140kaBP以来南海西南部上升流影响区沉积记录及其古海洋环境变化     

邹杨浩  冉莉华  Martin G Wiesner  刘飞  梁文  陈建芳  刘连文 《海洋地质与第四纪地质》2019,39(2)

对南海西南部现代上升流区沉积物柱样BIS-187-61孔有机碳、生物蛋白石、碳酸盐等各沉积组分进行了详细的分析,试图探讨末次间冰期(MIS 5)以来南海西南部夏季上升流影响区沉积过程及其所反映的海洋环境变化过程。研究结果发现,140kaBP以来该孔沉积记录期总体表现为:碳酸盐百分含量冰期低间冰期高,主要受周边陆源物质输入稀释的控制,为典型的"大西洋型碳酸盐旋回",有机碳、生物蛋白石、碳酸钙以及陆源沉积物的堆积速率均在MIS 2期、MIS 4期和MIS 5e期出现高值。其中,MIS 2期和MIS 4期生源和陆源沉积堆积速率增加可能与冰期时冬季风增强及海平面下降导致陆源营养物质输入增加对初级生产力的刺激有关,也可能与陆源物质输入增加对海洋生源颗粒物输出的压载作用增强有关。而MIS 5e期南海海平面高度与现代相仿,间冰期较强的夏季风引起的越南沿岸上升流增强是导致该时段本研究区域表层初级生产力增强,沉积物总堆积速率及各组分堆积速率都相应增加的主要原因。  相似文献   

Forearc ophiolite in Havana-Matanzas, Western Cuba: evidence from serpentinized mantle peridotite REE geochemistry and Cr-spinel composition     

LLANES CASTRO Angélica Isabel  PROENZA Joaquín Antonio  CRUZ GáMEZ Esther María 《《地质学报》英文版》2018,92(Z2):19-21

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渤海海域浮游病毒和浮游细菌的丰度变化与环境因子之间的耦联关系     

王彩霞  吴霖  王毅波  Paterson James S.  Mitchell James G.  胡晓珂 《海洋学报(英文版)》2020,39(6):72-83

Uncovering the role of environmental factors and finding critical factors which harbor significant fractions in governing microbial communities remain key questions in coastal marine systems. To detect the interactions between environmental factors and distributions of virio-and bacterioplankton in trophic coastal areas, we used flow cytometry to investigate the abundance of virio-and bacterioplankton covering 31 stations in the Bohai Sea of China. Our results suggested that the average abundance of total virus(TV) in winter(～2.29×10~8 particles/mL)was slightly lower than in summer(～3.83×10~8 particles/mL). The mean total bacterial abundance(TB) was much lower in winter(～2.54×107 particles/mL) than in summer(～5.43×10~7 particles/mL). Correlation analysis via redundancy analysis(RDA) and network analysis among virioplankton, bacterioplankton and environmental factors revealed that the abundances of viral and bacterial subpopulations depend on environmental factors. In winter, only temperature significantly influenced the abundances of virio-and bacterioplankton. In summer, in addition to temperature, both salinity and nutrient(SiO_2) had a remarkable impact on the distribution of virioand bacterioplankton. Our results showed a clear seasonal and trophic pattern throughout the whole water system, which revealed that temperature and eutrophication may play crucial roles in microbial distribution pattern.  相似文献   

大数据驱动下的数字古地理重建：现状与展望     

张蕾  钟瀚霆  陈安清  赵应权  黄可可  李凤杰  黄虎  刘宇  曹海洋  祝圣贤  穆财能  侯明才  JAMES G. Ogg 《高校地质学报》2020,26(1):73

古地理学是一门强数据依赖性学科,古地理重建作为古地理学的核心任务之一,着眼于研究地质历史时期地球表面的地理、生物、气候面貌及其演化规律。随着大数据时代的来临,海量古地理数据的不断积累和计算机技术的高速发展使得标准化、智能化的数字古地理重建成为可能。文章通过介绍国内外与古地理相关的代表数据库及团队,总结其优缺点,提出大数据驱动下的数字古地理重建核心思路:(1)建立标准化的古地理学知识体系;(2)建立开放互动、动态更新的古地理数据库,并利用机器阅读技术等拓展数据来源;(3)建立标准化的古地理学数据质量控制体系;(4)利用机器学习技术建立各类型古地理重建模型,深度挖掘数据;(5)以可实时更新的智能数字地图集或多维动画形式输出成果。  相似文献   

Backward automatic calibration for three-dimensional landslide models     

Giacomo Titti  Giulia Bossi  Gordon G.D.Zhou  Gianluca Marcato  Alessandro Pasuto 《地学前缘(英文版)》2021,12(1):231-241

