罗地河小流域侵蚀景观格局的变化

分析了罗地河小流域治理前后侵蚀景观的变化 .研究结果表明 :集中的强化治理虽然没能改变景观的基质 ,但能大大改变流域的侵蚀景观 ,且明显改善了生态环境 .对于强度流失而言 ,一次性的强化治理难以达到减轻流失程度的目的 ,只有持续地维护治理成果 。

水土保持碳汇项目管理信息系统的开发探索

水土保持碳汇项目信息化管理可以为水土保持碳汇项目开发提供科学规范的技术手段。分析了水土保持碳汇项目管理信息系统开发的主要挑战、建设目标及总体框架,以福建省长汀县罗地河小流域综合治理水土保持碳汇开发为研究对象,探索水土保持碳汇项目开发的全过程信息化体系建设,总结了系统在罗地河小流域综合治理过程中的应用情况以及存在的不足,并提出相关建议,以期为提升水土保持碳汇项目管理水平提供借鉴参考。

FOREST LANDSCAPE PATTERN DYNAMICS OF LUONINGCOUNTY IN HENAN PROVINCE AND ITS DRIVING FORCES

With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning County, Henan Province from 1983 to 1999. The results showed that: 1) The number and total area of patches were rapidly increased with time changes. The fragmentation degree of the landscape was increasing greatly. 2) The area of some forest patch types, especially shrub forest, economic forest, Populus spp. forest, Quercus spp. forest, sparse forest, deserted grassland etc. had been greatly changed. 3) The fragemation degree of each forest patch type became greater from 1983 to 1999. 4) The transition probabilities of deserted forest, economic forest, Pi-nus tabulaeformis forest, Populus spp. forest exceed 85%,Robinia pseuoacacia forest, deserted grassland, 65% and Quercus spp. forest, non-forest, shrub forest had smaller ones, which were 26.5%, 29.1% and 45.3%, respectively. The main transition trends of various patches were non-forest and Quercus spp. forest. During the course of transition, the types that 50% of area was remained were Quercus spp. forest, non-forest and shrub forest. According to above analyses, the main driving forces, such as the management policies, market economy factors and influences of human activities etc. were brought out.

Recent advances on study of hadrosaurid dinosaurs in Heilongjiang(Amur) River area between China and Russia

Four main dinosaur-bearing sites have been investigated in latest Cretaceous deposits from the Amur/Heilongjiang Region ： Jiayin and Wulaga in China （ Yuliangze Formation）, Blagoveschensk and Kundur in Russia （Udurchukan Formation）. More than 90% of the bones discovered in these localities belong to hollow-crested lambeosaurine hadrosaurids： Charonosaurus fiayinensis at Jiayin, Amurosaurus riabinini at Blagoveschensk, Olorotitan arharensis at Kundur, and Sahaliyania elunchunorum at Wulaga. Flat-headed hadrosaurine hadrosaurids are much less numerous, but appear well diversified as well： Kerberosaurus manakini at Blagoveschensk, Wulagasaurus dongi at Wulaga, and a new genus at Kundur. Theropods are represented by shed teeth and isolated bones; isolated scutes and teeth discovered at Kundur are tentatively attributed to nodosaurids. Palynological studies suggest that these sites are probably synchronous with the Lancian＇ vertebrate localities of western North America, which represent the youngest dinosaur faunas in this area. However, the latest Cretaceous dinosaur assemblages are completely different in the Amur/Heilongjiang region （lambeosaurines abundant, ceratopsids absent） and in western North America （ceratopsids abundant, lainbeosaurines extremely rare or absent）. This probably reflects some kind of geographical barrier between both areas by Maastrichtian time rather than strong differences in palaeoecological conditions.

Hydrologic Modeling Impacts of Post-mining Land Use Changes on Streamflow of Peace River, Florida

Whether mining activity results in reduced flow of surface water in the Peace River Watershed of Florida has been the subject of much debate. With increased dependence of downstream users on surface water flow of the Peace River as a source of drinking water for four coastal counties in Southwest Florida and problems of water security, the debate has been intensified. It is possible to assess relationships of mining with streamflow in the upper reaches of the Peace River Basin using hydrologic modeling and identify mined sub-basins. In this work, land-use change impacts were simulated by the Hydrological Simulation Program--Fortran （HSPF） model based on geographical information system （GIS） tools, to compare pre- and post-mining streamflows at a study site of the Peace River in west-central Florida. The purpose of this study was to determine if land-use changes caused by mining have negatively impacted streamflow in the Peace River. Changes of land use were identified before and after mining activities. A coupled volume-water depth-discharge （V-h-Q） model based on stage/storage and stage/discharge was applied using HSPF for the pre-mining and post-mining models, respectively. Daily simulated post-mining hydrographs from HSPF were plotted with the calibrated pre-mining results and streamflow hydrographs from the 18 gauging stations, to compare timing of peaks, low fows and flow trends. Analyses of percent ex- ceedances of flow frequency curves of the streams indicated that most streams had similar distributions for mined （reclaimed） and pre- mining periods. In the streamflow change analysis, streamflows actually increased in mining-affected basins at nearly half the stations. Streamflows at other stations diminished. Overall from this comprehensive study, there were declines in streamflow at most gauging stations on the mainstem of the Peace River and its tributaries. The results of this study suggest that regional planning is urgently needed to propose reclamation schemes that enhance regional hydrology.

