二叠纪海相碳酸盐的锶同位素演化及其意义

本文从沫阳和熊家场剖面二叠纪海相碳酸盐和玄武岩的锶同位素变化出发,讨论了碳酸盐的锶同位素组成与峨嵋山玄武岩喷发之间的关系,以及玄武岩中海相碳酸盐的锶同位素贫化原因,指出海相碳酸盐的锶同位素组成可作为了解地球构造演化的工具。     

河北省石人沟地区麻粒岩-紫苏花岗岩套岩石的矿物学和结晶温压条件

研究区内广泛出露的太古代岩石属于迁西群麻粒岩,包括麻粒岩、紫苏花岗岩、辉石-斜长片麻岩、角闪岩等。对这些岩石中辉石、角闪石、黑云母等矿物的研究结果表明,这些矿物具有明显的麻粒岩相成因特征,角闪石、黑云母同辉石等平衡共存。紫苏花岗岩中矿物除有序度增高外,其他特征与麻粒岩、片麻岩中的矿物相似。 根据矿物对地质温压计计算得到:本区第一期变质作用p-t条件为770-870℃,7.2-8.4k bar第二期为740-760℃,6.6-8.4k bar;矿物氧同位素温度为470-570℃,代表另一次程度较低的变质作用。     

水准测量网监测在德州市地面沉降中的应用

山东地面沉降灾害以鲁北平原最为严重,在德州地区的地面沉降已对当地人民的正常生产和生活构成了威胁,并制约了当地经济的可持续发展。通过建立水准测量网络及监测运行,查明了德州市地面沉降的规模和范围,研究成果表明工作区均存在地面沉降现象,截至2010年,德城区由于地下水开采强度大,地面沉降幅度最大,目前地面累计沉降量为-1186．9～-636．9mm,多年平均沉降速率为59．35mm／a,形成了以市区西北部为中心的地面沉降盆地。超量开采深层地下水是造成大规模地面沉降的重要因素。     

Geochemistry of meta-volcanic rocks from the Longbohe Cu deposit, Yunnan Province, China： Implications for the genesis and tectonic setting

The Longbohe Cu deposit, which is located in the southern part of the Honghe ore-forming zone, Yunnan Province, China, belongs to a typical ore field where volcanic rocks are of wide distribution and are associated with Cu mineralization in time and space. The volcanic rocks in the ore field, which have experienced varying degree of alteration or regional metamorphism, can be divided into three types, i.e., meta-andesite, meta-subvolcanic rock and meta-basic volcanic rock in accordance with their mineral assemblages. These three types of volcanic rocks in the ore field are relatively rich in Na and the main samples plot in the area of alkali basalts in the geochemical classification diagram. With the exception of very few elements, these three types of volcanic rocks are similar in the content of trace elements. In comparison to the basalts of different tectonic settings, the meta-volcanic rocks in the ore field are rich in high field strength elements (HFSE) such as Th, Nb, etc. and depleted in large ion lithophile elements (LILE) such as Sr, Ba, etc. and their primary mantle-normalized trace element patterns show remarkable negative Th and Nb anomalies and negative Sr and Ba anomalies. These three types of volcanic rocks are similar in REE content range and chondrite-normalized REE patterns with the exception of Eu anomaly. Various lines of evidence show that these three types of volcanic rocks in the ore field have the same source but are the products of different stages of magmatic evolution, their original magma is a product of partial melting of the metasomatically enriched mantle in the tensional tectonic setting within the continent plate, and the crystallization differentiation plays an important role in the process of magmatic evolution.     

松辽盆地北部宾参1井白垩系烃源岩的认识和评价及其意义

宾参1井是松辽盆地北部宾县断陷中的第一口参数井,钻遇白垩系地层,自下至上依次为沙河子组、营城组、登娄库组、泉头组和青山口组。在对宾参1井白垩系暗色泥岩进行一系列有机地球化学样品分析测试的基础上,从有机碳(TOC)、氯仿沥青"A"、有效碳(PC)、生烃潜量Pg(S1+S2)、热解峰温Tmax值、镜质体反射率(Ro)、烃源岩气相色谱特征、干酪根碳同位素特征、干酪根元素特征和源岩甾萜烷特征等方面着手,从有机质丰度、有机质类型和有机质成熟度三个角度认识该井白垩系烃源岩,并进行烃源岩的初步评价,认为:(1)青一段干酪根主要为Ⅱ1和Ⅱ2型,其中、下部已进入生油门限,属于非—差烃源岩,个别深度段为较好烃源岩,其上部及青二、三段处于未成熟阶段;(2)泉头组和登娄库组干酪根主要为Ⅲ型,已进入成熟生油阶段,前者属于非—差烃源岩,后者属于差烃源岩;(3)营城组和沙河子组干酪根主要为Ⅲ型,有些层段为Ⅱ2型,处于高成熟—过成熟阶段,以生气为主。对该井白垩系烃源岩的认识和初步评价为勘探程度极低的宾县凹陷含油气前景的评价预测和石油地质研究奠定了基础,具有现实意义和重要的理论意义。     

Characteristics of stable isotope and hydrochemistry of the groundwater around Qinghai Lake, NE Qinghai-Tibet Plateau, China

