depositional facies of coal-bearing series

例句：

1. 1.The study of sedimentary rocks is crucial for understanding the geological history of our planet.
   研究沉积岩对于理解我们星球的地质历史至关重要。
2. 2. The depositional facies of the coal-bearing series is a key factor in determining the source of the coal.
   含煤系沉积岩相是确定煤炭来源的关键因素。
3. 3. The depositional facies of the region has been studied extensively to understand the geological processes that shaped it.
   该地区的沉积岩相已经广泛研究，以了解塑造它的地质过程。