中国黄土与红色粘土记录的地磁极性界限及地质意义   总被引：13，自引：0，他引：13       下载免费PDF全文

岳乐平 《地球物理学报》1995,38(3):311-320

本文报道由蓝田、陕县、洛川、西峰、平凉、兰州及靖远等剖面获得的古地磁研究结果．主要结论为：１．中国黄土剖面记录了Ｂｒｕｎｈｅｓ正极性带与Ｍａｔｕｙａｍａ负极性带，Ｂｒｕｎｈｅｓ／Ｍａｔｕｙａｍａ极性转换过程位于第８层黄土（Ｌ８）．在段家坡黄土剖面该转换过程对应的地层厚度为０．３７５ｍ，持续时间约６０００ａ．转换过程由３次极性变化构成，每次经历的时间约为４００ａ．２．Ｊａｒａｍｉｌｌｏ正极性亚带（Ｊ）位于标志层Ｌ９至Ｌ１５之间，大约Ｓ１０－Ｓ１３位置．３．Ｏｌｄｕｖａｉ正极性亚带（Ｏ）对应的地层为Ｓ２７－Ｓ３３４．Ｒｅｕｎｉｏｎ正极性亚带（Ｒ）由两部分组成，在蓝田段家坡黄土剖面分别位于Ｌ３６和Ｓ３８５．Ｍａｔｕｙａｍａ负极性带与Ｇａｕｓｓ正极性带界限（Ｍ／Ｇａ）位于黄土和红色粘土交界处，中国黄土的底界年龄为２．４８Ｍａ左右．黄土与红色粘土为整合接触关系．６．黄土下伏的红色粘土记录了Ｇａｕｓｓ正极性带，Ｇｉｌｂｅｒｔ负极性带和古地磁年表编号５（Ｅｐｏｃｈ５）．  相似文献   

EUTROPHICATION AND RED TIDES AS CONSEQUENCES OF ECONOMIC DEVELOPMENT   总被引：4，自引：0，他引：4  

Zhao-Yin WANG  Yongsheng WU  and Guangqian WANG Prof.  Dept. of Hydraulic Engineering  Tsinghua University & International Research  Training Center on Erosion  Sedimentation  Beijing  China  Email: zywang@tsinghua.edu.cn or zywang@sun 《国际泥沙研究》2001,16(4)

1 mTRoorcnoxThe EnvirDment AgenCy of UK (l997) defins eUtIDPhication as "the enrichInnt of waters byinorgedc plant nUtrientS that result in the simulation of an mp Of syInPtOInati changes. These includethe inCrased PrOduCtiOn Of aigae or othe aquatic PlantS, affeChng the quallty of the water and distUIbingthe balance Of orpedsms Present within it. Such changes Inay be undesirable and intetw with wateuses." Sndth et al. (l999) indicated tha eopation of waters is mainly caused by h…  相似文献   

Environmental impact on construction limestone at humid regions with an emphasis on salt weathering,Al-hambra islamic archaeological site,Granada City,Spain: case study     

G. M. E. Kamh 《Environmental Geology》2007,52(8):1539-1547

Al-hambra is an immense and valuable archaeological site in Spain built on Sabika hill with red brick and natural sandy limestone. It exhibits weathering features indicating salt weathering process. The main aim of this study is to examine weathering processes and intensity acting on Al-hambra. Rock petrography and mineralogical composition have been examined using thin sections, scanning electron microscope, X-ray diffraction and X-ray fluorescence; limits of rock’s physical parameters using ultrasonic waves and mercury porosimeter; rock salt content through hydrochemical analysis. Salts attacking this structure are mainly from wet deposition of air pollutants on the long term chemical alteration of rock’s carbonate content to its equivalent salts. The salts’ concentration limit within the examined rock samples is considerably low but it is effective on the long run through hydration of sulphate salts and/or crystallization of chloride salts. Rock texture type and its silica as well as clay content reduces its resistance to internal stresses by salts as well as wetting and drying cycles at such humid area. The recession in limits of physical parameters examined for deep seated and weathered limestone samples quantitatively reflects weathering intensity on Al-hambra.  相似文献   

Comment on “Is there a paleolimnological explanation for ‘walking on water’ in the Sea of Galilee?”     

