graptolite

These provide base for the correct measurement and valuing of graptolite reflectivity.

从而为笔石反射率的正确测定和取值奠定了基础.

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The black graptolite shale facies indicate a deep - water, half enclosed and anoxic sedimentary environment.

中奥陶世黑色的笔石页岩为典型的半封闭缺氧的深水沉积环境,反映了海水逐步加深,水体也变得相对宁静.

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