共查询到20条相似文献，搜索用时 46 毫秒
1.
George W. Boehlert 《GeoJournal》1988,16(1):45-52
Ocean currents impinging on topographic obstacles such as seamounts create a high level of variability in mesoscale physical
oceanography. In the N Pacific, for example, the structure of the Kuroshio and its extension differ significantly E and W
of the Emperor Seamount chain, and eddy fields detected downstream may be attributed to seamount effects. Nearfield effects
of seamounts have been theoretically predicted for several decades but only recently has theory been confirmed by observation.
Taylor columns, quasi-stationary eddies over seamounts, alter flow patterns and thus have impacts on both benthos on seamounts
and on the biota in water overlying the seamount.
SE Hancock Seamount, located at the N end of the Hawaiian Ridge (29°47′N; 179°04′E), has a summit depth of 265 m. This seamount
is located near the subtropical front and is at the southerly extent of productive seamounts where trawl fisheries have existed
in the past. The pelagic ecosystem in the upper 200 m over the seamount clearly differs from waters at control stations at
distances of 10's of kilometers away as shown by plankton and midwater trawl hauls and hydroacoustic transects conducted during
1984 and 1985. Over the seamount, hydroacoustic transects show a significantly higher biomass of scatterers as compared to
control stations. Sampling these scattering layers with small midwater trawls demonstrates high densities of a resident micronekton
fauna dominated by the sternoptychid fish “Maurolicus muelleri” and the mysid “Gnathophausia longispina”; these taxa were
virtually absent from the control stations, were oceanic micronekton, particularly larger forms, were generally in higher
abundance than at the seamount stations. Similarly, ichthyoplankton abundance differs above the seamount and at reference
stations. In summer sampling, larval fishes were less abundant over the seamount whereas in winter the abundance was greater
there. The differences in distribution and abundance of both micronekton and ichthyoplankton are significant and consistently
observed, suggesting that physical or biological processes at the seamount have important effects on the pelagic ecosystem.
Hypotheses concerning current — topography interactions, exclusion of vertical migrators, and predation by resident micronekton
and fishes can be used to explain the observed effects.
Seamounts and other areas of complex topography are frequently sites of highly productive ecosystems; the S Emperor and N
Hawaiian Ridge seamounts provide a good example, with a catch of approximately one million tons of boarfish in ten years.
The interaction of ocean currents and complex topography may play an important role in this high productivity, as demonstrated
in the high biomass of lower trophic levels in the seamount ecosystem. Interannual variability in the latitudinal position
of the subtropical front and the strength of current flow over these seamounts may result in significant differences in mesoscale
physical oceanography and therefore in the productivity of these ecosystems. 相似文献
2.
Jonas B. Ruh 《地学学报》2016,28(3):163-170
Seamounts entering active subduction zone trenches initially collide with the frontal sedimentary accretionary wedges resulting in severe deformation of the overriding plate. A typical feature of this deformation is the occurrence of submarine landslides due to gravitational instabilities. Such landslides have been reported from the Middle America and Hikurangi trenches and potentially generate tsunami waves. Yet, the dynamics of accretionary wedges during seamount indentation, and landsliding as a mechanical response in particular, have not been investigated qualitatively. Here, I use 3D high‐resolution numerical experiments to model the collision of conical and flat‐topped seamounts into accreting sedimentary sequences. Results show that the topographical evolution of an accretionary wedge mainly depends on the volume of the entering seamount and not on its height. Submarine landslides occur only if seamounts are not completely buried by the sedimentary sequence, and the volume of the avalanche is roughly correlated with the seamount volume overtopping the incoming sediments. 相似文献
3.
深海化能合成生态系统(ChEss)是当前最大的国际海洋生物多样性研究计划--国际海洋生物普查计划的现场研究项目之一.深海化能合成生态系统主要包括热液、冷泉、鲸骨生态系统以及由其他高度还原型生境形成的生态系统.确定上述系统动物区系间的进化和生态学关系,对于了解全球尺度上化能合成生态系统物种分布的形成过程至关重要.重点介绍深海化能合成生态系统科学计划发起的背景、研究内容和目标、研究区域、研究技术与方法以及当前在该领域的研究进展和展望,综合国际上在深海化能合成生态系统生物地理学和生物多样性方面的最新进展,了解其中的驱动过程,以期为我国在深海化能合成生态系统、极端环境下的生物多样性和生物地理学研究提供参考. 相似文献
4.
