GEOL 100 Lecture 17: The Seafloor and Continental Margins
Document Summary
Cycle vast quantities of material and energy. Transforming and re releasing heat from sun. The vast majority of the oxygen circling the atmosphere comes from photosynthesizers in the ocean. We know they are connected because many of the features that begin on dry land continue off the coast. The deepest part of the ocean is more deep than the highest part of land is high. Used to be a river channel when sea levels were much lower (in the last ice age) Show that continents were not the same size or shape as they used to be. Variations in layer thickness record tectonics (subsidence) Use seismic-reflection profile of the ocean floor to map out ocean floor and features and sediments beneath the floor, allows us to search for oil and gas. Can get very detailed picture of orientation of ocean floor. Cheap and easy, but the ocean is big so it takes a long time.
