塔里木盆地哈得逊油田东河砂岩油藏原油特征和倾斜油-水界面成因初探

塔里木盆地哈得逊油田东河砂岩油藏内部存在着由北向南原油密度等物性呈现规律变化的特征.西北部的"重质油"（密度>0.34 g/cm³）与中-南部的"轻质油"（密度<0.34g/cm³）来源于同一套烃源岩,但原油族组成、原油成份等方面的特征存在着较大的差别.东河砂岩油藏的原油可能不是直接来自于烃源岩,而是来源于古油藏,原油物性的差异是晚喜马拉雅运动导致晚海西期形成的古油藏发生调整并在运移过程中造成的成份分异等原因所致.哈得逊鼻隆构造高点至今仍在迁移,东河砂岩油藏正处于充注、调整之中,导致了其油-气-水界面的大幅度倾斜.     

应用先进微波探测器AMSU资料遥感反演春季陆地表层湿度

利用先进微波探测器(AMSU)正演快速微波辐射传输模型,完成了AMSU 窗区通道亮温与地表温湿特征的相关性分析,根据模拟计算结果改进了现有业务上反演地表微波辐射率的统计分析方法,得到适用于我国非冻土积雪覆盖地区地表微波辐射率反演的指数分析模型;进一步通过地表微波辐射传输模型迭代反演得到土壤体积含水量信息.2001年相互匹配的AMSU资料和地面农业气象观测站地表相对湿度观测结果的对比分析表明二者间具有一定的相关性.利用2002年3月和2003年3月的AMSU资料,反演了我国陆地区域地表湿度;连续两年春季地表湿度反演结果的对比分析表明,与2002年春季相比,2003年我国北方沙尘暴发生源区地表湿度反演值普遍偏高,潮湿的下垫面特征与沙尘暴发生频次的减少之间有一定的对应关系.试验结果表明,利用AMSU遥感资料可以获取大范围陆地表层湿度信息,进行区域尺度陆地表层湿度特征的动态分析,为我国沙尘暴监测分析提供陆地表层湿度基础信息.     

土地质量地球化学评价成果与若干问题探讨:以浙江省金华市汤溪镇为例

为进一步总结完善丘陵盆地区中大比例尺土地质量地球化学调查评价方法技术,2013年在中国地质调查局的支持下,选择浙江省金华市汤溪镇农用地分布区开展了试点调查和采样密度对比试验。基于调查数据进行了土壤酸碱度(p H)、土壤养分丰缺、土壤环境质量和土壤质量地球化学综合评价与分级,探讨了丘陵盆地区野外采样密度。结果表明:区内土壤p H值低、酸性土壤广泛分布;土壤养分元素氮、磷、钾普遍缺乏;土壤环境质量总体较好,仅局部地区出现重金属元素超标;土壤质量地球化学综合等级以一等、二等为主,优良土地面积占调查区的92. 6%,土壤酸性强、养分缺乏是影响调查区土地质量的主要原因,建议采取适当措施调控土壤酸碱度、补充土壤养分;丘陵盆地区中大比例尺土地质量地球化学调查应适当提高土壤采样密度,有效控制土地利用图斑,以便于调查成果在土地资源管护中的应用。     

甘肃阿克塞县安南坝地区镁铁质麻粒岩锆石U-Pb年龄和Hf同位素组成:对塔里木东南缘前寒武纪地质演化的启示

甘肃阿克塞县安南坝地区镁铁质麻粒岩呈脉状或透镜状赋存于新太古代米兰岩群和TTG片麻岩中。岩石主要由斜方辉石（Opx）+单斜辉石（Cpx）+角闪石（Amp）+斜长石（Pl）+磁铁矿（Mt）等组成,具有典型中-低压麻粒岩相岩石的矿物组合特征。LA-ICP-MS锆石U-Pb测年结果显示镁铁质麻粒岩原岩形成时代可能为2 561±29 Ma,与塔里木东南缘2.6～2.5 Ga岩浆作用时代基本一致,说明新太古代晚期是塔里木东南缘重要的陆壳增生期。此外,通过测年还获得了～1.95 Ga、～1.86 Ga两期变质年龄。其中,～1.95 Ga的峰期变质年龄是塔里木克拉通东南缘古元古代晚期强烈构造—热事件的地质记录。～1.86 Ga的变质年龄可能与该地区古元古代末期构造—岩浆事件密切相关。镁铁质麻粒锆石¹⁷⁶Hf/¹⁷⁷Hf比值均＜0.281 621,ε_Hf(t) 值为-14.08～3.12,两阶段模式年龄（T_DM2）主要集中在～2.65 Ga,指示其原岩岩浆起源于新太古代富集岩石圈地幔。     

