红阳煤田的岩煤层对比

采用岩相旋回法、标志层法和煤岩层组合特征等多种方法,对红阳煤田的岩煤层进行综合对比,认为该煤系沉积稳定,标志层明显,易于辨认及对比,岩性、岩相变化有一定规律可循,具有比较明显的旋回结构,煤层层位在旋回上有一定的分布规律,为一套海陆交互相滨海平原型沉积。     

INTEGRATION OF THE MODELS OF ANNAGNPS AND REMM TO ASSESS RIPARIAN BUFFER SYSTEM FOR SEDIMENT REDUCTION

The United States Department of Agriculture (USDA) Annualized Agricultural Non-Point Source Pollution model (AnnAGNPS) is used to help evaluate a watershed response to agricultural management practices to control water quality. However, AnnAGNPS version 3.5 does not contain features to estimate the effect of a riparian buffer (RB) system on water quality. The Riparian Ecosystem Management Model (REMM) is used to simulate the impact of riparian buffer systems on water quality. However, frequently the lack of measured upland loadings that are required by REMM simulation limits the application of REMM. To address this data gap, a study was conducted to integrate AnnAGNPS with REMM for RB system simulation. AnnAGNPS was used to simulate water and sediment loadings from an upland field into a three-zone RB system at the Gibbs Farm located in the Georgia coastal plain. These AnnAGNPS outputs were used as the inputs to REMM. REMM was used to simulate water and sediment movement along the riparian buffers. The AnnAGNPS simulated amount of annual runoff at the edge of the field was close to observed amounts (Nash-Sutcliffe efficiency of 0.92). It is believed that a substantial portion of sand was removed from the runoff one meter into the grass buffer where the samplers were located; therefore, sand was excluded from the AnnAGNPS simulation for comparison with observed sediment. Excluding sand, the AnnAGNPS predicted amount of annual sediment matches the observed amount fairly well (Nash-Sutcliffe efficiency of 0.46). In addition, based on evaluating the percent reduction of sediment at each zonal interface, the AnnAGNPS/REMM model well simulated the function of the RB system to reduce sediment.     

Preservation of large titanosaur sauropods in overbank fluvial facies: A case study in the Cretaceous of Argentina

Patagonia exhibits a particularly abundant record of Cretaceous dinosaurs with worldwide relevance. Although paleontological studies are relatively numerous, few include taphonomic information about these faunas. This contribution provides the first detailed sedimentological and taphonomical analyses of a dinosaur bone quarry from northern Neuquén Basin. At Arroyo Seco (Mendoza Province, Argentina), a large parautochthonous/autochthonous accumulation of articulated and disarticulated bones that represent several sauropod individuals has been discovered. The fossil remains, assigned to Mendozasaurus neguyelap González Riga, correspond to a large (18–27-m long) sauropod titanosaur collected in the strata of the Río Neuquén Subgroup (late Turoronian–late Coniacian). A taphonomic viewpoint recognizes a two-fold division into biostratinomic and fossil-diagenetic processes. Biostratinomic processes include (1) subaerial biodegradation of sauropod carcasses on well-drained floodplains, (2) partial or total skeletal disarticulation, (3) reorientation of bones by sporadic overbank flows, and (4) subaerial weathering. Fossil-diagenetic processes include (1) plastic deformation of bones, (2) initial permineralization with hematite, (3) fracturing and brittle deformation due to lithostatic pressure; (4) secondary permineralization with calcite in vascular canals and fractures, and (5) postfossilization bone weathering. This type of bone concentration, also present in Rincón de los Sauces (northern Patagonia), suggests that overbank facies tended to accumulate large titanosaur bones. This taphonomic mode, referred to as “overbank bone assemblages”, outlines the potential of crevasse splay facies as important sources of paleontological data in Cretaceous meandering fluvial systems.     

