辽西晚侏罗世义县期植物群性质、时代及气候

迄今为止 ,在辽西义县—北票地区的义县期植物群中 ,已发现有 72个属的近 14 0个种 ,它们分别属于苔藓类、石松类、有节类、真蕨类、苏铁类、本内苏铁类、银杏类、茨康类、松柏类、买麻藤类及被子植物类等 11个类群。根据植物群性质、组合特征、各已知属种的时代分布、群落演替规律以及同期植物群对比 ,表明义县期植物群的时代最可能为晚侏罗世的最晚期。通过植物各大类群的生态及属种成分分析 ,认为义县期植物群应属于欧洲—中国古植物地理区的东亚省。按照无机界 (含化石的沉积层 )及有机界 (植物群本身 )所指示的生存环境 ,可以推测义县期植物群是生长在半干旱至半潮湿或季节性干旱的亚热带或亚热带至暖温带的气候环境中     

地质工作辉煌的50年——纪念福建省地质矿产勘查开发局建局50周年

福建省地质矿产勘查开发局是一支具有光荣历史和优良传统的队伍,建局50年来取得了丰硕的地质找矿成果,为福建省经济建设和社会发展作出了重要贡献。作为福建省地质工作的主力军,福建省地质矿产勘查开发局正积极融入海峡西岸经济区建设,不断拓宽地质工作服务领域,力争为福建经济发展作出更大的贡献。     

活动断裂的遥感影像研究

本文以遥感信息作为研究活动断裂的依据，探讨了利用不同种类、不同比例尺遥感图像分析活动断裂的方法、程序和效果。     

三叠纪海的硫同位素

前言自Ault和Kulp(1959)发表第一批海相硫酸盐岩的硫同位素分析数据以来,海相硫酸盐岩(石膏、硬石膏)的硫同位素研究工作已进行了二十余年。     

马氏珠母贝黄壳色选系F1和养殖群体形态性状比较

<正>马氏珠母贝(Pinctada martensii)是我国南方养殖的一种重要经济贝类,长期以来一直是我国主要的海水育珠的主要贝类,用马氏珠母贝育珠是广东、广西和海南沿海部分地区经济发展的支柱性产业。近年来,我国海水珍珠的质量出现明显滑坡,严重地削弱了在国际市场上的竞争力。为提高海水珍珠质量和在国际市场上的竞争力,国内科技工作者已经进行了大量的研究工作,这些工作主要包括对马氏珠母贝养殖群体性状的改良、育珠技术的优化和海水珍珠形成机理的研究[1-5]。     

黄铁矿热电结构

本文提出了半导体矿物热电结构的概念。以黄铁矿为例提出了热电结构的分类命名,金矿床黄铁矿热电结构系列的实例,广泛的标型意义,热电结构测试方法。     

青海聚乎更矿区煤层气富集条件

青海聚乎更矿区是世界上首次在中低纬度冻土区发现天然气水合物的地区,并且天然气水合物的气源是该矿区的煤层气。矿区主要含煤地层为中侏罗统的木里组,煤层厚度大、变质程度一般在气煤~焦煤,镜质组质量分数普遍较高（60%~80%）,煤层结构简单-较复杂,煤储层微观结构以小孔和微孔为主,割理裂隙发育。等温吸附实验结果表明,该区兰氏体积偏低,而压力偏高,储层吸附特性为中-好级别,顶底板封闭性好,地下水活动弱,有利于煤层气的形成与赋存。区内煤层下1煤含气量在0.05~5.52m3/t,下2煤在0.05~11.14m3/t,含气量普遍偏低可能与后期构造使得煤层埋深变浅导致储层压力降低、煤层甲烷大量解吸有关,此外,向斜两翼地层倾角大,也是造成矿区煤层气逸散的主要因素之一,但是在向斜转折部位及矿区深部,煤层气相对富集,是今后勘探开发重点研究区域。     

地面高精度磁测在煤田勘探中的应用

针对陕北煤田勘探中煤层自燃区自燃边界的确定,采用了地面高精度磁测的方法技术,通过求△T垂向一阶导数,来突出异常体边部影响,提高相邻异常体异常迭加的分辨率,认为该方法是解决煤层自燃区（火烧区边界）的一种行之有效的方法。     

Changes in stream flow regime in headwater catchments of the Yellow River basin since the 1950s

The headwater catchments of the Yellow River basin generate over 35% of the basin's total stream flow and play a vital role in meeting downstream water resources requirements. In recent years the Yellow River has experienced significant changes in its hydrological regime, including an increased number of zero‐flow days. These changes have serious implications for water security and basin management. We investigated changes in stream flow regime of four headwater catchments since the 1950s. The rank‐based non‐parametric Mann–Kendall test was used to detect trends in annual stream flow. The results showed no significant trend for the period 1956 to 2000. However, change‐point analysis showed that a significant change in annual stream flow occurred around 1990, and hence the stream‐flow data can be divided into two periods: 1956–1990 and 1991–2000. There was a considerable difference in average annual stream flow between the two periods, with a maximum reduction of 51%. Wet‐season rainfall appears to be the main factor responsible for the decreasing trend in annual stream flow. Reductions in annual stream flow were associated with decreased interannual variability in stream flow. Seasonal stream flow distribution changed from bimodal to unimodal between the two periods, with winter stream flow showing a greater reduction than other seasons. Daily stream flow regime represented by flow duration curves showed that all percentile flows were decreased in the second period. The high flow index (Q₅/Q₅₀) reduced by up to 28%, whereas the reduction in the low flow index (Q₉₅/Q₅₀) is more dramatic, with up to 100% reduction. Copyright © 2006 John Wiley & Sons, Ltd.     

Sustainable land use planning based on ecological health

This paper, taking Beiwenquan Town of Beibei, Chongqing as an example, assessed the impacts of land use on ecological health by comprehensive index method, and discussed methodological system of sustainable land use planning based on ecological health. Results indicated that: 1) From 1992 to 2002, land use changes focused on 12 patterns with the total conversion area of 92.11%, which were related to cultivated land, residential and industrial-mining area, and orchard land. Urbanization and economic reconstruction with the leading driving forces. 2) There was obvious difference of the areas of ecotypes driven by land use change in wide valley and mild slope between 1992 and 2002, while there were little or no difference in steep slope and very steep slope. 3) Both of the conditions of ecological health in 1992 and 2002 were sound, and the ecotypes focused on the types of health and sub-health. But, health ecosystem in 1992, with an area of 764.64ha, accounting for 38.51% of the total evaluation area, was better than that in 2002, with an area of 636.10ha, accounting for 34.19% of the total evaluation area. 4) The ecotypes involved into different ranges have already degenerated, due to humankind’s disturbance, while the conditions of ecological health in the same range in 1992, regardless of stability and reconstruction, were better than that in 2002. 5) The planning scenario based on ecological health was accorded with the practice condition of Beiwenquan Town: 388.29ha of cultivated land could meet the Beiwenquan demand of food and byproduct; 1045.26ha of forest land area, the Beiwenquan demand of ecological health; and 1004.73ha of the residential and industrial-mining area, the Beiwenquan building demand. 6) Sustainable land use planning based on ecological health had higher useful value, because it not only stood to ecological theory, but also satisfied the development demand of society and economy. Foundation item: Under the auspices of the Key Project of Science and Technology of the Ministry of Education (No. 03111) and Incubation Fund Project of Science and Technology Committee of Chongqing (No. 017079) Biography: SHAO Jing-an (1976-), male, a native of Bozhou of Anhui Province, Ph.D., specialized in land use and eco-environmental evolution. E-mail: shaojinganswau@yahoo.com.cn