Intra‐annual variation of the calcite deposition rate of drip water in Shihua Cave,Beijing, China and its implications for palaeoclimatic reconstructions     

BINGGUI CAI  JIAN ZHU  FENGMEI BAN  MING TAN 《Boreas: An International Journal of Quaternary Research》2011,40(3):525-535

Cai, B., Zhu, J., Ban, F. & Tan, M. 2011: Intra‐annual variation of the calcite deposition rate of drip water in Shihua Cave, Beijing, China and its implications for palaeoclimatic reconstructions. Boreas, Vol. 40, pp. 525–535. 10.1111/j.1502‐3885.2010.00201.x. ISSN 0300‐9483. Monthly in situ monitoring of the calcite deposition rate, drip‐water chemistry and surrounding cave environment was carried out at Shihua Cave, Beijing, China, through two hydrological years (from January 2006 to February 2008) to determine the seasonal variability and mechanisms of stalagmite growth in Shihua Cave. Calcite deposition rates exhibit significant intra‐annual variation, with the lowest values during the summer monsoonal rainy season (July–August) and peak values from autumn to spring. The temporal change in the calcite deposition rate is negatively correlated with the drip rate, cave‐air PCO₂ (CO₂ partial pressure) and Ca concentration, and positively correlated with the pH of the feeding drip water. The seasonal recharge regime of drip water is likely to be the primary control on the drip‐water quality and quantity, which, in turn, control the calcite deposition rate in Shihua Cave. During the summer rainy season, periodic and intense rainstorms increase the drip rate and cave‐air PCO₂, leading to drip water with a lower pH and saturation index of calcite, thereby reducing the calcite precipitation. It seems that the high cave‐air PCO₂ is the dominant control on the calcite deposition rate during the rainy season. Our previous study on the dissolved organic carbon of drip water concluded that the thin luminescent bands in stalagmite laminae from Shihua Cave form during the rainy season. The lower calcite deposition rate during the rainy season further supports this suggestion. The significant intra‐seasonal variability of the calcite deposition rate implies that the seasonal bias of δ¹⁸O of stalagmites should be considered when stalagmite δ¹⁸O is used as a high‐resolution palaeoclimatic archive.  相似文献   

云南罗平地区中三叠世龙鱼化石的发现   总被引：1，自引：0，他引：1  

张启跃  周长勇  吕涛  白建科 《地质通报》2010,29(1):26-30

记述了龙鱼属一新种,即云南龙鱼Saurichth ysyunnanensis sp.nov.。该种以具有长椭圆形的鳃盖骨、躯干部披6列鳞片为特征与其他种区别。化石产于云南省罗平县大凹子村中三叠世安尼期关岭组中。  相似文献   

沂河湿地规划设计初探   总被引：1，自引：1，他引：0  

王媛媛  陆发利  令狐荣钢  班誉峰  陈雪 《湿地科学与管理》2011,7(2):17-21

沂河纵贯临沂全境,湿地资源丰富,总面积达1.33万hm2。以建设大沂河湿地保护区为总体目标,沿河梯次设立湿地公园,全面加强沂河湿地生物多样性保护,维护湿地生态系统的生态特性和基本功能,保持和最大限度地发挥沂河湿地生态系统的各种功能和效益,力争使大沂河湿地最终以生态沂河湿地、人文沂河湿地、科普沂河湿地的面貌成为临沂大地又一靓丽的城市名片。  相似文献   

地震应急响应系统设计与实现   总被引：2，自引：0，他引：2  

班亚  王喜娜  马兰 《测绘科学》2014,39(11):57-61

文章应用开源GIS软件OpenScales、GeoServer、PostGIS/PostgreSQL等,以震区基础地理信息数据和地震基本参数作为数据源,构建了基于开源GIS软件的地震应急响应系统.系统在获得地震基本参数之后快速计算地震烈度分布,通过烈度分布分析地震影响区域的道路损毁情况和防护目标、危险源的分布,同时为决策者提供最佳救援线路,可以对救援物资和救援力量进行态势标绘,为应急指挥决策和救援行动提供有效的支持.  相似文献   

断层气测量用于银川地堑隐伏断裂活动性的研究   总被引：1，自引：0，他引：1  

焦德成  潘祖寿  王增光  何开明  班铁 《防灾减灾学报》2012,28(3):41-47

在系统分析银川地堑活动构造、物探、地震及航卫片解译的基础上,对其内部两条主要隐伏活动断裂进行气氡、气汞测量和分析,结合地堑构造环境、地震活动性,对断层气测量结果用于隐伏断裂的活动性做出了分析。  相似文献   

SARMA法在吉家河Ⅰ号滑坡稳定性分析中的应用     

班凤其  陈海明  王道轩  张洪涛 《安徽地质》2005,15(4):298-300

采用SAPRMA法,在充分考虑岩土参数、各种特殊结构（断层、层面）、地下水、地震等综合因素的基础上,对吉家河Ⅰ号滑坡进行稳定性分析,得出不同条件下滑坡的安全系数,为工程实际提供参考。  相似文献   

