华北南部晚古生代陆表海的沉积充填、聚煤特征和构造演化

华北南部晚古生代煤系为海退型剖面,沉积环境演化为由陆表海碳酸盐—碎屑海岸、碎屑潮坪至被河流三角洲充填的半咸水海湾。晚石炭世中期华北南缘与秦岭—大别山区因拉张分离出现了陆表海,陆源碎屑自北向南的充填表明北方蒙古—西伯利亚板块向华北板块北缘的对接俯冲。沉积中心和聚煤作用随之自北向南迁移,因此在华北南部集中了丰富的煤炭资源。聚煤最有利的沉积环境是海退形成的滨海平原和河流注入浅水海湾形成的三角洲平原。煤变质带自本区中部向南递减表明三叠纪沉积中心向北迁移,表明华北南缘与秦岭—大别山地块以及华南板块的对接拼合时间可能发生在煤系形成之后至三叠纪以前,海西末期的可能性较大。     

泌阳凹陷下第三系的层序地层格架及其对边界断裂.古气候和物源的响应

根据详细的相分析、地震地质解释及区域地质方面的研究,把泌阳凹陷内的下第三系划分为3个层序,依次代表湖盆的3个演化阶段.层序Ⅱ_1和层序Ⅱ_3分别是湖盆初陷阶段和萎缩阶段的产物,均为由冲积平原体系域和硫酸盐湖体系域构成的半旋回式二元结构,体现了干旱气候条件下湖盆的冲积-充填特征,但湖盆初陷阶段的边界断裂活动强度比湖盆萎缩阶段要大.层序Ⅱ_2为湖盆主陷阶段的产物,由湖进体系域、碳酸盐湖体系域和湖退体系域构成的一个完整的沉积旋回.在湖盆主陷阶段,气候较潮湿,边界断裂活动强度大,但因物源及边界断裂活动强度的差异,湖盆不同部位发育的沉积体系类型及规模明显不同.     

根据深部地球物理资料和古板块构造格架重新厘定槽台界线

大地电磁测深、地震测深、深部地球物理场特征和古板块构造格架表明，华北地台与蒙古—兴安古生代地槽褶皱区界线位于田水井—六驼山—温图高勒—巴音毛道—图克木—巴音查干—白音敖包—温都尔庙—那日图—西拉木伦构造线。从田水井向西，槽合界线进入准噶尔—塔里木板块构造区；从西拉木伦向东，槽台界线尖灭在松辽前寒武板块西南缘。     

鄂尔多斯盆地三叠系延长组长8—长7油层组高分辨率层序地层格架及其地质意义

鄂尔多斯盆地三叠系长8—长7油层组位于延长组中下部,代表湖盆最大扩张期,主要属于湖成三角洲相。运用高分辨率层序地层学原理,详细分析了鄂尔多斯盆地三叠系延长组长8—长7油层组地层沉积的基准面旋回特征,识别出1个长期旋回、3个中期旋回(MSC3、MSC4、MSC5)和15~25个短期旋回,分析得出长8油层组为三角洲环境,到长7油层组则演变为半深—深湖环境。3个中期旋回当中,MSC3、MSC4是以上升半旋回为主的不对称旋回,并在MSC4上升半旋回顶部形成盆地最大湖泛面,MSC5以下降半旋回为主的不对称旋回,发育浊积扇。对不同井基准面旋回的分析得出:储集层段多发育于短期基准面上升半旋回的水下分流河道、河口坝和浊流沉积砂体中,且砂体与前三角洲泥构成的烃源岩相匹配,形成岩性油气藏。运用高分辨率层序地层学原理建立地层格架对指导鄂尔多斯盆地延长组油气勘探具有重要指导意义。     

面向对象时空数据模型的研究

时空数据模型是建立TGIS的基础。首先指出了建立时空数据模型中应该考虑的问题,同时指出面向对象时空数据模型的优越性;然后提出了面向对象的时空数据模型。指出地理世界抽象是由时空属性对象组成,每个时空属性对象由空间、属性、时间3部分组成。系统分析了时空属性对象各个组成部分之间的关系并通过UML进行了表达。最后,以地籍管理中的宗地为例说明了该数据模型的实现。     

发达地区县域土地集约利用时空变化分析——以福建省福清市为例

采用综合评价法、聚类分析法、回归相关分析法对福清市土地集约利用的时空变化规律特征进行研究,并对其驱动因素进行深入的分析.研究结果表明:福清市土地集约利用水平具有明显的时空变化规律——1996~2005年土地集约利用水平呈分阶段性上升趋势,1996年和2005年土地集约利用在空间上呈5级分布格局,且空间分布状况变化不大.自然条件是影响土地集约利用最基础的因素,人口、经济、技术因素是造成区域土地集约利用差异的主要原因.同时,解释了土地集约利用的时空变化格局.     

