海平面上升与中国沿海地区的可持续发展

本文简明地分析了海平面上升的概念,同时提出了需预测防治对策的三个问题,即在空间上要扩大海岸防灾和管理的范围;在时间上要有足够的预见性;同时纳入沿海中长期经济规划中去。     

Volcanic stratigraphy of DSDP/ODP Hole 395A: An interpretation using well-logging data

Deep Sea Drilling Project/Ocean Drilling Program Hole 395A was drilled approximately 500 m deep into young oceanic crust west of the Mid-Atlantic Ridge. Core recovery is very poor in this hole and therefore continuous downhole measurements are important to understand the drilled lithology. Geophysical downhole measurements were carried out during several cruises. A new set of logs was recorded during Leg 174B in summer 1997. The new logging data show a significant improvement in data quality compared to older measurements from Leg 109. The lithostratigraphy established from cores gives only limited information because of the poor core recovery in this hole. The gaps in the core lithostratigraphy are filled by reconstructing a synthetic lithological profile using the standard well-logging data. Three types of lava morphologies, massive basalts, altered lava flows, and pillow basalts, may be distinguished using the logs because the lava morphologies show differences in their physical properties due to differences in fracturing and alteration. The synthetic lithological profile gives a more detailed and precise vertical definition of single layers than the core profile. The integration of further logging and core data enables a detailed reconstruction of the accretion history at the drill site. Cyclic, upward decreasing trends in the resistivity logs were already observed during earlier cruises and were referred to magmatic cycles. Similar trends occur in the density log and, inversely, in the total gamma ray log. The trends reflect gradual changes in fracturing, porosity, permeability, and alteration and cover depth intervals of several tens of meters. Boundaries between cycles are interpreted to correspond to periods of volcanic quiescence. Two types of boundaries may be identified. Boundaries correlating with reversals in the magnetic field and/or changes in the geochemical composition of the basalts are interpreted as long pauses. Basalts separated by these boundaries were probably fed by separate magma reservoirs. Boundaries identified only by changes in alteration but not in geochemistry are interpreted to represent shorter pauses. They separate basalts that were probably fed by the same magma chamber. This revised version was published online in November 2006 with corrections to the Cover Date.     

Seafloor Properties From Penetrometer Tests

Quasi-static and freely falling dynamic penetrometers are currently in extensive use for measuring the mechanical properties of sediments composing the littoral seafloor. Sediments in this zone are often inhomogeneous both laterally and with depth so that it is difficult to predict burial of mines and other objects when relying on models that assume uniform, homogeneous sediment. The results of penetrometer tests discussed in this paper show that there can be a wide spread in the penetration resistance that is measured depending on the degree of sediment inhomogeneity and the rate of penetration. Moreover, the dilative response of granular strata appears to further complicate matters because of the sudden, large changes in shear strength that can occur. As a result, mine burial models currently in use, which often rely on simple strain-rate factors and shear strength determined from experiments utilizing uniform, reconstituted sediment, do not appear to be adequate to handle real in situ conditions in many cases. The objective of this paper is to obtain a better understanding of in situ properties and how they may be incorporated into various burial models.     

水盾草(Cabomba caroliniana)入侵对沉水植物群落物种多样性组成的影响

采用群落学样方调查法, 对中国的水生入侵种水盾草所侵入的沉水植物群落进行研究.主要以28个样地（包括4个对照样地）为调查对象, 并将道场、太湖、陶堰、柯岩、方桥和五常6个作为固定样地进行每个季度的调查.α、β多样性测度公式分析, 结果表明, （1） 各个调查群落的物种组成差异都较大, 物种数目不等; 固定样地大多在不同季节中物种数目有所变化, 春夏季多, 冬季少. （2） 一般样地的3个α多样性指数中, Simpson指数和Shannon- Wiener指数变化较为一致, Pielou均匀度指数变化不太一致.物种多样性与水盾草的入侵程度有关, 水盾草优势程度越高, 物种多样性就越低.（3） 对照样地？？多样性指数与相应的一般样地比较, 多样性也与优势度相关.（4） 固定样地？？多样性指数一般冬季较其他三个季度低, 但2001年与2002年没有大的差异.（5）βT多样性指数显示, 在0.4-2.4m水深, 种类组成都有所改变, 在0.4-0.8m和0.8-1.2m种类改变较多, 且以稀有种类为主.水盾草对本土水生植物有负面影响, 应引起高度重视, 进行相关研究.     