重庆市沥鼻峡背斜盐井矿区龙潭组沉积特征及聚煤规律

通过对重庆市沥鼻峡背斜盐计矿区含煤地层研究，探讨了矿区龙潭组的沉积特征和聚煤规律，得出矿区龙潭组为泻湖-海湾-潮坪沉积体系，成煤时期的不同沉积环境，聚煤沉降幅度小，沉积速度和物质补偿均衡，有利于泥炭堆积，因此矿区含煤层数、煤层厚度较稳定，该区处于华蓥山潮坪地带，是龙潭期聚煤中心之一。     

对2005年盛夏十堰市一次连续强降水天气过程的分析

使用2005年8月14～23日各层(850、700、500 hPa等)天气图资料,以及有关物理量场资料、雷达回波资料和卫星云图资料,采取天气诊断分析方法,对2005年盛夏十堰市一次连续强降水天气过程进行了分析。结果表明:此次过程是在西太平洋副热带高压、"珊瑚"台风、东南急流、南支低槽、中低层低涡切变线等系统共同影响下形成的;贝加尔湖低槽持续分裂冷空气与副热带高压边缘暖湿气流对峙是该过程能够维持的基本条件;短带状强回波与新生的强对流窄回波带相叠加并维持较长时间,中-β尺度云团在本地发展为中-α尺度云团且受地形作用维持近5 h,使得灾情更趋严重。     

Modeling errors in upward continuation for INS gravity compensation

Accurate upward continuation of gravity anomalies supports future precision, free-inertial navigation systems, since the latter cannot by themselves sense the gravitational field and thus require appropriate gravity compensation. This compensation is in the form of horizontal gravity components. An analysis of the model errors in upward continuation using derivatives of the standard Pizzetti integral solution (spherical approximation) shows that discretization of the data and truncation of the integral are the major sources of error in the predicted horizontal components of the gravity disturbance. The irregular shape of the data boundary, even the relatively rough topography of a simulated mountainous region, has only secondary effect, except when the data resolution is very high (small discretization error). Other errors due to spherical approximation are even less important. The analysis excluded all measurement errors in the gravity anomaly data in order to quantify just the model errors. Based on a consistent gravity field/topographic surface simulation, upward continuation errors in the derivatives of the Pizzetti integral to mean altitudes of about 3,000 and 1,500 m above the mean surface ranged from less than 1 mGal (standard deviation) to less than 2 mGal (standard deviation), respectively, in the case of 2 arcmin data resolution. Least-squares collocation performs better than this, but may require significantly greater computational resources.     

Zircon U–Pb Ages and Lu–Hf Isotope of the Dongchuan Group in Central Yunnan, China, and their Geological Significance

On the southwestern margin of the Yangtze Block, the Dongchuan Group consists of slightly metamorphosed sedimentary rocks, including silty slate, argillaceous slate, clayey slate, arkose, dolomite, and minor volcanic rocks. To date, it is still a controversy over the depositional age and stratigraphic sequence of the Dongchuan Group. In this study, we analyzed five samples of meta-sedimentary rocks and one sample of meta-tuff from the Yinmin, Luoxue and Etouchang Formations of the Dongchuan Group in the Yuxi region for detrital zircon U-Pb ages and Lu-Hf isotope. The detrital zircon ages of the meta-sediments vary from 3073 to 1703 Ma, mainly clustered at three periods, from 1889 to 1840, 2490 to 2008 and 2878 to 2844 Ma. The youngest age peak of all the samples is ～1859 Ma, with the εHf(t) values of the zircons ranging from-20.3 to +4.3 and more than 90% being negative, indicating that the Paleoproterozoic crustal accretion on the southwestern margin of the Yangtze Block was dominated by reworking of the ancient crustal materials involved in the assembly and breakup of the Columbia supercontinent. Another important age range is between 2490 Ma and 2008 Ma, with εHf(t) values from-14.7 to +8.9 and 70% of them are negative, suggesting that the magmatism in the source area was also dominated by reworking and recycling of the ancient crustal materials, with minor juvenile mantle substances added. The detritus was probably derived from the Paleoproterozoic crystalline basement in the southern Yuxi region. The oldest peak age is ～2847 Ma and the εHf(t) values are from-7.7 to +7.0 with 50% of both positive and negative values, demonstrating a possible ～2.85 Ga ancient continental nucleus on the southwestern margin of the Yangtze Block and substantial growth in juvenile crust materials during this period. Besides, the weighted average age of the zircons from the meta-tuff of the Etouchang Formation is 1677 ± 14 Ma. Combining the previous research data and this study, we can constrain the depositional age of the Dongchuan Group in central Yunnan Province to the period from the late Paleoproterozoic to early Mesoproterozoic, slightly earlier than that of the Dongchuan Group in the Dongchuan area near to the southwestern Sichuan Province. The depositional age of the Dongchuan Group is older than that of the Kunyang Group.     

