末次冰消期亚洲季风强度变化的黄土高原西部万象洞石笋灰度记录

基于对石笋扫描图像灰度值的提取和10个230Th年代数据,建立了末次冰消期万象洞石笋灰度变化时间序列.在17.6～12.8kaB.P.期间,石笋灰度值在千年-亚千年尺度上呈现出明显的9次增大(峰)和9次减小(谷)交替变化的特征.对比分析发现,万象洞石笋灰度与密度指数在高频变化上呈显著的负相关关系,石笋灰度值的减小对应于...     

动态海水中保护电位对钙质沉积层形成的影响

采用恒电位阴极极化和线性极化法研究了天然海水中不同动态条件、不同初始保护电位下,阴极保护初期碳钢表面钙质沉积层的形成规律。扫描电镜(SEM)和能谱X-射线分析(EDX)分析了保护后碳钢表面的产物。结果表明:-800 mV(vs.SCE,下同)保护电位下,在静态和动态海水中碳钢表面形成的钙质沉积层质量都较差;-900 mV保护电位下,静态海水中形成致密的钙质沉积层,动态下钙质沉积层形成困难;-1 000 mV保护电位下,静态和动态海水中都形成良好的钙质沉积层。随流速增大,阴极保护电流密度显著增大,钙质沉积层中Ca/Mg比值增加;动态条件下,较负的保护电位,有利于阴极保护初期钙质沉积层的形成。     

动态海水中保护电位对钙质沉积层形成的影响

采用恒电位阴极极化和线性极化法研究了天然海水中不同动态条件、不同初始保护电位下,阴极保护初期碳钢表面钙质沉积层的形成规律.扫描电镜( SEM)和能谱X-射线分析(EDX)分析了保护后碳钢表面的产物.结果表明:-800 mV(vs.SCE,下同)保护电位下,在静态和动态海水中碳钢表面形成的钙质沉积层质量都较差;-900 mV保护电位下,静态海水中形成致密的钙质沉积层,动态下钙质沉积层形成困难;-1 000 mV保护电位下,静态和动态海水中都形成良好的钙质沉积层.随流速增大,阴极保护电流密度显著增大,钙质沉积层中Ca/Mg比值增加;动态条件下,较负的保护电位,有利于阴极保护初期钙质沉积层的形成.     

一种深层地温的推算方法

根据热传导方程，利用差分方法计算导温系数，并用逐层下移温度初始场技术来推算深层各月平均地温，并通过计算个例加以对比分析。结果表明，该方法简单实用，计算精度有较大提高，效果令人满意。     

Pattern and origin of spherulites in a rhyolite dike swarm,northeastern Cheongsong, Korea

IntroductionThe northeastern Cheongsong area is underlainby a sequence of sedi mentary rocks together within-trusive and extrusive volcanic rocks all of late Creta-ceous age(Lee&Hong,1973;Ki m&Park,1970;Hwang,1998).Theintrusions,comprising astock,a plug and numerous dikes,are well exposedat the current surface due tothe enormous erosion ofany sedi mentary or volcanic covered rocks.Thedikes forma dike swarmand some are intruded intothe plug.The dikes swarm may represent the subsurfaceexpress…     

新疆西准噶尔地区不同尺度地质构造的遥感标识特征及找矿意义

哈图金矿、包古图斑岩型铜金钼矿、杨庄铍铀矿及加曼钼钨铜矿等大型矿床的相继发现,使西准噶尔地区的地质找矿工作备受关注。作为重点研究对象,西准噶尔地区的地质构造研究已获得大量成果。但是,该区地域辽阔且地质构造较为复杂,传统的地质学研究方法不可能快速、有效和完全准确的解决地质构造的空间分布及规模等问题。利用多种分辨率的卫星遥感数据,通过遥感标识体系的建立能够客观、准确获取不同尺度地质构造的空间位置及规模。宏观和中等尺度的断裂构造均以明显的直线或弧形等形态特征、光谱特征(色调差异)及断层谷地、断层陡坎等地貌特征为主要标识,但侧重点有所不同;微观尺度即矿集区尺度的断裂构造地貌上为笔直的短小沟谷,常常需用弱信息挖掘方法才能突出构造的线性信息。通过独特的形态特征可快速识别褶皱构造。根据环形影像特征、色调差异及环形水系特征可识别不同尺度的岩体和(或)隐伏岩体。因此,地质构造的遥感识别可为地质构造演化及成矿构造背景分析提供科学依据;为西准噶尔地区成矿带(亚带)划分、遥感找矿模型的建立及高效圈定靶区等提供准确的空间信息依据。     

Estimation of submarine groundwater discharge in the Il‐Gwang watershed using water budget analysis and 222Rn mass balance

