Small-scale,patchy distributions of infauna in hydrodynamically mobile continental shelf sands: Do ripple crests and troughs support different communities?

Spatial variability of infauna with respect to distribution of topographic habitat features was examined in hydrodynamically mobile sandy sediments on the inner continental shelf off New Jersey, USA (39° 27.69′ N, 74° 15.81′W). Sediment cores for infauna were taken by SCUBA divers at multiple spatial scales over time at 12-m depth in the LEO-15 research area on Beach Haven Ridge. Crests, troughs and less consistently flanks of sand ripples 5–15-cm in height, were characterized by different infaunal community patterns at spatial scales of centimeters to kilometers on several sampling dates. Overall, infaunal community differences among ripple crests, troughs, and/or flanks within areas <1-m² were greater than those found for each of these habitats (i.e., either crests, troughs, or flanks) that were separated by distances of 2 m–4 km. Infaunal density and species richness were consistently higher in troughs compared to crests. Indirect measures of food resources such as particulate organic carbon, chl a, and pheophytin were associated with ripple crests and troughs. Troughs contained significantly higher levels of particulate organic carbon (~1.2 times higher) associated with finer sediments, compared with crests and flanks. Various combinations of taxa had higher densities in either crests or troughs of sand ripples depending on date, and the relative abundances of three taxa, the deposit-feeding polychaete Polygordius jouinae, the suspension-feeding surfclam Spisula solidissima, and predatory nemerteans were important in distinguishing between crests and troughs on most dates. Thus, a priori knowledge of whether a benthic sample comes from a crest or trough helped to explain small-scale infaunal patchiness in relatively homogeneous, subtidal sandy sediments. Consideration of such topographic features in sampling designs can help in explaining variation in species’ distributions at several spatial and temporal scales.     

白垩纪大洋红层：特征、分布与成因

“白垩纪大洋红层”（CORB）自20世纪末正式提出后已经迅速成为白垩纪新的研究方向之一。本文在参考国外CORB的学术研究成果基础上,重点对我们在西藏南部和意大利中部两个研究程度较高地区所获得的立典研究成果予以详细介绍,同时对CORB的全球性对比进行总结和归纳,对大洋红层蕴涵的古海洋、古气候信息进行详细评述。我们认为,CORB是沉积物在原地氧化条件下的产物,导致该氧化条件出现的主要因素是底层水高含量的溶解氧,而深层古洋流的发育很可能是导致高溶解氧含量的主要原因。     

Spatial Overlap and Coexistence in a Mussel-Associated Polychaete Assemblage on a South American Rocky Shore

Abstract. Mussel beds in the intertidal of subtropical South America are known to harbour a large number of invertebrates, particularly polychaetes. This paper presents a quantitative analysis of the patterns of spatial overlap and coexistence in an assemblage of polychaetes associated with mussel beds in a rocky intertidal habitat on the Pacific coast of Peru. Mussel beds are made up of two zones in the intertidal: the lower, more extensive zone formed by Semimytilus algosus and the upper zone formed by Perumytilus purpuratus . Null models were employed to assess the magnitude of spatial overlap between pairs of taxa encompassing a total of seven taxonomic groups. Two taxa belonging to the same functional group tended to be spatially segregated in the Semimytilus bed: Pseudonereis vs. Halosydna (large free-ranging predators) and Scoloplos vs. Mediomastus (deposit feeders), with further segregating tendencies between Pseudonereis and Mediomastus , and between Halosydna and Scoloplos . Small-sized, free-ranging ' Typosyllis ' and the bottom-dwelling scavenging predator Lumbrineris were also spatially associated. Thus, this polychaete assemblage appears to be loosely organised around groupings of taxa which are somewhat different in ecological traits and form mosaic patterns of distribution with reduced overlap within the Semimytilus bed. These relationships were weak to non-existent in the upper, drier Perumytilus habitat where polychaete density was low.     

