海平面变化、黄河改道与贝壳堤发育的对应关系

全新世海侵高峰过后，海平面一直处于幅度不大（约１ｍ左右）的振荡运动状态．对应四次“小高海面”时期，天津滨海平原上堆积了四道贝壳堤．历史上，黄河在本区入海，使贝壳堤的贝类组成发生了变化     

海平面变化,黄河改道与贝壳堤发育的对应关系

全新世海侵高峰过后，海平面一直处于幅度不大（约１ｍ左右）的振荡运动状态对应四次“小高海面”时期，天然滨海平原上堆积了四道贝壳堤历史上，黄河在本区入海，使贝壳堤的贝类组成发生了变化。     

天津古海岸遗迹与湿地

贝壳堤新建的天津市大港区高沙岭海滨浴场已成为京津居民度夏的好场所。这里,修筑了一条东西向的防波堤。不到一年的时间,南侧堤脚下就堆起了1米厚的贝壳,而北侧堤脚下则没有贝壳。游人在捡拾贝壳时常问浴场工作人员:“是你们把贝壳有意堆放在这儿的?”这当然不是,这是沿岸流及潮汐对海流泥沙及其中的贝壳进行搬运时,起了簸选作用,加上东南风的吹扬,便把贝壳堆积于南侧堤脚下。同样,东北风的作用,也可使沿海盐池东侧堆积些贝壳,西侧则没有     

黄骅的古贝壳堤

今年5～6月,宋庆龄基金会野生生物保护基金管理委员会组织开展了2000年“环渤海采访纪行”活动。7月上旬,笔者随同北京部分新闻单位记者,应邀赴河北省黄骅市采访计划实施情况,有幸来到闻名的黄骅古贝壳堤,耳闻目睹它的今昔,内心感受颇深。“贝壳堤”也称“蛤蜊堤”。《地质学词典》中解释:指海岸带淤泥质海岸平原上由海生贝壳碎屑和细沙、粉沙组成     

潮汕平原的贝壳堤

广东潮汕平原,散布着许多由贝壳碎屑堆积而成的长堤,地理学称为海滩岩,俗称贝壳堤,有的群众叫它(虫習)壁龙.大多数的贝壳堤,今已无法辨认其"庐山真面目",经过漫长岁月的泥砂堆积,已被埋没在冲积层中.聪明的潮汕先民,就利用它那坚实雄伟的身躯,兴建楼     

基于ANSYS的贝壳贴片切割机构

基于ANSYS软件设计了一种贝壳装饰贴片切割机构．该机构采用钢带压紧待加工的贝壳．使之随转盘同步旋转，即当贝壳落入到带有固定槽的转盘后很快被同步回转的钢带压紧．进入砂轮切割区进行切割加工．加工后的贝壳脱离钢带压紧区后自动脱落，保证了对贝壳的工艺要求．通过有限无分析及实际应用表明．该机构简单可靠，实现了夹紧过程自动化，提高了生产效率，具有一定的经济效益．     

四万年以来河北平原古海岸线的变化

根据海相沉积、贝壳堤、古生物和考古的发现,探讨河北平源古海岸线的变化。     

渤海湾滨岸风暴潮沉积

风暴潮是渤海湾常见的一种灾害性事件,它不仅给沿海地区造成巨大危害,同时还对滨岸地貌、沉积产生深刻影响．本文分析了渤海湾风暴潮的形成机制及其滨岸沉积作用,在大量资料分析研究的基础上,揭示了渤海湾沿岸潮上带低洼平原、贝壳堤及海河口风暴潮沉积的特征     

苏北滨海平原沉积特征探讨

野外地质调查发现，苏北岗身除了滨外砂堤型和滩脊型成因外，还发现风成砂堤型和风暴型。中岗属风成砂堤堆积。距今约４０００年时，古黄河北迁，导致本区原河口岸线废弃，在风力作用下发育成古砂岗；新岗发现风暴沉积。在潮上带粘土层顶部，出现具高流态平行层理的细砂层，杂乱堆积的贝壳砂层，细砂中重矿物含量可达１０％以上，明显系风暴增水沉积。本区岗身间洼地主要为潮坪沉积?西部砂质物占优，东部以泥质为主，反映了全新世晚     

黄河三角洲贝壳堤不同植被类型的土壤水分物理特征及蓄水潜能评价

贝壳堤生态系统具有典型性和脆弱性,土壤蓄水能力决定着贝壳堤系统的稳定性和植被生产力的高低.为阐明贝壳堤不同植被类型土壤蓄持水分能力及其影响因素,测定分析了贝壳砂土壤的基本物理参数、渗透性及土壤水分的温度响应特性,采用模糊数学隶属函数法评价了不同植被类型的土壤蓄水潜能.结果表明:酸枣林、杠柳林和草地能有效改善土壤通透性,土壤总孔隙度分别比裸地增加27.0%、19.3%和10.8%.在30℃和50℃恒温下,不同植被类型的土壤含水量随烘干时间的延长可分为土壤水分瞬变、渐变和平稳3个阶段.两种温度下,土壤饱和含水量、土壤达到恒重时间和失水率均表现为酸枣林杠柳林草地裸地.Horton模型适宜模拟贝壳砂生境的土壤入渗特征,灌木林土壤入渗性能好于草地.杠柳林和酸枣林的稳渗速率分别比裸地增加27.1%和5.4%,而草地比裸地降低76.6%.反映土壤蓄持水分的主要指标一类是土壤容重和孔隙度,另一类是土壤粗砂粒、粉粘粒分布和稳渗速率.贝壳砂土壤蓄水潜能综合评价为灌木林好于草地,酸枣林强于杠柳林,而裸地较差.     