5.
Jianghong Deng Lipeng Zhang He Liu Haiyang Liu Renqiang Liao Abdul Shakoor Mastoi Xiaoyong Yang Weidong Sun 《地学前缘(英文版)》2021,12(3):101117
Seamounts on the drifting oceanic crust are inevitably carried by plate motions and eventually accreted or subducted. However, the geochemical signatures of the subducted seamounts and the significance of seamount subduction are not well constrained. Hundreds of seamounts have subducted beneath the Philippine Sea Plate following the westward subduction of the Pacific Plate since the Eocene (~52 Ma). The subducted oceanic crust and seamount materials can be exhumed from the mantle depth to the seafloor in the Mariana forearc region by serpentinite mud volcanoes, providing exceptional opportunities to directly study the subducted oceanic crust and seamounts. The International Ocean Discovery Program (IODP) expedition 366 has recovered a few metamorphosed mafic clasts exhumed from the Mariana forearc serpentinite mud volcanoes, e.g., the Fantangisña and Asùt Tesoru seamounts. These mafic clasts have tholeiitic to alkaline affinities with distinct trace elements and Nd-Hf isotopes characteristics, suggesting different provenances and mantle sources. The tholeiites from the Fantangisña Seamount have trace element characteristics typical of mid-ocean ridge basalt. The Pacific-type Hf-Nd isotopic compositions, combined with the greenschist metamorphism of these tholeiites further suggest that they came from the subducted Pacific oceanic crust. The alkali basalts-dolerites from the Fantangisña and Asùt Tesoru seamounts show ocean island basalt (OIB)-like geochemical characteristics. The OIB-like geochemical signatures and the low-grade metamorphism of these alkali basalts-dolerites suggest they came from subducted seamounts that originally formed in an intraplate setting on the Pacific Plate. The Pacific Plate origin of these metabasites suggests they were formed in the Early Cretaceous or earlier.Two types of OIBs have been recognized from alkali metabasites, one of which is geochemically similar to the HIMU-EMI-type OIBs from the West Pacific Seamount Province, and another is similar to the EMII-type OIBs from the Samoa Island in southern Pacific, with negative Nb-Ta-Ti anomalies and enriched Nd-Hf isotopes. Generally, these alkali metabasites are sourced from the heterogeneous mantle sources that are similar to the present South Pacific Isotopic and Thermal Anomaly. This study provides direct evidence for seamount subduction in the Mariana convergent margins. We suggest seamount subduction is significant to element cycling, mantle heterogeneity, and mantle oxidation in subduction zones. 相似文献
6.
The analysis of geological and geophysical data on the Hawaiian-Emperor seamount chain indicates that the commonly assumed origin of its lithosphere is inconsistent with the geothermal model of the oceanic-bottom formation. To reveal the nature of the Hawaiian-Emperor Ridge, the main tectonic units of the North Pacific were thoroughly analyzed and a map of geothermal data, magnetic anomalies, and bottom age in this region has been compiled. The subsidence rate of the lithosphere that was thermally rejuvenated by plume material after the passing of the Pacific plate over the Hawaiian hot spot was calculated with the aid of the bathymetric database for the World Ocean. The calculated parameters show that the lithosphere, which underwent thermal rejuvenation, subsides at a much lower rate than it spreads. The obtained empirical equation describes the abrupt uplifting and further subsidence of the oceanic floor during the passing of the Pacific Plate over the Hawaiian plume. The heat flow calculated in line with the thermophysical model of the thermally rejuvenated lithosphere is close to the heat flow measured at the surface of the Hawaiian-Emperor Seamounts. Thus, the proposed model is realistic. Paleogeodynamic reconstructions of the thermal regime during the formation of the Hawaiian-Emperor seamount chain were made in absolute coordinate system for the period 90–20 Ma on the basis of geological and geophysical data and the calculated distribution of bottom ages in the North Pacific. 相似文献
7.
A total of 17 brachiopod species belonging to 15 genera are recorded from a limestone block of about 3×4 km2 in the Indus–Tsangbo suture zone at Xiukang in Lhaze County of Tibet. The brachiopod fauna generally indicates a Late Guadalupian age (late Wordian–Capitanian, late Middle Permian) based on its association with the Timorites-bearing ammonoid fauna and the presence of the brachiopod Urushtenoidea crenulata. Palaeobiogeographically, the fauna exhibits transitional/mixed characters between the warm-water Cathaysian and cold to temperate Gondwanan faunas and may have developed on a carbonate build-up or seamount on the oceanic crust. 相似文献
8.
