Solar Stokes Spectrum Observation at Yunnan Astronomical Observatory

1　ＳｉｇｎｉｆｉｃａｎｃｅｏｆＳｏｌａｒＳｔｏｋｅｓＳｐｅｃｔｒｕｍＯｂｓｅｒｖａｔｉｏｎＤｕｅｔｏｔｈｅｄｅｖｅｌｏｐｍｅｎｔｉｎｏｂｓｅｒｖｉｎｇｉｎｓｔｒｕｍｅｎｔ,ｔｈｅｃｏｎｃｅｐｔｏｆｓｏｌａｒｓｐｅｃｔｒｕｍｓｈｏｕｌｄｂｅｇｅｎｅｒａｌｉｚｅｄ .Ｉｎｔｈｅｐａｓｔ,ｉｔｉｓｏｎｌｙａｓｓｉｇｎｅｄｔｏｔｈｅｏｒｄｉｎａｒｙｏｒｕｎｐｏｌａｒｉｚｅｄｓｐｅｃｔｒｕｍｒｅｃｏｒｄｉｎｇｔｈｅｗａｖｅｌｅｎｇｔｈ ｄｉｓｔｒｉｂｕｔｅｄｉｎｔｅｎｓｉｔｙｏｆｔｈｅｃｏｎｔｉｎｕｕｍａｎｄ…     

The Holocene Evolution of the Ebre Delta Catalonia, Spain

１　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｆｉｒｓｔｒｅｌｅｖａｎｔｉｎｆｏｒｍａｔｉｏｎａｂｏｕｔｔｈｅｇｅｏｌｏｇｙａｎｄｅｖｏｌｕｔｉｏｎａｒｙｔｒｅｎｄｓｏｆｔｈｅＥｂｒｅｄｅｌｔａｃａｍｅａｓｐａｒｔｏｆａｓｔｒａｔｉｇｒａｐｈｉｃｓｔｕｄｙｂｙＭａｌｄｏｎａｄｏＡ［１］．Ｈｅｍｅｎｔｉｏｎｅｄｔｈａｔｄｕｒｉｎｇｔｈｅｌａｓｔｔｒａｎｓｇｒｅｓｓｉｖｅｅｖｅｎｔ,ｔｈａｔｉｓｂｅｆｏｒｅｓｅａｌｅｖｅｌｒｅａｃｈｅｄｉｔｓｐｒｅｓｅｎｔｌｅｖｅｌ,ｄｅｌｔａｉｃｐｒｏｇｒａｄａｔｉｏｎｏｎｌ…     

存在一个气候吸引子吗？

过去有关几百万年气候演变的信息,多半来卜＆过深海岩芯同位素记录的时间序列。气候学的一个主要任务是,从这些有限的信息中识别气候动刀学源的基本特征、我们利用非线性动力系统理论．仅用这些时间序列资料就可确定某些气候的关键特征。     

应用正交偶极Z测井资料测量EDA地层的横波各向异性

采用3种分析EDA地层横波各向异性的技术处理了从Wyoming Powder河谷用正交偶极子测井取得的数据资料.这些处理技术基于挠曲波在各向异性介质中发生分裂的现象而模拟VSP中的横波数据处理.四组分的正交偶极子测井数据是用Schlumberger公司的测井仪从井深3 550m的一段长为56m的垂向裂缝发育的地层中采集的.根据对各发射-接收器组记录数据处理结果的一致性与方差来看,非正交旋转法效果最好.但线性变换法的结果也是可以接受的.线性变换法的优点是节省机时.从这组数据处理的结果来看,极化能谱法计算量相对较大并且对噪音的影响较敏感.     

巨型中温热液金矿床的特征描述成因模式及勘查区的选择准则

中温热液金矿床赋存在由花岗岩侵位的碰撞造山带的各个时代的以火山岩为主和沉积岩为主的上壳岩带内。贫的和富的成矿带的主要区别是,富矿带容纳有异常大的矿床。这一模式是对区域内所属不同成矿带的矿区间进行成矿贫富性的详细对比而得出的。我们对该区域４７ 个巨型（＞ ６０ｔＡｕ）中温热液金矿床的地质特征和背景的研究表明,８０％ 的金矿床产在以火山岩为主的上壳岩带,而２０％ 的金矿床产在沉积岩为主的上壳岩带。几乎没有证据能够说明巨型矿床的产生是受矿物沉积规模所控制。例如：围岩岩性的复杂性控制着矿床构造的复杂性,而与矿床规模无关。从区域上讲,不管怎样,巨型金矿床特定的有利的岩石组合并可能与早期形成的金矿化体有显著关系。多数以火山岩为主的上壳岩带内的巨型金矿床出现在具有高镁火山岩（科马提岩）或侵入的岩带内,其中２０％ 与长英质火山岩共生;７５％ 含有前变质高铝热液蚀变矿物组合。一个巨型矿床和许多小型矿床与斑岩型Ｃｕ－Ａｕ 矿化关系密切。赋存在前寒武纪以沉积岩为主的上壳岩带内的巨型金矿床均以含铁建造为主,但在显生宙以沉积岩为主的上壳岩带内的矿床却不是这样。解释中温热液金矿床的共有特征,金矿床矿物学特有的事实说明与围岩环境有关。矿床的同位     

