沙尘暴垂直输运的两相流理论Ⅱ：气柱挟卷模式

为了改进气块法对沙尘沉降问题的研究,文中利用气柱法,考虑沙尘气体与环境的交换作用以及气柱内湍流交换作用.计算结果表明,均匀场中有利于沉降的条件为较大的初始沙尘浓度扰动与较小的初始温度扰动,而且温度扩散系数越大越有利于沙尘沉降,沙尘浓度扩散系数越大越不利于沙尘沉降,湍流过程在均匀场中对沙尘沉降影响不大.考虑剑更真实的环境场,得出在环境的垂直沙尘浓度梯度与温度梯度的参数域中,初始沙尘扰动越大越有利于沙尘沉降,初始温度扰动越大,越小利于沙尘沉降.同时给出4种不利于沙尘沉降的过程:(1)上升浓度变化过程;(2)下沉浓度变化过程;(3)上升温度变化过程;(4)下沉温度变化过程.根据这些过程分析参数对沙尘沉降的影响得到:温度扩散系数越大越有利沙尘沉降;沙尘浓度扩散系数越大不利十沙尘沉降;垂直温度湍流交换系数越大有利于缓降区甚至是非沉降区的上升;垂直沙尘浓度湍流交换系数越大越有利于沙尘沉降.     

Simulation of erosion-deposition processes at basin scale by a physically-based mathematical model

The development and application of the physically-based and spatially-distributed mathematical model CTSS8-SED is presented. The model simulates hydrologic-hydraulic processes produced by storm events and related soil erosion and sediment transport processes at basin scale in lowland areas. The model simulates (i) storm runoff,(ii) soil detachment by raindrop impact and overland flow (gross sediment yield),(iii) sediment transport by overland flow and associated erosion-deposition processes and (iv) sediment transport by stream flow and riverbed erosion-deposition processes. A quasi two-dimensional representation of water flow and sediment transport routing is made by means of interconnected cells approach. The model is applied to simulate two flooding events in the Luduea Creek basin (Santa Fe, Argentina) occurred in April 1994 and March 2007 due to extraordinary rainfalls.     

会泽金牛厂铅锌矿成矿地质条件

铅锌矿体赋存于下寒武统筇竹寺组八道湾段（∈1q^1）灰黑色中厚层状泥质粉砂岩中;筇竹寺组玉案山段（∈1q^2）灰黄色、灰黑色泥质页岩夹薄层状细砂岩为矿区成矿的隔挡层。北东向的关仓箐逆断裂为矿区的导矿构造,北西西向次级张扭性断裂和北北东向层间断裂为矿区的容矿构造。     

中国南方含油气区构造-沉积类型及其勘探潜力

南方含油气的复杂构造区根据构造—沉积类型的不同,可将其分为四种类型。通过对不同类型典型含油气区的生烃量及非构造运动天然气散失量的化学动力学计算,认为这四种类型含油气区的油气聚集潜力从好到坏依次为:喜马拉雅运动抬升暴露型、燕山运动抬升暴露型、反复抬升—沉降型和海西—印支运动抬升暴露—后期浅埋型。主要构造运动发生越晚,对油气保存越有利。     

Tectonic development of the Mid-Norway continental margin

The area reviewed covers the Mid-Norway continental margin between latitudes 62°N and 68°N. Main structural elements, as defined at the base Cretaceous level, are the Tröndelag Platform, underlying the inner shelf, the Möre and Vöring Basins, located beneath the outer shelf and slope, and the Möre Platform and the Outer Vöring Plateau, forming a base of slope trend of highs. Sediments contained in the Mid-Norway Basin range in age from Late Palaeozoic to Cenozoic. The basement was consolidated during the Caledonian orogenic cycle. Devonian and Early Carboniferous wrench movements along the axis of the Arctic-North Atlantic Caledonides are thought to have preceded the Namurian onset of crustal extension. Rifting processes were intermittently active for some 270 My until crustal separation between Greenland and Fennoscandia was achieved during the Early Eocene. During the evolution of the Norwegian-Greenland Sea rift system a stepwise concentration of tectonic activities to its axial zone (the area of subsequent continental separation) is observed. During the Late Palaeozoic to Mid-Jurassic a broad zone was affected by tensional faulting. During the Late Jurassic and Cretaceous the Tröndelag Platform was little affected by faulting whilst major rift systems in the Möre and Vöring Basins subsided rapidly and their shoulders became concomitantly upwarped. During the latest Cretaceous and Early Palaeogene terminal rifting phase only the western Möre and Vöring Basins were affected by intrusive and extrusive igneous activity. Following the Early Eocene crustal separation and the onset of sea floor spreading in the Norwegian-Greenland Sea, the Vöring segment of the Mid-Norway marginal basin subsided less rapidly than the Möre segment. During the Early and Mid Tertiary, minor compressional deformations affected the Vöring Basin and to a lesser degree the Möre Basin. Tensional forces dominated the Late Palaeozoic to Early Cenozoic evolution of the Mid-Norway Basin and effected strain mainly in the area where the crust was weakened by the previous lateral displacements. The lithosphere thinned progressively and the effects of the passively upwelling hot asthenospheric material became more pronounced. Massive dyke invasion of the thinned crust preceded its rupture.     

