CompuServe Thread

#Erosion in Ocean Basin

2 messages in this thread
#172226From: Jim YahrMar 5, 1995 10:08 PM
Hi Kamron, >>Between the land and the sediment cone there is a deep trench……Looks almost like the canyons were cut then the ocean basin shrunk away from the continents…. Its also strange that the deep trenches haven't filled with sediment.<< If I'm placing the geography properly, the trench is the subduction zone where the Pacific place (which is moving generally north-northwest) is being subducted under the Arctic (I think that's the name) plate. This is where the movement that causes the earthquakes on the San Andres fault in California is being <taken up>. The trench IS filling with sediments, they are just being subducted along with the plate. There is a subsea ridge of sediment that represents the position were the sediment is partially scraped of the plate. These is where present day ophilites are being formed. Jim
#172390From: Kamron KirkconnellMar 6, 1995 7:05 PM
Jim That is the location. If the charts i am rreferringto are accurate the erosion channels that radiate beyond the trench to the deeper parts of the basin have a wide gap between the coast and the sediment bed. This would eliminate the turbidity currents and the landslides associated with the steep wall of the continental edge. These canyons are present right to the edge of the trench. Looks like they were formed and then the trench gap widened. Kamron