用爆炸源和天然地震源对圣安德烈斯断层成像

现有证据说明,断层带的不均匀性可能在地震破裂局域化中起决定性的作用(Aki,1995)。这种不均匀性可以呈现多种形式,如物理性质(弹性、孔隙流体压力等)随空间的变化,或断层面的复杂性(弯曲、错断等)。P波和S波速度(v_p和v_S)结构的高分辨率三维模型以及精确的震源为研究断层带不均匀性对破裂局域化的作用     

Diurnal SST warming in the Bay of Biscay: satellite measurements and model prediction

INTRODUCTIONIt has long been recognized that a diurnal thermal cycle occurs in the upper layer of the ocean(Stommel et al., 1969; Price and Weller, 1986). Interest in the subject has revived in recentyears due to the importance of resolving the diurnal cycle for correctly coupling the ocean and atmosphere (Lukas, 1991 ). While the study of the diurnal cycle is of intrinsic scientific interest, italso offers the benefit to remote sensing scientists of identifying the bias caused by the di…     

Depth of closure: New calculation method based on sediment data

Obtaining depth of closure (DoC) in an accurate manner is a fundamental issue for coastal engineering, since good results for coastal structures and beach nourishment depend mainly on DoC. Currently, there are two methods for obtaining the DoC, mathematical formulations and profile surveys. However, these methods can incur important errors if one does not take into account the characteristics and morphology of the area, or if one does not have a sufficiently long time series. In this work the DoC is obtained from the break in the trend of the sediment with the depth, that is, in general with the increase of the depth a decrease in the size of the sediment takes place. However, at one point this tendency changes and the size increases, and then decreases again. When comparing the point where the minimum sediment size occurs before the increase, it is observed that the error incurred is small compared to other methods. If the Standard Deviation of Depth Change (SDDC) method is considered as the most accurate method, the error incurred by the proposed method is less than 7%. In addition, it can be seen that the dispersion of the sediment method always occurs outside the zone of bar movement. Whereas in the methods of profiles survey (using 2 cm precision profiles), sometimes the DoC is obtained within the active zone of bar movement. In addition, where the relative minimum of the median sediment size is found, and the sizes of 0.063 and 0.125 mm predominate in the composition of the sample. Therefore, this new method allows the precise location of the DoC to be obtained in a fast and simple way. Furthermore, this method has the advantage that it is not affected by the modifications that may be experienced by both the study area and the cross-shore beach profile.     

Field Relationships, Geochemistry, Zircon Ages and Evolution of a Late Archaean to Palaeoproterozoic Lower Crustal Section in the Hengshan Terrain of Northern China

The Hengshan complex forms part of the central zone of the North China Craton and consists predominantly of ductilely-deformed late Archaean to Palaeoproterozoic high-grade, partly migmatitic, granitoid orthogneisses, intruded by mafic dykes of gabbroic composition. Many highly strained rocks were previously misinterpreted as supracrustal sequences and represent mylonitized granitoids and sheared dykes. Our single zircon dating documents magmatic granitoid emplacement ages between 2.52 Ga and 2.48 Ga, with rare occurrences of 2.7 Ga gneisses, possibly reflecting an older basement. A few granitic gneisses have emplacement ages between 2.35 and 2.1 Ga and show the same structural features as the older rocks, indicating that the main deformation occurred after -2.1 Ga. Intrusion of gabbroic dykes occurred at -1920 Ma, and all Hengshan rocks underwent granulite-facies metamorphism at 1.88-1.85 Ga, followed by retrogression, sheafing and uplift. We interpret the Hengshan and adjacent Fuping granitoid gneisses as the lower, plutonic, part of a late Archaean to early Palaeoproterozoic Japan-type magmatic arc, with the upper, volcanic part represented by the nearby Wutai complex. Components of this arc may have evolved at a continental margin as indicated by the 2.7 Ga zircons. Major deformation and HP metamorphism occurred in the late Palaeoproterozoic during the Luliang orogeny when the Eastern and Western blocks of the North China Craton collided to form the Trans-North China orogen. Shear zones in the Hengshan are interpreted as major lower crustal discontinuities post-dating the peak of HP metamorphism, and we suggest that they formed during orogenic collapse and uplift of the Hengshan complex in the late Palaeoproterozoic （〈1.85 Ga）.