Interactions of Copper, Evaporite, and Organic Matter and Genesis of Sandstone-Hosted Copper Deposits in the Chuxiong Basin, Yunnan Province

Studies on organic geochemistry indicate that the origin, type and maturity of organic matter are different among coal-bearing, copper-bearing and evaporite formations in the Mesozoic continental Chuxiong Basin, Yunnan, China. A mechanism has been proposed that (1) during the diagenetic mineralization stage the short-chain organic acids dervied from kerogen played an important role in remobilizing copper from source beds, while oils acted as important carrier of copper, and that (2) during the transformation or remolding mineralization stage, meteoric water leached the evaporite layers and formed downward-percolating oxidizing SO42-rich fluids; meanwhile, the copper-bearing fluids migrating upwards along growth faults from the basement was contaminated by the coal-bearing series on the way and formed reducing organic-rich fluids; oxidation-reduction occurred and sulfides formed when the two kinds of fluids met within sandstones.     

DBSCAN Clustering Algorithm for the Detection of Nearby Open Clusters Based on Gaia-DR2two

In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on the Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the Sun) from the Gaia-DR2 catalog, and construct a five-dimensional phase space (three-dimensional spatial position and two-dimensional proper motion) in order to obtain reliable cluster members. At the data preprocessing stage, we normalize each dimension of data to the [0, 1] interval in order to avoid the effect of inconsistent units. Then, we use the k-dist graphs to determine the input parameters of the DBSCAN Algorithm. Finally, we obtain 133 reliable members using the DBSCAN algorithm, which correspond to two open clusters—Hyades and Coma. According to these cluster members, the distances to the Hyades and Coma clusters are determined to be (6.5 ± 0.3) pc and (4.9 ± 0.4) pc, respectively.     

Esophageal cancer spatial and correlation analyses: Water pollution,mortality rates,andsafe buffer distances in China简

Esophageal cancer exhibits one of the highest incidence and mortality rates in China. Malignant tumors caused by esophageal cancer, and the relationship to environmental factors has been the focus of many public health studies. This study applied spatial analysis to ascertain the relationship between water pollution and esophageal cancer mortality rates nationwide. We employed two datasets, including a national investigation of esophageal cancer rates and distribution, and national water quality grades in China＇s primary rivers and lakes. Esophageal cancer data were grouped based on different water quality grades, which included a scaled buffer distance from rivers and lakes. Non-parametric correlation analyses were performed to examine the presence or absence of the following correlations： （i） eso- phageal cancer mortality and buffer distance from rivers and lakes; and （ii） esophageal can- cer mortality and water quality grade values. The present study revealed a significant positive correlation between widespread water pollution and esophageal cancer mortality nationwide; and a significant negative correlation between esophageal cancer mortality, and buffer dis- tance from rivers and lakes.     

Influence of sand content on the flow characteristics of soft soil under cyclic and high-frequency vibration

The flow characteristics of foundation soils subjected to train loads can present engineering hazards in high-speed railways. In order to verify the feasibility of blending coarse sand in modifying soft subsoil, undrained pulling sphere tests were carried out and the train loads were simulated through localized and cyclic vibration at various frequencies. Laboratory testing results indicate that the flow characteristics of soft soil can be significantly enhanced by high-frequency vibration; meanwhile the continuous increase in flow characteristics caused by cyclic vibration may be an important reason for the long-term settlement of soft subsoil. The influence of sand content on flow characteristics is also studied in detail, and it is shown that the addition of coarse sand can weaken the flow characteristics of soft soil induced by sudden vibration at lower than 50 Hz. Under the condition of cyclic vibration, the growth of the flow characteristics of sand-clay mixtures is mainly caused by the first-time vibration in the cycle, and the increase in sand content can make the flow characteristics present a faster convergent tendency.     

