柴北缘的大地构造演化及其地质事件群

柴达木盆地北缘及邻区包括六个二级构造单元:中南祁连地块(宗务隆天山期裂陷槽)、欧龙布鲁克微陆块、柴北缘祁连期结合带、柴达木地块、东昆仑晚天山-印支期结合带(东昆北岩浆弧)和西秦岭结合带。其中柴北缘及邻区的大地构造演化,经历了前寒武纪基底成生与演化、祁连期洋-陆转化、天山-印支期板内变形和中新生代陆相盆地演化-高原隆升等四个阶段。本文在论述各个演化阶段的沉积事件、岩浆活动、变质作用、构造形迹和成矿作用等地质事件群的基础上,对柴北缘的变质基底、全球大地构造对比和显生宙花岗岩等重大基础地质问题进行了讨论。     

Environmental effect and genetic influence: a regional cancer predisposition survey in the Zonguldak region of Northwest Turkey

The Cretaceous-Eocene volcano-sedimentary units of the Zonguldak region of the western Black Sea consist of subalkaline andesite and tuff, and sandstone dominated by smectite, kaolinite, accessory chlorite, illite, mordenite, and analcime associated with feldspar, quartz, opal-CT, amphibole, and calcite. Kaolinization, chloritization, sericitization, albitization, Fe–Ti-oxidation, and the presence of zeolite, epidote, and illite in andesitic rocks and tuffaceous materials developed as a result of the degradation of a glass shards matrix, enclosed feldspar, and clinopyroxene-type phenocrysts, due to alteration processes. The association of feldspar and glass with smectite and kaolinite, and the suborientation of feldspar-edged, subparallel kaolinite plates to fracture axes may exhibit an authigenic smectite or kaolinite. Increased alteration degree upward in which Al, Fe, and Ti are gained, and Si, Na, K, and Ca are depleted, is due to the alteration following possible diagenesis and hydrothermal activities. Micromorphologically, fibrous mordenite in the altered units and the presence of needle-type chrysotile in the residential buildings in which cancer cases lived were detected. In addition, the segregation pattern of cancer susceptibility in the region strongly suggested an environmental effect and a genetic influence on the increased cancer incidence in the region. The most likely diagnosis was Li-Fraumeni syndrome, which is one of the hereditary cancer predisposition syndromes; however, no mutations were observed in the p53 gene, which is the major cause of Li-Fraumeni syndrome. The micromorphology observed in the altered units in which cancer cases were detected may have a role in the expression of an unidentified gene, but does not explain alone the occurrence of cancer as a primary cause in the region.     

Symbiodinium (internal transcribed spacer 2) diversity in the coral host Agaricia lamarcki (Cnidaria: Scleractinia) between shallow and mesophotic reefs in the Northern Caribbean (20–70 m)

This study investigated differences in Symbiodinium diversity in the scleractinian coral species Agaricia lamarcki between shallow (20–25 m) and mesophotic (50–70 m) depths in the Northern Caribbean. Corals were sampled in each of four shallow sites (20–25 m; n = 18) and three mesophotic sites (50–70 m; n = 18) from Mona Island (Puerto Rico) and the US Virgin Islands during a mesophotic exploratory cruise and from the La Parguera shelf edge, off Southwestern Puerto Rico. Symbiodinium diversity was assessed using internal transcribed spacer 2 sequences clustered into operational taxonomic units (OTUs). Clustering resulted in eight clade C OTUs and one clade D OTU. Of these, there were three common Symbiodinium OTUs consisting of C3 and D1a.N14 in shallow reefs and C11.N4 in mesophotic reefs. Statistical tests (permutational multivariate analysis of variance and analysis of similarity) showed significant differences between clade C Symbiodinium OTUs in A. lamarcki colonies located at shallow and mesophotic depths, indicating symbiont zonation. Symbiodinium diversity in A. lamarcki from the Northern Caribbean is comparable to previous reports in the Southern Caribbean for this species. This is the first report of the thermal tolerant species Symbiodinium trenchii (D1a) in A. lamarcki.     

Spatially constrained clustering of ecological units to facilitate the design of integrated water monitoring networks in the St. Lawrence Basin

Water monitoring networks are generally classified into surface water, precipitation, groundwater or water quality monitoring networks. The design of these networks typically occurs in isolation from each other. We present a regionalization approach to identify homogeneous subregions of large basins that are suitable as areas for the optimization of an integrated water monitoring network. The study area, which comprises a portion of the St. Lawrence Basin, was spatially divided using ecological units. For each ecological unit, 21 attributes were derived including both environmental and hydrological indicators. A spatially constrained regionalization technique was applied to define the final regions. A scree plot was used to determine the number of regions. The sensitivity of the technique to the correlation in the attribute data was removed by utilizing principal component analysis to reduce correlation between attribute data. During regionalization, the component values were weighted by their proportion of the total variance explained. The four regions in the final configuration had areas from 19% to 31% of the total area, 63,597 km². For the St. Lawrence Basin, this approach is effective for defining homogeneous regions that can be used in further research on the optimization of integrated water monitoring networks. The approach is portable to other regions and can incorporate any set of attribute data that is valuable to the regionalization objective.     

Application of change detection techniques in geomorphological evolution of coastal areas. Example: Mouth of the River Ebro (period 1957–2013)

This study aims to test the effectiveness of the changes detection techniques to determine the evolution of the various geomorphological units identified in Ebro River mouth, in order to establish their evolutionary trends and to explain the changes between 1957 and 2013 years. To evaluate the most significant changes in the Ebro River mouth, the different geomorphological units present in the area were obtained by interpretation of aerial imagery. It has been noted that the period 1957–1984 was more dynamic and intense than the period 1984–2013, indicating a loss of capacity of the processes causing changes, and the shoreline is evolving toward a more stable morphology. It was determined that the most important processes that took place were mainly marine erosion processes and anthropogenic expansion. On the characterization in the entire period studied, it was determined that growth or decrease processes (net change) are as relevant in the region as processes which include location changes (swap). The change analysis methodology allows analyzing the evolution of coastal geomorphology, since it allows the determination and characterization of the principal transitions amongst the identified geomorphological units, and, therefore, to obtain the main processes that dominate the area, which is particularly relevant on highly vulnerable environments, such as coastal deltaic areas.     

粤西水东湾现代沉积环境特征与泥沙搬运路径

对粤西水东湾沉积地貌单元的现代沉积物分布特征分析与泥沙净搬运矢量计算表明，滨面斜坡沉积物主要由砂粒级物质组成，粒级参数Ｍｄ，ＱＤ和ＳＫ具有从海向岸、自东向西变化的总趋势，泥沙净搬运趋势以向岸和西北为主。落潮三角洲沉积物较其邻近滨面斜坡有所粗化，分选从中部向两侧变好，泥沙在落潮流与波浪驱动下沿落潮三角洲边缘向西运动。口门内潮汐通道深槽泥沙净搬运趋势指向湖。湖区的沉积物以泥质为主，分选中等至差，并形成绕涨潮三角洲的泥沙环流元。