Submarine groundwater discharges (SGD) were investigated in a marine watershed in south‐eastern Korea using water budget analysis and a ²²²Rn mass balance model. Multi‐layered TOPMODEL added hydrological assumption was used to estimate groundwater components in the water budget analysis. Field observations of soil moisture, rainfall, runoff and groundwater fluctuations were used for calibration and validation of the hydrologic model. Based on observed hydrological data and terrain analyses, parameters for the hydrologic model were delineated and used to describe several hydrologic responses in the watershed. SGD estimations by ²²²Rn mass balance method were also performed at Il‐Gwang bay in July, 2010, and May, June, July and Nov. 2011. The estimated groundwater through hydrologic modeling and water balance analysis was 1.3x10⁶ m³/year, which rapidly increased during typhoon season due to heavy rainfall and permeable geologic structure. The estimated groundwater was approximately 3.7–27.1% of SGD as evaluated by ²²²Rn mass balance method ranges 3.44 and 17.45 m³m^?2year^?1. Even though SGD is predominantly influenced by tide fluctuation, the head gradient (difference) from hydrologic processes associated with heavy rainfalls can also have extra significant influences. Comprehensive understanding of SGD evaluation can be improved through a simultaneous application of both these approaches. Copyright © 2013 John Wiley & Sons, Ltd.     

Spatial and temporal variations in nutrient and chlorophyll-a concentrations in the northern East China Sea surrounding Cheju Island

Nutrients, chlorophyll-a (Chl-a), and environmental conditions were extensively investigated in the northern East China Sea (ECS) near Cheju Island during five research cruises from 2003 to 2007. In the eastern part of the study area, surface waters were characterized only by the Tsushima Current Water (TCW) during all five cruises. However, the western surface waters changed with season and were characterized by the Yellow Sea Cold Water (YSCW) in spring, the Changjiang Diluted Water (CDW) in summer, and the Yellow Sea Mixed Water (YSMW) in autumn. In spring and autumn, relatively high concentrations of nitrate and phosphate were observed in the surface waters in the western part of the study area, where vertical mixing brought large supplies of nutrients from deep waters. Changes in wind direction occasionally varied the inflow of the Changjiang plume in summer, clearly causing the annual variation in surface nitrate and phosphate concentrations in summer. In summer, the surface distribution of nitrate and phosphate did not coincide with that of silicate in the study area, which probably resulted from the significant drop in the Si:N ratio in the Changjiang plume since construction of the Three Gorges Dam (TGD). Despite large temporal and spatial variations in surface Chl-a concentrations, depth-integrated Chl-a concentrations exhibited little variation temporally and spatially. In the study area, surface Chl-a concentration did not well reflect the standing stocks of phytoplankton. The vertical distribution of Chl-a showed large temporal and spatial variations, and the main factor controlling the vertical distribution of Chl-a in summer was the availability of nitrate. The thermohaline front may play an important role for accumulation of phytoplankton biomass in spring and autumn.     

西藏地温的年际和年代际变化

利用1971-2005 年西藏10 个站的0.8 m、1.6 m 和3.2 m 逐月平均地温资料,采用气候倾向率等现代统计诊断方法,研究了近35 年西藏年、季平均地温的变化趋势、气候突变和异 常年份。结果表明：0.8 m 年平均地温在西藏东部的林芝、昌都呈现为下降趋势,其他各站以0.19~0.81 ^oC/10a 的速率升高;有5 个站的1.6 m 年平均地温呈显著的升高趋势,升温率为 0.20~0.60 ^oC/10a;3.2 m 年平均地温6 个站均表现为升高趋势,为0.13~0.52 ^oC/10a,以拉萨升温率最大。在0.8 m 处,① 大部分站点季平均地温呈明显的上升趋势,其中西藏西部、南 部以夏季升幅最大,特别是狮泉河达1.61 ^oC/10a;北部以冬季增温最突出。东部地区四分之三的季平均地温呈降温趋势。② 大部分站点年平均地温呈逐年代升高趋势,而昌都表现为逐年代降低趋势。③ 狮泉河春、夏季平均地温分别在1996 年和1983 年发生了气候突变;拉萨和日喀则年、季平均地温发生的气候突变是从一个相对偏冷期跃变为一个相对偏暖期,前者 出现在20 世纪80 年代,后者发生在20 世纪90 年代初;而林芝1993 年夏、秋季出现的气候 突变是从一个相对偏暖期跃变为一个相对偏冷期。④ 西藏西部年、季平均地温以异常偏高年份居多,且发生在20 世纪末至21 世纪前5 年;南部年、季平均地温均为异常偏高年份,主要出现在20 世纪90 年代中后期;北部年、季平均地温异常偏高年均出现在21 世纪前5 年, 异常偏低年份以20 世纪80 年代居多;东部年平均地温以异常偏低年为主。青藏铁路沿线西藏境内测站最大冻土深度以-4.5~-25.4 cm/10a 的速率呈显著减小趋势,安多减幅最大