Evaluation of the tropical variability from the Beijing Climate Center’s real-time operational global Ocean Data Assimilation System

The second-generation Global Ocean Data Assimilation System of the Beijing Climate Center(BCC_GODAS2.0) has been run daily in a pre-operational mode.It spans the period 1990 to the present day.The goal of this paper is to introduce the main components and to evaluate BCC_GODAS2.0 for the user community.BCC_GODAS2.0 consists of an observational data preprocess,ocean data quality control system,a three-dimensional variational(3DVAR) data assimilation,and global ocean circulation model[Modular Ocean Model 4(MOM4)].MOM4 is driven by six-hourly fluxes from the National Centers for Environmental Prediction.Satellite altimetry data,SST,and in-situ temperature and salinity data are assimilated in real time.The monthly results from the BCC_GODAS2.0 reanalysis are compared and assessed with observations for 1990-2011.The climatology of the mixed layer depth of BCC-GODAS2.0 is generally in agreement with that of World Ocean Atlas 2001.The modeled sea level variations in the tropical Pacific are consistent with observations from satellite altimetry on interannual to decadal time scales.Performances in predicting variations in the SST using BCC_GODAS2.0 are evaluated.The standard deviation of the SST in BCC-GODAS2.0 agrees well with observations in the tropical Pacific.BCC-GODAS2.0 is able to capture the main features of E1 Nino Modoki I and Modoki Ⅱ,which have different impacts on rainfall in southern China.In addition,the relationships between the Indian Ocean and the two types of E1 Nino Modoki are also reproduced.     

东北地区1∶5万区域地质图空间数据库建设与集成

东北地区1∶5万区域地质图空间数据库从1999年度试点工作到2015年底持续近16年的数据库建设工作,收集了大量20世纪60年代以来东北地区开展的1∶5万区域地质调查工作所获取的基础地质成果资料,对东北地区完成的区调和建库工作程度及资料状况进行核查、摸底、整合.完成了382个标准图幅传统填图1∶5万区域地质图空间数据库建设工作.建库过程中建立了完善的质量监控体系,健全了空间数据验收的方法和流程,规范了基本的评分方法和成果评价等级.     

西部弱胶结软岩细观结构及水理特性试验

为准确掌握西部弱胶结软岩的水理特性,对采自陕北矿区的红砂岩进行水理及力学特性试验,并基于电镜（SEM）扫描图像分析细观结构特性,建立岩石细观结构与其宏观水理特性间的联系。试验表明：红砂岩具有明显的饱水软化和吸水膨胀特性,其软化系数为0.64;无压力水侵蚀和干湿循环作用下饱水红砂岩性能将进一步劣化,宏观上表现为强度和弹性模量的减小和质量损失率的增大;细观上,红砂岩颗粒间的联系比较松散,具有明显的弱胶结结构特征。总体来说,亲水矿物溶解与弱胶结结构破坏的耦合作用,导致红砂岩特殊的宏观水理特性。研究结果可为类似地区软岩夹层工程治理提供借鉴。     

激光粒度分析与传统粒度分析方法相关对比

对 4 1个样品的激光法与传统法 (筛析部分—沉析部分 )的粒度分析成果 (粒级百分含量、粒度参数和海陆相样品的粒度成果 )作了相关对比。找出 2种分析方法之间的内在联系 ,以期在将来的粒度分析中 ,可以通过参数矫正来实现 2法的数据转换。从分析可知 ,海陆相沉积对样品的影响很小。 2种方法的原理不同 ,从而产生了激光法低估粘土部分百分含量的结果     

山东临沭地区早白垩世晚期恐龙足迹化石特征*

主要记述了山东临沭地区早白垩世晚期(大盛群沉积时期）、生活于干旱炎热气候条件下滨浅湖环境的恐龙所留下的大规模足迹化石群。初步研究表明,这些足迹以蜥脚类恐龙足迹占绝大多数,见少量鸟脚类、兽脚类和疑似甲龙类足迹(甲龙类足迹在中国罕见),足迹总体行进方向以向西和南西为主。通过对其中的2条蜥脚类和1条鸟脚类行迹及其行为学的分析认为其均处于慢行状态,而鸟脚类行迹的运动速度极慢,可能处于一种特殊的慢行状态。临沭地区早白垩世晚期大盛期如此大规模足迹化石群的发现,说明中国乃至东亚地区早白垩世普遍存在着以恐龙为代表的(包括鸟类在内）陆生脊椎动物群。足迹化石的研究将对进一步了解晚中生代陆地生物群的演化有着重要意义。对比其他地区早白垩世晚期地层中发现的恐龙足迹化石特征后认为,足迹的保存与当时的沉积环境有密切的关系,因此对恐龙足迹的研究又能进一步为恢复古生态、古地理环境等提供更丰富的信息。