Geochemical Characteristics and Genetic Significance of Datangpo‐Type Manganese Ore Deposits during the Cryogenian Period

The Datangpo‐type manganese ore deposits, which formed during the Nanhuan (Cryogenian) period and are located in northeastern Guizhou and adjacent areas, are one of the most important manganese resources in China, showing good prospecting potential. Many middle‐to‐large deposits, and even super‐large mineral deposits, have been discovered. However, the genesis of manganese ore deposits is still controversial and remains a long‐standing source of debate; there are several viewpoints including biogenesis, hydrothermal sedimentation, gravity flows, cold‐spring carbonates, etc. Geochemical data from several manganese ore deposits show that there are positive correlations between Al₂O₃ and TiO₂, SiO₂, K₂O, and Na₂O, and strong negative correlations between Al₂O₃ and CaO, MgO, and MnO in black shales and manganese ores. U, Mo, and V show distinct enrichment in black shales and inconspicuous enrichment in Mn ores. Ba and Rb show strong positive correlations with K₂O in manganese ores. Cu, Ni, and Zn show clear correlations with total iron in both manganese ores and black shales. ∑REE of manganese ores has a large range with evident positive Ce anomalies and positive Eu anomalies. The Post Archean Australian Shale (PAAS) normalized rare earth element (REE) distribution patterns of manganese ores present pronounced middle rare earth element (MREE) enrichment, producing “hat‐shaped” REE plots. ∑REE of black shales is more variable compared with PAAS, and the PAAS‐normalized REE distribution patterns appear as “flat‐shaped” REE plots, lacking evident anomaly characteristics. δ¹³C values of carbonate in both manganese ores and the black shales show observable negative excursions. The comprehensive analysis suggests that the black shales formed in a reducing and quiet water column, while the manganese ores formed in oxic muddy seawater, which resulted from periodic transgressions. There was an oxidation–reduction cycle of manganese between the top water body and the bottom water body caused by the transgressions during the early Datangpo, which resulted in the dissolution of manganese. Through the exchange of the euphotic zone water and the bottom water, and episodic inflow of oxygenated water, the manganese in the bottom water was oxidized to Mn‐oxyhydroxides and rapidly buried along with algae. In the early diagenetic stage, Mn‐oxyhydroxides were reduced and dissolved in the anoxic pore water and then transformed into Mn‐carbonates by reacting with HCO₃^? from the degradation of organic matter or from seawater. In the intervals between transgressions, continuous supplies of terrigenous clastics and the high productive rates of organic matter in the euphotic zone resulted in the deposition of the black shales enriched in organic matter.     

刘山岩铜锌矿床成矿地质特征及成矿预测

刘山岩铜锌矿是一座探明资源量面临枯竭的矿山。为寻求新的资源量,探讨该矿区进一步找矿的希望,解决矿山的生存问题,本文通过对刘山岩铜锌矿的地质勘察及开采期间的资料系统整理和研究,对过去的找矿思路进行仔细地分析,提出了刘山岩铜锌矿区深部找矿的具体方向,并对矿区进行了必要的物探工作,对隐伏矿体进行了矿体群的预测。     

会泽型(HZT)富锗银铅锌矿床成矿构造动力学研究及年代学约束

川-滇-黔多金属成矿域是会泽型(HZT)富锗银铅锌矿床的主要分布区。近十年来,该类矿床成矿时代及其成矿构造动力学一直是该区研究的主要热点之一。针对铅锌矿床准确定年的难题,首次综合应用地质推断-构造变形筛分-构造古应力系统测量-同位素定年技术,提出冲断褶皱构造形成时代与矿床成矿时代一致,其主体时代为印支晚期(2.0~2.3亿年)。研究认为,该期发生的铅锌多金属成矿作用是川-滇-黔接壤区重要的地质事件,其成矿构造动力学为印支晚期特提斯洋闭合与造山作用在扬子地块西南缘前陆盆地诱发强烈的斜冲走滑,形成一系列冲断褶皱构造带,并发生流体大规模运移,在有利的构造部位形成一批大型-超大型矿床。该认识对深化川-滇-黔多金属成矿域铅锌矿床成矿模型、优选找矿标志、圈定重点找矿靶区和实现找矿突破具有现实意义。     

Single epoch GPS deformation signals extraction and gross error detection technique based on wavelet transform

IntroductionGPS technique is widely used for deformationmonitoring thanks for the high precision. Usual-ly , there are three working modes associatedwith GPS deformation observation: periodicalGPS deformation monitoring net , GPS monito-ring array and rea…     

