What type of force caused the folds shown in the above cross section

The folds in the photograph above were caused by compression at a thrust fault or a convergent plate boundary. Compression usually occurs where two tectonic plates converge or collide. The compression will cause rocks to fold upwards and this upward folding over time can lead to the formation of extensive fold mountains. Examples of fold mountains include the Alps, Andes, and the Himalayas.