Sinolejeunea yimaensis gen.et sp.nov.(Hepaticae) from the Middle Jurassic Yima Formation in Henan Province of China

A new liverwort with perichaetium and perigonium collected from the Middle Jurassic Yima Formation is described. Gametopbyte is dorsivental, irregularly branched, bearing two-ranks of lateral leaves obliquely attached to main axis, and one rank of ventral leaves transversely attached to ventral surface of the axis. Lateral branch bearing perigonium arises from axil of ventral leaves. Perigonium consists of small paired perigonial bracts arranged in a spike. Two perichaetia are borne on the top of lat- eral branches with an ovate perianth bearing longitudinal ridges and grooves. Setae are thin and straight and stretch out from the aristulate perianth mouth. General morphology of this fossil bears resemblance to some living liverworts of Jungermanniales. It is so far the oldest fossil record of Jungermanniales in the world.

Chemical weathering in Malay Peninsula and North Borneo:Clay mineralogy and element geochemistry of river surface sediments

Weathering products of silicate rocks are particularly useful for evaluating the continental chemical weathering on the Earth's surface and its mechanism.Clay mineralogy and major-element geochemistry of surface sediment samples collected in major rivers of Malay Peninsula and North Borneo in the tropical Southeast Asian region are used to study the present chemical weathering process and its controlling factors of tropical regions.The results indicate that the clay mineral assemblage in Malay Peninsula consists dominantly of kaolinite(average 80%) and minor illite(average 17%),almost without chlorite and smectite,whereas in North Borneo it consists mainly of illite and chlorite,with minor amounts of kaolinite(average 14%) and no smectite.Total contents of illite and chlorite in both Northwest and Northeast Borneo are 84% and 87%,respectively.Major-element geochemical results of both bulk and clay-fraction sediments show intensive chemical weathering degree for both areas.Relatively,the chemical weathering degree is gradually strengthened from Northeast Borneo,Northwest Borneo,to Malay Peninsula,and it is extremely intensive in Malay Peninsula.Our results indicate that,in the tropical Southeast Asian region exampled by Malay Peninsula and Borneo,climatic condition of tropical warm temperature and East Asian monsoon rainfall is the first-order controlling factor on the chemical weathering,resulting in intensive chemical weathering throughout tropical areas,and tectonic activity and lithology of parent rocks are subordinate factors,which still have an important impact on the weathering products,forming completely different clay mineral assemblages between Malay Peninsula and Borneo.

A Comparative Analysis of Binary Logistic Regression and Analytical Hierarchy Process for Landslide Susceptibility Assessment in the Dobrovǎt River Basin,Romania

A correct assessment of the landslide susceptibility component is extremely useful for the diminution of associated potential risks to local economic development, particularly in regard to land use planning and soil conservation. The purpose of the present study was to compare the usefulness of two methods, i.e., binary logistic regression(BLR) and analytical hierarchy process(AHP), for the assessment of landslide susceptibility over a 130-km^2 area in the Moldavian Plateau(eastern Romania) region, where landslides affect large areas and render them unsuitable for agriculture. A large scale inventory mapping of all types of landslides(covering 13.7% of the total area) was performed using orthophoto images, topographical maps, and field surveys. A geographic information system database was created, comprising the nine potential factors considered as most relevant for the landsliding process. Five factors(altitude, slope angle, slope aspect, surface lithology, and land use) were further selected for analysis through the application of a tolerance test and the stepwise filtering procedure of BLR. For each predictor, a corresponding raster layer was built and a dense grid of equally spaced points was generated, with an approximately equal number of points inside and outside the landslide area, in order to extract the values of the predictors from raster layers. Approximately half of the total number of points was used for model computation, while the other half was used for validation. Analytical hierarchy process was employed to derive factor weights, with several pair-wise comparison matrices being tested for this purpose. The class weights, on a scale of 0 to 1, were taken as normalized landslide densities. A comparison of results achieved through these two approaches showed that BLR was better suited for mapping landslide susceptibility, with 82.8% of the landslide area falling into the high and very high susceptibility classes. The susceptibility class separation using standard deviation was superior to either the equal interval or the natural break method. Results from the study area suggest that the statistical model achieved by BLR could be successfully extrapolated to the entire area of the Moldavian Plateau.

A stress-rifting origin of Grand Canyon

The Grand Canyon is a massive rift in the Colorado Plateau. How and when it developed has been debated for nearly 150 years. Most geologists believe the unusual landscape was primarily shaped by water erosion.Here we propose a stress-rifting model to provide an alternative explanation for the origin of Grand Canyon.This paper adopts a brittle–ductile double layer model to simulate the deformation and rifting of the plateau due to the mantle-melting-induced expansion. Our results show that the uplift induced by thermal expansion and its associated horizontal extension can cause open fractures that extend from the brittle surface to the underlying ductile layer in a top-down way. In addition, we find that episodic uplift can deepen and connect multiple fractures together to form a larger fracture network. Our findings suggest that the formation of the Grand Canyon might have been driven by plateau uplift and its associated rifting under crustal extension, wherein water erosion played only a minor role in shaping the course of the Colorado River. The new paradigm provides simpler explanations to some of the long-standing geological mysteries surrounding the canyon.