华南沿海地区全新世海平面变化特征

１海平面变化特征１．１全新世中期海侵根据地层中所含硅藻属种雷州半岛海康南田乡一１５ｍ钻孔岩芯，含有丰富的硅藻，主要属种是①：具槽直链藻（Ｍｅｌｏｓｉｒａ　ｓｕｌｃａｔａ（Ｅｈｒ）Ｋｕｔｚ）、范氏回箱藻（Ｐｙｘｉｃｌｉｃｕｌａ　ｗｅｙｐｒｅｃｈｔｉｉＧｒｕｎ）、条纹小环藻（Ｃｙｃｌｏｔｅｌｌａｓｔｒｉａｔａ（Ｋｕｔｚ）Ｇｒｕｎ）、流水双菱藻（ＳｕｒｉｒｅｌｌａｆｌｕｍｉｎｅｎｓｉｓＧｒｕｎ）。上述硅藻主要是海相生活属种，今日南田乡已距离海岸线５ｋｍ。徐闻海安西侧一１８．５ｍ钻孔岩芯中的硅藻除上述属…     

含铜、铋和银的金精矿堆浸工艺综合回收试验研究

采用生物氧化技术和化学方法,利用堆浸工艺分步提取,对含Au 140~150 g/t、Ag 900~1 000 g/t、B i 9.0%~10.0%、Cu14%~17%的多金属浮选金精矿的综合回收工艺进行了研究。经小型搅拌试验,确定了生物氧化浸铜—氰化浸金、NaC l-FeC l3-HC l体系(氯盐法)浸出铋和银的技术方法。通过柱浸试验,研究了利用该方法分步浸取Au、Ag、Cu和B i在堆浸工艺中的可行性。在10 t精矿的扩大试验验中,验证了柱浸试验所取得的工艺指标和参数。试验中掺入骨架材料,解决了精矿在堆浸中的渗透问题;生物氧化过程中,菌种在含高浓度铜离子浸出液中反复驯化,对铜的耐受力提高到30 g/L;在NaC l-FeC l3-HC l体系浸出B i和Ag时,用H2O2将浸出液中的Fe2+氧化成Fe3+,使浸出液能循环使用,且B i和Ag同时浸出。Au、Ag、Cu和B i的最终浸出率分别为92.98%、65.09%、45.33%和53.49%。     

茂名城区GPS拟合高程精度的探讨

GPS控制网在联测水准点的基础上,利用GPS水准高程来实现GPS网点的大地高向正常高转换,其精度主要受所拟合的似大地水准面、已知点高程和GPS网点大地高3种误差的影响。     

Paleohydrology and paleoclimate records in a saline prairie lake core: mineral,isotope and organic indicators

This pilot study examines the potential of obtaining a sedimentary record of paleoenvironmental/climatic/hydrologic conditions for saline Redberry Lake in southern Saskatchewan, Canada. The tools are mineralogy, stable isotopes and pigments. The upper meter of an offshore sediment core contains 10 to 20% by weight aragonite (CaCO₃), which apparently precipitated in the water column. The ¹⁸O and ¹³C of the bulk aragonite (corrected for content of detrital calcite) vary by 4 to 5. Enrichment in ¹⁸O in aragonite is significantly correlated with pigment concentrations (chlorophyll a, phaeophytin). The ¹⁸O and pigment data provide evidence for relatively dry and/or warm conditions and high limnetic productivity for the period 2500 to 1500 yrs B.P. After 1500 B.P., the climate was apparently similar to the present, with two episodes of relatively enhanced productivity, dryness and/or warmth, at around 1000 to 900 and 500 to 200 B.P. During the past century, Redberry Lake has decreased approximately 8 m in depth and its salinity has doubled. No clear sedimentary signal was observed in response to these recent hydrologic trends. These changes have not been associated with a significant climate trend in the region, but may have been induced by land use changes in the catchment.This publication is the third of a series of papers presented at the Conference on Sedimentary and Paleolimnological Records of Saline Lakes. This Conference was held August 13–16, 1991 at the University of Saskatchewan, Saskatoon, Canada. Dr. Evans is serving as Guest Editor for this series.     

Automated threshold selection methods for extreme wave analysis

The study of the extreme values of a variable such as wave height is very important in flood risk assessment and coastal design. Often values above a sufficiently large threshold can be modelled using the Generalized Pareto Distribution, the parameters of which are estimated using maximum likelihood. There are several popular empirical techniques for choosing a suitable threshold, but these require the subjective interpretation of plots by the user.In this paper we present a pragmatic automated, simple and computationally inexpensive threshold selection method based on the distribution of the difference of parameter estimates when the threshold is changed, and apply it to a published rainfall and a new wave height data set. We assess the effect of the uncertainty associated with our threshold selection technique on return level estimation by using the bootstrap procedure. We illustrate the effectiveness of our methodology by a simulation study and compare it with the approach used in the JOINSEA software. In addition, we present an extension that allows the threshold selected to depend on the value of a covariate such as the cosine of wave direction.     

