Particle size distributions and organic-inorganic compositions of suspended particulate matters around the Bohai Strait     

Xiao Wang  Changwei Bian  Rong Bi  Wensheng Jiang  Hua Zhang  Xueqing Zhang 《中国海洋大学学报(英文版)》2017,16(1):25-34

Laser in situ scattering and transmissometry(LISST) significantly improves our ability to assess particle size distribu-tion(PSD) in seawater, while wide-ranging measurements of the organic-inorganic compositions of suspended particulate matters(SPM) are still difficult by using traditional methods such as microscopy. In this study, PSD properties and SPM compositions around the Bohai Strait(China) were investigated based on the measurements by LISST in combination with hydro-biological parameters collected from a field survey in summer 2014. Four typical PSD shapes were found in the region, namely right-peak, left-peak, dou-ble-peak and negative-skew shapes. The double-peak and negative-skew shapes may interconvert into each other along with strong hydrodynamic variation. In the upper layer of the Bohai Sea, organic particles were in the majority, with inorganic particles rarely observed. In the bottom layer, SPM were the mixture of organic and inorganic matters. LISST provided valuable baseline information on size-resolved organic-inorganic compositions of SPM: the size of organic particles mainly ranged from 4 to 20 μm and 40 to 100 μm, while most SPM ranging from 20 to 40 μm were composed of inorganic sediment.  相似文献   

黑龙江东部完达山地区水系沉积物地球化学特征及成矿预测          下载免费PDF全文

张国宾  杨言辰  梁冰  韩世炯  禚喜准  袁学旭 《中国地质》2017,44(3):588-603

完达山地区位于中国东北地区东部,主要由一套近南北走向的玄武岩、堆晶岩、(超)基性熔岩、硅质岩和泥质岩组成,为中国东部唯一的中生代海相地层发育区,出露有太平洋板块俯冲形成的增生杂岩组合。研究区矿产资源丰富,已发现中型矿床1处,小型矿床4处,找矿前景较好。在全区1∶20万水系沉积物测量基础上,对完达山地区16种成矿元素进行相关性分析、聚类分析、因子分析、单元素异常分析和组合异常分析。分析结果表明,Au、Ni、Cr、Bi、Hg异常高值点多、离散性强,地质及地球化学条件优越,成矿潜力强。Au成矿作用主要与中酸性岩浆岩相关,Ni、Cr成矿作用主要与(超)基性岩浆熔离作用相关。在此基础上,结合区内地质、构造、物探和已知矿床(点)等信息,优选出4处成矿远景区,即258高地金成矿远景区、八里桥—仙人台铜镍钨锡成矿远景区、四平山—358高地金银成矿远景区和跃进山—先锋北山金银铜铁成矿远景区,为完达山地区整体找矿工作部署和区域成矿规律研究提供科学依据。  相似文献   

Lake evolution and its implication for environ-mental changes in China during 1950?2000     

HUANG Zhihua  XUE Bi  YAO Shuchun  PANG Yong 《地理学报》2008,18(2):131-141

Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an im-portant role on the recent decades’ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume (water level, depth and area) in the eastern and western lake regions of China during 1950–2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect.  相似文献   

Study on the “beachrock field” in Haishan Island,Guangdong Province     

Bi Fuzhi  Yuan Youshen 《中国海洋湖沼学报》1988,6(4):343-357

Beachrocks like those in Haishan Island’s “beachrock field” are rarely found elsewhere. They contain typical cement-aragonite. The assemblages of foraminifera and ostracods show that they are typical littoral sediments, the middle and the lower beds of beachrocks being formed in the desalinized seawater, the upper bed in normal seawater. At least four coastal elevations and subsidences have occurred since Late Holocene. The amplitude of the last three subsidences increased each time and the sea coasts receded. Active elevation has been predominant since 600 years B.P. Periodical coastal elevation and subsidence in Fujian and Guangdong has been occurring for the past several thousand years. Each period was 500 years, 250 years of subsidence, 250 years of elevation. This study was financed by the Department of Science and Technology of the State Seismological Bureau and the Joint Seismological Science Foundation.  相似文献   

Book reviews     

Jiří Bičák  Hans Joachim Haubold 《Astrophysics and Space Science》1989,152(2):351-353

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远距离台风影响陕北突发性暴雨成因分析   总被引：27，自引：1，他引：27       下载免费PDF全文