贵金属材料分析

论述了贵金属材料分析的重要性和特殊性,指出应根据材料的类型和对分析的要点,优先考虑解决如测定贵金属元素的准确度、选择性或方法的灵敏等问题。评述了自１９９２年以来国内贵金属材料分析的发展,内容包括高含量、低含量和高纯贵金属材料的分析。涉及的分析技术主要有滴定法、精密库仑滴定法、等离子体－发射光谱法、原子吸收光谱法和光度法等。     

近水平红层开挖边坡变形破坏特征

通过对四川盆地近水平红层公路建设中路堑边坡开挖病害的调查分析,归纳出近水平红层边坡开挖引起的主要变形破坏型式是堆积层滑坡、顺层座滑型滑坡、边坡拉裂变形、边坡岩体倾倒破坏,总结了近水平红层边坡的主要工程地质特征,提出边坡变形破坏的过程一般经历开挖卸荷变形、陡倾节理发展扩大、变形破坏形成三个阶段,并结合工程实例分析了其形成机理。     

用测井曲线识别地质标志层位

利用动态规划算法进行有序序列匹配来识别地质标志层位,在选取特征模式参数时,不仅考虑了曲线形态的特征,而且考虑了地层岩性的特征。对特征模式向量进行了量纲一致性处理。识别时既可以对全孔所有层识别,也可以只做部分层位识别,还可以分段识别。对山东唐口地区的几口井做了识别处理,均取得较满意的结果。      

黄骅坳陷储集岩类型及其宏观特征

黄骅坳陷的储集岩有砂岩,碳酸盐岩和火山岩.砂岩是含油的主要储集岩,按其成因可分为河道砂体、三角洲砂体、近岸扇砂体、深水密度流砂体、堡砂坝、冲积扇砂体.这些砂体绝大多数集中在第三系,埋深在1500⁴000m.碳酸盐岩储集岩以粒屑灰岩为代表,是第三系渐新统中部的沉积,分布面积广,孔隙性能好.火山岩储层以中生界安山岩为代表.根据对岩芯的观察和大量镜下鉴定,将安山岩的储集空间分为8种类型.     

用综合地震特征参数解释煤层厚度

介绍了用综合地震特征参数解释煤层厚度的具体方法。通过对淮南潘三矿东3、东4采区地震资料的重新处理,提取出对应13-1煤的T₅波的多个地震波动力学参数,将有效参数综合并进行煤层厚度的定量解释,提供了煤层平面等厚线图,经井下资料验证解释精度可靠。      

渤海南部S3孔晚第四纪海相地层的划分及环境演变

根据微体化石、粒度、孢粉、粘土矿物和碳酸钙含量等多项分析资料,以及古地磁、１４Ｃ和ＥＳＲ等项测年资料,划分出７个海相地层,它们是：中更新世中、晚期的Ｈ７（４１７．０～４６０．０ｋａＢ．Ｐ．）和Ｈ６（１５７．５～２３１．３ｋａＢ．Ｐ．）海相层;晚更新世前半期末次间冰期的Ｈ５（１００．６～１２４．３ｋａＢ．Ｐ．）和Ｈ４（７６．５～８７．６ｋａＢ．Ｐ．）海相层,末次冰期里两间冰阶的Ｈ３（５８．２～６７．４ｋａＢ．Ｐ．）和Ｈ２（２８～３６ｋａＢ．Ｐ．）海相层,以及冰后期的Ｈ１（８．５ｋａＢ．Ｐ．以来）海相层。其中Ｈ７为渤海海底最新确定的年代最老的海相层。以Ｓ３孔为主,与渤海中部的ＢＣ－１孔和西部的辛集孔对比,阐明了渤海晚第四纪海侵海退古环境演变历史     

广义S变换与薄互层地震响应分析

Stockwell等人提出的S变换虽然与Fourier谱能保持直接联系，然而，由于S变换中的基本小波不适用于地震资料处理. 为此本文采用两个步骤对S变换加以推广，得到两种新变换（统称为广义S变换）. 首先， 用带有4个待定参数的调幅简谐波来代替S变换中的基本小波,定义广义S变换1，给出对应的逆变换；然后，以第一步中的基本小波的线性组合为新的基本小波，定义广义S变换2，并构造其逆变换公式. 最后，分别使用S变换及广义S变换对几种典型的薄互层模型进行分析计算. 结果表明，后者比前者有更强的探测能力， 后者可准确地确定厚度为1/8波长的薄互层中波阻抗界面位置，但前者却不能. 文中还用实际资料处理的结果，证明了广义S变换方法的有效性.