Electronic Structures of Square Planar Coordinated Transition Metal Ions in Compounds with Gillespite Structure

Electronic structures of square planar coordinated transition metal ions in BaCuSi₄O₁₀ and CaCrSi₄O₁₀ are investigated using the ligand-field theory (LFT), angular overlap model (AOM) and iterative extended Hückel molecular orbital theory (IET). The electronic energy levels of the natural mineral dioptase are also investigated, in which the Cu²⁺ ions occupy the sites of pseudo D_4h symmetry. Both LFT and AOM predict that the crystal-field levels of transition metal ions in these compounds follow such an order that E (²B_1g <E(²B_2g <E(²A_1g )<E(²E_g ), and the frequencies of the crystal-field transitions obtained from point charge calculations are in good agreement with those observed. However, the energy-level order cannot be determined unambiguously from the IET calculation because it depends on the values of parameters chosen for the calculation.     

嘉鱼断裂西向延伸与第四系活动特征

嘉鱼断裂为已证实的隐伏断层。该断裂从洪湖老湾西南横切长江,沿近东西—北东东向延展,经嘉鱼县城东北马鞍山北缘向东延伸于斧头湖,长约40 km,该断裂东端已有明显出露,而断裂尾部并没有明显出露。由于区内小尺度物探资料的缺乏,使得该断裂的走向和活动性都缺少相关证据。本文利用浅层地震反射结合折射层析成像方法,采用2 m道间距接收人工地震波,利用多次覆盖技术和密集炮集折射记录,分别对数据进行反射处理和层析成像,获取了浅层地震反射剖面和高分辨率折射层析成像剖面,并参考相关区域地震安全性评价钻孔资料进行解译。综合研究结果表明：浅层地震反射和高分辨率折射联合应用可互补,尤其在外界干扰较为严重的区域,利用高分辨率折射层析成像可减少浅层地震反射对断层的误判。此外,研究结果证实了嘉鱼断裂的具体位置,其性质为北盘下降、南盘上升的正断层,且该断层错断了第四系沉积层。     

龙门山北段九龙山构造几何学运动学分析

九龙山构造是川西北地区的重点勘探构造。据地震剖面分析,解析了九龙山的构造几何学特征。研究表明,九龙山背斜受到米仓山构造和龙门山构造的双重影响,主要经历了三期次构造叠加,其叠加组合形成了现今九龙山的复杂构造。通过合理的构造建模,对九龙山构造运动过程、多期构造叠加及油气运移与分布规律等有了新的认识。     

Observation of CO2 degassing in Tianshuihai Lake Basin of the Qinghai-Tibetan Plateau

A large volume of underground gas in the permafrost region of the Qinghai-Tibetan Plateau has been identified. Although many studies were performed to investigate the soil organic carbon dynamics and Earth degassing in volcanic areas, this is the first report of a large amount of non-volcanic CO₂ contained in permafrost. The gas was mostly CO₂ (81.76 vol. %) and nitrogen (14.59 vol. %). The gas composition and the evidence from carbon stable isotope values (?23.9 ‰, PDB) suggested that the gases possibly had a deep origin. The gas emissions may be triggered by permafrost degradation, which means mitigation of the barrier effect of permafrost for the gas. In addition, plate tectonic processes may also lead to gas emissions, as the tectonic activity is strong in the area. Therefore, particular attention should be paid to the underground gases in the study of global change and permafrost degradation.     

Is it possible to detect earlier ionospheric precursors before large earthquakes using principal component analysis (PCA)?

