Deep-sea mining of seafloor massive sulfides     

Porter Hoagland  Stace Beaulieu  Maurice A. Tivey  Roderick G. Eggert  Christopher German  Lyle Glowka  Jian Lin 《Marine Policy》2010

The potential emergence of an ocean mining industry to exploit seafloor massive sulfides could present opportunities for oceanographic science to facilitate seafloor mineral development in ways that lessen environmental harms.  相似文献   

Distribution of amphipods Ischyrocerus on the red king crab, Paralithodes camtschaticus: Possible interactions with the host in the Barents Sea     

Alexander G. Dvoretsky  Vladimir G. Dvoretsky 《Estuarine, Coastal and Shelf Science》2009

The determination of costs and benefits experienced by crustaceans as a result of occupation by their symbionts has received increased attention from marine ecologists. However, the interactions between some important species and their associates remain unclear. We examined the distribution of amphipods in the genus Ischyrocerus on the red king crab Paralithodes camtschaticus, a commercially important species, in two areas of the Barents Sea. Ischyrocerus commensalis was found on 30.5% of crabs in Dalnezelenetskaya Bay (DZB) with the mean number per crab being 55.1, in Dolgaya Bay (DLB) these rates were 28.6% with 19.3 specimens per crab. Sympatric species Ischyrocerus anguipes was found on 13.5% of crabs in DZB with a mean of 7.3 individuals per host, in DLB it had much lower occurrence (1.3% and 1.5 specimens per host). There were no significant differences between proportions of male and female crabs infested by amphipods in both areas examined. Prevalence of amphipods was similar among years examined except for I. commensalis on small crabs (carapace length CL <90 mm) and I. anguipes on large crabs (CL >90 mm) in DZB. We found that I. commensalis and I. anguipes are not egg predators of P. camtschaticus in the Barents Sea, at least in summer. High numbers of I. commensalis occur in crab gills, and both mean intensity of the amphipods and their empty tubes increased with crab size. In the gills, I. commensalis predominated in the section nearest the mouth parts. Possible negative impacts for the hosts due to gills infestation are discussed. In contrast, I. anguipes were predominately found on the carapace and limbs of crabs and appears to be a less specific symbiont of P. camtschaticus. Both amphipod species seem to be commensals, however possible negative impacts for the host could not be excluded.  相似文献   

论我国沉积改造金属矿床   总被引：6，自引：0，他引：6  

廖士范 《矿床地质》1996,15(3):229-237

在论述沉积改造金属矿床Ｈｇ、Ｐｂ、Ｚｎ、Ｓｂ和菱铁矿的成矿、改造机理及赋存深度的基础上，作者认为沉积改造金属矿床是先沉积后成矿或改造的，成因清楚，含义明确，应从“层控矿床”中划分出来，单独成为一类矿床类型。该矿床赋存深度在潜水面以下２００～３００ｍ或４００～５００ｍ以内、地下水滞流带以上“还原成矿改造带”中  相似文献   

墨西哥海参和菲律宾刺参的化学成分和降血脂作用比较   总被引：1，自引：0，他引：1  

徐杰  王静凤  逄龙  董平  薛长湖 《中国海洋大学学报(自然科学版)》2007,37(5):723-727

比较研究了墨西哥海参(Holothuria mexicana)、菲律宾刺参(Pearsonothuria graeffei)的化学成分和对实验性高脂血症大鼠血脂水平和抗氧化能力的影响。实验结果表明,墨西哥海参的Arg/Lys比值和降血脂氨基酸(Gly,Arg)含量明显高于菲律宾刺参,而菲律宾刺参的岩藻聚糖硫酸酯含量高于墨西哥海参。墨西哥海参和菲律宾刺参均能明显降低模型大鼠血清TC,LDL-C含量和动脉粥样硬化指数(P<0.05,P<0.01),提高HDL-C和NO(P<0.05,P<0.01)含量;显著降低血清和肝脏中MDA含量(P<0.05,P<0.01),提高血清SOD和GSH-PX(P<0.05,P<0.01)活性。其中,墨西哥海参对动脉粥样硬化指数的降低作用显著优于菲律宾刺参。提示了墨西哥海参和菲律宾刺参能有效预防高脂血症和动脉粥样硬化的形成,可能与蛋白质的氨基酸组成有关。  相似文献   

