Fine-grained Pleistocene deepwater turbidite channel system on the slope of Qiongdongnan Basin, northern South China Sea   总被引：2，自引：0，他引：2  

Yuan Shengqiang  Wu Shiguo  Lüdmann Thomas  Yao Genshun  Lv Fuliang  Cao Feng  Wang Hairong  Li Li 《Marine and Petroleum Geology》2009,26(8):1441-1451

Recently, as oil exploitation has become focused on deepwater slope areas, more multi-channel high resolution 2D and 3D seismic data were acquired in the deepwater part of the Qiongdongnan Basin, northern South China Sea. Based on 3D seismic data and coherence time slice, RMS and 3D visualization, a series of deepwater channels were recognized on the slope that probably developed in the late Quaternary period. These channels trend SW–NE to W–E and show bifurcations, levees, meander loops and avulsions. High Amplitude Reflections (HARs), typical for channel–levee complexes, are of only minor importance and were observed in one of the channel systems. Most of the detected channels are characterized by low-amplitude reflections, and so are different from the typical coarse-grained turbidite channels that had been discovered worldwide. The absence of well data in the study area made it difficult to determine the age and lithology of these channels. Using a neighboring drill hole and published data about such depositional systems worldwide, the lithology of these channels is likely to be dominated by mudstones with interbedded thin sandstones. These channels are formed by turbidity currents originated from the little scale mountain river of mid-Vietnam in SW direction and were probably accompanied by a relative sea level drop in the last glacial age. These channels discovered on the northern South China Sea slope are likely to be fine-grained, mud-dominant and low N:G deposits in a deepwater paleogeographic setting.  相似文献   

The variations in optical properties of CDOM throughout an algal bloom event     

Jun Zhao  Wenxi Cao  Guifen Wang  Dingtian Yang  Yuezhong Yang  Zhaohua Sun  Wen Zhou  Shaojun Liang 《Estuarine, Coastal and Shelf Science》2009

For studies in bio-optical oceanography, visible light properties by classes of dissolved organic matter should be characterized. The regional adjustment of model parameters is one approach which is being widely used to refine bio-optical models. In the present study, buoy and laboratory data were acquired, and during the 15-day observation period an algal bloom event occurred. The absorption coefficient of CDOM at 443 nm, a_g(443), changed in the range of 0.09–0.35 m⁻¹ and 0.1–0.34 m⁻¹ for two depths, 0.32 m and 2.3 m., respectively, throughout the entire period. CDOM absorption was larger for bloom conditions than for non-bloom conditions. In addition, the fraction of CDOM in total absorption was higher during the bloom event than that of non-bloom conditions. The spectral slope of CDOM absorption, S_g, regressed over 400–500 nm, ranged from 0.015 to 0.0185 nm⁻¹ with an average of 0.0166 nm⁻¹. CDOM fluorescence intensity (Fcdom) was obtained using an internal Raman standard and varied over the range of 467.44–1538.23 in relative units. Variations in Fcdom showed a similar pattern to that of CDOM absorption. A robust non-linear relationship between Fcdom and CDOM absorption was found, with a correlation coefficient of 0.893, throughout the whole observation. An attempt to describe S_g with absorption showed a promising consequence that can be described with a negative correlation during the bloom, however, without any distinguishable tendency for non-bloom time span. A two-band ratio algorithm was also carried out for retrieving CDOM absorption. The variations in optical properties of CDOM may be related to the complicated environment in the estuarine waters, which may result from different sources of CDOM.  相似文献   

减阻技术对海洋油气管线中多相流动与传热的影响     

刘磊  李操  吴东垠  周芳德 《海洋地质译丛》2009,(2):85-87

在海洋环境中多相流条件下应用减阻技术,可以在相同的管线压力下,有效提高油气输送量。减阻技术影响多相流的摩擦阻力、持液率和界面现象,可使多相流的的减阻率最高达到60%以上,可减少多相流体与管壁间的传热;某些情况下,减阻技术还能够改变多相流的流型、抑制剧烈弹状流,改善油气输送系统的运行工况。  相似文献   

从单一到多重空气污染管理——潜在可能及实现方案     

曹孜  陈洪波  朱世欣 《地理科学》2021,41(2):360-367

在阐述多重空气污染管理概念和意义的基础上,以美国佐治亚州为例,介绍了目前发达国家多重空气污染管理的步骤和方法,分析了信息技术应用在多重污染管理中的重要性,指出了对多重污染健康效应的研究是制定污染管理方案的前提.然后依据现有技术条件、管理体制提出多重污染管理优化调整的方向:污染标准制定的改进、加强跨学科合作研究、科学制定...  相似文献   

