What geological feature is formed as a trough with younger rock layers at its core?

The feature described as a trough with younger rock layers at its core is identified as a syncline. In geologic terms, a syncline is a type of fold that occurs when rock layers are compressed. This folding process creates a downward-curving structure where the youngest rock layers are positioned in the center of the trough, while older layers are located on the sides.

The formation of synclines is critical in understanding geological history, particularly in interpreting the sequence of rock layers and the processes that have shaped the Earth's crust over time. This characteristic of having younger rock layers at the core distinctly differentiates synclines from other geological features, providing insights into the tectonic forces and movements within the Earth's crust that lead to such formations. The presence of younger rocks at the center indicates that these layers were deposited after the surrounding layers during the process of sedimentation or volcanic activity.

Understanding synclines aids in reconstructing past environments and is crucial for resource exploration, such as identifying areas where fossil fuels or groundwater might be concentrated.