论松嫩平原深层地下水的福与祸——破解“平原型大骨节病”之谜

矿化程度极低的深层地下水，往往给人体健康带来各种危害，主要是欠缺某些化学元素引起的地方病，过去多被忽视。以为矿化程度越低水质越佳；饮用水标准中各种化学元素规定的下限值常不被重视，一旦发生了疾病，多从污染或元素超标中查找问题。由于这种认识偏差，常常造成防治不利，贻误战机。松嫩平原部分氟病区，因为饮了深层“超低氟水”（水中氟的质量分数小于0.2mg/L)新发了大骨节病或患了无名疼痛病，即为典型例证。防治办法，一要加强源头矿化，二要注意终端补氟。由此有“药疗不如食疗”、“饮疗胜于食疗”之说，饮茶是最佳补氟之举，而且要从孕期或婴幼儿做起。拟彻底根治，可深浅层地下水混合开采。     

应用模糊数学方法提取水体面积信息

讨论了应用ＮＯＡＡ－ＡＶＨＲＲ资料提取水体信息的方法。采用１．２通道反射率数据构成的归一化植指数（ＮＤＶＩ）来识别水体，并初步提出了应用模糊数学方法提取混合像元中的水体面积信息。     

The Relationship Between Mineralogical Characteristics and Isotopic Composition of Sphalerite,as Exemplified by the Huxu Deposit,China

The relationship between mineralogical characteristics and isotopic composition of sulfides has not received its proper share of attention from geologists, although many references are available concerning the application of sulfur isotopes to geological problems. Located in the vicinity of the contact region between the Yangtze Platform and the South China Caledonian Folding Zone, the Huxu deposit is hosted in a structural zone in quartz-diorite-porphyrite emplaced in Jurassic volcanic rocks. Sphalerite and galena are the principal ore minerals in the deposit. (1) Sphalerite is highly variable in color and this variation can be related to its chemical composition and sulfur isotopic characters. Dark colored sphalerites are poor in Zn and Ni, rich in Pb, Cu, Fe, Ag and Au and have high δ³⁴S values, while the opposite is true for light-colored ones. (2) δ³⁴S of sphalerite is negatively correlated with the contents of Zn and Ni and positively correlated with the contents of Pb, Cu, Ag and Au, with the absolute values of the correlation coefficients being greater than 0.7. The above two characters suggest that the sulfur isotopic composition of sphalerite is controlled not only by the physicochemical conditions under which the mineral was formed, but also by mineralogical characteristics of the host mineral. (3) Apparent correlations exist among the constituent elements in the sphalerite. For example, Zn is negatively correlated with Cu, Pb, Fe, Ag and Au and positively correlated with Ni. (4) Sphalerites of the same color in the same hand specimen always show similar characters with respect to trace element and sulfur isotopes. (5) Two distinct trends of evolution can be recognized between Zn and Cu, Zn and Pb, Zn and Ag and between these elements on one hand and δ³⁴S on the other, reflecting that the ore-forming solutions may have resulted from mixing of fluids of different origins. (6) Pb is uniformly distributed in sphalerite and shows positive correlations with Cu, Fe, Ag and δ³⁴S, suggesting isomorphic substitution in the sphalerite lattice. This project was financially supported by the Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences.     

南海北部大陆架现代礁源碳酸盐与陆源碎屑的混合沉积作用

在南海北部大陆架陆源碎屑沉积占优势的背景上，在珊瑚岸礁和堡礁周围，广泛发育着礁源碳酸盐和陆源碎屑组成的混合沉积。它们以砂屑、砂砾屑结构为主并含有生物格架结构。混合沉积的形成条件是具备碳酸盐和硅质碎屑两类物源，活跃的水动力，干湿交替的气候，此外，海平面的相对波动，也会造成积极的影响。混合沉积方式有随机式、相变式和随机 - 相变式等三种。混合沉积体常是多种混合方式交替、叠加而成的沉积复合体。礁源与陆源混合沉积相模式是从岸礁 - 堡礁相模式基础上发展而来，按沉积相和沉积结构可以分为五种混合沉积：1)礁基混积岩和礁格架混积岩，2）礁坪砂砾屑混积岩，3）礁后海滩 - 沙堤砾砂屑混合沉积，4）礁后泻湖砂屑混合沉积和5）礁前（翼）浅海砂屑混合沉积。礁源与陆源混合沉积的鉴别标志是珊瑚骨屑和岩屑各占10 - 50 ％，其它生物碎屑不计。南海大陆架现代混合沉积是一个典型的实例，可为全面研究现代南海沉积学和比较沉积学提供依据。     

Evolution of salinity field in the upper layers of the east central Arabian Sea and northern Bay of Bengal during summer monsoon experiments

The intra-seasonal variability observed in the salinity field of the upper layers at a few locations in the east central Arabian Sea and the northern Bay of Bengal during the summer monsoon seasons of 1977 and 1979 is documented with the aid of short time series (1–2 weeks) of salinity measurements made from USSR and Indian ships deployed during MONSOON-77 (1977) and MONEX-79 (1979) field experiments. In the Arabian Sea a typical subsurface maxima observed beneath the mixed layer base either disappeared or considerably weakened due to strong vertical mixing caused by the monsoonal forcing. In the northern Bay of Bengal the salinity variability in the top 30 m water column was rapid and appeared to be influenced by large amounts of fresh water from rain and probably from the major adjoining rivers. Some simple diagnostic calculations are presented to assess the relative importance of various processes which control the observed salinity variability.     

