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  • Smart Learning for All

  • Topic: Sinkholes.

  • What causes sinkholes?

  • Maybe water.

  • This time you are absolutely correct.

  • Yes.

  • A sinkhole is a depression or cavity in the ground which is caused by water erosion.

  • Water erosion is a naturally occurring process in which water wears off soil and rocks.

  • Wow.

  • Water is so powerful.

  • Indeed.

  • Now listen.

  • The upper layers of the soil comprise of sand, clay, etc.

  • While the bottommost layer called bedrock has rocks.

  • Generally, sinkholes form in places where the bedrock layer has rocks made up of limestone or dolomite.

  • When rain falls, it seeps into the soil reaching the bedrock.

  • Over time, the water dissolves these rocks and thus, erodes them forming hollow cavities.

  • As these cavities get bigger, the ceiling of the cavity, that is, the upper layers of soil cannot hold the weight, hence they collapse forming sinkholes.

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B2 中高級 美國腔

是什麼原因造成了天坑?| #aumsum (What causes Sinkholes? | #aumsum)

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    AumSum 發佈於 2021 年 01 月 14 日