柴达木盆地三湖地区第四系沉积相与生物气成藏   总被引：30，自引：3，他引：27       下载免费PDF全文

党玉琪  张道伟  徐子远  侯泽生 《古地理学报》2004,6(1):110-118

柴达木盆地三湖地区第四系蕴藏着巨大的生物气资源,目前已探明加控制天然气储量接近3×1011m3。更新世时期,柴达木盆地的湖相沉积主要分布在三湖(吉乃尔湖、涩聂湖和达布逊湖)地区,自山前至盆地中心依次发育了冲积扇、河流三角洲和湖相沉积,其中湖相沉积分布最为广泛。早更新世湖相沉积开始形成,中更新世湖相沉积扩张并且达到鼎盛,晚更新世湖相沉积开始萎缩并形成盐湖沉积。中、早更新世冰川的出现和青藏高原的崛起使柴达木盆地的古气候变得干旱寒冷,沉积水体温度较低,盐度较高。本区第四纪独特的沉积环境是形成大型生物气藏最重要的地质条件。高盐度的水体环境减缓了有机质的降解速度,长期的低温条件抑制了甲烷菌的活动,避免了沉积有机质在沉积浅埋阶段的过量消耗,推迟了生物产气的高峰期。而三湖地区巨厚的第四系暗色泥岩和频繁发育的砂岩提供了充足的气源条件和构成了良好的生储盖组合。  相似文献   

德国地震监测系统简介   总被引：1，自引：1，他引：0  

刘瑞丰  党京平  任克新  杨辉 《地震地磁观测与研究》2000,21(1):56-59

1　德国地震监测系统德国的地震监测工作由德国联邦地学与自然资源研究院(BGR)负责,具体工作由格拉芬堡地震台阵(GRF)、德国区域地震台网(GRSN)、格拉芬堡地震观测中心(SZGRF)和试验地震观测台阵(GERESS)完成。图1　格拉芬堡地震台阵和德国区域地震台网台站分布格拉芬堡地...  相似文献   

西北区域气象计量实验室综合能力比对结果分析     

党选发  黄蕊  刘永强  张红英  姚爱国  武安邦  吴宁  韩玉婷 《气象科技》2014,42(1):62-67

分析评价西北区域参加实验室比对的试验结果,及时发现问题并进行纠正,总结实施实验间比对工作的经验,提高实验室检定/校准能力和质量管理水平。参加比对的计量检定实验室分别对气压、温度、湿度、风速比对样品进行比对试验,用归一化偏差(En)进行统计分析。2011年西北区域气象计量检定的温度、湿度、气压实验室比对结果为满意,风速实验室比对结果为较满意。该次比对的实验数据客观、真实、可信,是对各参加比对实验室检定/校准能力的综合评价,较为客观地反映了各技术机构检定装置的测量能力、检定人员的技术水平以及西北区域气象计量标准装置的现状。  相似文献   

Instantaneous Shorelines as an Intermediate for Island Shoreline Mapping based on Aerial/Satellite Stereo Images     

Yamin Dang  Xinghua Zhou  Jun Xu  Shuqiang Xue 《Marine Geodesy》2018,41(3):219-229

Island shoreline mapping based on field measurements by collecting visually discernible features is costly and even unrealistic to be implemented in practice because of the nonuniqueness, fuzziness, and ambiguity of shoreline features. The MHHW (the mean higher high water) shoreline, i.e., the intersection of the coastal profile with the MHHW, is recommended to be chosen as a significant shoreline indicator of an island. An approach for mapping the MHHW shoreline using the aerial/satellite stereo images is proposed. In the proposed procedure, first, the height difference between the instantaneous shoreline and the MHHW shoreline is calculated by the ocean tide model; then the orthometric/normal height of the instantaneous shoreline is determined from the stereo images; last, the instantaneous shoreline is used as an intermediate for determination of the height of the MHHW shoreline. The proposed procedure is applied to the MiaoZiHu Island located in the East China Sea. Preliminary experimental result shows that in ideal cases, the horizontal positional accuracy of the extracted shoreline can reach 0.2 m from aerial images of 0.1 m resolution.  相似文献   

A history of breaking laws—Social dynamics of non-compliance in Vietnamese marine fisheries     

Wiebren J. Boonstra  Nguyen Bach Dang 《Marine Policy》2010

Whether or not fishers comply with regulation depends on the economic and social context in which they operate their vessels. This is how conventional theory explains the phenomenon of non-compliance. It treats state–community interaction processes not as direct causes for non-compliance but rather as background conditions shaping individual fishers’ perception and decisions for action. This paper argues that conventional theory fails to include the dynamics of tempo-relational processes between state and communities, which explains collective patterns of non-compliance in fisheries. The paper addresses this hiatus in the literature, using a process-sociological approach to analyse non-compliance in Vietnamese marine fisheries. The analysis highlights that Vietnamese marine fisheries are mainly regulated through informal networks of trust and mistrust, which function through their interplay with the highly centralised and formalised Vietnamese state. Based on this assessment, the paper concludes that outcomes of processes of the dynamic social interplay between state and communities are semi-dependent on individual perception and action, and as such have a causal effect of their own on patterns of non-compliance in fisheries.  相似文献   

GPS���ܵ��㶨λ��Ӱ������ʱ������ؼ���ʩ����   总被引：1，自引：0，他引：1  

郑作亚  党亚民  卢秀山  郭金运  阳凡林 《大地测量与地球动力学》2009,29(5):107-111

??GPS??????λ?????????У?????????????????估???????λ??????????????????????????????????????????λ????????????λ?????????????????????????????????????????????????????????伸?ι?????????????????????????????Щ???????????????????????????????????????????????????????  相似文献   

