青海玉树莫海拉亨铅锌矿床S、Pb、Sr-Nd同位素组成: 对成矿物质来源的指示——兼与东莫扎抓铅锌矿床的对比

青海玉树地区莫海拉亨铅锌矿床和东莫扎抓铅锌矿床均位于青藏高原金沙江缝合带和班公湖-怒江缝合带夹持的羌塘地体东北缘,是"三江"北段铜铅锌多金属成矿带铅锌矿床的2个典型代表。笔者曾通过对东莫扎抓铅锌矿床的S-Pb-Sr-Nd同位素组成特征研究,认为其成矿物质来源于沉积地层。本文在野外地质观察基础上,亦对莫海拉亨铅锌矿床的矿石矿物和重晶石进行了S同位素组成分析,对矿石矿物、脉石矿物和区域地层进行了Pb同位素组成分析,对脉石矿物进行了Sr-Nd同位素组成分析。分析结果表明,硫化物δ³⁴S值为-30.0‰~7.4‰,峰值为-18‰~-2‰,反映了总体富轻硫的特征,而重晶石δ³⁴S值为20.2‰~+24.2‰,来自于第三纪陆相盆地。宽的δ³⁴S变化可以解释为流体在盆地内活动期间与不同地层单元发生相互作用,从而继承了不同物质单元的S同位素特点,还原硫应主要来自于硫酸盐的细菌还原或者含硫有机质的热还原,反映硫来自沉积盆地。矿石矿物的²⁰⁶Pb/²⁰⁴Pb、²⁰⁷Pb/²⁰⁴Pb和²⁰⁸Pb/²⁰⁴Pb分别为18.298~18.694、15.298~15.721、38.169~38.894,而脉石矿物的²⁰⁶Pb/²⁰⁴Pb、²⁰⁷Pb/²⁰⁴Pb和²⁰⁸Pb/²⁰⁴Pb分别为18.418~18.672、15.418~15.719、38.403~38.845。矿石矿物和脉石矿物的Pb同位素组成介于区域上地壳Pb组成范围内,总体类似于MVT矿床,显示Pb等金属元素来源于上地壳岩石。脉石矿物的(⁸⁷Sr/⁸⁶Sr)_i、ε_Sr(t)、(¹⁴³Nd/¹⁴⁴Nd)_i和ε_Nd(t)分别为0.70851~0.70906、57.4~65.2、0.512265~0.512361、-6.5~-4.6。Sr-Nd同位素特征亦显示脉石矿物的物质来源于上地壳岩石。总体来说,莫海拉亨铅锌矿床的S-Pb-Sr-Nd同位素特征均与东莫扎抓铅锌矿床的一样,显示均来自沉积地层。并结合矿床地质特征和地球化学特征,讨论了莫海拉亨铅锌矿床和东莫扎抓铅锌矿床形成的动力学背景。     

Origin and source regions of PM10 in the Eastern Mediterranean atmosphere

A set of daily PM₁₀ (n = 281) samples collected from April 2001 to April 2002 at a rural site (Erdemli), located on the coast of the Eastern Mediterranean, were analyzed applying Mass Closure (MC), absolute principal factor analysis (APFA) and Positive Matrix Factorization (PMF) to determine source contributions. The results from the three techniques were compared to identify the similarities and differences in the sources and source contributions. Source apportionment analysis indicated that PM₁₀ were mainly originated from natural sources (sea salt + crustal ≈ 60%) whilst secondary aerosols and residual oil burning accounted for approximately 20% and 10% of the total PM₁₀ mass, respectively. Calculations for sulfate showed that on average 8% and 12% of its total concentration were originated from sea salt and biogenic emissions, respectively. However, the contribution by biogenic emissions may reach up to a maximum of ~ 40% in the summer. Potential Source Contribution Function (PSCF) analysis for identification of source regions showed that the Saharan desert was the main source area for crustal components. For secondary aerosol components the analysis revealed one source region, (i.e. the south-Eastern Black Sea), whereas for residual oil, Western Europe and the western Balkans areas were found to be the main source regions.     

Tracing suspended sediment and particulate phosphorus sources in catchments

Information on suspended sediment and particulate P (PP) sources is an important requirement in many catchment-based diffuse source pollution studies, in order to assist with model validation and to provide information to support the development of effective sediment and phosphorus control strategies. Such information is, however, frequently unavailable or difficult to assemble. In the study reported, source fingerprinting procedures were successfully used to assemble this information for seven sub-catchments in the Hampshire Avon catchment and five sub-catchments in the Middle Herefordshire Wye catchment. The results provide important new information on the relative importance of the contributions from surface and channel/subsurface sources to the suspended sediment and PP fluxes from the catchments. In the Wye sub-catchments channel/subsurface sources contributed 40–55% of the overall suspended sediment flux and 21–43% of the PP flux from the catchments. Equivalent values for the Avon were 1–41% and 1–54%, respectively. Combination of the information on the relative importance of surface and channel/subsurface sources with measured suspended sediment fluxes has provided the first estimates of the specific fluxes of sediment and PP attributable to channel/subsurface sources for UK catchments. The former are as high as 15–20 t km⁻² year⁻¹ in some of the Wye sub-catchments, whereas the latter exceeded 0.1 kgP ha⁻¹ year⁻¹ in the same sub-catchments. The results emphasize the need to take account of potential contributions from channel/subsurface sources when using measured suspended sediment and PP flux data to validate predictions derived from models incorporating only surface contributions.     

