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1.
龟山岛附近海域热液活动流体的来源   总被引:1,自引:0,他引:1  
台湾东北部龟山岛附近热液活动区流体的来源较为复杂,判断流体来源同时探讨该地区岩浆活动的程度对于龟山岛热液活动研究具有至关重要的意义。通过测定热液流体中的元素浓度和氢氧同位素特征显示:热液流体的微量元素浓度总体上接近海水值,但是通过Mg浓度为0回推得出热液流体的端员组分较为简单,而且有低Cl-浓度的组分(如地下水)加入,所测定热液流体中海水特征是由于取样过程中海水混入所致,氢氧同位素的对应曲线表明热液流体与该地区海水的同位素特征值不一致,并且不是单一龟山岛上地下淡水来源。龟山岛附近热液流体在氢氧同位素值分布特征上与南胡安得富卡洋脊的深水热液活动流体较为一致。可以初步判断龟山岛附近热液活动流体来源主要由两部分组成:深部物质和龟山岛上的大气降水,深部的岩浆物质在上升过程中,发生相分离,分离相在继续上升的过程中遇到下渗的淡水,两者混合构成了热液流体的端员组分。因此龟山岛热液活动的出现是由于深部物质活动造成的,表明目前该地区地壳活动较为活跃。  相似文献   

2.
由龟山岛热液气体推断几个可能化学反应方程式的存在,根据相关的假设条件,尽量接近于真实的龟山岛热液环境情况,通过计算、比较这些可能存在的化学反应在标况和龟山岛热液条件下的平衡常数,得出龟山岛热液活动区自然硫的形成可能反应式2H2S(g) O2(g)=2S(s) 2H2O(l)和CH4(g) SO2(g)=3S(s) 2H2O(l) CO2(g)起到了较大的作用。这与龟山岛热液活动所具有的水深浅,周围氧气含量高的事实以及采集的热液气体中含有大量CO2气体等情况十分一致。  相似文献   

3.
位于台湾岛东北部的龟山岛热液区属浅水型海底热液活动区,已探明有超过30处的热液喷口分布在约10—30m的水深范围内。通过机械封装、硬件电路以及配套软件的设计和加工,自制了散射光式水下浊度仪;2011年5月25—30日,使用该浊度仪,对龟山岛附近海域进行了拖航作业,在此次作业的东北方向发现一处新的热液喷口(24°5009N、121°5808E);海试结果表明,该水下浊度仪对于浊度较大海域有探测能力,对浊度较小海域的探测精度不高,还有待进一步改进。  相似文献   

4.
通过气相色谱-质谱联用仪(GC-MS)和气相色谱-同位素质谱仪(GC-IRMS),分别分析了冲绳海槽南部唐印和第四与那国热液区热液硫化物与热液沉积物中烷烃含量和正烷烃单体碳同位素组成特征。热液产物样品中正烷烃显示出明显的双峰分布,高分子正烷烃显示出明显的奇数碳优势,其丰度最大值位于C31处;低分子正烷烃显示出偶数碳优势,其丰度最大值位于C18处。正烷烃的分布特征以及正烷烃碳同位素组成表明,样品中正烷烃主要来源于热液微生物代谢活动和陆源高等植物的输入,其中,低分子的正烷烃主要来源于热液微生物代谢活动,而高分子的正烷烃主要来源于陆源高等植物。热液硫化物样品中低分子正烷烃含量和比重都高于热液沉积物,表明热液硫化物中热液微生物活动可能更加繁盛。热液硫化物中正烷烃单体的δ13C表现出随碳原子个数增加,同位素值减小的趋势,暗示该区非生物合成有机质的贡献可能不能忽略。  相似文献   