Data on the composition of rocks in linear tectono-magmatic rises in the Brazil Basin indicate that volcanic rocks in the Vitoria—Trindade seamount chain were derived from a mantle reservoir unevenly enriched in phosphorus under the effect of melts close to subalkaline picrobasalt. These melts contained much of the EM I mantle component because the plume material was contaminated with continental lithospheric component. A long-lived isotopic homogeneity of the source is typical of the whole structure, including the Trindade and Martin Vaz Islands and the Abrolhos Plateau. The analogous isotopic ratios of rocks at the Fernando de Noronha Islands are reportedly explained by a similar mechanism of melt derivation and the similar evolution of the mantle plume material, which was originally situated beneath the South American continent. Compared to the melts of volcanic rocks of all other seamounts discussed herein, the parental melts of volcanics at the Victoria—Trindade Seamounts were derived at lower degrees of melting of enriched source material at a greater depth. The overwhelming majority of volcanic rocks at the northern chain of the Bahia Seamounts were produced by melts generated with the involvement of material of the HIMU type. At the same time, one of our rock samples was derived from a source of composition close to DM with a certain admixture of enriched material like EM I. The mantle source of rocks of the Pernambuco Seamounts consisted of a mixture of DM and HIMU material with a certain admixture of EM I (or, perhaps, EM II). The 10°–11° S Seamounts were formed near the MAR axial zone at the decompressional melting of chemically homogeneous mantle source that consisted of DM material with an admixture of EM I (or, perhaps, EM II) component. 相似文献
9.
Zhenyu Song Yunpeng Xiao Chuantao Xiao 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(2):147-157
The biodiversity changes of trilobites in the middle Yangtze region of South China in the Great Ordovician Biodiversification Event and the end-Ordovician mass extinction have been analysed. The Ordovician trilobites in this region originated in the early Tremadocian and radiated from the late Floian to the early Katian. Two peaks of diversity appeared in the late Dapingian to the early Darriwilian and the early Katian. The extinction occurred in the late Katian, followed by a survival period in the Hirnantian. The Whiterock fauna began to surpass the Ibex fauna during the early Katian and were dominant by the late Katian to the Hirnantian, indicating that Cambrian Evolutionary Fauna was gradually replaced. The study once again confirms the view that the effects of factors such as sea level, climate, oxygen content, nutrient supply, and tectogenesis differ temporally and to different degrees in different regions, resulting in differences in the vertical sequence and horizontal combination of ecosystems, which is the reason for the different evolution patterns of Ordovician trilobites in different regions. 相似文献
10.
通过大洋一号船DY105--12 /14 航次采集的结壳样品,对中太平洋CL、CM2、CM3、CX、CQ、 CA、CB 海山结壳的主要成壳元素Mn、Fe、Co、Ni、Cu 的含量进行了测试统计,并与邻区的麦哲伦海山、马绍尔群岛、夏威夷群岛和莱恩群岛进行了对比,中太平洋各海山以及不同区域海山结壳的主成分之间存在一些差异,这主要与各海山结壳的物质来源、成壳环境和成壳时代的差异有关。不同形态类型的结壳主成分具有一定的差别,其主要原因可能是生长机制和形成环境不同造成的。 相似文献
11.
Zheng-Gang Li Yan-Hui Dong Ji-Qiang Liu Ling Chen 《International Geology Review》2015,57(5-8):978-997
Seamounts are an integral part of element recycling in global subduction zones. The published trace element and Pb-Sr-Nd isotope data for basaltic lavas from three key segments (Central Lau Spreading Ridge (CLSR), Eastern Lau Spreading Ridge (ELSR), and Valu Fa Ridge (VFR)) of the Lau back-arc basin were compiled to evaluate the contribution of Louisville seamount materials to their magma genesis. Two geochemical transitions, separating three provinces with distinct geochemical characteristics independent of ridge segmentation, were identified based on abrupt geochemical shifts. The origin of the geochemical transitions was determined to be the result of drastic compositional changes of subduction components added into the mantle source, rather than the transition from Indian to Pacific mid-ocean ridge basalt (MORB) mantle, or due to variable mantle fertilities. The most likely explanation for the drastic shifts in subduction input is the superimposition of Louisville materials on ‘normal’ subduction components consisting predominantly of aqueous fluids liberated from the down-going altered oceanic crust and minor pelagic sediment melts. Quantitative estimation reveals that Louisville materials contributed 0–74% and 21–83% of the Th budget, respectively, to CLSR and VFR lavas, but had no definite contribution to the lavas from the ELSR, which lies farthest away from the subducted Louisville seamount chain (LSC). The spatial association of the subducted LSC with the Louisville-affected segments suggests that the Louisville signature is regionally but not locally available in the Tonga subduction zone. Besides, the preferential melting of subducted old Cretaceous LSC crust instead of the old normal Pacific oceanic crust at similar depths implies that elevated temperature across the subduction interface or seamount erosion and rupture were required to trigger melting. A wider implication of this study, thus, is that seamount subduction may promote efficiency of element recycling in subduction zones. 相似文献
12.
