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1.
地球是个水的行星,海洋面积有3.61亿平方公里,约占地球总面积5.1亿平方公里的71%。海洋是生命的摇蓝,风雨的故乡,资源的宝库,友谊的纽带,贸易的坦途,战略的要地.开发海洋,发展海洋事业,已成为世界新产业革命的重要内容,因此,考察、认识、研究、开发、利用和保护海洋,已成为当今世界关注的问题,《大洋洲岛国地理》迎合这一世界趋势而问世,具有重要的现实意义在世界最大的洋,浩瀚的太平洋西部,赤道两侧南北回归线之间的热带、亚热带湛兰海域,散布着大洋洲的美拉尼西亚、密克罗尼西亚、波利尼西亚三大群岛中的一万多个岛屿,其中以夏威夷群岛属火山岛,少数岛屿属大陆岛以外,多数属珊瑚岛,而且气候暖湿,森林茂密,出产椰子、甘蔗、菠萝、香蕉、海鱼、磷、镍、铬、金等物产,其中许多岛屿是联系各大洲海、空航线和海底电缆经过的地方,在国际交  相似文献   

2.
珊瑚岛的动态演变及其稳定性研究综述   总被引:1,自引:0,他引:1  
珊瑚岛是指发育在珊瑚礁的礁坪上,高潮时也不会被淹没的生物碎屑堆积体。珊瑚岛在珊瑚礁区广泛分布,可划分为无植被沙岛、无植被砾岛、有植被沙岛、有植被砾岛、有植被的沙砾岛、红树林岛和成熟的低林岛等7种类型,不同类型珊瑚岛的地貌特征存在差异。珊瑚岛受多种因素影响而在不同空间和时间尺度上处在动态变化中,珊瑚礁健康状况、珊瑚岛沉积特征、台风和海平面变化是影响珊瑚岛稳定性的重要因素。全球变化引起海水表面温度升高、海洋酸化、海平面上升及台风活动增强,直接或间接影响了珊瑚岛的沉积物供给、运移、堆积等动力学过程的各个方面,珊瑚岛的发展具有不确定性。迫切需要加强对珊瑚礁动态演变及其稳定性研究,建议从珊瑚岛的生物地貌动力学过程及全球变化对珊瑚岛动态演变的影响方面进行重点分析。  相似文献   

3.
章小明 《地理教学》2011,(15):2+65-F0002,F0003
泰国普吉有世界最美的岛屿、最美的海水、最美的海湾、最美的海滩。紧靠马来半岛西侧的印度洋安达曼海是一片辽阔的热带海洋。普吉及其她附近的岛屿就像天女散花一样散落在这里。惊奇的是这些岛屿不同于印度洋马尔代夫的珊瑚岛很低很平,而是一座座拔海而起的山地岛。其特点是:岛的四周多为高几十米的悬崖峭壁,直插海底,船到跟前须仰望之。各种海蚀地貌清晰可见。  相似文献   

4.
塞舌尔共和国是西印度群岛上的一个岛国,由115个大小岛屿组成。口地面积455.39平方千米,领海面积40万平方千米,专属海洋经济区面积100万平方千米。塞舌尔西距非洲大陆东岸1500千米,南距马达加斯加900多千米。地处欧、亚、非三大洲中心地带,为亚、非两洲交通要冲,地理位置十分重要。塞舌尔群岛分为4个密集的岛群:马埃岛和它周围的卫星岛;锡卢埃特岛和北岛;普拉斯莱岛群;弗中吉特岛及其附近的礁屿。全国分为25个区。人口8.5万。首都维多利亚。居民主要为班图人、  相似文献   

5.
长山群岛位于辽东半岛东南的北黄海海域中,由外长山列岛(包括狮子岛、海洋岛)和内长山列岛(包括广鹿、大长山岛、小长山岛等)组成。在长山群岛北部还有石城列岛(石城岛,大、小王家岛)。这些岛屿归大连市长海县管辖。长海县共有152个岛、坨和礁,岛陆面积152.3平方公里,滩涂面积38.67平方公里,海域面积3429平方公里,海岸线长128公里。住人岛24个,共有人口81125人(1989年)。1949年11月置县,始称长山县,1953年改称长海县,1981年5月25日国务院批准为我国海岛边境县,是我国12个海岛县中最北的一个,全县有4个乡,3个镇。  相似文献   

6.
聂双双 《地理教学》2010,(6):57-57,59
温柔的海洋 这是个安静的岛屿,非常安静,没有那么多的人和事,像是北海热热闹闹人群外的“蓬莱岛”。  相似文献   