缺氧沉积物中硫化物对镉的生物可利用性的影响   总被引：2，自引：0，他引：2  

韩建波  李丽娟  闫启仑  王菊英  马德毅  全燮 《海洋学报》2005,27(5):173-176

镉是水环境中主要的金属污染物质,趋向于在沉积物中富集,对底栖生物造成潜在的威胁,并且通过食物链最终影响人体的健康.已经证明,作为沉积物中两大主要污染物的有机物和金属,有机碳是控制沉积物中非离子态有机化合物生物可利用性的主要因子[1],因此利用有机碳归一化方法判断沉积物是否受到有机物污染成为可能,而沉积物中金属的毒性或它的生物可利用性会受到诸如生物、物理和化学因子的影响,其中沉积物的部分化学组成会影响金属在固相与间隙水之间的分配,从而成为控制金属生物可利用性的关键因子[2,3].  相似文献   

降水对逆温强度的减幅作用     

宋润田  王伟民  郁亚宁 《海洋预报》2001,18(2):7-12

本文利用DDAR Doppler声雷达的高精度激光雨量计所测的雨强资料，对雨强≥0.02mm/h的时段及其相邻的前后时段与降水时段相对应的回波强度参数及其演变进行了对比分析，得出与各降水时段对应的回波和降水前时段相比，有明显增强的趋势；而降水后相应时段的回波与降水时段相比，有较大幅度的减弱，其相对应的逆温强度γ（℃/mm）趋于减小，较强的降水时段和有效的连续降水将大幅度消弱回波强度，并使其较长时间地维持在低指数状态，其相应能见度也大为改善。  相似文献   

Geological Fluid Mapping in the Tongling Area： Implications for the Paleozoic Submarine Hydrothermal System in the Middle-Lower Yangtze Metallogenic Belt, East China   总被引：1，自引：0，他引：1       下载免费PDF全文

HOU Zengqian YANG Zhusen MENG Yifeng ZENG Pusheng LI Hongyang XU Wenyi 《《地质学报》英文版》2007,81(5):833-860

The Tongling area is one of the 7 ore-cluster areas in the Middle-Lower Yangtze metallogenic belt,East China,and has tectonically undergone a long-term geologic history from the late Paleozoic continental rifting,through the Middle Triassic continent-continent collision to the Jurassic-Cretaceous intracontinental tectono-magmatic activation.The Carboniferous sedimentary-exhalative processes in the area produced widespread massive sulfides with ages of 303-321 Ma,which partly formed massive pyrite-Cu deposits,but mostly provided significant sulfur and metals to the skarn Cu mineralization associated with the Yanshanian felsic intrusions. To understand the Carboniferous submarine hydrothermal system,an area of about 1046 km~2 was chosen to carry out the geological fluid mapping.Associated with massive sulfide formation,footwall sequences 948 m to 1146m thick,composed of the Lower Silurian-Upper Devonian sandstone,siltstone and thin-layered shale,were widely altered.This hydrothermal alteration is interpreted to reflect large- scale hydrothermal fluid flow associated with the late Paleozoic crustal rifting and subsidence.Three hydrothermal alteration types,i.e.,deep-level semiconformable silicification(S_1),fracture-controlled quartz-sericite-pyrite alteration(S_(2-3)),and upper-level sub-discordant quartz-sericite-chlorite alteration(D_3),were developed to form distinct zones in the mapped area.About 50-m thick semiconformable silicification zones are located at～1-km depth below massive sulfides and developed between an impermeable shale caprock(S_1)and the underlying Ordovician unaltered limestone. Comparisons with modern geothermal systems suggest that the alteration zones record a sub-seafloor aquifer with the most productive hydrothermal fluid flow.Fracture-controlled quartz-sericite-pyrite alteration formed transgressive zones,which downward crosscut the semiconformable alteration zones, and upwards grade into sub-discordant alteration zones that enveloped no economic stringer- stockwork zones beneath massive sulfides.This transgressive zone likely marks an upflow path of high- flux fluids from the hydrothermal aquifer.Lateral zonation of the sub-discordant alteration zones and their relationship to overlying massive sulfide lenses suggest lateral flows and diffusive discharging of the hydrothermal fluids in a permeable sandstone sequence.Three large-sized,14 middle-small massive sulfide deposits,and 40 massive sulfide sites have been mapped in detail.They show regional strata- bound characters and two major styles,i.e.,the layered sheet plus strata-bound stringer-style and the mound-style.Associated exhalite and chemical sedimentary rock suites include(1)anhydrite-barite,(2) jasper-chert,(3)Mg-rich mudstone-pyrite shale,(4)barite lens,(5)siderite-Fe-bearing dolomite,and (6)Mn-rich shale-mudstone,which usually comprise three sulfide-exhalite cyclic units in the area. The spatial distribution of these alteration zones(minerals)and associated massive sulfides and exhalites,and regional variation inδ~(34)S of hydrothermal pyrite and inδ~(18)O-δ~(34)C of hanging wall carbonates,suggest three WNW-extending domains of fluid flow,controlled by the basement faults and syn-depositional faults.Each fluid domain appears to have at least two upflow zones,with estimated even spacing of about 5-8 km in the mapped area.The repeated appearance of sulfide-sulfate or sulfide-carbonate rhythmic units in the area suggests episodically venting of fluids through the upflow conduits by breaking the overlying seals of the hydrothermal aquifer.  相似文献   

