海洋风暴沉积的微体生物研究进展

微体生物和它们的化石在研究现代风暴和古风暴沉积方面是一个很好和有效的指标。本文综述了国内外近几十年来有关海洋风暴沉积研究中微体生物的应用。目前主要的研究成果集中在对古风暴层有孔虫、硅藻的研究上,而孢粉方面的研究较少。应用微体化石揭示地质历史时期古风暴的发生频率已较为成熟。但未来需提高古风暴重建的可靠性、准确性和精确性,以及探讨微体化石记录与风暴强度之间的相关关系。有关现代风暴过程中微体生物的研究稍显逊色,研究程度较低。了解现代风暴过程中不同沉积环境下微体生物的沉积特征、面貌,它们的形成和保存机制等将成为未来的研究热点和方向。     

基于有孔虫指数评估西沙群岛羚羊礁过去2600年的生态环境状况

有孔虫指数（Foram Index, FI）是利用珊瑚礁区沉积物中底栖有孔虫功能组（藻类共生种、机会种、非自养种）的含量评估珊瑚礁区生态环境健康状况的指标,迄今中国对该指标的应用还较少。文章以西沙群岛羚羊礁的潟湖中钻取的LYJ2岩芯为材料（全长287 cm,底部对应的年代为2 665 a BP）,以0.5 cm的间隔取样,在显微镜下鉴定有孔虫功能组,计算FI值。结果显示：1）近2600年的FI变化范围为4.1～7.9,均值为5.9。2)FI成波动变化的模式,具体可分为3个上升期：2380―1628,1212―572和252―92 a BP;3个快速下降期：1628―1212,572―252和92 a BP至今及1个小幅下降期：2665―2380 a BP;3) FI在长期变化趋势上叠加不同尺度的年代际波动,具有66.7、54.4 a等周期。基于FI值对珊瑚礁健康状况的评估标准,推测近2600年来西沙羚羊礁的生态环境总体是健康的;基于FI值与海表温度对比分析,推测羚羊礁FI值主要受海表温度影响,与气候变化具有一致性,FI高值与中世纪暖期、罗马暖期大致对应,而低值与小冰期、黑暗时代冷期大致...     

Sea surface temperature and salinity reconstruction based on stable isotopes and Mg/Ca of planktonic foraminifera in the western Pacific Warm Pool during the last 155 ka

Changes in sea surface temperature(SST), seawater oxygen isotope(δ 18 O sw), and local salinity proxy(δ 18 O sw-ss) in the past 155 ka were studied using a sediment core(MD06-3052) from the northern edge of the western Pacifi c Warm Pool(WPWP), within the fl ow path of the bifurcation of the North Equatorial Current. Our records reveal a lead-lag relationship between paired Mg/Ca-SST and δ 18 O during Termination II and the last interglacial period. Similarity in SST between our site and the Antarctic temperature proxy and in CO 2 profi le showed a close connection between the WPWP and the Antarctic. Values of δ 18 O sw exhibited very similar variations to those of mean ocean δ 18 O sw, owing to the past sea-level changes on glacial-interglacial timescale. Calculated values of δ 18 O sw-ss refl ect a more saline condition during high local summer insolation(SI) periods. Such correspondence between δ 18 O sw-ss and local SI in the WPWP may refl ect complex interaction between ENSO and monsoon, which was stimulated by changes in solar irradiance and their infl uence on the local hydrologic cycle. This then caused a striking reorganization of atmospheric circulation over the WPWP.     

Eualus heterodactylus sp. nov., a new hippolytid shrimp from Chinese coast of the Yellow Sea （Crustacea,Decapoda, Caridea）

A new species from the caridean family Hippolytidae, Eualus heterodactylus sp. nov. is described and illustrated based on the specimens collected from Chinese coast of the Yellow Sea. The new species is a part of an informal species group characterized by the possession of epipods on the anterior three pairs of pereopods, and is distinguished from other species of this group by the dactyli of the third to fifth pereopods possessing distinctly stair-like flexor margins in males.     

有孔虫初房特征变化在珠江三角洲晚全新世东亚夏季风降雨研究中的应用

研究中国降雨格局变化对理解东亚夏季风演化意义重大。本文分析了珠江三角洲柱状样ZJK03-Z中浅水底栖有孔虫常见种Rotalidium annectens的平均初房大小、微球型/显球型比值和壳体δ18O值,以及底栖有孔虫组合中瓷质壳的百分含量,探讨它们对由夏季风降雨引起的河口水体盐度变化的响应,得到了珠江三角洲3114—1260a BP季风降雨的强度变化,识别出了这期间14次季风降雨减少的偏干期。与南美洲Cariaco海盆的钛含量记录对比,二者一致的结果表明,珠江三角洲晚全新世的东亚夏季风降雨与热带辐合带(ITCZ)的南北移动密切相关:夏季风降雨减少,对应于ITCZ纬度位置的南移。     