地震前兆复杂性成因机理研究的讨论（二）：地震前兆复杂性成因机理

针对前兆复杂性的种种表现,作从震源、构造应力场、断裂力学、前兆监测等方面探讨了前兆复杂性产生的可能原因。认为前兆复杂性是客观存在的,与共性一起构成前兆的二重性,因此在研究前兆时,既要研究共性,也要研究复杂性,才能更好地掌握或认识前兆。同时从复杂性中再寻求普遍性,进一步完善孕震理论和开发新的分析预报方法;造成前兆复杂性的根本原因是孕震的物理力学过程的复杂性,其中包括地质构造、孕震环境、动力学过程、     

PM10 Source Apportionment in Ahvaz,Iran, Using Positive Matrix Factorization

Source apportionment of particulate matter <10 µm in diameter (PM₁₀), having considerable impacts on human health and the environment, is of high priority in air quality management. The present study, therefore, aimed at identifying the potential sources of PM₁₀ in an arid area of Ahvaz located in southwest of Iran. For this purpose, we collected 24‐h PM₁₀ samples by a high volume air sampler. The samples were then analyzed for their elemental (Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Se, Si, Sn, Sr, Li, Ti, V, Zn, Mo, and Sb) and ionic (NH, Cl^?, NO, and SO) components using inductively coupled plasma optical emission spectrometry and ion chromatography instruments, respectively. Eight factors were identified by positive matrix factorization: crustal dust (41.5%), road dust (5.5%), motor vehicles (11.5%), marine aerosol (8.0%), secondary aerosol (9.5%), metallurgical plants (6.0%), petrochemical industries and fossil fuel combustion (13.0%), and vegetative burning (5.0%). Result of this study suggested that the natural sources contribute most to PM₁₀ particles in the area, followed closely by the anthropogenic sources.     

京西北地区地应变观测与小震震源机制解一致性研究

以京西北地区作为研究区域,采用应变参数方法解算定点地应变观测数据,将所得应变参数时间序列作为研究对象,利用该结果与研究区内同期小震震源机制解进行一致性分析,研究得出呈拉张性质的定点观测最大主应变方位与震源机制解最大拉张变形方向（T轴）水平投影具有良好的对应性,整体以NNW—NE向为主,且自西向东排布的测点最大主应变方位与震源机制解最大拉张变形方向均表现为逐渐东向偏移的趋势,与华北平原块体北部发生顺时针旋转活动的特征相吻合,结果进一步检验了地应变观测反映区域应变场信息的能力。     

2019年12月26日湖北应城M4.9地震震源参数及余震活动性研究

2019年12月26日湖北应城发生M4.9有感地震,其震感波及武汉大部分地区。为了分析该地震的发震构造及余震活动性,本文利用波形拟合方法测定了不同速度模型下该地震的震源机制解和矩心深度,并用Bootstrapping抽样反演技术评价反演结果;此外,利用模板匹配技术匹配主震和目录余震波形,获取了更为完整的余震目录。结果显示,应城地震以走滑为主,矩心深度7.5km左右,矩震级M_W4.67;应城地震有1个前震和17个余震,余震序列缺少M2~4事件,表明应城地震为孤立型地震,M2以下地震的b值为0.8。     

钾盐矿床的物质来源和成矿机制

讨论钾及其有关物质的理化性质和地化行为，钾盐的物质来源，盐卤的变质、结晶分异、成矿条件和机制。富钾热液是形成钾盐矿床的重要物质来源之一。矿物岩石流体包裹体的富钾成分、富钾热泉、富钾盐湖均是寻找钾盐矿床的重要指示。     

贝尔凹陷“源断势”对油成藏与分布的控制作用

为了研究贝尔凹陷源岩、断裂和势能场(简称“源断势”)控藏模式,采用油藏分布与源、断、势叠合方法,分别对油成藏、分布控制作用和控藏模式进行了研究,结果得到:1)南一段油源区控制着油藏形成与分布的范围;2)低势区控制着油聚集的部位;反向断裂翘倾隆起的低势区控制着南屯组和铜钵庙组油聚集成藏,反转构造低势区控制着大磨拐河组油聚...     

1901—2018年三江源地区大气冻融指数变化特征

三江源地区是我国重要生态安全屏障,冻土是其高寒生态系统的重要组成部分,冻土的变化深刻影响高寒生态系统固碳及水源涵养。基于英国东英吉利大学(University of East Anglia,UEA)气候研究中心(Climatic Research Unit,CRU)月平均气温再分析资料,利用线性倾向法和滑动平均法并结合GIS空间分析和制图,计算并分析了三江源地区1901—2018年冻融指数变化趋势及其空间分布特征。结果表明:三江源地区冻结指数在1901—2018年整体以-1.1℃·d·a^-1的斜率呈波动减少趋势,经历了三个波动变化阶段:1901—1943年的下降(-3.4℃·d·a^-1)、1943—1966年的升高(8.8℃·d·a^-1)、1966—2018年的再次下降(-4.3℃·d·a^-1)。融化指数与冻结指数的变化相反,整体以0.34℃·d·a^-1的斜率呈波动上升趋势,呈现升高(1901—1943年,3.3℃·d·a^-1)、下降(1943—1981年...