The content of element rises slightly in vertical from deep to shallow location, with a circle variation of high-low-high-low or low-high-low-high.

元素的含量在垂向上由深到浅呈现轻微的上升趋势，呈高—低—高—低或低—高—低—高波动式循环变化；

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The content of element rises slightly in vertical from deep to shallow location, with a circle variation of high-low-high-low or low-high-low-high.

元素的含量在垂向上由深到浅呈现轻微的上升趋势，呈高—低—高—低或低—高—低—高波动式循环变化；

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