The integrated use of isotopic and hydrochemical tracers is an effective approach for investigating complex hydrological processes of groundwater. The stable isotope composition and hydrochemistry of the groundwater around Qinghai Lake were investigated to study the sources and recharge areas. Most of the groundwater points lie close to the local meteoric water line, indicating that the ground waters were recharged primarily from precipitation in the basin, though it had undergone varying degrees of evaporation. The hydrochemical analysis showed that the groundwater was mainly freshwater and that the hydrochemical type was Ca–Mg–HCO₃; the results of the boomerang envelope model and solutes calculated indicated that the groundwater chemistry was mainly controlled by carbonate dissolution around Qinghai Lake. The recharge altitudes of groundwater were relatively low (at 3,400 m.a.s.l) on the northern shore of Qinghai Lake (locations G1 and G5), relatively high (above 3,900 m.a.s.l) on the southern shore (locations G3 and G4), and approximately 3,700 m.a.s.l on the western shore (location G2). Furthermore, groundwater samples from the fault zone (e.g., G3) would be recharged in part from fissure or inter-basin water. High salinity of groundwater on the western shore (location G2) was related with the evaporite dissolution, the groundwater is unsuitable for drinking, and the drinking water should be improved and enhanced in this area. Knowledge of our research can promote effective management of water resources in this cold and semiarid region and add new data to global groundwater database.     

新疆东天山中段金铜成矿系统研究

以构造动力学体制、成矿机理和含矿建造等为原则,将东天山中段铜金成矿系统划分为晚泥盆世—早石炭世板块碰撞体制下的大南湖—头苏泉岩浆热液金铜、早石炭世板内伸展体制下的阿齐山—雅满苏火山热液铜铁和早二叠世陆内造山体制下的康古尔塔格韧性剪切铜金三个成矿系统。以成矿系统的研究内容和方法为指导,阐述了各成矿系统的地质背景、成矿系统的时空特征、控制因素、成矿系统要素、典型矿床的剖析或成矿系统内各矿床特征的对比,建立了各成矿系统模型,并总结了成矿系统的演化过程和演化谱系。     

Catastrophic debris flows triggered by a 14 August 2010 rainfall at the epicenter of the Wenchuan earthquake

The Wenchuan earthquake of May 12, 2008 produced large amounts of loose material (landslide debris) that are still present on the steep slopes and in the gullies. This loose material creates an important hazard as strong rainfall can cause the development of devastating debris flows that will endanger the resettled population and destroy the result of reconstruction efforts. On 14 August 2010, a total of 21 debris flows were triggered by heavy rainfall around the town of Yingxue, located near the epicenter of the Wenchuan earthquake. One of these debris flows produced a debris dam, which then changed the course of the river and resulted in the flooding of the newly reconstructed Yinxue town. Prior to this catastrophic event, debris flow hazard had been recognized in the region, but its potential for such widespread and devastating impacts was not fully appreciated. Our primary objective for this study was to analyze the characteristics of the triggering rainfall and the sediment supply conditions leading to this event. Our field observations show that even small debris flow catchment areas have caused widespread sediment deposition on the existing fans. It is concluded that the whole of the area shaken by the Wenchuan earthquake is more susceptible to debris flows, initiated by localized heavy rainfall, than had been assumed earlier. The results of this study contribute to a better understanding of the conditions leading to catastrophic debris flow events in the earthquake-hit area. This is essential for the implementation of proper early warning, prevention, and mitigation measures as well as a better land use planning in this area.     

塔河油田奥陶系生物扰动型储集层的三维重构及启示意义*

塔河油田奥陶系鹰山组和一间房组生物扰动型储集层发育。在岩心观测的基础上,通过典型岩样切片、偏光显微镜、阴极发光显微镜和X射线显微镜观测以及XRD测试分析,对研究区奥陶系生物扰动型储集层的发育特征进行了研究。研究区奥陶系可识别的生物扰动分为2类,分别是 Thalassinoides和Helminthopsis,但以Thalassinoides最为发育,扰动体积可达90%;生物潜穴充填物以白云石颗粒为主,可达90%以上;宿主围岩为泥晶灰岩。随着塔河油田早—中奥陶世海侵、海退沉积环境的变化,生物潜穴的发育呈现出明显的周期性演化规律。在综合提取生物扰动型储集层特征信息的基础上,以沉积学和遗迹学理论为指导,应用3ds Max软件对研究区奥陶系生物扰动型储集层进行了三维重构。该研究虚拟再现了塔河油田生物扰动型储集层的内部结构与微观特征,不仅为后续研究这类储集层的宏观非均质性与微观各向异性、定量表征该类储集层微观尺度上的渗流特征奠定了基础,而且还为完善塔河油田奥陶系油藏模型提供了一种新思路。     

青岛灵山岛南背来石下白垩统大型砂脉的发现及其形成动力学研究

青岛灵山岛南背来石剖面发育了两层大型不规则砂脉。其主要特征如下：上层大型不规则砂脉呈分散团块状顺黄褐色凝灰质泥岩分布,断续延伸约60 m,宽数米;有17个侵入砂团块。砂团块多呈浅灰色,主要岩性为砂岩、砂砾岩;砂团块直径在1~2 m。砂团块的形态非常复杂,侧向极易尖灭或突然中止。边界与围岩多突变,某些地方与节理发育方向相同。下层大型不规则砂脉浅灰色,主要底部为砂岩、顶部为砂砾岩,呈透镜状顺层产于灰黑色薄层砂泥岩中,均一团块状和边缘含大量泥砾;厚18 m,宽度和高度不详;上层砂脉发育在浅湖中;下层大型不规则砂脉发育在三角洲前缘。与此同时还探讨了上层砂脉的形成的动力学机制,建立了顺层砂脉的形成深度与液化层的深度之间的关系式（h=0.29H）。该公式可以用来预测顺层的侵位深度和寻找砂脉,为含油气盆地砂脉储层预测提供理论依据和新方法。通过流化公式计算获得了形成上层砂脉的流体上侵速度为1.26 m/s。通过本文的论述,进一步为理解灵山岛地区下白垩统的沉积环境和沉积动力学特征提供了新的岩石学证据。