31. Here, compression does not result in appreciable mountain building , which is mostly accommodated by folding and stacking of thrusts. 32. The shale was metamorphosed into slate during the Acadian orogeny ( a mountain building period 375 million years ago ). 33. During long periods of mountain building , the shale and sandstone were slowly transformed into the schist and quartzite found today. 34. Approximately 70 to 80 million years ago, a series of mountain building events called the Laramide orogeny uplifted the entire region. 35. And remember that the interiors of the plates do not deform-spreading, subduction and mountain building happen at the boundaries between plates. 36. The later half of the period experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea. 37. The mountain building period known as the Variscan orogeny, which occurred around 280 Ma, caused major deformation in south west England. 38. This flat-slab subduction process is thought to be one of the main causes of mountain building and deformation in South America. 39. This was just the first of a series of mountain building plate collisions that contributed to the formation of the Appalachians. 40. During this time the Alpine mountain building , and much of the movement in the palaeozoic region was probably connected with it.