The goal of this study was to determine whether principal component analysis (PCA) can be used to process GPS ionospheric total electron content (TEC) data on a monthly basis to identify early earthquake-associated TEC anomalies. PCA is applied to GPS (mean value of a month) ionospheric TEC records collected from the Japan GEONET system to detect TEC anomalies associated with 10 earthquakes in Japan (M?≥?6.0) from 2006 to 2007. According to the results, PCA was able to discriminate clear TEC anomalies in the months when all 10 earthquakes occurred. After reviewing the months when no M?≥?6.0 earthquake occurred but the geomagnetic storm activity was present, it is possible that the maximal principal eigenvalues PCA returned for these 10 earthquakes indicate earthquake-associated TEC anomalies. Previously, PCA has been used to discriminate earthquake-associated TEC anomalies recognized by other researchers who found that a statistical association between large earthquakes and TEC anomalies could be established in the 5 days before earthquake nucleation and in 24 h before earthquake; however, since PCA uses the characteristics of principal eigenvalues to determine earthquake-related TEC anomalies, it is possible to show that such anomalies existed earlier than this 5-day statistical window. In this paper, this is shown through the application of PCA to one-dimensional TEC data relating to the earthquake of 17 February 2007 (M?=?6.0). The analysis is applied to daily TEC and reveals a large principal eigenvalue (representative of an earthquake-associated anomaly) for 02 February, 15 days before the 17 February earthquake.     

青藏高原多年冻土区高寒草甸植物种群物候学定量研究

采用青藏高原腹地北麓河多年冻土区高寒草甸14种代表性植物种群2009年和2010年两个生长季的物候观测资料, 进行植物种群物候学特征的定量分析, 划分物候类型并指出影响不同物候期的环境因子主次. 结果表明: 营养期和结实期的物候指数都较大, 分别为32.70和24.39, 其他物候期则相对较小; 整个生长期持续天数较短, 为155 d左右. 14种植物可划分为3种类型和6大类群. 在营养期和整个生长期, 与物候变化最为密切的环境因子为降水量, 其次为日照时数, 温度居第三; 而影响其他物候期的因子均以日照时数为主, 降水量和温度依次居后.     

U–Pb and Hf isotopic study of zircons from migmatised amphibolites in the Cathaysia Block: Implications for the early Paleozoic peak tectonothermal event in Southeastern China

Amphibolites occur in a number of localities in the Cathaysia Block, some of them have been migmatised and their protoliths represent basaltic magmas erupted in various tectonic settings. Four migmatised amphibolites were collected from Jiangxi and Fujian Provinces. Cathodo-luminescence images of zircons extracted from the representative amphibolites show unzoned or sector-zoned structure. LA-ICP-MS analysis indicates that most zircons have high Th/U ratios and yield U–Pb zircon ages of 446 ± 5, 435 ± 2, 434 ± 4 and 423 ± 2 Ma, respectively. Lu–Hf isotopic analysis on these zircons gives Hf model ages ranging from 900 to 1200 Ma. Based on lithological observations and previously published geochronological data, we interpret that these U–Pb ages record an important tectonothermal event that led to the migmatization. This early Paleozoic (Caledonian) tectonothermal event in the Southeastern China has a great tectonic implication for the evolutionary history of the Cathaysia Block.     

深孔绳索取心安全打捞器的研制与应用

设计了一种可适用于深孔和干孔的绳索打捞、投放内管总成工具。介绍了深孔绳索取心安全打捞器的工作原理及结构组成;对工具内部的机械控制和井下脱卡控制原理进行了研究;介绍了打捞器井下脱卡的具体方法;最后通过野外试验证实了该打捞器可以减少处理事故的时间,性能稳定,拆装、维护方便。     

黔北后槽下石炭统含铝岩系的粘土矿物

为揭示黔北下石炭统含铝岩系的沉积环境,本文利用贵州遵义县后槽TC718剖面系统试样的粘土矿物进行X-射线衍射测试及特征分析.含铝岩系粘土岩与下伏桐梓组粘土页岩在矿物组合和成分上均有明显的差异,水云母的结晶度指数、开形指数在剖面纵向上有三个变化拐点一是含铝岩系与下伏桐梓组粘土页岩分界处;二是含铝岩系上、下段的接触带;三是含铝岩系顶部含炭质粘土岩出现的临界面.其变化特征表明,本区下石炭统含铝岩系粘土岩段为海相或海陆过渡相,铝质岩段为残积-坡积相,顶部为大陆湖沼相;下奥陶统桐梓组页岩段为海相.