An Early Cretaceous slab window beneath central Tibet,SW China: Evidence from OIB‐like alkaline gabbros in the Duolong area

The geodynamic mechanism of the late Early Cretaceous magmatic flare‐up in the collisional zone between the Lhasa and Qiangtang terranes in Tibet is controversial because of a scarcity of robust evidence. To address this problem, we report geochronological, geochemical and Hf isotopic data for the newly discovered Gufeng gabbros from the Duolong Cu–Au mineral district of the western Bangong–Nujiang Suture Zone (BNSZ). The gabbro samples, dated at 126.3 ± 1.8 Ma, show geochemical similarities to typical ocean island basalt (OIB) and have positive εHf(t) values of +3.3 to +6.9. The gabbros were generated by decompression melting of deep upwelling asthenosphere. This event is best explained by slab break‐off and the resultant development of a slab window beneath central Tibet.     

轴对称稳恒磁场的一种解法

本文依据稳恒磁场中的高斯定理和安培环路定理，用迭代法推导出对称轴上的磁感应强度与空间任意一点磁感应强度的关系式，从而可得出轴对称稳恒磁场的无电流分布空间的解式。     

一种新的振幅滤波法在化磁极中的应用

本文针对低纬度地区频率域化磁极存在的问题，在频谱分析的基础上，提出了一种新的滤波方法即振幅滤波法。该方法能将低纬度地区化极磁场的频谱恢复到垂直磁化磁场的频谱，大大提高了低纬度地区化磁极的精度。     

Influences of wind on vertical structures of temperature and salinity,and upwelling off Zhejiang coast in summer

In this paper the influences of short-term wind on vertical structures of temperature and salinity, and the upwelling off the Zhejiang coast are studied on the basis of hydrographic data and wind near the coast in Summer (1959–1979). It is pointed out that the variations of vertical distributions of temperature and salinity, and upwelling in this region are closely related to short-term (several days to a week) variation of wind observed. The occurrence of double thermocline, a special oceanographic phenomenon, is partially related to unstable SSW wind field. SSW and NE winds in June are two dynamic factors making intermediate warm water form or disappear. Contribution No. 792 from the Institute of Oceanology, Academia Sinica. This paper was published in Chinese inOceanologia et Limnologia Sinica 14 (1): 14–21, 1983.     

The Hα-cyclonic spectra of a flare loop system on 1981 April 27

The data such as the H-spectrum-spectroheliographic (SSHG) observations, the H-chromospheric observations, etc., of a flare loop prominence which occurred on the western solar limb on 1981 April 27 have been obtained at Yunnan Observatory. The distribution of the internal motions and the macroscopical motion of the flare loop prominence with time and space in the course of its eruption and ascension is derived from the comprehensive analysis of the data. The possible physical pictures and the instability of the motions of the loop are inferred and discussed.     

Silicon isotope fractionation in bamboo and its significance to the biogeochemical cycle of silicon

A systematic investigation on silica contents and silicon isotope compositions of bamboos was undertaken. Seven bamboo plants and related soils were collected from seven locations in China. The roots, stem, branch and leaves for each plant were sampled and their silica contents and silicon isotope compositions were determined. The silica contents and silicon isotope compositions of bulk and water-soluble fraction of soils were also measured. The silica contents of studied bamboo organs vary from 0.30% to 9.95%. Within bamboo plant the silica contents show an increasing trend from stem, through branch, to leaves. In bamboo roots the silica is exclusively in the endodermis cells, but in stem, branch and leaves, the silica is accumulated mainly in epidermal cells. The silicon isotope compositions of bamboos exhibit significant variation, from −2.3‰ to 1.8‰, and large and systematic silicon isotope fractionation was observed within each bamboo. The δ³⁰Si values decrease from roots to stem, but then increase from stem, through branch, to leaves. The ranges of δ³⁰Si values within each bamboo vary from 1.0‰ to 3.3‰. Considering the total range of silicon isotope composition in terrestrial samples is only 7‰, the observed silicon isotope variation in single bamboo is significant and remarkable. This kind of silicon isotope variation might be caused by isotope fractionation in a Rayleigh process when SiO₂ precipitated in stem, branches and leaves gradually from plant fluid. In this process the Si isotope fractionation factor between dissolved Si and precipitated Si in bamboo (α_pre-sol) is estimated to be 0.9981. However, other factors should be considered to explain the decrease of δ³⁰Si value from roots to stem, including larger ratio of dissolved H₄SiO₄ to precipitated SiO₂ in roots than in stem. There is a positive correlation between the δ³⁰Si values of water-soluble fractions in soils and those of bulk bamboos, indicating that the dissolved silicon in pore water and phytoliths in soil is the direct sources of silicon taken up by bamboo roots. A biochemical silicon isotope fractionation exists in process of silicon uptake by bamboo roots. Its silicon isotope fractionation factor (α_bam-wa) is estimated to be 0.9988. Considering the distribution patterns of SiO₂ contents and δ³⁰Si values among different bamboo organs, evapotranspiration may be the driving force for an upward flow of a silicon-bearing fluid and silica precipitation. Passive silicon uptake and transportation may be important for bamboo, although the role of active uptake of silicic acid by roots may not be neglected. The samples with relatively high δ³⁰Si values all grew in soils showing high content of organic materials. In contrast, the samples with relatively low δ³⁰Si values all grew in soil showing low content of organic materials. The silicon isotope composition of bamboo may reflect the local soil type and growth conditions. Our study suggests that bamboos may play an important role in global silicon cycle.     