关于东昆仑地区前寒武纪地质的几点认识

以1∶25万区域地质调查资料为基础,对东昆仑造山带前寒武纪地质演化的几个关键问题进行了探讨。东昆仑地区3206Ma±14Ma的锆石207Pb/206Pb年龄信息表明,该区存在古太古代基底。代表东昆仑地区基底的"金水口岩群"可以解体为太古宙—古元古代的白沙河岩群和中元古代的小庙岩群,两者是2个不同构造旋回的产物。东昆仑地区万宝沟群的时代应限定在中元古代,而不能延续到新元古代。东昆仑地区的年代构造格架显示,前寒武纪存在3次强烈的区域性构造热事件,分别发生在2400～2500Ma、1800～1900Ma和大约1000Ma。1000Ma左右的聚合事件导致中元古代分隔的不同小陆块的有限裂解小洋盆闭合,陆块聚合形成"西域板块",并可能是整个Rodinia超大陆的组成部分。     

西部严重缺水地区地下水勘查技术方法体系研究

本文主要介绍1999~2005年中国地质调查局组织实施的“西部严重缺水地区人畜饮用地下水勘查示范工程”中建立的西北内陆盆地、青海东部和甘肃中东部中小型碎屑岩盆地、宁夏南部和陕西北部黄土高原区、鄂尔多斯盆地周边岩溶区、内蒙古高原和川渝滇红层等不同复杂水文地质区以遥感、综合物探、钻探等方法为主要内容的地下水勘查技术方法体系研究成果。为继续推进上述地区人畜饮用水困难问题的解决提供技术指导。     

Explanation of land use in mountainous area,China: from field to village level

Few studies of land use change were particularly considered the hierarchical data structure originating from different scales and levels. Using interviewing data collected from 107 villages, 1,050 households and 4,780 fields between November 2003 and August 2005, the objective of this paper is to predict the occurrence of land use from field to village level in mountainous area, China, and to improve our understanding of the causes of land use. Household’s behavior in the choice of land use type is guided by multiple, often confiding, household objectives, subject to the available resources, possible productive activities, and external economic and biophysical constraints. For rice model, the household level variables cannot be substituted by village level aggregates. Aggregated variables at village level do not capture any of the variability at the household level. Village level variables can virtually be explained in virtue of the variables of field and household level. The households and the villages show significant clustering of the occurrence of rice, and they explain the 11.3 and 4.5% variance, respectively. For corn model, corn as dependent variable does not show any significant variance component. The variables of household and village level have lower effects on the occurrence of corn. There is a significant relation between slope of a field and the choice to cultivate corn and a significant random effect at the village level. However, cropland size, input–output, transportation cost, even family income in household level and road density and food market development in village level, at some extent, are controlled by slope. These variables do not influence corn cultivation significantly and that those are predominantly determined by slope. In a word, the household level can be crucial in explaining land use at the field level. Multilevel analysis can be applied to statistically model the occurrence of land use, and to explore a number of cross-scale propositions. An erratum to this article can be found at     

Paleolimnological assessment of the impact of logging on small boreal lakes

In Finland a great number of forest lakes are affected by silvicultural practices such as logging. Logging affects water chemistry and thus the ecological state of lakes by causing nutrient loads and increasing erosion and humic substances in water. Water quality assessment requires definition of natural background conditions and ecological status of water bodies. Therefore it is necessary to determine the impact of these practices on aquatic organisms. In the absence of long-term monitoring data, paleolimnological methods provide a powerful tool for determining human-induced changes in lakes. In this study diatom assemblages, diatom-inferred water total phosphorus and total organic carbon, and sediment chemistry were analyzed from the sediments of six lakes with a logged catchment area (11-53%). According to one-way analysis of similarities (ANOSIM) the diatom communities of three lakes were different before, immediately after and more than 10 years after logging and diatom assemblages in remaining three lakes did not show statistically significant differences between these times. However, all changes were minor, and at present the diatom assemblages and diatom-inferred water chemistry of all the lakes are close to the pre-logging conditions. The minor alterations are probably due to the wide protective zones around the lakes.