7.
平潭县渔业资源开发利用与水产业发展规划汤小华(福建师范大学地理研究所)平潭是福建省沿海一个海岛县。岛屿陆域位于北纬25°16'-25°45'和东经119°32'-119°57'之间。全县陆城由146个岛屿组成,面积308.98km2。主岛海坛岛面积2...  相似文献   

8.
在海南省万宁市东南部的海面上, 有一个被誉为“海南第一岛”、“南海明珠”的岛屿——大洲岛。它是海南省沿海最大的岛屿,也是通往东南亚国家的必经要道。是我国唐宋以来一直沿用的航海标志岛,也是我国惟一的金丝燕栖息地。大洲岛已被列为国家级海洋生态气候自然保护区。  相似文献   

9.
何沛东 《地理研究》2022,41(3):777-793
海域地名是中国海洋文明的历史见证,在维护海洋权益、发展海洋经济等方面发挥着重要作用。依据地方志等历史资料,以“海(洋)”地名为例,对中国海域地名的源流和时空特征进行分析。研究表明:①中国海域地名具有较强的稳定性和生命力,其发展可以分为海域地名的空间指代模糊时期(先秦至宋代)、海域地名的空间指代清晰时期(宋代至清末)、海域地名中西融合时期(清末至1949年)、海域地名的系统整理和有序管理时期(1949年以后)4个阶段。②中国海域地名的得名原因主要可分为7种:因方位得名、因岛礁沙洲得名、因水文特征得名、因沿陆岸(或较大岛屿岛岸)的地理事物(政区、聚落、山峰等)得名、因航海相关的传说等得名、因海洋出产得名、因海域地形得名。③中国海域地名的空间分布呈现出明显的南北差异,以长江口为界,南方沿海诸省级行政区(含香港特别行政区、澳门特别行政区)的海域地名数量远高于北方,南方又以浙江、福建、广东三省为最,岛屿数量等自然地理因素和海洋贸易等社会经济因素是造成此种差异的主要原因。④2018年国家海洋局、民政部受权公布了《我国部分海域海岛标准名称》,其中的“海(洋)”地名是1980年代中国海域海岛地名普查成果的体现。针对中国海域地名整理和研究的现状,提出加强海域地名的整理、公布与命名,明确海域的相关概念,规定海域地名的通名,海域地名的处理需符合国家海洋权益4条建议。  相似文献   

10.
海岛山地利用是山地利用的一种类型 .海岛面积虽小 ,但可作为开发海洋的基地 ,海岛山地的持续发展对开发海洋意义重大 .我国海岛 (包括南沙诸岛在内 )共 650 0多个 ,多数是大陆山脉向海延伸形成的大陆岛  相似文献   

11.
研究区位于南天山早古生代大洋东段构造带.乌什塔拉地区阿拉塔格组火山岩为超基性—基性岩组合以及中酸性岩组合.其中超基性岩为大洋二辉橄榄岩,基性岩主要为玄武岩,中酸性岩主要有安山岩、英安岩、粗安岩和流纹岩.通过研究分析发现阿拉塔格组火山岩中基性岩产于大洋中脊环境,中酸性火山岩的构造环境应属于活动大陆边缘性质,由于这两套岩石组合均有不同程度的变质变形,以及阿拉塔格组出现的蛇绿岩,可说明这两套火山岩应该不属于同一地区,是由构造拼合而成的.  相似文献   

12.
13.
This study presents an integrated provenance record for ancient forearc strata in southern Alaska. Paleocene–Eocene sedimentary and volcanic strata >2000 m thick in the southern Talkeetna Mountains record nonmarine sediment accumulation in a remnant forearc basin. In these strata, igneous detritus dominates conglomerate and sandstone detrital modes, including plutonic and volcanic clasts, plagioclase feldspar, and monocrystalline quartz. Volcanic detritus is more abundant and increases upsection in eastern sandstone and conglomerate. U‐Pb ages of >1600 detrital zircons from 19 sandstone samples document three main populations: 60–48 Ma (late Paleocene–Eocene; 14% of all grains), 85–60 Ma (late Cretaceous–early Paleocene; 64%) and 200–100 Ma (Jurassic–Early Cretaceous; 11%). Eastern sections exhibit the broadest distribution of detrital ages, including a principal population of late Paleocene–Eocene ages. In contrast, central and western sections yield mainly late Cretaceous–early Paleocene detrital ages. Collectively, our results permit reconstruction of individual fluvial drainages oriented transverse to a dissected arc. Specifically, new data suggest: (1) Detritus was eroded from volcanic‐plutonic sources exposed along the arcward margin of the sampled forearc basin fill, primarily Jurassic–Paleocene magmatic‐arc plutons and spatially limited late Paleocene–Eocene volcanic centers; (2) Eastern deposystems received higher proportions of juvenile volcanic detritus through time from late Paleocene–Eocene volcanic centers, consistent with emplacement of a slab window beneath the northeastern part of the basin during spreading‐ridge subduction; (3) Western deposystems transported volcanic‐plutonic detritus from Jurassic–Paleocene remnant arc plutons and local eruptive centers that flanked the northwestern part of the basin; (4) Diagnostic evidence of sediment derivation from accretionary‐prism strata exposed trenchward of the basin fill is lacking. Our results provide geologic evidence for latest Cretaceous–early Paleocene exhumation of arc plutons and marine forearc strata followed by nonmarine sediment accumulation and slab‐window magmatism. This inferred history supports models that invoke spreading‐ridge subduction beneath southern Alaska during Paleogene time, providing a framework for understanding a mature continental‐arc/forearc‐basin system modified by ridge subduction. Conventional provenance models predict reduced input of volcanic detritus to forearc basins during progressive exhumation of the volcanic edifice and increasing exposure of subvolcanic plutons. In contrast, our results show that forearc basins influenced by ridge subduction may record localized increases in juvenile volcanic detritus during late‐stage evolution in response to accumulation of volcanic sequences formed from slab‐window eruptive centers.  相似文献   