5.
类脂物生物标志化合物(简称类脂物生标)记录了原始生物母质的分子组成信息,是研究极微生物群落、探索生命起源与演化的重要载体。综述了海底热液喷口区类脂物生标的主要研究进展,重点探讨烷烃、脂肪酸、醚类生标的应用及科学意义。类脂物生标研究表明,海底热液喷口区具有独特而又丰富的生物群落,喷口区动物群落与其他深海环境相似物种在饮食结构上有明显差别,它们主要捕食化能自养细菌或古细菌,且不同物种所捕食的微生物种类也具有选择性。为应对喷口区的极端物化环境,热液细菌和古菌形成了独特细胞分子组构。类脂物生标及单体同位素组成显示,喷口区存在嗜热型氨氧化和甲烷缺氧氧化古菌活动,在热液流体富H2的情况下硫酸盐还原菌与产甲烷古菌能够共存,碳限制条件下能产生富13 C(-11.8‰~+3.6‰PDB)的类脂物生标。类脂物生标对于揭示热液微生物种群与营养关系、指示热液环境条件、反映热液区甲烷代谢作用以及探索生命起源与进化过程具有重要的研究意义,今后还需加强其应用范围及相关指示性机理等方面的研究。  相似文献   

6.
测定了冲绳海槽中部Jade热液活动区中18个热液沉积物样品的硫同位素组式,其中10个硫化物样品的δ34S值为5.2×10-3~7.2×10-3,7个硫酸盐样品的34S值为16.3×10-3~22.3×10-3,1个自然硫样品的δ34S值为8.2×10-3热液沉积物的硫主要来自中、酸性火山岩和海水,并且在流体与沉积物相互作用过程中海底沉积物也可能为热液沉积物的形成提供部分的硫.导致本区热液沉积物中硫化物与其他热液活动区的硫同位素组成不同的原因,主要是各热液活动区的硫源以及有关岩浆活动和构造演变的不同.海底热液体系中硫的演化是一个复杂的过程,涉及被加热海水的上升、流体与火山岩的相互作用、海水硫酸盐和中、酸性火山岩中流的混合作用以及流体与沉积物相互作周等一系列海底热液活动,其中海水和中、酸性火山岩的相互作用是本区硫演化的一个重要机制.  相似文献   

7.
近23年的调查研究,使我们认识到分布于洋中脊、弧后盆地、岛弧和热点等环境的海底热液活动发育在多种围岩类型之上,包括超基性岩石、基性岩石、中性岩石、酸性岩石和沉积物。海底热液活动经历了岩浆去气作用、流体-岩石/沉积物相互作用和流体-海水混合,获取了岩浆、岩石、海水和沉积物的物质,构成了热液循环,产生了高温、低氧、高或低pH值、富含Fe、Mn、Cu、Zn、Pb、Hg、As等元素以及气体组分(甲烷、氢等)的喷口流体,影响了海水、沉积、岩石和生物环境,形成了热液柱、硫化物、含金属沉积物和蚀变岩石等热液产物,组成了海底热液系统。未来,促进海底热液活动探测技术和热液产物测试方法的发展,对海底热液区的岩石、喷口流体、热液柱、硫化物、含金属沉积物以及热液循环、生物活动的持续观测与研究,无疑将为人类探知海底地质过程及生命活动、保护海底热液环境和合理开发利用海底资源提供有力的工作支撑。  相似文献   

8.
深海热液喷口生物群落的研究进展   总被引:11,自引:0,他引:11  
深海热液喷口生物群落并不依赖光合作用获取能量,它们是一类独特的生物类型,其食物链的基础是化学合成细菌,这些细菌依靠喷口热液中的还原无机物氧化.利用CO。合成有机碳,它们共生于大个体动物的软组织或绍中,向寄主提供生存必需的有机碳。地质时期古热液喷口生物群落的研究还表明,该类生物群落在古生代(可能更早)即已出现。此外,现代热液喷口与古热液喷口生物群落的比较研究,在探索该生物群落乃至早期生命的起源、演化方面也取得了可喜进展。  相似文献   

9.
为了探讨龟山岛附近热液自然硫烟囱体的物质来源,通过测定烟囱体内铅同位素的组成特征,分析了该地区热液活动的铅元素物源.研究结果表明,龟山岛附近热液自然硫烟囱体中的铅同位素组成具有很小的变化范围和较均一的铅同位素组成特征,但是与其它深海热液沉积物的铅源不同,与北半球铅同位素的参考线(NHRL)相距甚远.虽然自然硫烟囱体出现在海水环境,但是海水对其不存在铅的贡献,烟囱体内的元素铅主要是陆壳来源.根据以上结果可以进一步推断,龟山岛热液活动区的下伏地层中,存在一定分布范围的陆壳,这对于研究该地区复杂的地质构造特征具有一定意义.  相似文献   