渤海莱州湾地区晚更新世以来有孔虫特征反映的古环境变化

Controlled by climate changes, there were three large-scale transgressions and regressions around the Bohai Sea during the late Quaternary, which were accepted by most geologists. However, a big controversy still exists about the time when the transgressions occurred separately. In order to find out the process of the paleoenvironmental changes around the Bohai Sea in the late Quaternary, the foraminifera assemblages from a new borehole Lz908 in the southern coast of the Laizhou Bay were studied, and then the transgressive strata were indentified. Combined with accelerator mass spectrometry radiocarbon 14C（AMS14C） and optically stimulated luminescence（OSL） ages, the occurrence time of these transgressions were re-determined. The result showed that three major large-scale transgressions occurred separately at the beginning of marine isotopic stage 7（MIS7）, the last interglacial period（MIS5） and the Holocene. In addition, a small-scale transgression occurred in the mid-MIS6, and the corresponding transgressive stratum was deposited. The transgressive deposition of MIS3 was also discovered in this study. However, the characteristics of the foraminifera indicated the environment during this period was colder than that in the MIS5. By comparison with the global sea-level changes, the paleoenvironmental changes around the Bohai Sea in the late Quaternary can be consistent with the global climate changes.     

中国近海蛾螺科系统分类学研究现状与展望

<正>1蛾螺科简介蛾螺科(Buccinidae)隶属于软体动物门(Mollusca),腹足纲(Gastropoda),新腹足目(Neogastropoda)。蛾螺科种类个体从小到大,小的壳长不足10 mm,而大的可达150 mm。贝壳多呈卵圆形或纺锤形,壳质通常坚硬,表面常被有壳皮或具短的绒毛。壳面较平滑或具螺肋、纵肋和结节突起;缝合线(Suture)深或浅;前水管沟(Siphonal canal)有的稍长,有的宽短。壳口大或狭窄,外唇(Outer lip)简单或厚;内唇(Inner lip)平滑或具褶襞。厣(Operculum)角质,通常为黄色、     

江西乐平沿沟二叠纪末有孔虫的演变及对鲕状灰岩的古环境指示意义

江西乐平沿沟剖面均一的碳酸盐相岩沉积, 完整地记录了二叠系-三叠系界线附近生物演变过程.通过对该剖面系统的化石切片研究, 共鉴别出有孔虫27属39种, 包含类4属7种.该剖面有孔虫的演变在二叠纪-三叠纪之交呈现出单幕式的消减过程, 对应于华南两幕生物灭绝中的第1幕.有孔虫的个体数和多样性在21-2层顶部发生了突然降低.4个不同有孔虫组合的演替关系, 揭示了有孔虫在灭绝事件中的演变过程, 即由灭绝前的高丰度、高分异度组合转变为灭绝后低丰度、低分异度组合.通过对二叠系-三叠系界线处鲕状灰岩的化石和沉积特征研究, 发现Hindeodus changxingensis带内的鲕状灰岩中仍存在较为丰富的有孔虫等化石.剧烈的海平面变化以及鲕状灰岩形成使下伏地层中的化石颗粒发生再沉积作用, 是形成这一特殊现象的主要原因.通过对鲕状灰岩中化石和沉积特征的深入研究, 论证了该鲕状灰岩形成于二叠纪-三叠纪之交大灭绝之后, 是当时特殊的海洋生态系产物, 反映了当时较高的海水回旋速率、微生物繁盛、海水碳酸盐超饱和等异常的环境条件.      

国内矿产品经济形势及走势分析

受国民经济发展对矿产资源需求快速增长和国内外矿产品市场价格持续上扬的合力推动,我国矿业经济保持持续增长态势:采掘业对社会经济发展贡献突出,固定资产投资增势强劲;大宗矿产品消费旺盛,国内供应能力得到强化,但依然处于供不应求的状态;矿产品价格高位运行,进出口贸易逆差持续扩大.可以说,我国矿业经济目前已处于繁荣阶段.     

中国新近纪大型植食性哺乳动物演化和生物地层

中国新近纪大型植食性哺乳动物包括长鼻目、蹄兔目、奇蹄目、偶蹄目4个目至少32科,超过300种。它们在全球的演化和迁徙受到新近纪全球气候改变的驱动以及海陆分布的影响,各门类组成和地理分布由古近纪的古老面貌向第四纪的现代面貌转变。长鼻目和蹄兔目是非洲起源的类群;中国蹄兔目的种类和地史分布非常局限,但非常特化;中国的长鼻目则相当繁盛,成为长鼻类的第二演化中心和跨洲交流的十字路口。奇蹄目和偶蹄目是欧亚大陆起源的类群;相比古近纪,奇蹄类在新近纪持续衰落,但马科和犀科的多样性高,演化速率快,成为地层对比的标志性类群;偶蹄类则呈持续繁荣的状态,特别是反刍的优势使鹿科和牛科达到非常高的多样性,成为新近纪大型植食性哺乳动物中占优势的类群。中国新近纪大型植食性哺乳动物各门类中的现代类型均在山旺阶开始适应辐射,时间上对应于中中新气候适宜期,到通古尔阶中中新气候转型期开始多样性下降,在通古尔和灞河阶界线上发生了大型哺乳动物的灭绝和重组事件,90%的类群灭绝;至灞河阶下部,开阔生态系统成为中国北方的主导,产生了早期适应开阔环境的哺乳动物群,并逐渐扩散到全球;保德阶上部气候转湿润,诱发了南方哺乳动物群的北迁事件,...