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991.
The control of syndepositional faulting on the Eogene sedimentary basin fills of the Dongying and Zhanhua sags, Bohai Bay Basin 总被引:9,自引:0,他引:9
LIN Changsong ZHENG Herong REN Jianye LIU Jingyan & Qiu Yigang . Department of Energy Geology China University of Geosciences Beijing China . Petroleum Exploration Production Institute Sino-Petroleum Chemistry Cooperation Beijing China 《中国科学D辑(英文版)》2004,47(9)
CopyrightbyScienceinChinaPress2004Theconfigurationandpredictionofdepositionalsystemsinasedimentarybasinhavelongbeenoneofthemajortasksofbasinanalysisandsedimentarygeologicalresearch.Intermsofsequencestratigraphy,originallyestablishedinstudyoftectonicallytablecontinentalmargins,thesealevelchangehasbeenusedtoeffectivelyinterpretandpredictthedistributionandevolutionofdepositionalsystemsinthesebasins[1,2].Butintectonicallyactivebasins,tectonismmaycontrolpredominatelythearchitectureandevolutionofth… 相似文献
992.
993.
~(210) Po and ~(210) Pb are increasingly used to constrain particle dynamics in the open oceans, however they are less used in coastal waters. Here, distributions and partitions of ~(210) Po and ~(210) Pb were examined in the Taiwan Strait, as well as their application to quantify particle sinking. Activity concentrations of dissolved ~(210) Po and ~(210) Pb(0.6 μm)ranged from 1.21 to 7.63 dpm/(100 L) and from 1.07 to 6.33 dpm/(100 L), respectively. Activity concentrations of particulate ~(210) Po and ~(210) Pb varied from 1.96 to 36.74 dpm/(100 L) and from 3.11 to 38.06 dpm/(100 L). Overall,particulate ~(210) Po and ~(210) Pb accounted for the majority of the bulk ~(210) Po and ~(210) Pb. 210 Po either in dissolved or particulate phases showed similar spatial patterns to 210 Pb, indicating similar mechanisms for controlling the distributions of ~(210) Po and ~(210) Pb in the Taiwan Strait. The different fractionation coefficients indicated that particles in the Zhemin Coastal Current(ZCC) inclined to absorb 210 Po prior to 210 Pb while they showed an opposite effect in the Taiwan Warm Current(TWC). Based on the disequilibria between ~(210) Po and ~(210) Pb, the sinking fluxes of total particulate matter(TPM) were estimated to range from –0.22 to 3.84 g/(m2·d), showing an overall comparable spatial distribution to previous reported sediment accumulation rates. However, our sinking fluxes were lower than the sedimentation rates, indicating a sediment resuspension in winter and horizontal transport of particulate matter from the Taiwan Strait to the East China Sea. 相似文献
994.
Earth fissures in Jiangsu Province,China and geological investigation of Hetang earth fissure 总被引:1,自引:0,他引:1
Earth fissures are a geohazard in Jiangsu Province, China. They can be caused by earthquakes and active faults, underground
mining, groundwater extraction and landslides. In order to establish a provincial rehabilitation plan in Jiangsu, a range
of monitoring programs, surveys, geological investigations and modeling have been implemented or planned. One of the focuses
of the project is the land subsidence and earth fissures caused by excessive groundwater withdrawal in Suzhou, Wuxi and Changzhou
(Su-Xi-Chang) area, southern Jiangsu Province. Hetang earth fissure within the Su-Xi-Chang area was first reported in 1995
and a series of investigation has been conducted since then. The site investigations and geophysical survey in 1997 have recognized
the causative factor as the excessive groundwater drawdown coupled by the underlying bedrock ridge. An open trench excavation
in 2007 and a plane strain analysis suggest that Hetang earth fissures may have cracked from the bedrock ridge to ground surface.
Geological drilling in 2007 has further confirmed the existence and configuration of the ridge and extracted soil samples
for laboratory tests to obtain soil parameters for numerical analyses and modeling of land subsidence and earth fissures in
the Su-Xi-Chang area, Jiangsu, China. The laboratory tests are currently in progress and the result of numerical analyses
and modeling is expected to be presented in the near future. 相似文献
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1 INTRODUCTION In recent decades, red tides that induced by in- creasing eutrophication occur frequently in coastal areas worldwide. This has caused serious problems in marine environment, aquaculture industries and human health (Qi et al., 1993; Horner e… 相似文献
998.
999.
地震应变变化的理论量级与最大传递距离关系 总被引:1,自引:0,他引:1
为了与实际观测资料对比 ,用线弹性理论位错公式算出了各种断层的地震应变变化并进行了全面、系统的分析 ,归纳了一些特点 ,阐明了理论应变变化量级与其最大传递距离的关系。分析表明 :对于一定震级的地震 ,当断层出露地面、倾角为 4 5°、并且为倾滑运动时 ,一定量级的应变变化传递的距离最长 ;其中一个主应变传递得最远 ,其次为体应变 ,再其次为最大剪应变 ,另一个主应变的最大传递距离最短 ;泊松比和断层的长宽比的变化对应变传递距离的影响极小 ,可以忽略 相似文献
1000.
New Variable Stars Discovered as By-product of the Beijing Astronomical Observatory Supernova Survey
The Beijing Astronomical Observatory (BAO) 0.6 m telescope has been used for nearby supernova survey in more than 3000 fields, covering a total area of 235 deg2. More than 260000 CCD images have been collected since April 1996, with 45 supernovae discovered. We searched for variables in about 90000 images taken during 1996-1998. For the fields in which long period variables (LPVs) were discovered, we reduced further images taken from 1999 to 2000, for the period estimation. Among the 280000 stars selected from the survey fields, i.e., brighter than 18 mag, we discovered seven new LPVs and reconfirmed three known LPVs. Additionally, we found 146 variable star candidates, and reconfirmed about 20 previously known or suspected objects. 相似文献