10.
热液柱的形态研究   总被引:6,自引:0,他引:6  
热液柱是海底热液系统将其自身的能量输入海水的一种重要形式,是进行热液活动环境效应研究的主要物理对象。给出了描述热液柱形成与演化的运动方程、连续性方程和能量方程,并给出了问题的近似解。通过解的分析指出,热液流体从海底喷口喷出以后,由于初速度和浮力的存在将沿一个通道上升,随离海底距离的增大上升的速度迅速低,同时,热液流体的上升通道在侧向上将随这扩展,到达中性浮力面后不再上升,而仅在一个层面上扩展。在不考虑底层流的情况下,热液柱由热液颈和热液透镜组成。热液颈上粗下细,下部与热液喷口连接,上部与热液透镜连接;热液透镜呈宽扁的透镜状。  相似文献   

11.
海底热液喷发形成的热液羽状流中富含成矿物质,并沉淀在距离热液喷口不等的范围内。对西南印度洋中脊热液喷口附近、距离喷口中等距离、远离喷口的六个表层沉积物样品开展了不同粒度沉积物的便携式XRF(PXRF)分析。结果表明,PXRF可以有效获得的洋中脊钙质沉积物中成矿元素的富集特征。>40目的沉积物样品具有较高的Cu、Zn、Fe、Mn等元素含量,40目以下沉积物中则相对稳定,可能与粗粒沉积物中玄武岩碎屑/玻璃含量较高有关,与镜下鉴定结果一致。以热液喷口为中心,表层沉积物中表现出Cu、Zn、As、Fe、Mn的元素分带,靠近喷口的沉积物中具有较高的成矿元素的含量,并具有较高的Cu/Fe、Zn/Fe比值或者Cu/Mn与Zn/Mn比值。上述结论表明,洋中脊沉积物中成矿元素的含量主要受与喷口的距离的影响,而与粒度的关系不大,洋中脊沉积物地球化学找矿应采用40目以下粒径沉积物作为分析样品。通过PXRF获得的Cu、Zn、As、Fe、Mn等元素含量及其比值特征可以作为海底多金属硫化物沉积物地球化学找矿的指标,该方法满足快速有效识别洋中脊沉积物中地球化学异常的要求。  相似文献   

12.
Spatial distribution, diversity, and composition of bacterial communities within the shallow sub-seafloor at the deep-sea hydrothermal field of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific Ocean, were investigated. Fluids were sampled from four boreholes in this area. Each borehole was located near or away from active vents, the distance ranging 2–40 m from active vents. In addition, fluids discharging from a natural vent and ambient seawater were sampled in this area. We extracted DNA from each sample, amplified bacterial 16S rRNA genes by PCR, cloned the PCR products and sequenced. The total number of clones analyzed was 348. Most of the detected phylotypes were affiliated with the phylum Proteobacteria, of which the detection frequency in each clone library ranged from 84.6% to 100%. The bacterial community diversity and composition were different between hydrothermal fluids and seawater, between fluids from the boreholes and the vent, and even among fluids from each borehole. The relative abundances of the phylotypes related to Thiomicrospira, Methylobacterium and Sphingomonas were significantly different among fluids from each borehole. The phylotypes related to Thiomicrospira and Alcanivorax were detected in all of the boreholes and vent samples. Our findings provide insights into bacterial communities in the shallow sub-seafloor environments at active deep-sea hydrothermal vent fields.  相似文献   

13.
Kueishan Tao (24°51′N, 121°55′E) is located at a tectonic junction of the fault system extension of Taiwan and the southern rifting end of the Okinawa Trough. A cluster of over 30 vents, at a water depth of about 10-20 m off the eastern tip of the tao emits hy-drothermal fluids and volcanic gases such as H2S. A sulfur chimney or mound, formed by condensation of the sulfur contained in the hydrothermal fluid, can usually be seen around the  相似文献   

