大背斜层

例句：

1. 1. The geological survey revealed that the strata were composed of large anticlines and synclines.
   地质调查发现，地层由大型背斜和向斜组成。
2. 2. The study of stratigraphy is crucial for understanding the history of Earth's crust.
   研究地层学对于理解地球地壳的历史至关重要。
3. 3. The formation of these layers is closely related to the tectonic activity of the region.
   这些层的形成与该地区的构造活动密切相关。