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  • At divergent margins, lithospheric plates move in opposite directions.

  • The plates, which include crust and part of the upper mantle, ride over the asthenosphere.

  • As hot mantle rock rises to shallow depths, it begins to melt due to lowered pressure.

  • This forms magma. Dense plutonic rock is created as the magma

  • is injected into the crust. Small magma chambers form low in the crust. Less than one quarter

  • of the magma ever reaches the surface to erupt as pillow lavas.

  • As it moves away from the ridge, the cooling rock sits progressively lower than the hotter,

  • more bouyant, rock at the ridge. Like two giant conveyor belts the plates transport

  • newly formed oceanic crust away from the ridge crest at 3 to 10 centimeters per year.

At divergent margins, lithospheric plates move in opposite directions.

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B2 中高級

分歧邊界-快速蔓延的山脊教育。 (Divergent Boundary—Fast Spreading Ridge Educational)

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    羅紹桀 發佈於 2021 年 01 月 14 日
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