A stochastic model of sedimentation

A mathematical model is presented which describes the origin of the earth's geological record in terms of a stochastic process involving random events of sedimentation and erosion. The model yields quantitative predictions of the percentages of the earth's land area in which sediments of one geological period directly overlie those of any given earlier period. It also predicts the total amount of sediment dating from each geological period, and the percentage of the earth's surface marked by outcrops of this sediment. These computed quantities are shown to correlate well with corresponding quantities derived from empirical investigation.     

Predicting cumulative sediment depostition in large reservoirs

Sediment deposition and its accumulation in a large resorvoir depends on the inflow and reservoir storage content, respectively. Because of this fact it is possible to model the cumulative deposition of sediment as an additive process defined on a bivariate Markov chain. Using the bivariate Markov chain model the mean and variance of the cumulative deposition of John Martin Reservoir, Colorado, U.S.A. are estimated and compared with observed sedimentation data.     

THE ADVERSE IMPACT OF HUMAN ACTIVITIES ON FLOOD CONTROL IN THE HUAIHE BASIN

LIN~DUCnONTheHuaiheBasinislOCatedbetWeen31"-36"llorthemlahtudeand112"-121"easternlongitude,andcoversatotalareaofabout269,000sq.kin,OfwhichthemountainousandhillyareasocCUPyl/3,theplainsandlow-iringland2/3.ThebasinelicitSsalientphysicalgeographicalfeatllTesasfollowsf(l)Thereisnoobviousmountaindividebe~ntheWatershedoftheriVerandtheYellowforerBasinaswellastheYangtZeRadBasin.MostofthetributariesinthenoalbudoftheHuaiheforertakethesouthdikesOftheYellowherasthedivide.(2)TheriVerbedofthetr…     

西菲律宾海晚第四纪沉积地球化学特征

对１９８８对取自西菲律宾海区的３个沉积物柱样进行系统的地球化学研究。结果表明，本区的沉积物属半远洋沉积物，其地球化学特征受控于陆源沉积作用、海洋生物沉积作用和海底火山常积作用。据主要化学元素和ＣａＣＯ５的柱状变化进行地层划分和古气候的恢复，区分出末次冰期的亚间冰期沉积、冰期最盛期沉积和全新世沉积。本区的ＣａＣＯ３变化表现出两种类型，ＷＰ１柱样属大西洋型溶解旋回；ＷＰ２和ＷＰ４０柱样属太平洋型溶解旋     

闽江河口沉积结构与沉积作用

结合已有的闽江河口航道整治研究成果，在该河口采集了130多个表层沉积物样品。根据对沉积结构、河口沙坝类型和水动力条件的分析，探讨了闽江河口沉积物的分布规律和沉积作用机制。研究结果表明，1）闽江河口可划分为砂质、混合和泥质3个沉积区，它们分别代表三角洲前缘、前缘斜坡和前三角洲沉积环境；2）闽江河口各汊道径、潮流强度对比不同，河口沉积过程有显著差异。径流在川石水道的发育中居主导作用，潮流是塑造梅花水道的主要因素；3）河口沙坝类型受制于输出水流的扩散形式，闽江河口有多种类型的河口沙坝，川石水道的河口沙坝为水下突堤型，乌猪水道北侧发育了水下突堤型沙坝，熨斗水道为拦门沙型河口沙坝，梅花水道则是潮流脊型的河口沙坝。