14.
The main source of siliciclastic sediment in the Barbados accretionary prism is off‐scraped quartzose to feldspatho‐litho‐quartzose metasedimentaclastic turbidites, ultimately supplied from South America chiefly via the Orinoco fluvio‐deltaic system. Modern sand on Barbados island is either quartzose with depleted heavy‐mineral suites recycled from Cenozoic turbidites and including epidote, zircon, tourmaline, andalusite, garnet, staurolite and chloritoid, or calcareous and derived from Pleistocene coral reefs. The ubiquitous occurrence of clinopyroxene and hypersthene, associated with green‐brown kaersutitic hornblende in the north or olivine in the south, points to reworking of ash‐fall tephra erupted from andesitic (St Lucia) and basaltic (St Vincent) volcanic centres in the Lesser Antilles arc. Modern sediments on Barbados island and those shed by larger accretionary prisms such as the Indo‐Burman Ranges and Andaman‐Nicobar Ridge define the distinctive mineralogical signature of Subduction Complex Provenance, which is invariably composite. Detritus recycled from accreted turbidites and oceanic mudrocks is mixed in various proportions with detritus from the adjacent volcanic arc or carbonate reefs widely developed at tropical latitudes. Ophiolitic detritus, locally prominent on the Andaman Islands, is absent on Barbados, where the prism formed above a westward subduction zone with a shallow décollement plane. The four‐dimensional complexities inherent with multicyclic sediment dispersal along and across convergent plate boundaries require quantitative provenance analysis as a basic tool in paleogeographic reconstructions. Such analysis provides the link between faraway factories of detritus and depositional sinks, as well as clues on subduction geometry and the nature of associated growing orogenic belts, and even information on climate, atmospheric circulation and weathering intensity in source regions.  相似文献   

15.
南沙群岛景观分5种类型:礁丘热带海洋生物繁生景观,环礁带海洋生物繁生景观,灰沙岛热带常绿刮灌林磷积石灰土景观,大陆架热带海海海洋生物繁生景观,深海热带大洋性和深海性海洋生物景观,这5种景观归纳为两类,一类为热带海洋景观,包括浅海和深海;另一类为热带珊瑚礁景观,下分礁丘,环礁和灰沙岛3种,南沙群岛景观类型分布和演化与古地理和现代化环境条件有关。  相似文献   

16.
The avifauna of three oceanic islands of the Revillagigedo archipelago in the eastern Pacific Ocean consists of 14 endemic landbird taxa and 3 recent continental colonists. This study analyzes the origin, areography of continental relatives, ecological characteristics, and role of immigration and extinction factors as regulators of the islands' species. Only two natural extinctions have been detected on this archipelago in more than 130 years. The endemic nature of the pristine avifauna is interpreted as an indication of high stability over thousands of years. The MacArthur–Wilson (1967) “equilibrium theory of island biogeography” cannot explain or predict the persistence of this avifauna adapted to stable and unique island ecosystems. Lack's (1976) “theory of ecological poverty” regulating island avifaunas, however, predicts stability and a resource-limited bird community. The Revillagigedo avifauna can be understood as an interactive community of a few highly adapted and competitive ecological generalists that have effectively filled all niche spaces and closed off the islands to further colonization. Catastrophic change or anthropogenic landscape degradation may, however, create novel niche spaces and open affected islands to new colonists. This appraisal lends support to the call for a shift away from application of the equilibrium model of island biogeography in conservation science. [Key words: island biogeography, equilibrium theory, island stability, island avifauna, MacArthur-Wilson, Lack, Revillagigedo Islands, Socorro Island.]  相似文献   