Meiobenthos in estuary part of ha long bay (gulf of tonkin, south china sea, vietnam)   总被引：1，自引：0，他引：1  

Olga Pavlyuk  Yulia Trebukhova  Nguyen Vu Thanh  Nguyen Dinh Tu 《Ocean Science Journal》2008,43(3):153-160

The distribution of the taxonomical composition and the density of meiobenthos depending on some factors of environment has been studied in bottom sediments of the northern estuary part of Ha Long Bay (Cua Luc estuary). The basic factor of influence on meiobenthic community structure was the granulometric composition of sediment. The greatest taxonomic diversity is noted in the silted sands, lowest — in the silty sediments. The density of meiobenthic community was higher in the silty sediments. Slightly expressed correlation between the density of nematodes and the percentage of silty particles in the sediments is detected (Spearman rank correlation coefficient was 0.49±0.21, p=0.035). The nematodes were dominant at all stations. In total, representatives of 66 species of nematodes belonging to 17 families and 52 genera were identified.  相似文献   

森林植被动态变化信息的遥感检测   总被引：10，自引：1，他引：9  

杨存建  欧晓昆  党承林  张增祥 《地球信息科学学报》2000,2(4):71-74

本文以云南省泸水县为例,探讨了利用遥感技术从LANDSAT TM图像中检测森林植被动态变化的方法。该方法,首先对1988年的LANDSAT TM图像进行几何校正,并将1999年的L ANDSAT TM图像与其配准。其次,分别从1988年和1999年的L ANDSAT TM图像中提取植被指数。然后,将1999年的植被指数减去1988年的植被指数,得到植被指数差值图像。最后,利用目视识别的方法,在植被指数差值图像上确定森林植被增加和减少的阈值,从而提取出森林植被的动态变化信息。由于云和雪的影响,造成一些伪变化的信息,为此,进一步将云和雪的信息提取出来,并将这部分伪变化信息掩模掉。该研究表明,此法可以简单有效地将森林植被的动态变化信息予以检测.  相似文献   

藏东南部泥石流堵河试验研究   总被引：4，自引：0，他引：4  

程尊兰  党超  刘晶晶  宫怡文 《地学前缘》2007,14(6):181-187

通过模型试验对泥石流入汇主河后堵塞坝形成过程以及堵塞坝体溃决后主河河床形态特征进行了研究。实验历时3个月,共13组试验。在支主沟交汇角为90°的情况下,通过改变支沟泥石流容重、支主沟的流量比和动量比,建立了泥石流堵河的判别公式,当r>1 001.16时容易发生堵河现象,并对培龙沟两次泥石流堵河事件进行了判定;定义了主河的束窄率S与主河流速变异系数Fv,并发现了主河的束窄率与支主沟动量比之间存在线性关系;主河稳定后的平均宽度与流速变异系数之间存在幂的关系。该实验能够较好地模拟泥石流堵塞坝形成的过程,结果比较合理,并为泥石流灾害的防治提供了相应的理论基础。  相似文献   

Palaeo-hydrogeological control on groundwater As levels in Red River delta,Vietnam     

Søren Jessen  Flemming Larsen  Dieke Postma  Pham Hung Viet  Nguyen Thi Ha  Pham Quy Nhan  Dang Duc Nhan  Mai Thanh Duc  Nguyen Thi Minh Hue  Trieu Duc Huy  Tran Thi Luu  Dang Hoang Ha  Rasmus Jakobsen 《Applied Geochemistry》2008

To study the geological control on groundwater As concentrations in Red River delta, depth-specific groundwater sampling and geophysical logging in 11 monitoring wells was conducted along a 45 km transect across the southern and central part of the delta, and the literature on the Red River delta’s Quaternary geological development was reviewed. The water samples (n = 30) were analyzed for As, major ions, Fe²⁺, H₂S, NH₄, CH₄, δ¹⁸O and δD, and the geophysical log suite included natural gamma-ray, formation and fluid electrical conductivity. The SW part of the transect intersects deposits of grey estuarine clays and deltaic sands in a 15–20 km wide and 50–60 m deep Holocene incised valley. The NE part of the transect consists of 60–120 m of Pleistocene yellowish alluvial deposits underneath 10–30 m of estuarine clay overlain by a 10–20 m veneer of Holocene sediments. The distribution of δ¹⁸O-values (range −12.2‰ to −6.3‰) and hydraulic head in the sample wells indicate that the estuarine clay units divide the flow system into an upper Holocene aquifer and a lower Pleistocene aquifer. The groundwater samples were all anoxic, and contained Fe²⁺ (0.03–2.0 mM), Mn (0.7–320 μM), SO₄ (<2.1 μM–0.75 mM), H₂S (<0.1–7.0 μM), NH₄ (0.03–4.4 mM), and CH₄ (0.08–14.5 mM). Generally, higher concentrations of NH₄ and CH₄ and low concentrations of SO₄ were found in the SW part of the transect, dominated by Holocene deposits, while the opposite was the case for the NE part of the transect. The distribution of the groundwater As concentration (<0.013–11.7 μM; median 0.12 μM (9 μg/L)) is related to the distribution of NH₄, CH₄ and SO₄. Low concentrations of As (?0.32 μM) were found in the Pleistocene aquifer, while the highest As concentrations were found in the Holocene aquifer. PHREEQC-2 speciation calculations indicated that Fe²⁺ and H₂S concentrations are controlled by equilibrium for disordered mackinawite and precipitation of siderite. An elevated groundwater salinity (Cl range 0.19–65.1 mM) was observed in both aquifers, and dominated in the deep aquifer. A negative correlation between aqueous As and an estimate of reduced SO₄ was observed, indicating that Fe sulphide precipitation poses a secondary control on the groundwater As concentration.  相似文献