井喜 贺文彬毕旭  艾丽华 《应用气象学报》2005,16(5):655-662

该文对2002年7月4～5日发生在陕西子长县受远距离台风影响而产生的突发性暴雨进行了诊断分析。结果表明:子长特大暴雨是由于β-中尺度强对流云团在子长重复出现而产生的。中低纬度系统的相互作用形成了有利于中尺度强对流云团在子长生成、发展和重复出现的水汽条件、不稳定条件、动力条件和天气尺度环流背景。湿位涡诊断分析表明:当台风向西北方向行进时, (1)暴雨区对流层低层MPV1负值发展的同时伴随对流高层MPV1正值的发展, 为对流层低层不稳定能量的充分积累创造了条件;(2)暴雨区形成有利于中尺度强对流云团生成发展的湿位涡正压项、斜压项垂直结构配置;(3)850 hPa等压面上MP V2等值线密集区和MPV1=-2 PVU中尺度强对流不稳定核心区形成耦合, 耦合区对下游中尺度强对流云团发生发展指示意义明显。当台风向北偏东方向行进时, 暴雨区对流层低层和高层形成双层不稳定;850 hPaMPV2等值线密集区东移, 暴雨区MPV2正值发展, 积累的对流不稳定能量在子长形成集中猛烈释放。  相似文献   

贵州烤烟气候适宜性分区研究   总被引：10，自引：0，他引：10  

童碧庆  帅士章  徐永灵  杨远恒 《贵州气象》2005,29(Z1):48-50

通过对优质烤烟气候条件和贵州省气候资源的简要分析,对贵州省烤烟气候适宜性进行分区,并对分区进行了评述.  相似文献   

Precise molybdenite Re–Os and mica Ar–Ar dating of the Mesozoic Yaogangxian tungsten deposit, central Nanling district, South China     

Jiantang Peng  Mei-Fu Zhou  Ruizhong Hu  Nengping Shen  Shunda Yuan  Xianwu Bi  Andao Du  Wenjun Qu 《Mineralium Deposita》2006,41(7):661-669

The Yaogangxian deposit in the central Nanling region, South China consists of vein-type ore bodies hosted in Cambrian to Jurassic strata and Mesozoic granitic intrusions. Wolframite and molybdenite are the dominant ore minerals intergrown with gangue minerals of quartz, feldspar, phlogopite, and muscovite. We have carried out molybdenite Re–Os and phlogopite and muscovite ⁴⁰Ar/³⁹Ar dating to better understand the timing and genesis of mineralization. Re–Os dating of eight molybdenite samples yielded model ages ranging from 152.0±3.5 to 161.1±4.5 Ma, with an average of 156.0 Ma. The Re–Os analyses give a well-defined ¹⁸⁷Re/¹⁸⁷Os isochron with an age of 154.9±2.6 Ma (MSWD=2.4). Hydrothermal phlogopite and muscovite display extremely flat ⁴⁰Ar/³⁹Ar age spectra. Phlogopite yields a ⁴⁰Ar/³⁹Ar plateau age of 153.0±1.1 Ma, whereas muscovite yields a plateau age of 155.1±1.1 Ma. Both ⁴⁰Ar/³⁹Ar ages are in good agreement with the Re–Os ages, placing the timing of tungsten mineralization at about 154 Ma. This age is consistent with the field relationships. Our new data, when combined with published geochronological results from other major deposits in this region, suggest that large scale W–Sn mineralization occurred throughout the central Nanling region in the Late Jurassic.  相似文献   

皖西白大山群的发现及其地质意义   总被引：7，自引：0，他引：7  

毕治国  李玉发  汤加富  侯明金 《安徽地质》1994,(Z1)

皖、豫交界的白大山－茶庵一带，出露一套碎屑岩夹碳酸盐岩地层，以往被置于青白口系八公山群。近期笔者等赴该地再次进行了调查和研究，结果发现该群地层组合内含有大量球藻类和植物碎片化石，这些微古植物分子在国内外多见于下古生代。并从岩石组合特征对比分析，认为该套地层属志留－泥盆系的可能性最大。对这套地层及微古植物的发现，具有两方面重要的地质意义：１．过去对华北地台南缘从未见有这个时代地层的报导，这就为该区地层填补了一个空白；２．从已采获的微古植物组合及岩性组合特征等分析，这有可能对华北地台南缘的岩相古地理图及地史发展等问题，进行一些必要的改写与补充。  相似文献   

The surge-like eruption of a miniature filament     

Jia-Yan Yang  Yun-Chun Jiang  Dan Yang  Yi Bi  Bo Yang  Rui-Sheng Zheng  Jun-Chao Hong 《天体物理学报》2012,(3):300-312

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