GEO 103 Lecture 30: Cenozoic Land
28 Apr 2017
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Document Summary
Before eocene, entire pacific coast a convergent boundary. Farallon plate consumed at subduction zone extending from mexico to alaska. As north america overrode pacific-farallon ridge, transform faults developed. Interior lowlands, made up of great plains and central lowlands. Cretaceous zuni epeiric sea largely withdrawn by early neogene. Small remnant in north dakota area - fed sediment from eroding laramide orogen. Transition to terrestrial, mainly fluvial, sedimentation that underlie most of region. Climate became more arid and evolved from semitropical forests to grasslands. Little igneous activity - several volcanoes and plutons in western part. Area of active erosion with sediment transported to gulf coastal plain. This sets up the modern day mississippi delta. By end of mesozoic, parts of appalachian eroded to near base level. Much of the present topography due to cenozoic uplift and erosion (delaware water gap good indicator of uplift) Sheds sediment into gulf and atlantic coastal plains. Briefly influenced by tejas epeiric sea, reaching maximum in paleogene.