Back-analysis is broadly used for approaching geotechnical problems when monitoring data are available and information about the soils properties is of poor quality.For landslide stability assessment back-analysis calibration is usually carried out by time consuming trial-and-error procedure.This paper presents a new automatic Decision Support System that supports the selection of the soil parameters for three-dimensional models of landslides based on monitoring data.The method considering a pool of possible solutions,generated through permutation of soil parameters,selects the best ten configurations that are more congruent with the measured displacements.This reduces the operator biases while on the other hand allows the operator to control each step of the computation.The final selection of the preferred solution among the ten best-fitting solutions is carried out by an operator.The operator control is necessary as he may include in the final decision process all the qualitative elements that cannot be included in a qualitative analysis but nevertheless characterize a landslide dynamic as a whole epistemological subject,for example on the base of geomorphological evidence.A landslide located in Northeast Italy has been selected as example for showing the system potentiality.The proposed method is straightforward,scalable and robust and could be useful for researchers and practitioners.  相似文献   

Physical Properties, Morphology and Petrological Characteristics of Pumices from the Central Indian Ocean Basin     

Niyati G. KALANGUTKAR  Sridhar D. IYER  Dandaydayudapani ILANGOVAN 《《地质学报》英文版》2011,85(14):826-839

About 400 pumice clasts collected from the Central Indian Ocean Basin (CIOB) were studied for their morphology and were classified based on their shape and size. A majority of the samples range between <1 cm and 36 cm and in the Zinggs shape diagram plot in the equant and oblate fields. The Corey Shape Factor for most of the samples is close to 0.7, which is common for volcaniclastic material. The physical properties such as density, specific gravity, void ratio, porosity, moisture content and degree of saturation, were determined for 30 pumice samples. Density varies from 0.21 to 0.74 g/cm3 specific gravity 1.84 to 3.27, void ratio 2.21 to 10.67, porosity 67% to 91%, moisture content during sinking 0.44 to 2.35 and degree of saturation varies from 26.5% to 86%. Binocular and electron microscopy studies reveal that 60% of the vesicles are elongated, 30% are spherical and 10% are fibrous. Petrography of the pumices exhibits vitrophyric texture with phenocrysts of feldspars and clinopyroxenes. X-ray diffractrogram and mineral analyses confirm plagioclase to be a major phase, while quartz and orthoclase are not uncommon. Todorokite is commonly present in the ferromanganese oxide coating present over some of the pumices. This paper also delves into some details concerning the controversial origin of the pumices and glass shards in the CIOB.  相似文献   

西藏纳木错现代沉积速率的空间分布特征及近60年来的变化研究   总被引：5，自引：3，他引：2  

王君波  朱立平  汪勇  高少鹏  G.Daut 《第四纪研究》2011,31(3):535-543

利用<'210>Pb和<'137>Ca方法对采自青藏高原纳木错不同位置的8支岩芯进行了现代沉积速率的研究,其中6支岩芯的<'210>Pb<,ex>比活度变化具有较好的记录,而只有位于湖泊开阔深水区的NMCS08-1岩芯显示了<'137>Cs比活度的蓄积峰.结果显示不同位置岩芯的平均沉积速率具有明显的空间差异,自约195...  相似文献   

Small-Scale Mineralogical Heterogeneity from Variations in Phase Assemblages in the Transition Zone and D Layer Predicted by Convection Modelling     

Arie P van den Berg  David A Yuen  Michael H G Jacobs  Maarten V de Hoop 《中国地质大学学报(英文版)》2011,(2)

Small-scale heterogeneity in the deep mantle is concentrated in the upper-mantle transi-tion zone(TZ),in the depth range 410-660 km and also at the bottom 250 km D region.This encour-ages a more detailed investigation of the potential for seismic reflectivity imaging by modelling hetero-geneous structures in mantle convection models including phase transitions of the TZ and D regions.We applied finite elements with variable spacing near the boundary layers in 2-D cylindrical geometry that allow for sufficie...  相似文献   

水平定向钻法铺设HDPE管的短期和长期反应     

Abdul  G.  Chehab  Ian  D.  Moore  胡雪译 《岩土钻凿工程》2011,(6):16-20

在水平定向钻进施工设计时,回拖力的估算是一项重要内容。正确估计管道轴囱应力分布对于预测管道的长期性能极其重要。本文展示了HDD不同施工参数对聚合物管和钢管长期和短期反应的影响调查结果。结果表明,应力、应变在管道的整个使用寿命当中持续变化。一些施工参数对短期回拖力以及长期的轴向应力有着显著的影响,并对其使用寿命有潜在影响。这项研究表明,在施工过程中,最大短期轴向应力的一半可以作为长期轴向应力的一种保守措施。  相似文献   

中国东海和韩国马山湾海域2株原甲藻的形态结构和分子序列比较   总被引：2，自引：0，他引：2  

王红霞  陆斗定  黄海燕  夏平  戴鑫烽  Jeanette G 《海洋学研究》2011,29(1):42-48

对采自我国东海温岭海域和韩国南部马山湾海域的2株原甲藻进行了藻种分离、纯化培养及rDNA ITS分子序列的PCR扩增与测序,并运用显微镜、扫描电镜、Jukes-Cantor距离矩阵及构建的系统发育树,比较研究了2株原甲藻的形态结构和分子序列.结果表明:温岭藻株(LAMB090508)和马山湾藻株(PDKS0206)具有...  相似文献