一种制备单原子碳链的方案     

曹荣根  王音  林正喆  明辰  庄军  宁西京 《海洋学报》2010,32(9):6438-6442

考虑到迄今为止实验上尚不能制备含有上百个原子的自由单原子链,本文提出利用探针从graphene中拉伸较长单原子碳链的设想,并通过分子动力学计算发现,室温下可以利用C60探针以1 m/s的速度从graphene的zigzag边缘拉出较长的一维单原子碳链,为实验提供了一种制备单原子碳链的可能方案.  相似文献   

Water quality assessment for Ulansuhai Lake using fuzzy clustering and pattern recognition   总被引：1，自引：0，他引：1  

任春涛  李畅游  贾克力  张生  李卫平  曹有玲 《中国海洋湖沼学报》2008,26(3):339-344

Water quality assessment of lakes is important to determine functional zones of water use. Considering the fuzziness during the partitioning process for lake water quality in an arid area, a multiplex model of fuzzy clustering with pattern recognition was developed by integrating transitive closure method, ISODATA algorithm in fuzzy clustering and fuzzy pattern recognition. The model was applied to partition the Ulansuhai Lake, a typical shallow lake in arid climate zone in the west part of Inner Mongolia, China and grade the condition of water quality divisions. The results showed that the partition well matched the real conditions of the lake, and the method has been proved accurate in the application.  相似文献   

Retrieval Snow Depth by Artificial Neural Network Methodology from Integrated AMSR-E and In-situ Data —— A Case Study in Qinghai-Tibet Plateau     

CAO Yungang  ;YANG Xiuchun  ;ZHU Xiaohua 《中国地理科学(英文版)》2008,18(4):356-360

On the basis of artificial neural network （ANN） model, this paper presents an algorithm for inversing snow depth with use of AMSR-E （Advanced Microwave Scanning Radiometer-Earth Observing System （EOS）） dataset, i.e., brightness temperature at 18.7 and 36.5GHz in Qinghai-Tibet Plateau during the snow season of 2002-2003. In order to overcome the overfitting problem in ANN modeling, this methodology adopts a Bayesian regularization approach. The experiments are performed to compare the results obtained from the ANN-based algorithm with those obtained from other existing algorithms, i.e., Chang algorithm, spectral polarization difference （SPD） algorithm, and temperature gradient （TG） algorithm. The experimental results show that the presented algorithm has the highest accuracy in estimating snow depth. In addition, the effects of the noises in datasets on model fitting can be decreased due to adopting the Bayesian regularization approach.  相似文献   

山东栖霞金矿的空间分布及其矿化特征   总被引：1，自引：0，他引：1       下载免费PDF全文

余普贤  徐怀峰  曹铁生  胡伟华 《山东国土资源》2008,24(3):31-35

破碎蚀变岩型金矿与裂隙充填石英脉型金矿是栖霞地区主要金矿化类型,破碎蚀变岩型金矿分布于郭家岭超单元西石硼单元或玲珑超单元郭家店单元二长花岗岩体内外接触带附近;而裂隙充填石英脉型金矿主要分布于栖霞-桃村一带的古老基底构造轴部附近,且集中分布于该地区南北宽不超过20km的范围内。而大部分含金矿脉其附近往往发育有成群成带的中基性岩脉,中基性岩脉特别是煌斑岩为该区找金的一个间接标志。  相似文献   

干旱对河西走廊植被净初级生产力的影响     

李传华  殷欢欢  朱同斌  周敏  王玉涛  孙皓  曹红娟  韩海燕 《中国沙漠》2021,41(1):145-155

干旱对生态系统碳循环具有重要影响,随着气候变暖,全球干旱事件频率不断上升,研究干旱对植被净初级生产力的影响具有重要意义.提高植被净初级生产力(NPP)的时间分辨率是认识干旱对其影响机制的重要途径.基于5天NDVI遥感数据,以河西走廊为研究区,利用CASA模型估算2010-2015年5天步长尺度的NPP,将5天降水为零定...  相似文献   

钝缀锦蛤(Tapes dorsatus)稚贝的温度和盐度耐受性研究     

张柯馨  曹楚畑  刘志刚  吴加莹  张元  展建强  陈麟广 《海洋学报》2022,44(4):57-64

本实验在室内控制条件下,采用实验生态学方法研究了钝缀锦蛤(Tapes dorsatus)稚贝对温度和盐度的耐受性.在温度耐受性方面:(1)稚贝在低温端温度为4℃、6℃、8℃、10℃时保持90％～100％存活的时间分别为0?d、2?d、3?d、7?d;在高温端温度为33℃、34℃、35℃、36℃时保持90％～100％存活...  相似文献