基于GDAL的遥感影像快速裁切技术

介绍了基于开源GDAL类库开发,实现遥感影像的大批量快速裁切的技术,经应用测试,该技术提高了遥感影像处理的作业效率和自动化水平,降低了生产成本。     

Evolution of the north flank of Tenerife by recurrent giant landslides

Geomorphologic analysis of submarine and subaerial surface features using a combined topographic/bathymetric digital elevation model coupled with onshore geological and geophysical data constrain the age and geometry of giant landslides affecting the north flank of Tenerife. Shaded relief and contour maps, and topographic profiles of the submarine north flank, permit the identification of two generations of post-shield landslides. Older landslide materials accumulated near the shore (<40-km) and comprise 700 km³ of debris. Thickening towards a prominent axis suggests one major landslide deposit. Younger landslide materials accumulated 40–70 km offshore and comprise the products of three major landslides: the La Orotava landslide complex, the Icod landslide and the East Dorsal landslide complex, each with an onshore scar, a proximal submarine trough, and a distal deposit lobe. Estimated lobe volumes are 80, 80 and 100 km³, respectively. The old post-shield landslide scar is an amphitheatre, 20–25 km wide, partly submarine, now completely filled with younger materials. Age–width relationships for Tenerife's coastal platform plus onshore geological constraints suggest an age of ca. 3 Ma for the old collapse. Young landslides are all less than 560 ka old. The La Orotava and Icod slides involved failures of slabs of subaerial flank to form the subaerial La Orotava and Icod valleys. Offshore, they excavated troughs by sudden loading and basal erosion of older slide debris. The onshore East Dorsal slide also triggered secondary failure of older debris offshore. The slab-like geometry of young failures was controlled by weak layers, deep drainage channels and flank truncation by marine erosion. The (partly) submarine geometry of the older amphitheatre reflects the absence of these features. Relatively low H/L ratios for the young slides are attributed to filling of the slope break at the base of the submarine edifice by old landslide materials, low aspect ratios of the failed slabs and channelling within troughs. Post-shield landslides on Tenerife correlate with major falls in sea level, reflecting increased rates of volcanism and coastal erosion, and reduced support for the flank. Landslide head zones have strongly influenced the pattern of volcanism on Tenerife, providing sites for major volcanic centres.     

GALILEO系统局域完备性监测设计与实现

根据GALILEO系统局域完备性概念和网络RTK的基本理论,建立导航系统局域网络完备性监测理论和算法。算法主要包括网络系统完备性算法和用户完备性算法,内容包括网络误差模型的建立、插值算法的选择、误差改正数完备性指标的计算、完备性指标的验证和用户保护水平的计算等。仿真结果表明,采用网络RTK技术和完备性监测算法,飞机的平面保护水平和垂直保护水平均小于完备性告警门限值,可以满足飞机Ⅱ类和Ⅲ类精密进近的完备性要求,为卫星导航系统在民航中的应用提供完备性理论基础。     

山西流体观测井水位与气压相关性分析

分析了山西省流体观测井水位动态特征,利用高阶差分、回归分析方法计算了2008年山西省各观测井水位与气压相关系数,得到了气压系数的背景值,进而对气压干扰因素进行定量化的排除,并对各井的气压系数进行对比分析。结果表明,不同的观测井孔水位受气压影响程度不同,对于某一个观测井孔而言,气压系数及相关系数的变化是有一定规律的。     

中高频带地下水位对气压和固体潮的响应特征分析

我国前兆观测网络数字化改造的完成, 使得对地震地下水位观测的孕震信息提取和干扰因素排除的研究拓宽至更广的频率范围, 而对原有一些认识的重新考察也成为可能。 本文从中国地震前兆台网挑选出数据质量较好的10个台站, 分析各个台站2008年1月1日至5月11日的地下水位和气压资料及理论重力固体潮的频谱及其频域相关性特征, 并分析了地下水位对气压响应的时移。 结果表明, 中高频带地下水位对气压的响应没有低频带好, 两者相关性随周期的减小而减弱; 含水层岩性对中高频带地下水位的气压和固体潮响应特征有较大影响, 部分灰岩井在高频频段存在地下水位对气压响应异常的现象; 时移效应对水位的气压响应整体特征影响不大, 体现出两种信号自身的复杂性。