Geologic time unit, rock stratigraphic units and time stratigraphic unit.

地质年代单位、岩石地层单位、年代地层单位。

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Commonly, the isopachs, or contours that make up an isopach map, display the stratigraphic thickness of a rock unit as opposed to the true vertical thickness.

通常由等厚线(或等值线)构成等厚图，展示岩石单位的(与真垂直厚度相对的)地层厚度。

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Commonly, the isopachs, or contours that make up an isopach map, display the stratigraphic thickness of a rock unit as opposed to the true vertical thickness.

通常由等厚线(或等值线)构成等厚图，展示岩石单位的(与真垂直厚度相对的)地层厚度。

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