北大别罗田榴辉岩的减压出溶结构与超高压变质作用

岩石学研究表明北大别罗田榴辉岩经过了榴辉岩相、麻粒岩相和角闪岩相变质作用,表现出多种减压出溶结构.特征性的减压出溶结构有单斜辉石和石榴石中分别发育石英+角闪石+斜长石等与金红石+单斜辉石+角闪石等针状矿物出溶体,以及锆石中含有柯石英残晶.这些进一步证明北大别南部（罗田一带）同北部（如黄尾河、百丈岩等地）榴辉岩一样经过了>5～7CPa的超高压变质作用.     

The missing half of the subduction factory: shipboard results from the Izu rear arc,IODP Expedition 350

IODP Expedition 350 was the first to be drilled in the rear part of the Izu-Bonin, although several sites had been drilled in the arc axis to fore-arc region; the scientific objective was to understand the evolution of the Izu rear arc, by drilling a deep-water volcaniclastic section with a long temporal record (Site U1437). The Izu rear arc is dominated by a series of basaltic to dacitic seamount chains up to ~100-km long roughly perpendicular to the arc front. Dredge samples from these are geochemically distinct from arc front rocks, and drilling was undertaken to understand this arc asymmetry. Site U1437 lies in an ~20-km-wide basin between two rear arc seamount chains, ~90-km west of the arc front, and was drilled to 1804 m below the sea floor (mbsf) with excellent recovery. We expected to drill a volcaniclastic apron, but the section is much more mud-rich than expected (~60%), and the remaining fraction of the section is much finer-grained than predicted from its position within the Izu arc, composed half of ashes/tuffs, and half of lapilli tuffs of fine grain size (clasts <3 cm). Volcanic blocks (>6.4 cm) are only sparsely scattered through the lowermost 25% of the section, and only one igneous unit was encountered, a rhyolite peperite intrusion at ~1390 mbsf. The lowest biostratigaphic datum is at 867 mbsf (~6.5 Ma), the lowest palaeomagnetic datum is at ~1300 mbsf (~9 Ma), and the rhyolite peperite at ~1390 mbsf has yielded a U–Pb zircon concordia intercept age of (13.6 + 1.6/?1.7) Ma. Both arc front and rear arc sources contributed to the fine-grained (distal) tephras of the upper 1320 m, but the coarse-grained (proximal) volcaniclastics in the lowest 25% of the section are geochemically similar to the arc front, suggesting arc asymmetry is not recorded in rocks older than ~13 Ma.     

江西朱溪铜钨矿床成因:来自矿物学和年代学的启示

江西景德镇朱溪铜钨矿床是近年来发现的一个世界级超大型铜钨矿床。矿床地质特征、矽卡岩矿物学和成矿岩体年代学的研究表明,矿体赋存于上石炭统黄龙组大理岩与新元古界双桥山群变质岩之间的不整合界面之上,空间上具有明显的矿物组合分带特征。根据矽卡岩产状、矿物共生组合和相互关系,把成矿作用划分为矽卡岩阶段、退化蚀变阶段、石英-硫化物阶段、碳酸盐-萤石阶段。代表性的矽卡岩矿物组合有石榴子石、透辉石、透闪石、硅灰石、符山石、蛇纹石、绿泥石等。电子探针分析表明,石榴子石为钙铝榴石—钙铁榴石系列,辉石为透辉石—钙铁辉石系列。同位素年代学及岩浆与成矿关系的研究表明：花岗闪长岩与早期矽卡岩型矿化相关,矿化范围较小,矿石品位较低;黑云母花岗岩与云英岩型和晚期矽卡岩型的矿化相关,矿化范围较广,矿石品位较高,并获得黑云母花岗岩LA-ICP-MS锆石U-Pb年龄为（147.7±2.2）Ma。综合分析指出,朱溪铜钨矿床为晚侏罗世花岗岩浆有关的热液与晚古生代碳酸盐岩发生多阶段交代作用而形成,成矿作用以矽卡岩型和云英岩型为主。     

