The inner inner core of the Earth: Texturing of iron crystals from three-dimensional seismic anisotropy

We present a three-dimensional model of the seismic anisotropy and texturing of iron crystals in the inner core. The form of the anisotropy changes suddenly at slightly less than half of the inner core radius. The outer part is composed of iron crystals of a single phase with different degrees of preferred alignment along the spin axis of the Earth. The inner part may be composed of a different phase of crystalline iron or have a different pattern of alignment.     

ANALYSIS OF Cu, Cd, Co AND Ni IN SURFACE WATER OF THE KUROSHIO AREA IN THE EAST CHINA SEA

Study of 1986 and 1987 heavy metal distribution in surface water of the Kuroshio area in the East China Sea showed regional and slight seasonal variations in distribution and concentration . Heavy metal levels in Taiwan Strait, the sea area north of Taiwan and the continental shelf are higher than those in the main axis of the Kuroshio . Dissolved Cu in summer and winter decreases with the increase of salinity , but dissolved Cd has no obvious change with salinity .     

The mid- to late Holocene paleoceanographic changes in the northern North Atlantic

A high-resolution diatom record from core MD99-2275 shows a general paleoceanographic change in the northern North Atlantic since 5000 cal. a B.P. by Principle Component Analysis. Sea surface temperature (SST) increased gradually during 5000 and 3000 cal. a B.P. on the North Icelandic shelf as a result of increasing influence of warm Atlantic water mass from the Irminger Current. It apparently started to decrease since 3000 cal. a B.P. due to the weakening influence of warm water and enhanced influence of the Polar and Arctic water masses from the East Greenland Current and the East Icelandic Current. Abrupt decreases in SST and intrusions of Polar and Arctic water superimposed on the late Holocene cooling trend during 3000-2600, 1300-1000 and 600-200 cal. a B.P.. The paleoceanographic record revealed from core MD99-2275 corresponds well with δ¹⁸O record from the GISP2 and is generally consistent with other SST records based on diatom on the North Icelandic shelf. __________ Translated from Marine Science Bulletin, 2008, 27(5) [译自:海洋通报]     

中国海与现代科学技术

中国既是一个大陆国家又是一个海洋国家，约３００万平方公里的海域与６５００多个岛屿如同陆地资源一样为中国人民提供了舟辑之便与渔盐之利，还蕴藏着丰富的矿产资源。     

Architecture and recognition criteria of ancient shelf ridges; an example from Campanian Almond Formation in Hanna Basin,USA

Shelf ridges are sedimentary bodies formed on the continental shelf due to transgressive reworking (tidal or storm) of lowstand deposits. Common on modern shelves, they are under‐represented in the geological record due to a lack of recognition criteria and facies model. This article proposes a new facies and architectural model for shelf ridges, linked to their inception–evolution–abandonment cycle and the process regime of the basin. The model is mainly based on new outcrop data and interpretations from three sandstone bodies of the Almond Formation, an overall transgressive interval during the infill of the Campanian Western Interior Seaway. Building from the case study, and ancient and modern examples, six characteristics are proposed for the recognition of ancient shelf ridges. Shelf ridges: (i) are encased between thick marine mudstone intervals; (ii) have a basal unconformity that erodes into marine muds or into the remnants of a previous shoreline; (iii) have a non‐erosional upper boundary that transitions into marine muds; (iv) are characterized by clean and well‐sorted sandstones, often cross‐bedded; (v) contain fully marine ichnofauna; and (vi) present compound architectures with large accretion surfaces and lower order structures. Although shelf ridges have been described in previous studies as generated exclusively by either tidal or storm currents, it is clear, from modern examples and the case study, that these two processes can be recorded and preserved in a single shelf ridge. The stratigraphy of these sandstone bodies is therefore much more complex than previously recognized, bearing the signature of changing tidal and storm intensity through time. Because they are developed during transgressions, shelf ridges are commonly subject to strong changes in process regime as sea‐level changes can easily affect the oceanographic conditions and the morphology of the basin. For this reason, shelf ridges can provide the best record of shelf process variability during transgressions.     

珠江口盆地陆架坡折带海底滑坡及其影响因素

为了解海底滑坡在陆架坡折演化过程中所起的作用并分析影响海底滑坡发育的因素,以最新采集的二维和三维地震资料为基础,综合运用了地貌分析和地震解释技术,通过对滑坡的地貌形态特征及地震响应特征进行详细刻画,在珠江口盆地陆架坡折带新近纪地层中识别出多处海底滑坡,明确了其分布范围并建立了滑坡发育的地质模式。分析认为,珠江口盆地相对海平面变化和流体活动的综合作用是导致研究区海底不稳定的主要因素。海底滑坡发源于海底峡谷的朔源侵蚀,向上陆坡扩展并终止于陆架坡折带。     

从原岩建造角度探讨辽河群的形成环境

文章通过对辽河群上百条实测剖面中岩石类型进行了加权平均统计,得出了辽河群中各种岩石类型的百分含量;对辽河群中已有的上千组岩石化学数据进行了筛选,选取具有代表性的94组数据,用以对辽河群原岩建造恢复和形成构造环境的讨论。认为辽河群的原岩建造为巨厚的陆源沉积碎屑岩—内源沉积碳酸盐岩(夹少量火山岩)建造,具有典型的大陆架沉积特征;这在威尔逊旋回中属于成年期洋盆(大西洋)阶段所独具的沉积特征,这个洋盆暂且称之为辽吉古元古洋。     

黄海西南部陆架锋区锋断面环流数值模拟

浅水陆架锋是近岸混合区与外海层化区的分界面,对近海海雾形成、渔业生产及污染扩散有重要影响。赵保仁根据实测SST资料利用Simpson-Hunter参量提出黄海沿岸区域存在潮混合控制的浅水陆架锋,他还进一步指出,黄海沿陆架锋与冷水团边界区是黄海的主要上升流区,即锋面上升流区,夏季黄海西部沿岸存在沿冷水团锋面南下的强流。James用这一诊断模型讨论过锋区环流情况,Garret等用的是半诊断模型。他们均得出垂直于锋面的断面内在锋区附近存在着双环流结构。