来自蛇绿岩地幔的硫（砷）化物矿物组合   总被引：1，自引：0，他引：1  

白文吉陶淑凤  杨经绥方青松施倪承  李国武 《岩石矿物学杂志》2007,26(5):418-428

近来在西藏雅鲁藏布江蛇绿岩带的罗布莎蛇绿岩块的地幔豆荚状铬铁矿中发现一个包括金刚石、柯石英、自然元素、合金、氧化物以及硫(砷)化物组成的地幔矿物群。该矿物群的硫(砷)化物具有特殊化学成分并呈包裹体分布在贱金属(BM)和铂族元素(PGE)或它们的合金中,大量化学成分分析得知它们主要由下列元素组成:S、As、Te、Fe、Ni、Co、Cu、Pt、Pd、Ru、Rh、Os、Ir、Mn和Ti。根据化学成分可辨别出约30种硫(砷)化物矿物:FeS、NiS、(Ni,Fe)S、Fe3S2、Ni3S2、(Ru,Os,Ir)S2、Rh7As3、Rh5Ni(Cu)As4、Pd4Rh3As3、Pd8As2、Pd3TeAs、Pd7Te3、RuAs、PtAs2、Ni4Rh3As3、Rh(As,S)2、(Rh,Ir)(As,S)2、Ir(As,S)2、MnS、Ti7S3、Ti7N3、Rh3.5Se3.5CuS2、RhS、Ir2S3、(Ir,Cu)2、S3(Co,Ni,Fe)2(As,S)3、(Ir,Pt)(As,S)2、Ru3(As,S)7以及(BM)x(PGE)yS10-(x y)等,其中包括已定名和未定名的矿物。由于矿物粒度小(<25μm),缺乏X射线分析资料,有待进一步研究。  相似文献   

"防震减灾重点地区遥感数据库"项目成果介绍     

张景发 《国际地震动态》2006,(10):17-21

主要介绍了“防震减灾重点地区遥感数据库”项目的立项背景、目标、所开展的主要工作、取得的成果及研究成果的社会效益,并展望了该领域未来的研究工作。  相似文献   

网壳结构的粘弹阻尼器减振分析   总被引：10，自引：0，他引：10  

范峰  沈世钊 《地震工程与工程振动》2003,23(3):156-159

本文将粘弹阻尼器引入网壳结构，针对网壳结构粘弹阻尼器减振系统，编制了有限元分析程序，利用该程序对单层球面网壳和单层柱面网壳进行了大量的减振分析。计算结果表明，粘弹阻尼器减振系统对大跨网壳结构的减振效果是十分明显的，是一种适合大跨网壳结构的减振系统。  相似文献