Matthias Prange  Helge Arz  Frank Lamy 《Journal of Paleolimnology》2007,38(4):589-593

In a recent paper, Nof et al. (J Paleolimnol 35:417–439, 2006) suggest a physical mechanism which could account for the formation of ice on Lake Kinneret (Sea of Galilee) in northern Israel. Based on the sea surface temperature record of sediment cores from the Mediterranean Sea the authors argue that centennial-scale cold events had the potential to trigger local ‘springs ice’ formation on the lake in the past. Here, we demonstrate that a closer inspection of the paleoceanographic record in combination with correlation and regression analyses of meteorological data provides no evidence for such cold events in the lake region during the last 10,000 years. Thus, the formation of ‘springs ice’ on Lake Kinneret was unlikely at least since the beginning of the Neolithic.  相似文献   

陶器资源——江西红土岩开发   总被引：4，自引：0，他引：4  

王平  彭人勇  周萍华 《华东地质学院学报》2001,24(2):131-134

依据江西红土岩物质组成特征及与宜兴紫砂土的相似性，对江西红土岩进行了较系统的陶器实验与研究。江西红土岩系的化学成分、矿物成分及工艺特征适合陶器要求。按其分布规律和物质组成特征可分成两类：酸性红土岩和碱性红土岩。在详细分析两类岩系工艺性质的基础上，对江西红土岩这一陶器资源进行了产品开发。  相似文献   

泥浆含砂率对桩基质量的影响     

宋明智  许谷星 《江西地质》2001,15(4):301-304

本文通过对泥浆中颗粒的沉降特性分析，从量上得出泥浆性能对泥浆中颗粒的悬浮携渣能力。泥浆是一流变性的流体，对泥浆性能的把握，应综合考虑，而不偏向于某个指标。提出了在实践中对泥浆的正确使用和泥浆性能取用的建议。  相似文献   

成槽作业中泥浆的护壁作用分析   总被引：1，自引：0，他引：1       下载免费PDF全文

李小青  潘鸿宝 《探矿工程》2001,(4):21-23

根据土层的物理力学性质、地下水位分析护壁泥浆对地下连续墙槽壁稳定性的影响，导出槽壁稳定性数学模型公式，并提出相应的护壁措施，防止槽壁的坍塌。  相似文献   

国内外泥浆材料的现状及发展趋势   总被引：7，自引：0，他引：7       下载免费PDF全文

何远信 《探矿工程》2001,(5):47-49

系统介绍了泥浆材料的现状及发展趋势，重点叙述了水基泥浆、油基泥浆及合成基泥浆这3大类泥浆材料的现状及发展趋势。  相似文献   

“科钻一井”一开泥浆技术          下载免费PDF全文

陈小明李传武  孙德宇李发东　和昔 《探矿工程》2001,(6):63-64

“科钻一井”一开井段采用了钠膨润土-高粘CMC泥浆体系，视漏失情况添加GD-Ⅲ随钻堵漏剂，满足了施工携带岩屑和堵漏防漏要求。介绍了该井一开井段的泥浆技术，并对泥浆成本进行了分析。  相似文献   

青藏高原东北部古喀斯特过程与环境   总被引：6，自引：0，他引：6  

崔之久  陈怀录 《地理学报》1996,51(5):408-417,T001

本文介绍了青藏高原东北部地区的古喀斯特现象，并对相关沉积进行了化学成、粘土矿物的Ｘ－射线衍射以及石英砂表面结构等气候代用指标的分析。分析结果一致，指示了温暖湿润的亚热带气候条件。重结晶方解石的裂变径迹测年结果表明，该地区古喀斯特发育于中中新世。  相似文献