舟山枸杞水域的污损生物生态

本文系１９８８年９月～１９８９年９月在舟山枸杞乌里西岙水域进行挂板试验的结果。共获污损生物１３５种，其中，近岸的油库码头获７７种，远岸的养殖筏获１１０种。动物以亚热带高盐性种类为主，三角藤壶Ｂａｌａｎｕｓｔｒｉｇｕｎｕｓ、小海葵Ａｃｔｉｎｉａ、柯氏分胞孔苔虫Ｃｅｌｌｅｐｏｒｉｎａｃｏｓｔａｚｉｉ、西方三胞苔虫Ｔｒｉｃｅｌａｒｉａｏｃｃｉｄｅｎｔａｌｉｓ、艾氏美熄Ｃｌｔｉａｅｄｗａｒｄｓｉ、广口小桧叶螅Ｓｅｒｔｕｌａｒｅｌｌａｍｉｕｒｒｅｎｓｉｓ等占优势，藻类常见的有长石莼Ｕｌｖａｌｉｎｚａ、肠浒苔Ｅｎｔｅｒｏｍｏｒｐｈｙｉｎｔｅｓｔｉｎａｌｉｓ和日本多管藻Ｐｏｌｙｓｉｐｈｏｎｉａｊａｐｏｎｉｃａ。枸杞污损生物的附着期主要在夏季，附着量也以夏季最大。不同地点附着量的差异极大。夏季由于近岸三角藤壶大量附着，故生物量明显大子远岸，其他季节均是远岸大于近岸。夏季近岸三角藤壶的覆盖面积达１００％，生物量达１８１１９ｇ／ｍ２，占污损生物总生物量的９８％。故夏季是污损生物防除的主要季节，三角藤壶是防除的主要对象。与１９７５～１９７６年嵊山污损生物进行比较，发现两地污损生物的种类组成和群落结构极为相似，说明１０多年以来嵊山     

秦山核电站邻近水域的流况分析

本文分析了秦山核电站邻近水域各测站的实测流、潮流和佘流分布及季节变化。结果表明:测区内潮流为非正规丰日浅海潮流,其运动形式呈往复流。核电站二期工程取水口附近(L_1,18站)为一大流速区,而一期工程出水口周围(L_2,L_2′站)有一相对小的流速区。大流速区落潮流历时大于涨潮流历时,而相对小流速区则相反;大流速区的余流较小,而小流速区的余流大。在四个季节中,涨潮流速秋季最大,春季次之,夏季最小;落潮流速秋季最大,夏季次之,春季最小。余流冬、秋两季较大。在实测流中以潮流为主,径流和季风的作用也相当显著。     

珠江口东岸池养鲻鱼的年龄与生长

研究池养条件下鲻鱼ＭｕｇｉｌｃｅｐｈａｌｕｓＬｉｎｎａｅｕｓ的年龄和生长特性，结果表明，鳞片新年轮主要在１０—１月出现；鳞长与体长关系式为：Ｒ—０．００９０７Ｌ（０．７７６４）；Ｉ—Ｖ龄鱼体长和体重相对生长率和生长指标随着年龄增长而逐渐下降；体长与体重关系式为：Ｗ＝１．２７１６×１０（－５）Ｌ（３．０６９５），体长与全长关系式为：ＬＴ＝１０．３７１１＋１．１８０６ＬＢ，当年鱼体长和体重生长与月龄的关系分别为：ＬＢ＝８．６６６９＋２５．５７６９ｔ，Ｗ＝０．１１７０ｔ（３．５５３０），ｖｏｎＢｅｒｔａｌｌａｎｆｆｙ生长参数Ｌ∞＝６１３．２５ｍｍ，Ｋ＝０．３４１２，ｔ０＝－０．８２５，体重生长拐点值为２．４６ａ。     

The second order spectrum of two-dimensional random waves

Ｔｈｅｓｅｃｏｎｄｏｒｄｅｒｓｐｅｃｔｒｕｍｏｆｔｗｏ－ｄｉｍｅｎｓｉｏｎａｌｒａｎｄｏｍｗａｖｅｓ￥ＤｉｎｇＰｉｎｇｘｉｎｇ；ＳｕｎＦｕａｎｄＹｕＺｈｏｕｗｅｎ（ＲｅｃｅｉｖｅｄＪａｎｕａｒｙ１５，１９９３；ａｃｃｅｐｔｅｄＭａｙ３１，１９９３）Ａ...