Practical Experiences with Films, Cameras and Navigation Systems

The first author commenced his experiences with aerial photography in 1945, when he joined the Royal Air Force (RAF). The aerial cameras used at that time were the Williamson F24 and F52, with Ilford HP3 and FP3 panchromatic films. Subsequently the Williamson F95 camera was tested against the USAF Sonne 11 camera. During his final years in the RAF, a variety of film types was employed: colour, monochrome infra-red and false colour infra-red. Additional experience was gained when the author was employed by the International Training Centre (ITC), The Netherlands and he saw the further development of the air camera from the Wild RC8 and Zeiss (Oberkochen) RMK 15/23 to the Wild RC20, Zeiss (Jena) LMK and Zeiss (Oberkochen) RMK TOP. He predicts that the future lies with digital cameras.
The second author started working with aerial photography in the 1950s. Details are given of cameras, visual navigation sights and survey aircraft dating from that period. Overseas operations, carried out mainly by Hunting Surveys and Fairey Surveys, posed particular problems because the majority of the work there was undertaken without the aid of existing maps. The introduction of external navigation systems is described, from the Decca ship navigation system, through the GNS-200 VLF/Omega low frequency radio system to INS, the Inertial Navigation System. The author later joined the ITC, which enabled him to participate in trials of the Computer-controlled Photo Navigation System. Eventually practical experience was gained with differential GPS, particularly in countries in southeast Asia. Aerial photography currently appears to benefit less from financial investment than the photographic, aviation and survey industries. However, the satisfaction of making a significant contribution to major overseas development projects outweighs the frustration of lack of acceptance of plans for the future of the air survey industry.     

MINQUE for block diagonal bordered systems such as those encountered in VLBI data analysis

A sparse matrix method is developed for computing variance factors for block-diagonal, bordered systems of equations using MINQUE (Minimum Norm Quadratic Unbiased Estimation). This method greatly reduces the computational effort required to apply MINQUE, thus making it practical to compute variance factors for some very large systems of equations. The computer implementation of the method is described and applied to the computation of variance factors for a combination of 1609 VLBI (Very Long Baseline Interferometry) observing sessions. The purpose of this test was to compute a variance factor for each of the data sets and, perhaps, to obtain more realistic variance estimates to replace those in common use for the analysis of VLBI data. It was found that the method is satisfactory for use with such large problems, and the test served to verify that the variances in current use in VLBI data adjustments are adequate. Received: 26 November 1996 / Accepted: 12 December 1997     

扇三角洲沉积体系及其与油气聚集关系

扇三角洲沉积体系是断陷盆地中极为发育的一种沉积体系,主要由扇三角洲平原组合、扇三角洲前缘组合和前三角洲沉积构成,可识别出9种成因相。受沉积物供给速率、可容空间增长速率及盆缘断裂产状等因素控制可划分出退积型、加积型、前积型、陡坡型和缓坡型5种扇三角洲类型。位于扇三角洲平原的辫状分流河道砂体及其位于扇三角洲前缘的与之有成因联系的水下分流河口坝、洪水型重力流砂体等物性好,可以构成优质储层。含油性勘探成果亦证实各主力油层段平面上主要分布于扇三角洲前缘及分流间湾区,小部分位于扇三角洲平原区。受埋藏深度和成岩场的影响,不同地区、不同层位主力油层段的物性与岩性相关性各异。因此,应用沉积体系分布与油气聚集规律挖掘剩余油层及进行远景区预测是有效的与可行的。