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  • General

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  • 火山地貌

    Shiprock, an ancient volcanic neck in New Mexico, rising prominently against the sky.
     

    Why does this massive rock stick out like this?
    ::为什么这块巨大的岩石会像这样伸出来?

    Shiprock in New Mexico is visible for many miles around. Shiprock is the neck of an old volcano. The  magma  cooled into a   that was harder than the surrounding volcano. So the volcano eroded away and left the neck. The peak is on the land of the Navajo Nation, for whom it has great religious significance.
    ::在新墨西哥州,船舶在周围许多英里处都可以看到。 船舶是一座老火山的脖子。 岩浆冷却成一座比周围火山更坚硬的火山。 因此火山侵蚀而离开脖子。 峰值位于纳瓦霍民族土地上,对纳瓦霍民族具有重大宗教意义。

    Landforms from Lava
    ::来自Lava的地貌

    Extrusive    cool at the surface.   are one type of feature that forms from extrusive rocks. Several other interesting  landforms  are also extrusive features.  Intrusive  igneous rocks cool below the surface. These rocks do not always remain hidden. Rocks that formed in the  crust  are exposed when the rock and  sediment  that covers them is eroded away.
    ::地表的侵扰性冷却。 是来自挤压性岩石的一种特征。 其他一些有趣的陆地形态也具有挤压性特征。 地表下有侵扰性、 有色岩石冷却。 这些岩石并不总是隐藏在地下。 当岩石和覆盖岩石的沉积物被侵蚀时, 地壳中形成的岩石会暴露在外 。

    Volcanoes and Vents
    ::火山和文体

    The most obvious landforms created by  lava  are volcanoes. These are mostly cinder cones, composite volcanoes, and  shield  volcanoes. Eruptions also take place through other types of vents, commonly from fissures ( Figure   ). The eruptions that created the entire ocean floor are essentially  fissure  eruptions.
    ::熔岩造就的最明显的土形是火山。 这些火山大多是煤灰锥、复合火山和屏蔽火山。 火山爆发还发生在其他类型的喷口中,通常来自裂缝(图 ) 。 形成整个洋底的火山爆发基本上是裂缝喷发。

    Lava flow during a fissure eruption at sunset, showing smoke and glowing lava.
     
    A fissure eruption on Mauna Loa in Hawaii travels toward Mauna Kea on the Big Island.

    Lava Domes
    ::岩层

    When lava is thick, it flows slowly. If thick lava makes it to the surface, it cannot flow far from the vent. It often stays right in the middle of a  crater  at the top of a volcano. Here the lava creates a large, round  lava dome  ( Figure   ). Lava flows often make mounds right in the middle of craters at the top of volcanoes ( Figure   ).
    ::当熔岩厚时,熔岩会缓慢流动。如果熔岩厚到地表,它就不会远离喷口。它常常停留在火山顶部的火山坑中间。在这里,熔岩会形成一个巨大的圆状熔岩穹顶(Figure ) 。 岩浆流常常在火山顶部的火山坑中间形成土丘(Figure ) 。

    Aerial view of a volcano crater with a prominent lava dome in the center.
     
    Lava domes may form in the crater of composite volcanoes, as at Mount St. Helens.

    Lava Plateaus
    ::岩层高原

    A  lava plateau  is made of a large amount of fluid lava. The lava flows over a large area and cools. This creates a large, flat surface of  igneous rock . Lava plateaus may be huge. The Columbia  Plateau  covers over 161,000 square kilometers (63,000 square miles). It makes up parts of the states of Washington, Oregon, and Idaho ( Figure   ).
    ::熔岩高原由大量的流体熔岩组成,熔岩在大面积的面积和冷藏处流动,形成一个巨大的、平坦的有色岩石表面。 岩浆高原可能很大。 哥伦比亚高原覆盖了161,000平方公里(63000平方英里 ) 。 它由华盛顿州、俄勒冈州和爱达荷州(图 ) 的部分地区组成。

    Overlooking a river and forested cliffs, depicting volcanic landforms in the Columbia Plateau.
     
    Layer upon layer of basalt have created the Columbia Plateau, which covers more than 161,000 square kilometers (63,000 square miles) in Washington, Oregon, and Idaho.

    Land
    ::土地土地土地土地土地土地

    New land is created in volcanic eruptions. The Hawaiian Islands are shield volcanoes. These volcanoes formed from fluid lava ( Figure   ). The island grows as lava is added on the coast. New land may also emerge from lava that erupts from beneath the  water . This is one way that new land is created.
    ::火山爆发创造了新的土地。夏威夷群岛是屏蔽火山。这些火山由流体熔岩形成(图)。岛屿随着熔岩在海岸上增加而成长。新的土地也可能来自从水下喷发的熔岩。这是创造新土地的一种方式。

    Lava erupts from the ocean in Hawaii, forming new land with smoke plumes.
     
    Lava erupts into the Pacific Ocean in Hawaii, creating new land.

    Landforms from Magma
    ::来自Magma的地表土

    Magma that cools underground forms  intrusions  ( Figure   ). Usually this magma is very viscous  felsic  magma. This magma does not rise easily and so cools slowly underground. Intrusions become land formations if they are exposed at the surface by  uplift  and  erosion .
    ::能够冷却地下入侵的磁石( 图表 ) 。 通常, 这块岩浆是非常粘稠的浮岩。 这块岩浆不会轻易地上升, 因而会慢慢地在地下冷却。 如果通过上升和侵蚀暴露在表面, 入侵就变成了土地的形成。

    Granite intrusion in the Sierra Nevada, showcasing vertical rock formation and waterfall.
     
    The granite intrusions that form the Sierra Nevada in California are well exposed.

    Summary
    ::摘要

    • Landforms created by lava include volcanoes, domes, and plateaus.
      ::熔岩形成的地形包括火山、圆丘和高原。
    • New land can be created by volcanic eruptions.
      ::火山爆发可以创造新的土地。
    • Landforms created by magma include volcanic necks and domes.
      ::岩浆形成的地表包括火山颈和穹顶。

    Review
    ::回顾

    1. Why is it important that volcanic eruptions can form new land?
      ::为什么火山爆发能形成新的土地?
    1. How do lava plateaus form?
      ::熔岩高原如何形成?
    1. Describe the granite exposed in the photo of the Sierra Nevada. What is its history?
      ::描述内华达山脉照片中暴露的花岗岩 其历史是什么?

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

     

    1. How were the rock columns in the video formed?
      ::视频中的岩石柱是如何形成的?
    1. In what geologic layers can these columns of rock be found around the world?
      ::在世界各地,这些岩石柱在地质层中可以找到什么呢?
    1. What part of the original lava flow do the tops of the columns in this video represent?
      ::原始熔岩流的哪个部分 代表了这段视频的柱子的顶部?
    1. Are each of the rock columns in the formations seen in this video exactly identical? 
      ::这段影片所看到的每个岩石柱 是否完全相同?