痕量元素和碳氧同位素在塔里木盆地西南缘棋盘组沉积环境研究中的应用

以塔里木盆地西南缘中二叠统棋盘组为例,通过痕量元素和碳氧同位素对古盐度、古气候和氧化还原环境进行分析,进而恢复沉积环境。用 ICP-MS 光谱仪和 MAT-251稳定同位素质谱仪分别对棋盘组样品进行痕量元素和碳氧同位素测试分析,选取 B 含量、B／Ga、Sr／Ba和 V／（V＋Ni）和碳氧同位素作为判别沉积环境的指标,分析结果表明棋盘组主要发育在盐度较高、温暖－炎热的近岸海相沉积环境和有利于有机质形成的贫氧－厌氧环境;分析垂向上痕量元素和碳氧同位素参数与海平面变化的关系,认为参数的变化与海平面升降有一定的相关性,棋盘组下段整体上表现为一个海退到海侵的过程,其中有4次完整的次级旋回,由于海平面的不断变化使得棋盘组岩性表现为泥岩和生物碎屑灰岩的频繁互层。     

贵州罗甸大文二叠三叠系界线剖面海平面变化及其全球对比

对华南地区贵州罗甸大文剖面早三叠世早期的凝块石进行了系统的沉积学描述,区分出斑状、层状、枝状和网状4种中型构造。凝块石所具有的沉积构造特征和岩石学统计数据表明其形成于潮下带沉积环境,其中,斑状和层状中型构造的凝块石形成于能量较低的深潮下带,而枝状和网状中型构造的凝块石形成于能量较高的浅潮下带。18个向上变浅的沉积旋回显示Hindeodus parvus带内部海平面逐渐降低;Isarcicellastaeschei带和I.isarcica带早期,海平面降到最低,之后海平面开始升高。通过与其他地区二叠–三叠系界线剖面的海平面变化情况对比发现,全球普遍存在二叠–三叠纪之交的海平面下降,而大文剖面早三叠世早期的H.parvus带、I.staeschei带和I.isarcica带的海平面变化情况在古特提斯洋范围内可以广泛对比,可能主要受到全球海平面变化的影响。     

Recent mass balance of polar ice sheets inferred from patterns of global sea-level change

Global sea level is an indicator of climate change, as it is sensitive to both thermal expansion of the oceans and a reduction of land-based glaciers. Global sea-level rise has been estimated by correcting observations from tide gauges for glacial isostatic adjustment--the continuing sea-level response due to melting of Late Pleistocene ice--and by computing the global mean of these residual trends. In such analyses, spatial patterns of sea-level rise are assumed to be signals that will average out over geographically distributed tide-gauge data. But a long history of modelling studies has demonstrated that non-uniform--that is, non-eustatic--sea-level redistributions can be produced by variations in the volume of the polar ice sheets. Here we present numerical predictions of gravitationally consistent patterns of sea-level change following variations in either the Antarctic or Greenland ice sheets or the melting of a suite of small mountain glaciers. These predictions are characterized by geometrically distinct patterns that reconcile spatial variations in previously published sea-level records. Under the--albeit coarse--assumption of a globally uniform thermal expansion of the oceans, our approach suggests melting of the Greenland ice complex over the last century equivalent to -0.6 mm yr(-1) of sea-level rise.     

Detection of human influence on sea-level pressure

Greenhouse gases and tropospheric sulphate aerosols--the main human influences on climate--have been shown to have had a detectable effect on surface air temperature, the temperature of the free troposphere and stratosphere and ocean temperature. Nevertheless, the question remains as to whether human influence is detectable in any variable other than temperature. Here we detect an influence of anthropogenic greenhouse gases and sulphate aerosols in observations of winter sea-level pressure (December to February), using combined simulations from four climate models. We find increases in sea-level pressure over the subtropical North Atlantic Ocean, southern Europe and North Africa, and decreases in the polar regions and the North Pacific Ocean, in response to human influence. Our analysis also indicates that the climate models substantially underestimate the magnitude of the sea-level pressure response. This discrepancy suggests that the upward trend in the North Atlantic Oscillation index (corresponding to strengthened westerlies in the North Atlantic region), as simulated in a number of global warming scenarios, may be too small, leading to an underestimation of the impacts of anthropogenic climate change on European climate.     

