钼矿样品进行Re-Os同位素测年所获得的模式年龄为233.3±3.3～248.2±3.5Ma,等时线年龄为239±13Ma,表明矿床形成于中三叠世。矿床的成矿作用发生于华北与扬子两个板块碰撞对接的晚期阶段。区域上整体的挤压造成了局部的剪切和伸展环境,这种环境为控矿断裂的形成和成矿流体的运移提供了有利条件。嵩县境内现已发现的多处脉型钼矿床很可能形成于同一时期(三叠纪),它们构成了熊耳山与外方山之间的嵩县脉型钼矿田。     

运用STOMP数值模拟器进行多空介质中尿素水解以及方解石沉淀数值模拟

遍布于美国能源部所辖野外场地的地下放射性核素和痕量金属污染对美国能源部的长期监管职能提出了最严峻的挑战。目前较有前景的一个原地固化污染物方法是利用尿素酶催化尿素水解,进而推动方解石沉淀及与之共同沉淀。运用STOMP数值模拟器实施一系列反应性溶质数值模拟来研究系统中水流、运移、反应与反应导致的介质性质变化之间的紧密的非线性耦合,并在研究中系统性增加反应系统的复杂度和物理-化学的非均质性以考察模拟效果。通过调整反应速率表达式中尿素酶浓度和沉淀反应常数,对尿素水解和方解石沉淀速率进行了敏感度分析。结果显示:尿素水解速率是矿物沉淀总量的决定性因素,沉淀物的空间分布既取决于水解速率也取决于沉淀速率;在一维水流柱6个空隙体积的时间段模拟中,观察到了5%的最大空隙度减少;当二维模拟中考虑一个低渗透性包裹体时,被改变的流场重新对生成的沉淀组成物进行了分布,形成了扭曲的反应锋面。模拟结果也显示沉淀在低渗透性区域边界上形成,这说明位于这个区域里面的污染物可能被囊裹而从流线中被隔离起来。     

高放废物处置库天然类比及其有关的地球化学问题

介绍了高放废物处置库天然类比研究的主要内容,重点阐述了类比研究中涉及的地球化学问题,包括核素溶解度和化学形态研究、核素迁移速率研究、核素迁移影响因素研究,并总结相关问题研究取得的成果和认识.     

The distribution and geological significance of carbazole compounds in Silurian paleo-pools of the Tarim Basin,Northwest China

The results presented in this paper indicated that the carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has high concentrations and a complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in the study of hydrocarbon migration of the paleo-pools. The difference in the contents of nitrogen compounds in the Silurian dry asphalts from the Awati, Tabei and Tazhong areas is attributed to the difference in the extent of oxidation and （or） bio-degradation for the areas; the Awati and Tabei areas underwent relatively strong oxidation and bio-degradation. During the first stage of hydrocarbon pool formation in the Silurian system in the Tazhong and Tabei areas of the Tarim Basin （at the end of the Silurian period） and at the second stage in the Awati area （in Permian）, the hydrocarbons experienced a long-distance migration.     

伊拉克哈勒法耶油田Mishrif组滩相储层特征及其成因分析

伊拉克哈勒法耶油田Mishrif组滩相储层发育,是研究区内最主要的产油层位。利用岩心、薄片、测井资料对Mishrif组沉积相进行了研究,结果表明该组发育局限台地、开阔台地、台内洼地和台地边缘4种沉积相,滩相储层主要发育在开阔台地和台地边缘相带。并综合利用铸体薄片、物性实验数据及压汞曲线等资料对滩相储层特征和成因进行了分析。滩相储层岩石类型多样,发育生屑灰岩、生屑泥粒/粒泥灰岩、砂屑灰岩等多种岩石类型,岩石颗粒较粗。孔隙类型多样,主要以铸模孔、粒间孔、溶孔和体腔孔为主,其中以粒间孔和铸模孔发育最为广泛。各类滩相储层孔隙度较高,渗透率差异明显,平均渗透率为(2.35~139.17)×10~(-3)μm~2。整体孔隙结构较好,排驱压力较低,大喉道较为发育。滩相储层发育受沉积环境控制和成岩作用改造程度影响,有利的沉积条件是滩相储层原生孔隙发育的基础,同生期溶蚀作用的改造形成大量次生孔隙,从而提高了储层的储集性能。