Radiometric dating volcanic rock
states of Washington, Oregon, Idaho, Nevada, and California.
Erosion resulting from the Missoula Floods has extensively exposed these lava flows, laying bare many layers of the basalt flows at Wallula Gap, the lower Palouse River, the Columbia River Gorge and throughout the Channeled Scablands.
The Torlesse supergroup rocks were deposited further away from a landmass, mostly in deep water, and the Murihiku rocks represent mainly 4.
The Rangitata Orogeny, Early Cretaceous period (about 142 to 99 million years ago) During this orogeny, the previously deposited geosyncline (3) sediments were compressed and folded.
The early sedimentation depositional phase, Cambrian to Devonian period (about 545 to 370 million years) This was the period when the earliest major recorded rock formation was taking place, with the oldest rocks being found on the west coast of the South Island.Sometimes the land uplifted only to be worn down again and be pushed back into the sea. The Tuhua Orogeny, late Devonian to Carboniferous period (about 370 to 330 million years ago) The long period of sedimentation ended with a period of pressure and uplift.Sea floor sediments were pushed up, folded and melted together to form mountains.The collision of these plates caused the Pacific plate to subduct underneath the Australian plate which carries the North Island.To the south of the South Island, the situation is reversed.