The results of annual parasitological monitoring in the coastal area near the Abram-mys (Kola Bay, Barents Sea) are presented.
The studies were performed in 2006–2007 and included complex examination of the intermediate hosts (mollusks and crustaceans)
and definitive hosts (marine fish and birds) of the helminths. The biodiversity of the parasite fauna, seasonal dynamics,
and functioning patterns of the parasite systems were investigated. The basic regularities in parasite circulation were assessed
in relation to their life cycle strategies and the ecological features of the intermediate and definitive hosts. The factors
affecting the success of parasite circulation in the coastal ecosystems were revealed through analysis of parasite biodiversity
and abundance dynamics. 相似文献
13.
利用富钴结壳碳酸盐基岩有孔虫矿物标型重建古海洋温度 总被引：1，自引：0，他引：1
重建古海洋海表温度(SST),是研究地质历史时期气候变化控制过程的关键。组成有孔虫化石的矿物Mg/Ca值是海水温度的可靠代用指标,是重建古海洋SST的一个非常好的手段。麦哲伦海山区的富钴结壳和基岩中普遍存在有孔虫化石,这对重建该区的SST有重要意义。利用LA-ICP-MS测得西太平洋麦哲伦海山区富钴结壳碳酸盐基岩中8颗浮游有孔虫化石Globigerinoides sacculifer的Mg/Ca值为3.84±0.36(mmol/mol),通过线性公式:T(℃)=2.898Mg/Ca(mmol/mol)+13.76及已有的定年数据,得到0.91Ma±西太平洋麦哲伦海山区海表温度为24.9+1.1/-1.0℃,未能检索到前人关于该区0.91Ma±前海表温度数据。 相似文献
14.
Floréal Solé Corentin Noiret Delphine Desmares Sylvain Adnet Louis Taverne Thierry De Putter Florias Mees Johan Yans Thomas Steeman Stephen Louwye Annelise Folie Nancy J.Stevens Gregg F.Gunnell Daniel Baudet Nicole Kitambala Yaya Thierry Smith 《地学前缘(英文版)》2019,10(3):1039-1063
The early Paleogene is critical for understanding global biodiversity patterns in modern ecosystems. During this interval, Southern Hemisphere continents were largely characterized by isolation and faunal endemism following the breakup of Gondwana. Africa has been proposed as an important source area for the origin of several marine vertebrate groups but its Paleogene record is poorly sampled, especially from sub-Saharan Africa. To document the early Paleogene marine ecosystems of Central Africa, we revised the stratigraphic context of sedimentary deposits from three fossil-rich vertebrate localities: the Landana section in the Cabinda exclave(Angola), and the Manzadi and Bololo localities in western Democratic Republic of Congo.We provide more refined age constraints for these three localities based on invertebrate and vertebrate faunas, foraminiferal and dinoflagellate cyst assemblages, and carbon isotope records. We find an almost complete absence of Danian-aged rocks in the Landana section, contrary to prevailing interpretations over the last half a century(only the layer 1, at the base of the section, seems to be Danian). Refining the age of these Paleocene layers is crucial for analyzing fish evolution in a global framework, with implications for the early appearance of Scombridae(tunas and mackerels) and Tetraodontiformes(puffer fishes). The combination of vertebrate fossil records from Manzadi and Landana sections suggests important environmental changes around the K/Pg transition characterized by an important modification of the ichthyofauna. A small faunal shift may have occurred during the Selandian. More dramatic is the distinct decrease in overall richness that lasts from the Selandian to the Ypresian. The Lutetian of West Central Africa is characterized by the first appearance of numerous cartilaginous and bony fishes. Our analysis of the ichthyofauna moreover indicates two periods of faunal exchanges: one during the Paleocene, where Central Africa appears to have been a source for the European marine fauna, and another during the Eocene when Europe was the source of the Central Africa fauna. These data indicate that Central Africa has had connections with the Tethyian realm. 相似文献
15.