GPS sidereal filtering: coordinate- and carrier-phase-level strategies

Multipath error is considered one of the major errors affecting GPS observations. One can benefit from the repetition of satellite geometry approximately every sidereal day, and apply filtering to help minimize this error. For GPS data at 1 s interval processed using a double-difference strategy, using the day-to-day coordinate or carrier-phase residual autocorrelation determined with a 10-h window leads to the steadiest estimates of the error-repeat lag, although a window as short as 2 h can produce an acceptable value with > 97% of the optimal lag’s correlation. We conclude that although the lag may vary with time, such variation is marginal and there is little advantage in using a satellite-specific or other time-varying lag in double-difference processing. We filter the GPS data either by stacking a number of days of processed coordinate residuals using the optimum “sidereal” lag (23 h 55 m 54 s), and removing these stacked residuals from the day in question (coordinate space), or by a similar method using double-difference carrier-phase residuals (observational space). Either method results in more consistent and homogeneous set of coordinates throughout the dataset compared with unfiltered processing. Coordinate stacking reduces geometry-related repeating errors (mainly multipath) better than carrier-phase residual stacking, although the latter takes less processing time to achieve final filtered coordinates. Thus, the optimal stacking method will depend on whether coordinate precision or computational time is the over-riding criterion.     

不同截止高度角下BDS-3SPP精度分析

针对卫星可见数与历元可用率较低情况下的BDS-3定位性能,本文基于MEGX跟踪站BDS-3与GPS实测数据,分析了不同高度角（10°、20°、30°、40°）下BDS-3卫星B1I、B1C、B2a、B3I,以及GPS系统L1频率的单点定位（SPP）精度。研究发现,BDS-3平均卫星可见数与卫星空间几何构型优于GPS,且随着高度角的增加呈线性变化。BDS-3的4个频率的SPP精度随着高度角的增加呈先增加后降低的趋势,高度角为20°时,定位精度最高,高度角达到40°时,定位精度最低,且历元可用率也最低;但B1I和B3I历元可用率仍大于90%,而B1C和B2a历元可用率大于70%;不论是SPP定位精度还是历元可用率,均优于GPS系统L1频率。     

GPS历元比较时间对齐方法

基于“齿轮转动”思想,本文设计了对GPS历元时间对齐比较的方法,实现了两个GPS历元文件各历元准确遍历自动查询,有效解决了历元比较时间对齐耗时、费力问题;通过文件两两比较可实现三文件比较,该方法查询速度快、省时简便,同时为其他具有相同特性的数据比较提供了很好的经验,具有较好的实际应用价值。     

Scalar-tensor cosmology for traceless matter field in the large coupling function limit

Scalar tensor (ST) theories of gravitation contain an attractor mechanism towards general relativity. The mechanism is supposed to start back at time of inflation. Consequently the characteristic coupling function of the ST theories could attain a very large value during the radiation epoch. Here ST cosmology in the radiation dominated universe is studied under such situation. A general solution of the scale factor in the radiation dominated flat universe is obtained that is characterized by an additional degree of freedom. An implication of this extra parameter is discussed.      

辽宁水泉金矿成矿规律及矿山远景评价

用综合信息矿产资源定量预测的理论和方法，系统研究了辽宁水泉金矿成矿规律及控矿因素，特别是对控矿构造特征作了深入的研究，并建立了研究区的综合信息找矿模型。对水泉金矿的区域成矿远景和深部成矿远景进行了综合预测。     

新疆小热泉子铜(锌)矿床同位素研究

小热泉子矿床是我国最近发现的一个中型富铜(锌)矿床,其矿床成因为众多的矿床学家所关注.本文对该矿床中不同类型矿石、矿物的S、O、H、Si及稀有(惰性)气体He、Ar同位素特征作了较祥细的论述,同时用K-Ar法对硫化物的年龄测定进行了初步尝试.该矿床硫化物的δ34S值为+1.5‰~+11.1‰,平均为6.15‰(46);3He/4He(初始)值为5×10-8~2.17×10-6,平均为0.64×10-6(6),40Ar/36Ar值为305.27~439.81,平均为353.57(6);容矿岩中石英的δ18O值为+7.5‰~+11.7‰,平均为9.23‰(8),δ30Si值为0~-0.8‰,平均为-0.3‰(8);δD值为-66‰~-121‰,平均为-97‰(3).硫化物的K-Ar法年龄主要为339.1Ma、230.2Ma及98.4Ma,这些数据均显示出该矿床的成矿物质具壳幔混合的特征,矿床的形成具同生及多次成矿作用的特点.上述资料为该矿床的成因研究提供了重要的同位素信息.