Spatiotemporal modeling of monthly soil temperature using artificial neural networks

Soil temperature data are critical for understanding land–atmosphere interactions. However, in many cases, they are limited at both spatial and temporal scales. In the current study, an attempt was made to predict monthly mean soil temperature at a depth of 10 cm using artificial neural networks (ANNs) over a large region with complex terrain. Gridded independent variables, including latitude, longitude, elevation, topographic wetness index, and normalized difference vegetation index, were derived from a digital elevation model and remote sensing images with a resolution of 1 km. The good performance and robustness of the proposed ANNs were demonstrated by comparisons with multiple linear regressions. On average, the developed ANNs presented a relative improvement of about 44 % in root mean square error, 70 % in mean absolute percentage error, and 18 % in coefficient of determination over classical linear models. The proposed ANN models were then applied to predict soil temperatures at unsampled locations across the study area. Spatiotemporal variability of soil temperature was investigated based on the obtained database. Future work will be needed to test the applicability of ANNs for estimating soil temperature at finer scales.     

栾川群大红口组火山岩研究初探

河南省栾川群大红口组火山岩 ,岩性以碱性粗面质熔岩为主 ,经受不同程度的区域变质、动力变质及热液变质作用。喷发类型以裂隙式为主 ,有 4个喷发韵律 ,喷发环境为浅海 ;岩石地球化学特征显示 :其碱性火山岩属钾质型 ,形成于板内裂谷环境 ,与其伴生的辉长岩为同源岩浆成因 ,均来源于上地幔与下地壳的部分熔融产物     

Modeling seismic reflections from thin-bed dolomite layers in diatomite formation

Abstract The origin of dolomite and its diagenesis are still not fully understood. The timing and occurrence of dolomite beds remain key problems. Many thin‐bed layers of dolomite in marine sediments were discovered at drill sites in the forearc basin west of the Japan Trench during the Ocean Drilling Program Leg 186. The thickness of the dolomite layers ranges from 0.5 to 2 m, estimated from the well log. These thin‐bed dolomite layers were able to be identified on seismic data, through quantitative analysis and comparison of the data with synthetic seismograms. Amplitude‐preserved seismic data processing with broadband high‐resolution enhancement helps to estimate the reflectivity series dominated by the large impedance contrast between the dolomite layers and the host sediments. In this report, the first geophysical evidence of large‐scale dolomitization is provided. The occurrence of thin dolomitic layers embedded in diatomaceous sediments is on a basin scale rather than being an isolated event, which constrains the type of dolomitization and the timing of layered dolomitization. It was found that thin‐bed dolomite layers occur where there is an abrupt change in sedimentation rate. Layered dolomitization starts when sedimentation rate changes (from high to low or vice versa). Two dolomite layers coincide with the Miocene–Pliocene and Pliocene–Pleistocene age boundaries. Formation of dolomite beds could be a timing signal of a dramatic change in paleoceanographic and paleoclimatic environments.     

岩石孔隙结构的地震信号特征

岩石孔隙结构是控制砂岩和碳酸盐岩的地震波速度和渗透率的重要参数之一。如果两种类似的岩石其孔隙度一定,而渗透率不同,那么它们的声波速度相差2km/s,而渗透率两者则可能相差近6个数量级,即从0.01mD到20mO。在本文中我们总结了由一个广义孔隙弹性理论简化的一个双参数弹性速度模型，以描述孔隙结构对弹性波的影响。由于矿物和储层的流体是给定的,我们用孔隙度和骨架的柔性(挠性)因子来确定速度模型,这个模型可以用于地震反演和储层表征,已改善孔隙度和储量的计算骨架柔性因子可用于岩石结构(PST)类型的定量分类,并可以利用叠前、叠后的两种地震资料将其与孔隙的连通性和渗透率联系起来。本项研究同时也有助于说明为什么振幅与偏移距(AVO)分析用于流体检测在某些情况下失败。这是由于孔隙结构对地震波的影响能够掩盖所有流体效应，特别是在碳酸岩中。     

青岛近岸特征环境中海洋异养细菌的分布规律及其分子鉴定

研究海洋微生物特征,从青岛近岸养殖密集区、工业区、洁净区分离了428株海洋异养细菌,采用BIOLOG技术对其进行了鉴定和聚类,从中选出13株具有代表性的菌株,克隆其16SrDNA片段,进行分子鉴定。结果表明,它们分别属于弧菌属(Vibrio)、不动杆菌属(Acinetobacter)、假交替单胞菌属(Pseudoalteromonas)、假单胞菌属(Pseudomonas)、海单胞菌属(Oceanimonas)、噬纤维菌属(Cellulophaga)、赤细菌属(Erythrobacter)和Rhodovirga。在3种特征环境中,海洋异养细菌的分布具有一定的规律性:其中洁净区的特征类群属于弧菌属(Vibrio),工业区的特征类群属于弧菌属(Vibrio)和不动杆菌属(Acinetobacter),养殖密集区的特征类群属于弧菌属(Vibrio)、假交替单胞菌属(Pseudoalteromonas)、假单胞菌属(Pseu-domonas)、海单胞菌属(Oceanimonas)、赤细菌属(Erythrobacter)、噬纤维菌属(Cellulophaga)和噬冷菌属(Algoriphagus)。