古海山是缝合带的关键组成部分,中亚造山带西段的天山造山带内已发现多处古海山,而北山地区却鲜有报道,古海山的发现可以弥补该地区海山研究的不足.通过在北山中部野马泉开展地质调查、测制剖面,发现了一套原始层序完整、以玄武岩、玄武质凝灰岩和大理岩为主的地层,具有火山岩基座和碳酸盐岩顶盖的结构,二者原始接触关系为整合接触,符合海山的沉积特征.依据地层中的岩石组合和沉积构造,确定其形成于海山斜坡相.野马泉古海山残骸呈NWW-SEE向延伸,东南部更接近海山顶.该海山中的玄武岩富集大离子亲石元素、亏损高场强元素,具有岛弧玄武岩的特征.该海山为洋内弧型海山,野马泉一带位于海山斜坡,其被构造肢解后呈NWW-SEE向分布. 相似文献
16.
P. G. Quilty 《Australian Journal of Earth Sciences》2013,60(5):633-641
A Late Eocene foraminiferal fauna of free specimens is recorded from Cascade Seamount, a feature of volcanic origin, whose age and fauna were previously studied only in thin section. The fauna is of Late Eocene (P15) age because of the presence of Globigerapsis index, Globigerapsis rubriformis, Subbotina linaperta, Subbotina angiporoides and Chiloguembelina cubensis. Many typical Eocene indicators, such as Hantkenina, Pseudohastigerina and key globorotaliids, are absent. The age is a little older than that estimated for previous samples from the seamount. The fauna is dominated (78%) by benthic species, especially species of Cibicides that have greater affinities with New Zealand faunas than with coeval southern Australian faunas. The sediment and its fauna accumulated near the lower limits of wave activity, off the coast of a volcano that probably stood at least 400 m above sea level. The location has subsided nearly 1000 m over the past 40 million years to its present water depth of 1000 m, suggesting that the entire East Tasman Plateau was approximately 1000 m above its current depth at the time. Conditions were cool temperate and the fauna lacks any warm water indices, consistent with a palaeolatitude of 55–60°S, but also with cool waters at a time of oscillating conditions in southern Australia and also in Antarctica. There is essentially no infauna and the waters were highly oxygenated in the turbulent zone. 相似文献
17.
During the 28th trip of the R/V Akademik Sergei Vavilov undertaken in 2009, exploration was carried out using a Parasound acoustic profilograph that permitted examining the upper
portion of the sedimentary cover and getting transverse bathymetric profiles through a number of seamounts within the northern
range of the Bahia group of seamounts, which were also sampled by dredging. The studies performed indicated that this linear
structure consists of paleovolcanoes and formed under impulse conditions of volcanic activity. A number of seamount types
have been distinguished, the morphostructural settings and the positions of which reflect the intensity of volcanic impulses
and the association with deep permeable zones. The strongest impulse led to the formation of a northwest striking arched uplift,
on which there are several central type paleovolcanoes of different heights. The largest of these paleovolcanoes, including
the Stocks and Groll Seamounts, have flattened tops formed as a result of marine abrasion. Isolated seamounts have formed
during shorter and lower power impulses of volcanic activity. The northern range of the Bahia seamounts, which have a major
northwesterly strike, is an ensemble of structures with northwesterly, nearly east-west, and nearly north-south strikes, which
indicates the presence of relevant deep permeable zones for the mantle matter; that mantle matter is the source of the melts,
eruptions of which led to the formation of the volcanic edifices. The prevailing zone of weakness has a northwesterly strike.
Volcanic activity in the Bahia group of seamounts ended in the Paleocene, but tectonic movements continued there up until
the Holocene. Neotectonic structures are represented by horsts, diapirlike piercement structures, and folded zones. The paleovolcanoes
are areas where slope processes of transport of sedimentary material occurred. 相似文献
18.