14.
Investigations of the diffusion activities both within and outside the seafloor hydrothermal vents, as well as related mineral genesis, have been one of the key focuses of ocean biogeochemistry studies. Many hydrothermal vents are distributed close to the southern Okinawa Trough on the less-than-30-m deep shallow seafloor off Kueishan Tao, northeast of Taiwan Island. Investigations of temperature, pH and Eh at four depths of hydrothermal plume were carried out near Kueishan Tao at the white(24.83°N, 121.96°E) and yellow(24.83°N, 121.96°E) vents. An 87 h of temperature time series observation-undertaken near the white vent showed that tide is the main factor affecting the background environment. Based on the observed data, 3-dimensional sliced diffusion fields were obtained and analyzed. It was concluded that the plume diffused mainly from north to south due to ebb tide. The yellow vent's plume could effect as far as the white vent surface. From the temperature diffusion field, the vortices of the plume were observed. The Eh negative abnormality was a better indicator to search for hydrothermal plumes and locate hydrothermal vents than high temperature and low pH abnormalities.  相似文献   

15.

Since the discovery of hydrothermal vents in the late 1970s, deep-sea hydrothermal vent fields have attracted great attention as biological hotspots. However, compared with other ocean ridges, the structure and function of microbial communities inhabiting vent fields in the Central Indian ridge (CIR) remain understudied. Here, we provide for the first time 16S rRNA gene-based comparative metagenomic analysis of the sediment-associated microbial communities from three newly discovered vent fields in the CIR. Sediment samples collected in the Invent B, Invent E and Onnuri vent fields varied in geochemical properties, elemental concentrations and associated microbial communities. Proteobacteria (Gammaproteobacteria) was the dominant phylum in Invent B and Onnuri vent fields. In contrast, Invent E mainly consisted of Chloroflexi and Euryarchaeota. Predicted functional profiling revealed that the microbial communities in the three vents are dominated by chemoheterotrophic functions. In addition, microbial communities capable of respiration of sulfur compounds, nitrification, nitrite oxidation, methylotrophy, and methanotropy were found to be the main chemolithoautotrophs. Compared to other vent fields, Invent E showed a predominance of archaeal methanogens suggesting it exhibits slightly different geochemistry. Multivariate analysis indicated that the biogeochemical and trace metal differences are reflected in the sediment microbial compositions of the three vent fields. This study expands our current understanding of the microbial community structure and potential ecological functions of the newly discovered hydrothermal vent fields in the CIR.

  相似文献   

16.
TheSnake Pit Hydrothermal Site lies on the axis of the Mid-Atlantic Ridge at 23°22′ N latitude, about 30 km south of the Kane Transform Intersection. Active ‘black smoker’ vents and a surrounding field of hydrothermal sediment occur at the crest of a laterally extensive neovolcanic ridge. It is one of the first active hydrothermal vent fields to be found on a slow-spreading ridge axis and despite significant differences in its geologic setting from those of the East Pacific Rise, has many similarities to its fast-spreading counterparts. Although preliminary reports have documented many interesting aspects of these vents and their surroundings, new data collected from the manned submersible ALVIN and the deep-towed ANGUS camera system define the regional tectonic setting as well as the local geologic environment of this fascinating area. The Snake Pit vents are located on a local peak of a volcanic constructional ridge at a depth of 3450 m, 700–800 m deeper than vents known from the East Pacific Rise, Galapagos, or Juan de Fuca spreading centers. The vent field is at least 600 m long and up to 200 m wide and is covered by a thick blanket of greenish to yellow-orange hydrothermal sediment. Both active and extinct vents are perched along the crests of steep-sided sulfide mounds that reach heights of over 40 m. High-temperature (350° C) fluids are vented from black smoker chimneys and low-temperature (226° C) fluids seep from sulphide domes and subordinate anhydrite constructions. Water temperatures, flow rates, fluid chemistries, and mineralization are strikingly similar to vents of faster spreading ridge crests; however, a somewhat distinct fauna inhabit the area.  相似文献   

