As mentioned previously, tectonics haven't exactly been kind to the Xiagou Formation outcrops in the Changma Basin -- nice enough to keep most of our fossils intact, but the structural geology in the area is quite complex. I haven't wrapped my head around most of it yet, but that's largely because the Xiagou Formation weathers so easily and buries its own outcrops in colluvium, so seeing the actual outcrops themselves is pretty difficult -- only in roadcuts and along the sides of arroyos. But it reminds me of the thin-skinned tectonics I saw in western Montana back in field school... Here is a pretty sharp fold (left) truncated against a fault (middle -- compare the dips on either side).
ChangmaXiagou Formationstructural geologyfoldfault