Hydrochemistry,multidimensional statistics,and rock mechanics investigations for Sanshandao Gold Mine,China

Prediction of bursting water in a submarine mine (Sanshandao Gold Mine) is very important. The aim of this study was to understand the water sources, mixing ratios, and flow paths in a mining region by using hydrochemistry, principal component analysis (PCA), and rock mechanics. Field observations reveal that there are unusual geothermal gradients and complicated geological conditions. Samples collected from the surface and every depth of the tunnel were analyzed for various ions and isotopes (¹⁸O and D). PCA was used to identify the most likely water sources on the foundation of hydrochemistry and a conceptual model. Four kinds of water sources were identified: (1) water mixture of surface freshwater and seawater, (2) brine derived from a deep closed environment, (3) thermal brine derived from the northwestern fault (F3), and (4) Quaternary water. The water sources were variable with time at a sampling site. The combination of water sources in a specific sampling campaign can be decided by the positive scores on principal components (PCs). The PCA results indicate that the first and the fourth kind of water source appear in the deep tunnel with the continual mining activity. Mixing ratio calculations for each sampling campaign show that the first and the fourth kind of water source constitute a small proportion of the total water. The main water sources are the second and third kinds of water. Finally, water flow paths were determined based on the PCA, and rock mechanics is used to explain the change in the water flow paths after excavation. The results show the following: (1) There are several strong water diversion zones that distribute at a certain spacing interval on the large scale and (2) “zonal disintegration” is also found in the tunnel. The fractured zone and the non-fractured zone appear in turn around the tunnel. The rock mass in these two zones represents the tensile and compressive properties, respectively. Thus, volumes of water and permeability of joints and fractures in these two zones are great different.     

Temporal variation of intertidal seagrass in southern China (2008–2014)

Understanding the temporal dynamics of seagrasses and the major influences on seagrass growth is critical for seagrass habitat conservation and administration. However, little work has been done regarding these issues in southern China. To examine inter-annual and seasonal variations of the intertidal Halophila ovalis community in southern China, we conducted quarterly sampling using the SeagrassNet methodology and assessed environmental conditions as well as direct anthropogenic impacts on the seagrass meadow from July 2008 to October 2014. Our study demonstrated strong inter-annual and seasonal dynamics of the intertidal seagrass meadow in the study area. Generally, the community performed best (highest seagrass cover, leaf area, shoot density, total biomass) in summer and worst in spring among the 4 seasons. The temporal variations in the seagrass community attributes (e.g. above-ground biomass) were significantly affected by precipitation, atmospheric visibility, and salinity, while leaf width was significantly negatively correlated with temperature, atmospheric visibility and salinity. Temperature was a major factor influencing the seagrass community (both macroalgae and seagrass), with temperature data showing an inverse relationship between seagrass and macroalgae. The above-ground: below-ground biomass ratio and leaf width of H. ovalis were the most sensitive plant parameters monitored when assessing environmental interactions. Human physical disturbances did not have a significant effect on seagrass dynamics in the study area. We concluded that long-term monitoring (like SeagrassNet) is valuable in understanding the relationship between environmental variables and seagrasses.     

内蒙古双尖子山银多金属矿床花岗斑岩年代学、地球化学特征及构造意义

本文对内蒙古双尖子山银多金属矿床花岗斑岩进行了锆石SHRIMP U-Pb定年,并对花岗斑岩的主量元素、微量元素组成进行了分析研究。结果显示,双尖子山花岗斑岩加权平均年龄为(133.4±1.2)Ma,为大兴安岭南段早白垩世岩浆活动集中期产物;花岗斑岩SiO_2含量为68.81%~70.05%,低MgO、TiO_2,K_2O/Na_2O为0.97~1.27,较为富钾;A/CNK在0.94~1.12之间,属准铝-弱过铝系列;富集Rb、Th、U、K等大离子亲石元素(LILE),亏损Sr、P、Ti等高场强元素(HFSE);稀土总量ΣREE中等,δEu为0.55~0.62,Eu中等负异常。本文认为双尖子山银多金属矿床为多期次叠加的岩浆热液型矿床,160Ma和133Ma可能分别是岩浆活动的两个高峰期。花岗斑岩形成于陆内晚造山期-造山期后的伸展环境,蒙古-鄂霍次克洋俯冲板片在深部断离,引发软流圈物质上涌,这是导致大兴安岭南段早白垩世岩石圈伸展环境的主要机制。