全球生态系统的状况与趋势 总被引：3，自引：0，他引：3
简要介绍了千年生态系统评估（MA）项目状况与趋势工作组的报告《生态系统与人类福祉：现状与趋势》中的第3部分，即“对提供生态系统服务的各类系统的评估”。评估结果表明，在20世纪的后50年，全球生态系统的变化幅度和速度皆超过了人类历史上有记录的任何一个相等时间段的情况，目前人类活动实际上已经显著地改变了地球上的所有生态系统。这些变化主要表现在：① 大约1/4的地球陆地表层已经转变为垦殖系统，而且在1950年之后的30年中，转变为农田的土地面积比1700—1850年这150年间转变的总和还要多；②全球大多数的重要流域，由于水资源利用造成的栖息地丧失与破碎化，以及由于养分、沉积物、盐分及有毒物质造成的污染，已经显著地破坏了河流、湖泊和盐水沼泽等湿地生态系统的功能与生物多样性；③ 旱区系统存在着水资源匮乏、过度垦殖、过度放牧和过度砍伐树木等问题，生态状况尤其令人担忧；④ 栖息地的丧失与破碎化、过度开发、污染以及气候变化，已经对海滨系统造成了严重的生态威胁；⑤ 不可持续的农业开发模式，已经严重地破坏了热带森林生态系统的结构与功能。 相似文献
19.
Geochemistry of Lavas from the Emperor Seamounts, and the Geochemical Evolution of Hawaiian Magmatism from 85 to 42 Ma 总被引：4，自引：1，他引：4
The Hawaiian–Emperor Seamount Chain (ESC), in the northernPacific Ocean, was produced during the passage of the PacificPlate over the Hawaiian hotspot. Major and trace element concentrationsand Sr–Nd–Pb isotopic compositions of shield andpost-shield lavas from nine of the Emperor Seamounts providea 43 Myr record of the chemistry of the oldest preserved Hawaiianmagmatism during the Late Mesozoic and Early Cenozoic (from85 to 42 Ma). These data demonstrate that there were large variationsin the composition of Hawaiian magmatism over this period. Tholeiiticbasalts from Meiji Seamount (85 Ma), at the northernmost endof the ESC, have low concentrations of incompatible trace elements,and unradiogenic Sr isotopic compositions, compared with youngerlavas from the volcanoes of the Hawaiian Chain (<43 Ma).Lavas from Detroit Seamount (81 Ma) have highly depleted incompatibletrace element and Sr–Nd isotopic compositions, which aresimilar to those of Pacific mid-ocean ridge basalts. Lavas fromthe younger Emperor Seamounts (62–42 Ma) have trace elementcompositions similar to those of lavas from the Hawaiian Islands,but initial 87Sr/86Sr ratios extend to lower values. From 81to 42 Ma there was a systematic increase in 87Sr/86Sr of boththoleiitic and alkalic lavas. The age of the oceanic lithosphereat the time of seamount formation decreases northwards alongthe Emperor Seamount Chain, and the oldest Emperor Seamountswere built upon young, thin lithosphere close to a former spreadingcentre. However, the inferred distance of the Hawaiian plumefrom a former spreading centre, and the isotopic compositionsof the oldest Emperor lavas appear to rule out plume–ridgeinteraction as an explanation for their depleted compositions.We suggest that the observed temporal chemical and isotopicvariations may instead be due to variations in the degree ofmelting of a heterogeneous mantle, resulting from differencesin the thickness of the oceanic lithosphere upon which the EmperorSeamounts were constructed. During the Cretaceous, when theHawaiian plume was situated beneath young, thin lithosphere,the degree of melting within the plume was greater, and incompatibletrace element depleted, refractory mantle components contributedmore to melting. KEY WORDS: Emperor Seamounts; Hawaiian plume; lava geochemistry; lithosphere thickness; mantle heterogeneity 相似文献
20.
西太平洋海域海山地形分形特征研究 总被引：1，自引：0，他引：1
对太平洋麦哲伦海山区、威克—马尔库斯海山区、马绍尔群岛、中太平洋海山区及莱恩群岛5个海山区的平顶海山与尖顶海山地形进行分形研究,结果表明两种类型海山地形具有不同的分形特征。海山形态投影覆盖法揭示平顶海山具有单分形的大尺度构造分形,尖顶海山具有大尺度构造分形和小尺度结构分形的双分形结构。海山等高线尺度法分形结果显示,同一海山区平顶海山分维值小于尖顶海山的;同一海山不同高程段等高线分维值基本保持稳定,垂向上具有明显的分段性,可以参考并使用它进行地貌垂向分带。 相似文献