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  • 大洋-大洋收敛板块边界

    Satellite image of an erupting volcano in the Aleutian Islands, surrounded by water.
     

    What do you see in this satellite photo?
    ::卫星照片上你看到了什么?

    We continue our trip up western North America to find a  convergent plate boundary  where  oceanic crust  subducts beneath oceanic crust. A line of  , known as the Aleutian Islands, lie off the southwestern coast of Alaska and extend across the northern Pacific Ocean towards Russia. These islands are the result of ocean-ocean convergence. In this  satellite  image is an erupting volcano, topped by  snow  or ice, and surrounded by seawater - a member of the Aleutian chain. Let’s take a look at this boundary and the volcanic arc.
    ::我们继续前往北美西部,以寻找海洋地壳下方的海洋结壳下沉通道的汇合板块边界。 一条被称为阿留申群岛的线位于阿拉斯加西南海岸,横跨北太平洋向俄罗斯延伸。 这些岛屿是海洋与海洋汇合的结果。 在这个卫星图象中,火山喷发,由雪或冰覆盖,周围是海水 — — 阿留申河链的成员。 让我们看看这个边界和火山弧。

    Convergent Plate Boundaries
    ::一致的盘点边界

    When two  plates  converge, what happens depends on the types of  lithosphere  that meet. When oceanic crust meets  continental crust , the oceanic crust subducts below the  continent . Another type of convergent plate boundary is found where two oceanic plates meet. In this case the older, denser slab of oceanic crust will plunge beneath the less dense one.
    ::当两个板块交汇时,结果取决于相撞的岩层类型。当大洋结壳与大陆结壳相交时,大陆下的海洋结壳下水道。另一种类型的聚板边界是两个海洋板块相交时发现的。在这种情况下,较老的、较稠密的大洋结壳板块将在较不稠密的板块下沉没。

    Ocean-Ocean
    ::海洋-海洋

    The features of a  subduction zone  where an oceanic plate subducts beneath another oceanic plate are the same as a continent-ocean subduction zone. An ocean  trench  marks the   where the plate is pushed down into the mantle. In this case, the line of volcanoes that grows on the upper oceanic plate is an  island arc . Do you think   are common in these regions ( Figure   )?
    ::下潜潜带的特征是,在另一海洋板块下方的海洋板块下方的下水道与大陆海洋下潜带相同。 海洋战壕标记板块被推到地壳的下方。 在这种情况下, 上海洋板块上生长的火山线是一个岛屿弧。 您认为这些区域是常见的( 图 ) 吗 ?

    Ocean-ocean convergent plate boundaries, showing trench, island arc, and crust layers.
     
    Subduction of an ocean plate beneath other oceanic crust results in a volcanic island arc, an ocean trench, and many earthquakes

    In the north Pacific, the Pacific Plate is subducting beneath the North American Plate just as it was off of the coast of the Pacific Northwest. The difference is that here the North American plate is covered with oceanic crust. Remember that most plates are made of different types of  crust . This  subduction  creates the Aleutian Islands, many of which are currently active (see  Figure   ). Airplanes sometimes must avoid flying over these volcanoes for fear of being caught in an  eruption .
    ::在北太平洋,太平洋板块正像在西北太平洋海岸外的北美板块下沉。 区别在于这里北美板块被洋壳覆盖。 记住大部分板块是由不同种类的地壳制成的。 这种稀释创造了阿留申群岛,其中许多目前仍在活动(见图 ) 。 飞机有时必须避免飞过这些火山,因为害怕被火山喷发。

    Map showing North Pacific air routes over the Aleutian Islands and active volcanoes.
     
    The arc of the island arc that is the Aleutian Islands is easily seen in this map of North Pacific air routes over the region.

    Summary
    ::摘要

    • If the two plates that meet at a convergent plate boundary both are of oceanic crust, the older, denser plate will subduct beneath the less dense plate.
      ::如果在聚集板块边界相交的两个板块都是海洋地壳, 较老的、较稠密的板块就会沉入密度较低的板块下面。
    • The features of an ocean-ocean subduction zone are the same as those of an ocean-continent subduction zone, except that the volcanic arc will be a set of islands known as an island arc.
      ::海洋下潜带的特征与海洋内分泌下潜带的特征相同,但火山弧将是称为岛屿弧的一组岛屿。
    • The older plate subducts into a trench, resulting in earthquakes. Melting of mantle material creates volcanoes at the subduction zone.
      ::旧板块渗入沟渠,导致地震,地壳材料熔化,在潜入区形成火山。

    Review
    ::回顾

    1. Compare and contrast the features of an ocean-ocean convergent plate boundary with the features of an ocean-continent convergent plate boundary.
      ::比较和比较海洋-海洋汇合板块边界的特征和海洋-海洋汇合板块边界的特征。
    1. How did the Aleutian volcanos form?
      ::阿留申火山是如何形成的?
    1. What kind of plate boundary creates island arcs?
      ::什么样的板块边界产生岛弧?