Site formation processes at Donggutuo: a major Early Pleistocene site in the Nihewan Basin,North China     

Zhenxiu Jia  Shuwen Pei  Alfonso Benito‐Calvo  Dongdong Ma  Laura Sanchez‐Romero  Qi Wei 《第四纪科学杂志》2019,34(8):621-632

Understanding site formation processes is crucial for interpreting archaeological context patterns and hominin behaviour as these affect the preserved condition of a site and the integrity of archaeological remains. The fluvio‐lacustrine sequences in the Nihewan Basin of North China are rich sources of early Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adapted behaviours in East Asia. Although many Palaeolithic sites have been reported from the Nihewan Basin, North China, few of them focus on site formation processes before interpreting the hominin behaviour patterns. Here, we present a site formation study of four archaeological layers (Layers 6D, 6C, 6B and 6A) in Trench 1 from the Donggutuo (namely DGT‐T1) site in the Nihewan Basin with an age of 1.1 Ma. Through the study of sedimentary contexts, spatial distributions of artefacts and fossils, intra‐assemblage category ratios, debitage size distributions, lithic abrasion, artifact orientation and planar dip, our results show that all the layers had been disturbed by low‐energy sheet wash across the lake shore setting, but to differing extents. The post‐depositional disturbance caused by water decreased from the lower to the upper layers, from Layer 6D to Layer 6A. This indicates that the archaeological remains in DGT‐T1 have not been subject to significant natural modifications and are thus suitable for studying early hominin behaviour in North China. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   

基于地震背景噪声监测山东临沂地区地下水位变化     

顾悦  裴烁瑾  梁姗姗  樊春燕  周元泽 《中国地震》2021,37(4):857-867

选取山东省临沂地区的JUN与JUX台站数据资料,运用背景噪声互相关技术计算了2009年1月1日—2011年1月1日台站对间的互相关函数,利用移动窗互谱法计算相对速度变化,并分析其与莒县气象观测站记录的降水和莒南鲁14号井记录的地下水水位变化的关联性。研究结果表明,区域降水呈季节性变化,夏季降水量大,冬季降水量小;地下水水位呈季节性变化,初夏季水位较低,随后水位值逐渐增加,初冬季水位较高,随后水位值逐渐减少;地下介质速度变化亦具有季节性特征,变化幅度约为±0.2%,与水位变化呈一定的负相关趋势,即夏季水位增加、相对速度变化降低,冬季水位减少、相对速度变化升高。  相似文献   

微生物胶结橡胶土性能试验研究     

尤浩  王伟岩  陶元洪  李沛  周启文 《华南地震》2021,41(3):26-32

橡胶土都是一种常用的减震材料,但是强度较低.采用MICP技术胶结掺入3％以内的橡胶粉末砂土,试验研究了微生物胶结后橡胶砂土单轴抗压强度、循环加卸载作用特性及其微观结构.研究表明微生物胶结后横波波速和试样密度随橡胶含量增加而增加,其单轴抗压强度变化不大,受橡胶含量影响较小.随加卸载循环次数增加,微生物胶结橡胶粉末砂土阻尼比和滞回环面积逐渐减小,但是其刚度变化较小.相同加卸载循环次数条件下,微生物胶结橡胶粉末砂土阻尼比、滞回曲线面积及其刚度随橡胶粉末含量增加而增加.在微生物胶结橡胶粉末砂土中砂土胶结颗粒间,橡胶粉末与碳酸钙晶体形成了具有一定微观强度的蜂窝孔状结构,有利于缓冲砂颗粒在外界动荷载作用的位置变动,吸收砂颗粒传递过来的能量,从而起到减震作用.  相似文献   

Study on Gyroscopic Effect of Floating Offshore Wind Turbines     

CHEN Jia-hao  PEI Ai-guo  CHEN Peng  HU Zhi-qiang 《中国海洋工程》2021,35(2):201-214

Compared with bottom-fixed wind turbines,the supporting platform of a floating offshore wind turbine has a larger range of motion,so the gyroscopic effects of the system will be more obvious.In this paper,the mathematical analytic expression of the gyroscopic moment of a floating offshore wind turbine is derived firstly.Then,FAST software is utilized to perform a numerical analysis on the model of a spar-type horizontal axis floating offshore wind turbine,OC3-Hywind,so as to verify the correctness of the theoretical analytical formula and take an investigation on the characteristics of gyroscopic effect.It is found that the gyroscopic moment of the horizontal axis floating offshore wind turbine is essentially caused by the vector change of the rotating rotor,which may be due to the pitch or yaw motion of the floating platform or the yawing motion of the nacelle.When the rotor is rotating,the pitch motion of the platform mainly excites the gyroscopic moment in the rotor’s yaw direction,and the yaw motion of the platform largely excites the rotor’s gyroscopic moment in pitch direction,accordingly.The results show that the gyroscopic moment of the FOWT is roughly linearly related to the rotor’s inertia,the rotor speed,and the angular velocity of the platform motion.  相似文献   