17.
Interpretation of long‐offset 2D depth‐imaged seismic data suggests that outer continental margins collapse and tilt basinward rapidly as rifting yields to seafloor spreading and thermal subsidence of the margin. This collapse post‐dates rifting and stretching of the crust, but occurs roughly ten times faster than thermal subsidence of young oceanic crust, and thus is tectonic and pre‐dates the ‘drift stage’. We term this middle stage of margin development ‘outer margin collapse’, and it accords with the exhumation stage of other authors. Outer continental margins, already thinned by rifting processes, become hanging walls of crustal‐scale half grabens associated with landward‐dipping shear zones and zones of low‐shear strength magma at the base of the thinned crust. The footwalls of the shear zones comprise serpentinized sub‐continental mantle that commonly becomes exhumed from beneath the embrittled continental margin. At magma‐poor margins, outer continental margins collapse and tilt basinward to depths of about 3 km subsea at the continent–ocean transition, often deeper than the adjacent oceanic crust (accreted later between 2 and 3 km). We use the term ‘collapse’ because of the apparent rapidity of deepening (<3 Myr). Rapid salt deposition, clastic sedimentation (deltaic), or magmatism (magmatic margins) may accompany collapse, with salt thicknesses reaching 5 km and volcanic piles 1525 km. This mechanism of rapid salt deposition allows mega‐salt basins to be deposited on end‐rift unconformities at global sea level, as opposed to deep, air‐filled sub‐sea depressions. Outer marginal collapse is ‘post‐rift’ from the perspective of faulting in the continental crust, but of tectonic, not of thermal, origin. Although this appears to be a global process, the Gulf of Mexico is an excellent example because regional stratigraphic and structural relations indicate that the pre‐salt rift basin was filled to sea level by syn‐rift strata, which helps to calibrate the rate and magnitude of collapse. We examine the role of outer marginal detachments in the formation of East India, southern Brazil and the Gulf of Mexico, and how outer marginal collapse can migrate diachronously along strike, much like the onset of seafloor spreading. We suggest that backstripping estimates of lithospheric thinning (beta factor) at outer continental margins may be excessive because they probably attribute marginal collapse to thermal subsidence.  相似文献   

18.
I.MesozoicEraVolcanicAchvityDlepre-Tertlalyl11etal11olphicbase111entisOnlyexposedalongtheeastemflankoftheBackboneRangeoftl1eCentraIRangeinTaiwan(Figurel).Overlpngthebasen1e11t,tl1estratumofTertiarytoQuaten1alysysten11sexposed(Flgure2).Deposltlonofthepre-TertlaryrocksprobablybopninPen1llanperiodandextendedintoMesozoic.Theserockswerelatertectonizedandlnotal1lorPhosedinlateMesozoictil11earldtl1el11aJororogenic111ovelnentisnamedYenshanlllovelnent(t1ieNanaoorogenylnTaiwan).A:lthe111eta11…  相似文献   

19.
试论海洋经济地理学   总被引:4,自引:0,他引:4  
作者认为海洋经济地理学属于经济地理学范畴,其研究对象为海洋产业布局,以及海洋经济体系的形成过程、结构特点和发展规律。海洋产业可分为传统的、新兴的和未来的三种,作者探讨了它们的内容及其与国民经济建设的关系。我国海洋经济地理学研究的重点,80年代以海岸带、90年代以海岛为主,以后将以大陆架和专属经济区为主。海洋经济地理学的研究方法以系统方法为主,文章结合作者住长山群岛的实践,阐述了海洋开发的若干问题,提出开展海洋经济地理研究的同时,要开展更广泛的海洋人文地理研究。  相似文献   

20.
The deep seismic reflection profile Western Approaches Margin (WAM) cuts across the Goban Spur continental margin, located southwest of Ireland- This non-volcanic margin is characterized by a few tilted blocks parallel to the margin. A volcanic sill has been emplaced on the westernmost tilted block. The shape of the eastern part of this sill is known from seismic data, but neither seismic nor gravity data allow a precise determination of the extent and shape of the volcanic body at depth. Forward modelling and inversion of magnetic data constrain the shape of this volcanic sill and the location of the ocean-continent transition. The volcanic body thickens towards the ocean, and seems to be in direct contact with the oceanic crust. In the contact zone, the volcanic body and the oceanic magnetic layer display approximately the same thickness. The oceanic magnetic layer is anomalously thick immediately west of the volcanic body, and gradually thins to reach more typical values 40 km further to the west. The volcanic sill would therefore represent the very first formation of oceanic crust, just before or at the continental break-up. The ocean-continent transition is limited to a zone 15 km wide. The continental magnetic layer seems to thin gradually oceanwards, as does the continental crust, but no simple relation is observed between their respective thinnings.  相似文献   

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