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  • 6.3折

    Rocky terrain showing various geological folds in the desert landscape.

     

    What folds can you see?
    ::你能看到什么折叠吗?

    Moving around the  desert  Southwest, we see a lot of folds. This view is near the  Valley  of the Gods in Utah. Can you see all of the types of folds mentioned below? All of the folds mentioned in the text below are found in the arid Southwestern U.S.
    ::环绕西南沙漠,我们看到许多折叠。 这个视图在犹他州的神谷附近。 您能看到下面提到的各类折叠吗? 下面提到的折叠都在美国西南部干旱地区。

    Folds
    ::折叠

    Deep within the  crust , as  plates  collide,   crumple into  folds . You can  model  these folds by placing your hands on opposite edges of a piece of cloth and pushing your hands together. Your hands moving toward each other creates compressive  stress . In  , you can easily trace the folding of the layers ( Figure   ). In the image below, the rock layers are no longer horizontal. They tilt downhill from right to left in a  monocline . Once rocks are folded, they do not return to their original shape.
    ::在地壳深处,作为板块相撞, 折叠成折叠。 您可以将手放在一块布的对面, 将手拉在一起, 从而模拟这些折叠。 手向对方移动会产生压缩压力 。 在下面的图像中, 您可以很容易地追踪各层的折叠( 图表 ) 。 在下面的图像中, 岩石层不再是水平的。 它们从右向左倾斜, 以单曲线向左倾斜。 一旦岩石折叠, 它们就不会回到原来的形状 。

    Geologic cross section showing folded rock layers in the Grand Staircase, Utah.

     

    This is a geologic cross section of the Grand Staircase in Utah. Where the rocks fold up, at the left of the diagram, is a small syncline.
    ::这是犹他州大楼梯的地质十字路段, 岩石折叠在图的左侧, 是一个小同步线 。

    There are three types of folds: monoclines,  anticlines , and synclines.
    ::折叠有三种类型:单线、直线和同步线。

    Monocline
    ::单单线

    A  monocline  is a simple “one step“ bend in the rock layers ( Figure   ). In a monocline, the oldest rocks are at the bottom, and the youngest are at the top.
    ::单极岩层是一个简单的“一步”弯曲岩层(图 ) 。 在单极岩层中,最古老的岩石位于底部,最年轻的岩石位于顶部。

    Tilted rock layers in a landscape, illustrating a monocline formation in geology.

     

    The rock layers in the center left are tilted in one direction, forming a monocline.
    ::中间左侧的岩石层 向一个方向倾斜 形成一个单晶体

    Anticline
    ::胶胶胶

    An  anticline  is a  fold  that  arches  upward. The rocks  dip  away from the center of the fold ( Figure   ). The oldest rocks are found at the center of an anticline. The youngest rocks are draped over them at the top of the structure. When upward folding rocks form a circular structure, that structure is called a  dome . If the top of the dome is eroded off, the oldest rocks are exposed at the center.
    ::粘结线是一个向上倾斜的折叠体。 岩石从折叠的中心( 图表 ) 向下倾斜。 最古老的岩石在反斜线的中心找到。 最小的岩石在结构的顶部被覆盖。 当向上折叠的岩石形成圆形结构时, 结构被称为圆顶。 如果穹顶被侵蚀, 最古老的岩石在中间被暴露 。

    An illustration and photo showing upward-folded layers of rock, depicting an anticline formation.

     

    (A) An anticline is a convex upward fold. (B) This anticline is at Calico Ghost Town, California.
    :sadB) 该抗菌素位于加利福尼亚州Calico Ghost镇。

    Syncline
    ::同步线同步

    A  syncline  is a fold that bends downward ( Figure   ). In a syncline, the youngest rocks are at the center. The oldest rocks are at the outside edges. When rocks bend downward in a circular structure, it is called a  basin . If the rocks are eroded, the youngest rocks are at the center. Basins can be enormous, like the Michigan Basin.
    ::同步线是一个向下弯曲的折叠( 图表 ) 。 在同步线中, 最小的岩石位于中心。 最古老的岩石位于外部边缘 。 当岩石在圆形结构中向下弯曲时, 它被称为盆地。 如果岩石被侵蚀, 最小的岩石位于中心 。 盆地可以是巨大的, 如密歇根河流域 。

    A syncline structure and a photo of a syncline in California.

     

    (A) A syncline is a concave downward fold. (B) This syncline is seen at Calico Ghost Town near Barstow, California.
    :sadA) 同步线是一个向下折叠的混合物。 (B) 这一同步线见于加利福尼亚州巴斯托附近的卡利科幽灵镇。

    Summary
    ::摘要

    • Rocks deform by compressive stress into folds.
      ::岩石因压缩压力变形成折叠
    • A monocline is a simple bend in one-direction.
      ::单向线是单向的简单弯曲。
    • In an anticline, rocks arch upward. A three-dimensional anticline is a dome.
      ::三维抗菌素就是圆顶
    • In a syncline, rocks arch downward. A three-dimensional syncline is a basin.
      ::在同步线中,岩石向下倾斜,三维同步线是一个盆地。

    Review
    ::回顾

    1. Draw a picture to show how compressive stresses lead to folds. Can these stresses create anticlines and synclines?
      ::绘制一张图片以显示压缩压力如何导致折叠。 这些压力能产生抗斜线和同步线吗 ?
    1. Do you think that anticlines and synclines are ordinarily found separately or next to each other?
      ::您认为直线和同步线通常是单独或相邻发现的吗?
    1. Describe domes and basins. Where are the youngest rocks in each?
      ::描述穹顶和盆地。每个岩石中最小的岩石在哪里?

    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. What is a geologic fold and what causes one to form?
      ::什么是地质折叠? 是什么导致形成?
    1. What types of forces create a set of folds?
      ::哪些类型的力量创建一组折叠 ?
    1. What is a monocline? Where are the older rocks found?
      ::什么是单晶体岩?
    1. What is an anticline? Where are the older rocks found?
      ::什么是抗菌素?老岩石在哪里被发现?
    1. What is a syncline? Where are the older rocks found?
      ::什么是同步线?