PRELIMINARY STUDY ON THE CAVE DEVELOPMENT AND ENVIRONMENTAL BACKGROUND OF HOMININ OCCUPATION AT BAILONG CAVE,YUNXI COUNTY, HUBEI PROVINCE     

Li Xiaoli  Wu Xianzhu  Pei Shuwen 《第四纪研究》2012,32(2)

湖北省郧西县白龙洞是20世纪70年代发现的一处重要的中更新世古人类遗址,先后经过4次正式发掘,除出土7枚直立人牙齿化石和60余件石制品外,还有2件骨制品和29种伴生哺乳动物化石.本文对白龙洞洞穴发育进行分析,对堆积物的粒度、磁化率、粘土矿物、氧化物和哺乳动物群等进行分析和测试.结果表明,白龙洞发育起始于上新统沙坪组碳酸盐岩和下伏中元古界武当山群变质岩系不整合接触面,洞穴围岩为沙坪组砾岩、藻灰岩和生物格架灰岩;洞穴发育初期由沿不整合面渗流的裂隙水引起,之后垂直渗流为溶蚀的主要方式.洞穴堆积物主要为红色粘土,形成于北亚热带-暖温带温暖湿润环境,堆积物充填早期气候相对较为干凉,后期逐渐转为相对温暖湿润的森林草原环境,动植物资源繁盛,有利于古人类生存和活动.白龙洞古人类生存环境的研究对揭示鄂西-三峡地区中更新世古人类生存环境背景具有重要意义.  相似文献   

东昆仑东段晚古生代—中生代若干不整合面特征及其对重大构造事件的响应   总被引：14，自引：0，他引：14       下载免费PDF全文

李瑞保  裴先治  李佐臣  刘战庆  陈国超  陈有炘  魏方辉  高景民  刘成军  裴磊 《地学前缘》2012,19(5):244-254

地层不整合接触是研究地质发展历史和鉴定地壳运动特征的重要依据。通过大范围露头尺度和填图尺度不整合面的识别,结合不同时代地层沉积体系的特征及构造变形样式的对比研究,发现东昆仑造山带东段晚古生代—中生代地层由底到顶共发育有4个不同类型的不整合面,分别是上二叠统格曲组与上石炭统浩特洛哇组之间的角度不整合面、中三叠统希里可特组与闹仓坚沟组之间的微角度不整合面、上三叠统八宝山组与下伏不同时代地层之间的角度不整合面、下侏罗统羊曲组与上三叠统八宝山组之间的平行不整合面。这几个不同时代的不整合面分别代表了东昆仑东段晚古生代—中生代地质演化时期中特定的构造事件。其中,格曲组与浩特洛哇组角度不整合关系代表东昆仑造山带南缘阿尼玛卿—布青山古特提斯洋晚二叠世开始向北俯冲的构造事件;希里可特组与闹仓坚沟组微角度不整合关系与陆(弧)陆局部差异性初始碰撞的洋陆转换构造事件密切相关;八宝山组与下伏不同时代地层角度不整合关系是东昆仑地区分布较广、意义重大的一个不整合面,代表中三叠世晚期—晚三叠世早期东昆仑地区陆(弧)陆全面碰撞的主造山构造事件,同时该期碰撞造山事件铸就了东昆仑及其周缘地区的基本构造格架。羊曲组与八宝山组之间平行不整合面则与晚三叠世晚期—早侏罗世早期陆内演化过程中地壳垂向抬升事件相关。这些不整合面的厘定及其代表的相应构造事件对于合理建立东昆仑地区晚古生代—中生代构造演化过程具有重要意义。  相似文献   