大陆岩石圈、地幔底部异常体与地幔对流相互作用的数值模拟          下载免费PDF全文

杨亭  傅容珊  黄川  班磊 《地球物理学报》2014,57(4):1049-1061

在地球表层存在着占地表面积约30%的具有低固有密度、高黏度的大陆岩石圈.由于其特殊的物理化学性质,大陆岩石圈通常不直接参与下方的地幔对流,但其与地幔对流格局有着重要的相互影响.大量研究显示,在中太平洋和非洲的下地幔底部,存在着两块占核幔边界（CMB）面积约20%的高密度热化学异常体（由于其剪切波速度较低,常称作低剪切波速度省（LSVPs））.LSVPs的演化既受地幔对流的影响,同时也影响地幔物质运动的格局和动力学过程.本文系统研究了存在大陆岩石圈,下地幔LSVPs的地幔对流模型.模拟结果显示：（1）当大陆体积较小时,其边缘常伴随着俯冲,大陆区域地幔常处于下涌状态,其上地幔温度较低,大陆岩石圈在水平方向处于压应力状态.随着大陆体积的增大,大陆边缘的俯冲逐渐减弱,大陆区域地幔由下涌转为上涌,其上地幔温度较高,大陆岩石圈水平方向处于拉应力状态.（2） 岩石圈与软流圈边界（LAB）在大陆下方较深,温度较低;在海洋区域较浅,温度较高.随着大陆体积的增大,陆洋之间LAB深度、温度的差异逐渐减小.（3）大陆区域地幔底部LSVPs物质的丰度与大陆的体积呈正相关.当大陆体积较小时,大陆下方的LSVPs丰度比海洋区域少.随着大陆体积的增大,大陆下方LSVPs的丰度逐渐增大.（4）海洋地区地表热流高,且随时间波动大,大陆地区地表热流低,随时间波动较小;LSVPs区域的核幔边界热流低.  相似文献   

雷达-雨量计-粒子激光探测仪联合估算降水量   总被引：3，自引：2，他引：1  

房彬  班显秀  郭学良 《大气科学》2010,34(3):513-519

为了提高区域降水量观测的空间分辨率, 提出了雷达-雨量计-粒子激光探测仪联合校准法。首先, 利用粒子激光探测仪观测到的滴谱资料建立实时的Z-I关系, 然后, 利用变分法对同时有雷达回波和雨量计资料的点的实测校准因子进行校准, 获得最优校准因子分析场, 最后, 对有雨量计的点取雨量计实际观测值, 没有雨量计的点利用最优校准因子分析场估算降水。利用此方法对辽宁省2007年5月15日一次天气过程进行降水量估算, 结果表明: 雷达-雨量计-粒子激光探测仪联合校准法结合了雨量站观测资料单点精度高和雷达资料时空分辨率高的优点, 提高了降水量的估算精度, 更好地反映了降水的空间分布。  相似文献   

CINRAD/SC天气雷达发射系统反峰过流故障与排除     

李洋  班显秀  刘小东  张维全  万绪江  卢秉红  朱轶明 《辽宁气象》2012,(5):71-74

概述CINRAD/SC新一代天气雷达发射系统调制器的组成和工作原理,以新一代天气雷达一次＂反峰过流＂故障为例,根据故障检查方法和排除故障的全过程,对故障产生原因进行分析。结果表明：＂反峰过流＂故障主要原因为发射系统的脉冲变压器次级匝间短路,造成调制器失配,反峰电流激增,烧毁保护电阻,引起电流继电器动作,形成＂反峰电流保护＂并切断高压,输出＂反峰过流＂故障。更换脉冲变压器铁芯及绕组,注入新的25号变压器油,开机测试,各项技术指标均正常,故障排除,保障了雷达系统的正常运行。  相似文献   

Re-recognition of the Dajiuhu Wetland in Shennongjia Mountains,Central China     

XIAO Fei  DU Yun  XUE Huaiping  LING Feng  BAN Xuan 《湿地科学》2012,10(3):278-284

The Dajiuhu wetland,a famous sub-alpine wetland located in the the Shennongjia Mountains,north-subtropical region of Central China,has suffered from adverse impacts of unsustainable human practices over the past 60 years.The Dajiuhu wetland reflects the development process that has been accompanied by human activities.Based on field survey data,high resolution remote sensing image and historical records,the present paper provided a review on exploitation and restoration of the wetland.The results showed that the Dajiuhu wetland degraded quickly from 1950 to 2005.During that time,bog shrinkage,lake disappearance,biodiversity decline,sphagnum reduction,and vegetation succession from wetland communities to terrestrial communities in the Dajiuhu wetland,which were the main manifestations of the wetland degradation.Human activities,such as agricultural reclamation and construction of drainage works,have been the main factors resulting in ecological degradation of the wetland since 1986.Poverty and the short-term economic benefits had been the driving forces for wetland drainage and reclamation over the past years.  相似文献