Integrated biostratigraphic and sequence stratigraphic framework for Upper Cretaceous strata of the eastern Gulf Coastal Plain, USA

Upper Cretaceous (Santonian-Maastrichtian stages) strata of the eastern US Gulf Coastal Plain represent a relatively complete section of marine to nonmarine mixed siliciclastic and carbonate sediments. This section includes three depositional sequences which display characteristic systems tracts and distinct physical defining surfaces. The marine lithofacies are rich in calcareous nannoplankton and planktonic foraminifera which can be used for biostratigraphic zonation. Integration of this zonation with the lithostratigraphy and sequence stratigraphy of these strata results in a framework that can be used for local and regional intrabasin correlation and potentially for global interbasin correlation. Only the synchronous maximum flooding surfaces of these depositional sequences, however, have chronostratigraphic significance. The sequence boundaries and initial flooding surfaces are diachronous, and their use for correlation can produce conflicting results. The availability of high resolution biostratigraphy is critical for global correlation of depositional sequences.     

Radiometric ages of Alpine metamorphic rocks in the western and central Alps

Abstract The chronological characteristics of Alpine metamorphic rocks are described and Alpine metamorphic events are reinterpreted on the basis of chronological data for the western and central Alps from 1960 to 1992. Metamorphic rocks of the Lepontine, Gran San Bernardo, Piemonte, Internal Crystalline Massifs and Sesia-Lanzo mostly date Alpine metamorphic events, but some (along with granitoids and gneisses from the Helvetic and Southern Alps) result from the Variscan, Caledonian or older events and thus predate the Alpine events. Radiometric age data from the Lepontine area show systematic age relations: U-Pb monazite (23-29 Ma), Rb-Sr muscovite (15–40 Ma) and biotite (15–30 Ma), K-Ar biotite (10-30 Ma), muscovite (15–25 Ma) and hornblende (25-35 Ma), and FT zircon (10-20 Ma) and apatite (5-15 Ma), which can be explained by the different closure temperatures of the isotopic systems. A 121 Ma U-Pb zircon age for a coesite-bearing whiteschist (metaquartzite) from the Dora-Maira represents the peak of ultra-high pressure metamorphism. Coesite-free eclogites and blueschists related to ultra-high pressure rocks in the Penninic crystalline massifs yield an ⁴⁰Ar-³⁹Ar plateau age of about 100 Ma for phengites, interpreted as the cooling age. From about 50 Ma, eclogites and glaucophane schists have also been reported from the Piemonte ophiolites and calcschists, suggesting the existence of a second high P/T metamorphic event. Alpine rocks therefore record three major metamorphic events: (i) ultra-high and related high P/T metamorphism in the early Cretaceous, which is well preserved in continental material such as the Sesia-Lanzo and the Penninic Internal Crystalline Massifs; (ii) a second high P/T metamorphic event in the Eocene, which is recognized in the ophiolites and calcschists of the Mesozoic Tethys; and (iii) medium P/T metamorphism, in which both types of high P/T metamorphic rocks were variably reset by Oligocene thermal events. Due to the mixture of minerals formed in the three metamorphic events, there is a possibility that almost all geochronological data reported from the Alpine metamorphic belt show mixed ages. Early Cretaceous subduction of a Tethyan mid-ocean ridge and Eocene continental collision triggered off the exhumation of the high pressure rocks.     

电离层赤道异常对返回散射电离图的影响

本文给出了太阳黑子高年冬季跨电离层赤道异常区传播试验的高频返回散射电离图.经过分类研究,指出了有一类双回波区组合型P ′（f）返回散射电离图是一种新的形态.通过射线追踪合成技术分析,表明了这类型实验返回散射电离图是沿探测路径存在双峰电子浓度分布的反映,时序电离图的变化特征显示了赤道异常区的电子浓度变化规律,因而证明了高频返回散射技术在研究赤道异常区电离层峰运动的可能性及其潜力.     

解混合边值问题直接计算位系数的变分原理

本文提出了利用变分法解混合边值问题直接计算位系数的原理。根据这一原理可解第一、第二和第三边值问题的混合边值问题直接求得位系数。利用这一原理可较简单地联合利用经典重力测量(即重力点的平面位置由天文或三角测量确定,高程由水准或三角高程确定)、卫星重力测量(即利用卫星定位技术确定重力点的平面位置和大地高)以及卫星测高数据研究地球的重力场。     

Synoptic distributions of thermal surface mixed layer and thermocline in the southern yellow and East China Seas

Synoptic distributions of thermal surface mixed layer and thermocline were identified using four airborne expendable bathythermograph (AXBT) surveys (September 1992 and February, May, and September 1993) in the southern Yellow and East China Seas. Seasonality and a dominant driving mechanism of the surface mixed layer were examined. The dominant driving mechanisms differ between seasons and between on-shelf and off-shelf regimes. Currents, eddies, and migration of bottom cold waters (on the shelf) also affect the surface mixed layer. Thermocline thickness, temperature difference from thermocline top to bottom, and thermocline intensity in warm seasons were measured, and their synoptic features were also discussed.