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海山是一个地貌术语,通常分为出露于海平面以上和淹没于以下的两类.海山具有复杂的成因,可产于各种不同的构造环境,其出露的岩性主要有:洋岛玄武岩(OIB)、大洋中脊玄武岩(MORB)、弧后盆地玄武岩(BABB)、岛弧玄武岩(IAB)和大陆边缘玄武岩(CMB)等.本文的研究表明,CMB和OIB的地球化学性质大体相似,但是,二者的成因可能既有相似性,也存在某些差异性.0IB产于板块内部,属于板内岩浆活动的产物,通常认为与“热点”或“地幔柱”有关;而CMB则可能是古大陆岩石圈与年轻洋壳发生浅部再循环的结果.所以,除“热点”理论外,古大陆岩石圈和年轻洋壳的浅部再循环在海山和洋岛火山形成过程中也扮演了重要的角色.来自IAB的样品明显亏损Nb、Ta和富集K、Pb、Cs、Rb等大离子亲石元素,表明IAB的形成与俯冲作用有关.研究表明,全球可能存在3种类型的热点:第一类是原生的热点,来自深部地幔;第二类是次生的热点,可能形成在地幔柱的浅部,来自超级地幔柱的上部;第三类来自上地幔,可能是大洋岩石圈伸展的产物.因此,海山的成因不可能用地幔柱一种模式予以解释,还应当考虑板块活动中其他各种因素(洋壳再循环、古老陆壳再循环、消减带物质以及水的加入,部分熔融程度、岩浆混合作用、不同地幔端元混合等)的影响.“,”The seamount is a landform term,usually divided into two categories,one is exposed above sea level,another is covered in it.Seamount have complex causes and it can be produced in different tectonic environment,mainly including:The ocean-island basalt (OIB),mid-ocean ridge basalt (MORB),back-arc basin basalt (BABB),island arc basalt (IAB),continental marginal basalt (CMB),etc.In this paper,the research shows that the geochemical characteristics of the CMB and OIB are nearly similar,and there are some similarities and differences of them in the cause.The OIB is the product of intra-plate magmatic activities,which is generally thought that related to “hot spots” or “mantle plume”:While the CMB may be formed by shallow recycling of ancient continental lithosphere and young oceanic crust.Therefore,the shallow recycling of ancient continental lithosphere and young oceanic crust also plays an important role in the process of the formation of the mountain and ocean island volcano besides the “hot spots”.Samples from the IAB have characteristic deletion in Nb,Ta and enrichment in some large ion lithophile elements,such as Nb,Ta,P and Ti etc,which shows that the formation of the IAB is related to the subduction.Research suggests that there may be three types hotspots on earth:the first kind is Primary hotspots,which originate from deep mantle:The second type is secondary hotspots,possibly coming from the top of the superplume.Third type hotspots may have a superficial origin,linked to tensile stresses in the lithosphere and decompression melting.As a result,the cause of the seamount can not be explained perfectly by “mantle plume” mode,it should also consider the influence of other factors (such as recycling of the young oceanic crust and old continental crust,subduction sediment and the addition of water,the degree of partial melting,mantle magma mingling,the mixing of the different end member component of mantle,etc.).