德兴铜厂斑岩铜矿成矿流体演化特征   总被引：1，自引：0，他引：1  

姚静  倪培  赵葵东  王洪涛 《矿物岩石地球化学通报》2012,31(2):97-104

为探讨成矿流体的特征和演化过程,对德兴铜厂斑岩铜矿床不同蚀变—矿化带石英细脉中的流体包裹体进行详细的岩相学观察、显微测温、显微激光喇曼探针工作.结果显示,德兴铜厂斑岩铜矿主要有三类流体包裹体:富液相包裹体(Ⅰ型),富气相包裹体(Ⅱ型)、多相包裹体(Ⅲ型);成矿早期的Ⅰ型包裹体,主成矿期的Ⅱ型和Ⅲ型包裹体,以及成矿晚期的Ⅰ型包裹体的平均均—温度和平均盐度分别为:481℃,8.1％; 410℃,1.2％;389℃,56％和215℃,3.1％;主成矿期的Ⅱ型和Ⅲ型包裹体的平均均—温度相近,但盐度相差很大,指示了沸腾作用的发生;从早期到晚期,成矿流体呈现温度降低,挥发分逸出的趋势.  相似文献   

一井多层地下水监测井施工关键技术与设备   总被引：2，自引：0，他引：2  

林沛  夏孟  刘久荣  张建良  周涛  王家忠 《城市地质》2012,7(1):38-41

一井多层地下水监测井引入了westbay分层监测系统,实现了一井多层地下水监测,推动了地下水监测技术发展。一井多层监测井,在施工材料和施工工艺方面有所创新。  相似文献   

吉林延边金苍矿化带黄铁矿地球化学特征及找矿意义     

贾大成  唐烁  裴尧  高文  宋运红  郭威  张传乐 《吉林大学学报(地球科学版)》2012,(4):1069-1075

金苍是吉林延边中生代火山岩成矿带内的一个重要矿化区,矿化带内发育黄铁矿化,包括脉状细粒黄铁矿和浸染状粗粒黄铁矿2种类型,对这2种黄铁矿分别进行了主元素和微量元素分析。结果表明:2类黄铁矿主元素含量低于标准黄铁矿,属于硫亏损型,表现出深部、高温的形成环境;黄铁矿微量元素差异较大,为2个成矿期产物;Au及Ag的含量较低,以Cu、Pb、Zn为主,高温Ni相对Co的含量较高,反映其形成温度较高。黄铁矿既存在Co、Ni对Fe的类质同象替代,也存在As、Sb对S的类质同象替代。在与典型热液型金矿床黄铁矿对比后,显示金苍矿化带中黄铁矿不是与火山热液型金成矿有关的成分标型,更多地体现出Cu等金属的成矿特征。黄铁矿的成分地球化学特征不仅能较好地了解矿物的形成环境,而且可以为矿产勘查提供重要的找矿标志。  相似文献   

The characteristics and failure mechanism of the largest landslide triggered by the Wenchuan earthquake, May 12, 2008, China   总被引：9，自引：7，他引：2  

Runqiu Huang  Xiangjun Pei  Xuanmei Fan  Weifeng Zhang  Shigui Li  Biliang Li 《Landslides》2012,9(1):131-142

Strong earthquakes are among the prime triggering factors of landslides. The 2008 Wenchuan earthquake (M _w = 7.9) triggered tens of thousands of landslides. Among them, the Daguangbao landslide is the largest one, which covered an area of 7.8 km² with a maximum width of 2.2 km and an estimated volume of 7.5 × 10⁸ m³. The landslide is located on the hanging wall of the seismogenic fault, the Yingxiu–Beichuan fault in Anxian town, Sichuan Province. The sliding mass travelled about 4.5 km and blocked the Huangdongzi valley, forming a landslide dam nearly 600 m high. Compared to other coseismic landslides in the study area, the Daguangbao landslide attained phenomenal kinetic energy, intense cracking, and deformation, exposing a 1-km long head scarp in the rear of the landslide. Based on the field investigation, we conclude that the occurrence of the landslide is controlled mainly by the seismic, terrain, and geological factors. The special location of the landslide and the possible topographic amplification of ground motions due to the terrain features governed the landslide failure. The effects of earthquakes on the stability of slopes were considered in two aspects: First, the ground shaking may reduce the frictional strength of the substrate by shattering of rock mass. Second, the seismic acceleration may result in short-lived and episodic changes of the normal (tensile) and shear stresses in the hillshopes during earthquakes. According to the failure mechanism, the dynamic process of the landslide might contain four stages: (a) the cracking of rock mass in the rear of the slope mainly due to the tensile stress generated by the ground shaking; (b) the shattering of the substrate due to the ground shaking, which reduced the frictional strength of the substrate; (c) the shearing failure of the toe of the landslide due to the large shear stress caused by the landslide gravity; and (d) the deposition stage.  相似文献