Volcanoes and climate: Krakatoa's signature persists in the ocean

We have analysed a suite of 12 state-of-the-art climate models and show that ocean warming and sea-level rise in the twentieth century were substantially reduced by the colossal eruption in 1883 of the volcano Krakatoa in the Sunda strait, Indonesia. Volcanically induced cooling of the ocean surface penetrated into deeper layers, where it persisted for decades after the event. This remarkable effect on oceanic thermal structure is longer lasting than has previously been suspected and is sufficient to offset a large fraction of ocean warming and sea-level rise caused by anthropogenic influences.     

Records of the tsunami induced by the 2010 Chilean earthquake from Xiaoqushan seafloor observatory in the East China Sea

Sea-level variation can be induced by periodic tides, stochastic wind, air pressure, and swell. Larger sea-level variation has the potential to cause coastal disasters. In this paper, real-time continuous data obtained by the Xiaoqushan seafloor observatory in the East China Sea were analyzed employing frequency power spectral and tidal harmonic methods to extract the major components and periodicities of sea-level change. The sea-level anomaly (sla) was calculated by subtracting the tidal components from the observed sea level data. In the study period, the correlation between sla and the local north-south wind speed was high with a correlation coefficient of 0.65 at the 95% confidence level. The local wind-induced sea-level anomaly (sla wind ) was therefore computed through linear fitting. Although sla wind is one of the main components of sla, the residual sea-level anomaly (sla residual ) obtained by subtracting sla wind from sla is not zero, suggesting that there are other factors besides wind. Detailed analysis of the sea-level data at the time of the 8.8-magnitude Chilean earthquake on February 27, 2010 showed a peak sla residual value of 0.48 m at around 15:00 on February 28, which was highly coincident with the tsunami arrival time forecast by the Pacific Tsunami Warning Center. The peak sla residual event is therefore linked with the tsunami induced by the 2010 Chilean earthquake. This is the first time that a tsunami has been detected using real-time continuous data recorded by a seafloor observatory in the sea off China. Such observations are expected to improve tsunami forecast models and promote the development of a tsunami warning system and a seafloor observatory network in the East China Sea.     

黔南独山泥盆纪海平面变化与生物群的关系

通过对黔南独山地区泥盆纪地层、古生物群面貌和海平面相对变化的研究，认为海平面的升降变化不仅控制和影响着生物群落的取代和演替，同时对生物的灭绝与复苏等方面也起着重要的影响作用。     

恰什古伊地区碳氧同位素地层学分析

土库曼斯坦恰什古伊地区有效储集层为卡洛夫-牛津阶碳酸盐岩,该段GR 变化小,旋回分析困难,导致
有利储层预测难。利用该区Cha–21 井所取岩芯中采集的41 个样品测定的碳氧同位素,结合区域沉积演化分析资
料,探讨了卡洛夫-牛津阶储层段沉积时的海平面变化。结果表明,氧同位素的原始信息已被成岩作用破坏,而碳
同位素基本保持了原始特征,因此碳同位素可用于同位素地层研究和古环境分析;据此计算出盐度指数变化范围为
128.25～136.63,明显大于海水和淡水的分界标准,反映成岩流体具有较高盐度海源水性质;由δ13C 的变化所确定的研
究区的海平面变化曲线与卡洛夫-牛津阶全球海平面变化曲线吻合,印证了该区储层地质年代定为卡洛夫-牛津期
是准确的;依据海平面变化曲线,将卡洛夫-牛津阶主力储层段分为3 个沉积旋回5 个演化阶段。该成果填补了该区
碳氧同位素地层研究的空白,对深化盆地沉积演化规律的认识及预测储层有利区块具有重要意义。     

Interannual and interdecadal variations in the North Atlantic Oscillation spatial shift

The spatial shift of the North Atlantic Oscillation (NAO) is analyzed by using the Twentieth Century Reanalysis version 2 dataset and identifying NAO action centers directly on winter mean sealevel pressure (SLP) anomaly maps. The spatial shift of the NAO is characterized by four NAO spatial shift indices: the zonal and meridional shifts of the NAO southern and northern action centers. It is found that the zonal and meridional shift trends of the NAO action centers move along a path of southwest-northwest direction. Spectral analysis shows that the four NAO spatial shift indices have periodicity of 2-6 years and the NAO index has periodicity of 2-3 years in terms of high-frequency variations. On a decadal time scale, the NAO spatial shift indices are closely (positively) related to the NAO index, which is in agreement with previous studies of the relationship between the NAO index and the spatial shift of the NAO pattern. However, there is no relationship between the NAO index and the meridional shift of the northern action center on an interannual time scale. The significant relationship between the NAO index and the interannual variability of NAO spatial shift indices is very likely to be associated with synopticscale Rossby wave breaking, which generates surface pressure anomalies and thus affects the phase and pattern of the NAO. The correlations of winter westerly winds over 90°W-0° and the NAO index and the NAO spatial shift indices have a ’+ - + -’ structure from the Equator to the North Pole. Although there is close correlation between the NAO spatial shift indices and the strength of the zonal winds in the North Atlantic region, the effect of the zonal winds on the NAO spatial shift differs at different latitudes. Hence, the role of the zonal winds is probably a result of the NAO spatial shifts.