17.
Western Pacific hydrothermal vents will soon be subjected to deep‐sea mining and peripheral sites are considered the most practical targets. The limited information on community dynamics and temporal change in these communities makes it difficult to anticipate the impact of mining activities and recovery trajectories. We studied community composition of peripheral communities along a cline in hydrothermal chemistry on the Eastern Lau Spreading Center and Valu Fa Ridge (ELSC‐VFR) and also studied patterns of temporal change. Peripheral communities located in the northern vent fields of the ELSC‐VFR are significantly different from those in the southern vent fields. Higher abundances of zoanthids and anemones were found in northern peripheral sites and the symbiont‐containing mussel Bathymodiolus brevior, brisingid seastars and polynoids were only present in the northern peripheral sites. By contrast, certain faunal groups were seen only in the southern peripheral sites, such as lollipop sponges, pycnogonids and ophiuroids. Taxonomic richness of the peripheral communities was similar to that of active vent communities, due to the presence of non‐vent endemic species that balanced the absence of species found in areas of active venting. The communities present at waning active sites resemble those of peripheral sites, indicating that peripheral species can colonize previously active vent sites in addition to settling in the periphery of areas of venting. Growth and mortality were observed in a number of the normally slow‐growing cladorhizid stick sponges, indicating that these animals may exhibit life history strategies in the vicinity of vents that differ from those previously recorded. A novel facultative association between polynoids and anemones is proposed based on their correlated distributions.  相似文献   

18.
硼(B)是流体迁移元素,趋向于在热液流体中富集而成为常量元素。不同来源的B其同位素组成有着明显的区别。因此,B的含量及其同位素组成可标识热液流体(元素)的物质来源、水–岩反应程度及沉积物(元素)混入等重要过程,对海底热液活动及其成矿作用过程具有重要的示踪意义。迄今,对全球主要热液活动区热液流体中B的含量及同位素组成特征已做了大量的测试分析及研究工作,积累了丰富的资料和重要研究成果。但是,对不同地质背景(构造环境)条件下热液流体中B的含量及同位素组成特征尚缺乏系统性的对比分析,进而对造成不同环境热液流体中元素及其同位素组成的系统性差异的原因或机制尚缺乏深入的认识。本文在获取了洋中脊和弧后盆地主要热液活动区热液端元流体中B的含量及其同位素组成数据的基础上,定量估算了热液流体中B的主要来源,并对洋中脊和弧后盆地热液端元流体中B同位素组成的系统性差异进行了分析及成因探讨。结果表明,不同热液活动区热液端元流体的δ11B值都具有较大的变化范围,水–岩反应过程中不同来源B的混合是热液流体B同位素组成变化的主要原因。无沉积物覆盖的洋中脊和弧后盆地热液区热液流体中的B主要为海水与基底岩石来源B的混合,弧后盆地岩浆挥发性组分对热液系统的直接贡献及两种不同地质背景下基底岩石地球化学组成与水–岩反应程度的差异是其热液端元流体B同位素组成差异的主要原因。在有沉积物覆盖的弧后盆地热液区,热液流体中B的同位素组成与前两者之间存在显著差异,具有异常低的δ11B值,水–岩反应过程中沉积物来源B的加入是导致热液流体中δ11B值系统性降低的主要原因,沉积物的吸附作用也在一定程度上影响了热液流体的B同位素组成。有沉积物覆盖的洋中脊热液区热液流体同样受到了沉积物来源B加入的影响,具有较低的δ11B值,且相对于冲绳海槽受到了更强烈的沉积物吸附作用的影响。基于以上分析,并结合热液流体的Sr同位素组成特征,本文提出了洋中脊和弧后盆地这两大构造环境中热液流体B同位素组成系统性差异的成因模式。  相似文献   

19.
Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders (MAPR) attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/VDayang Iin the “Precious Stone Mountain” hydrothermal field on the Gala-pagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activ-ity in this field, indicating the presence of a new hydrothermal vent.  相似文献   

20.
现代海底低温热液弥散流区微生物生态的发育情况已经成为当前热液系统研究关注的热点之一。大量的分析表明在低温热液弥散流区赋存着丰富的化能自养微生物,以硫、铁等元素的氧化还原反应获取新陈代谢能量,这些微生物的分布与低温热液流体的物理化学条件有着密切的联系。这些发现极大地丰富了我们对低温弥散流区微生物生态、关键地球化学过程与微生物新陈代谢耦合关系的认识。此外,低温热液流体是研究洋壳深部生物圈的窗口,通过这个窗口可以了解地壳内部生命的新陈代谢方式,进而理解地球内部微生物与洋壳内部流体、岩石之间的相互作用机制。  相似文献   

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