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101.
太平洋中国开辟区锰结核生物成因研究 总被引:13,自引:2,他引:11
本文对叠层石(微小叠层石与奇异叠层石)及其建造者(中华微放线菌与太平洋螺球孢菌)在结核中显示的规律性特征,叠层石纹层与超微生物生长,主要锰矿物及Fe、Mn元素与叠层石类型之间关系以及超微生物直接成矿等作了深入研究。结果表明:锰结核中叠层石柱体一般都显示出纹层、纹层组与纹层带3个级别的生长韵律,明层菌丝体密集,暗层菌丝体稀疏;两种叠层石类型与超微生物化石种存在着良好的对应关系;主要锰矿物含量变化与叠层石类型密切相关;叠层石柱体内Fe、Mn元素分布比柱间空隙具有明显的规律性,而全球性大气化程度比生殖菌丝强;超微生物的生化作用与沉积粘附作用直接造成了结核中Fe、Mn元素的富集,而全球性大气修与洋底微环境的周期性变化,影响了微生物生长的兴衰,导致了明暗相间纹层的交替出现。我们认为,叠层石纹层显示的韵律性特征,是胶体化学作用与沉积作用难以形成的,只有微生物群体的世代繁衍,才能构筑成几乎固定不变的叠层石柱体形态。上述研究成果,进一步确立了大洋锰结核的生物成因观点。 相似文献
102.
Autumn intensification of the Ryukyu Current during 2003-2007 总被引:2,自引:0,他引:2
ZHU Xiao-Hua HUANG DaJi & GUO XinYu State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration Hangzhou China Center for Marine Environmental Study Ehime University - Bunkyo-cho Matsuyama - Japan 《中国科学:地球科学(英文版)》2010,(4)
Inverse calculations using data from 16 repeat hydrographic transects collected from April 2003 to June 2007 have yielded velocity structures and volume transports(VTs) of the Ryukyu Current in the region east of the northern Ryukyu Islands.The inverse calculation results show that the Ryukyu Current is dominated by a subsurface velocity core with maximum velocities from 15.1 to 80.0 cm/s,whose positions vary between 110 and 600 dbar and 27.2°-28.2°N along the transect.The mean velocity exhibits a subsurface velocity core with a maximum value of 24.6 cm/s at 326 dbar depth,a VT of 14.0 Sv(1 Sv≡106 m3/s),a vertical dimension of 800 m,and a horizontal dimension of 60 km.The seasonal mean velocities show that the Ryukyu Current is stronger in autumn than in other seasons.It is suggested that this seasonal variation is coincident with the intensification of the anticyclonic eddy south of Shikoku,Japan. 相似文献
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The latest two versions of the IAP Flexible Global Ocean-Atmosphere-Land System (FGOALS) model- versions g1.0 and g1.1, are described in this study. Both two versions are fully coupled GCMs without any flux correction, major changes for g1.1 mainly lie in four aspects: (1) advection schemes for tracer in the ocean component model; (2) zonal filter scheme in high latitudes in the ocean component model; (3) coupling scheme for fresh water flux in high latitudes; and (4) an improved algorithm of airsea turbule... 相似文献
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Weiwen Chen Sidao Ni Shengji Wei Zhenjie Wang Jun Xie Mengcheng National Geophysical Observatory University of Science Technology of China Hefei China CAS Key Laboratory of Geodynamical Geodesy 《地震学报(英文版)》2011,(2):221-227
Ground deformation as observed with GPS or InSAR has been broadly inverted in constraining source parameter of earthquakes. However, for earthquakes occurring beneath sedimentary basins, the very slow sub-surface shear velocity (v S , down to 200 m/s) may cause substantial bias to earthquake source inversion if simple crustal models are used. For Bohai basin, Sichuan basin and rock-sites, we test effects of sub-surface shear velocity structure on ground deformation, and find that up to a factor of 2 overest... 相似文献
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The investigation of size-fractionated chlorophyll a and primary productivity were carried out in three longitudinal sections (63°-69°12'S, 70°30'E, 73°E and 75(30'E) at December 18-26, 1998 and January 12-18, 1999 in Prydz Bay and its north sea area, Antarctica. The results showed that surface chlorophyll a concentration were 0. 16 -3. 99 μg dm-3. The high values of chlorophyll a concentration (more than 3.5 μg dm -3) were in Prydz Bay and in the west Ladies Bank. The average chlorophyll a concentration at sub-surface layer was higher than that at surface layer; its concentration at the deeper layers of 50 m decreased with increasing depth and that at 200 m depth was only 0. 01 -0. 95μg dm -3. The results of size-fractionated chlorophyll a showed that the contribution of the netplanktion to total chlorophyll a was 56% , those of the nanoplankton and the picoplankton were 24% and 20% respectively in the surveyed area. The potential primary productivity at the euphotic zone in the surveyed area wa 相似文献
110.
西藏札达县夏浦沟的放射虫硅质岩和岛弧火山岩: 新特提斯洋内俯冲体系的记录? 总被引:1,自引:0,他引:1
在西藏阿里地区夏浦沟野外调查发现放射虫硅质岩、熔岩组合.放射虫硅质岩SiO2含量在89.47%~92.94%之间, Si/Al在43~67之间, Al/ (Al+Fe+Mn) 比值在0.68~0.74之间, MnO/TiO2平均比值为0.60, Ce/Ce*平均值为0.89, LaN/CeN平均值1.09, 指示它位于洋盆和大陆边缘过渡的环境, 总体更接近大陆边缘环境.伴生的火山熔岩以安山质为主, 具低TiO2 (0.75%~0.98%)、轻稀土弱富集和源自板片流体的易溶元素如Ba、U、Pb相对轻稀土富集, 亏损高场强元素(HFSE) Nb、Ta、Ti等, 指示形成于岛弧环境, 很可能是中生代新特提斯洋洋内俯冲系统的组分.放射虫动物群主要包括Alievium cf.regulare、Alievium cf.fatuum、Archaeospongoprunum cf.patricki、Archaeodictyimitra mitra Dumitrica等早白垩世分子, 其提供了岛弧活动时间上限的约束. 相似文献