Structure-and-Evolution-of-Ocean-Basins (1).pdf

GROUP 4  What is Ocean Basins? About 70% of the planet’s surface is made up of ocean basins, which are the regions that are below sea level. These areas hold the majority of the planet’s water. The floors of our world’s oceans contain feature that you might recognize as being similar to s...

GROUP 4  What is Ocean Basins? About 70% of the planet’s surface is made up of ocean basins, which are the regions that are below sea level. These areas hold the majority of the planet’s water. The floors of our world’s oceans contain feature that you might recognize as being similar to some structures on land. Oceanic Ridges Plates can spread apart by moving away from each other. This creates gaps where hot molten rock, called magma, from the earth’s mantle can rise up. When the magma seeps through the gaps, it solidifies as it cools, creating a new layer of ocean crust. This creates structures such as oceanic ridges, which are continuous mountain chains located under the surface of the sea. Oceanic Ridges oceanic ridge, any of several continuous submarine mountain chains rising from the ocean floor. Individually, oceanic ridges are the largest features in ocean basins. Abyssal Hill Another raised feature found within ocean basins. It is a small elevated landform that rises from the great depths of the ocean. It is a hill found on the deep ocean floor. Abyssal Hill An abyssal hill has sharply defined edges but will remain relatively small, generally growing not much larger than 500 feet in height and a few miles in width.  What causes abyssal hills? Apparently, the hills are constructed by two processes: volcanism and block faulting. The relative contribution of each may depend on the spreading rate. At slower rates, faulting of the oceanic crust is a dominant factor in forming the relief, and the relief of the hills is greater as the rate is slower.  Guyot Similar to a seamount, but it is a submerged volcanic mountain with a flat top. It received their flat top after years of erosion caused by waves and other erosive processes.  Seamount A large submerge volcanic mountain rising from the ocean floor. It can be very large, reaching the heights of up to 10, 000 feet, yet they remain submerged under the surface of the water.  Seamount vs. Guyot Guyot reached at one point reached the surface and was eroded away by wind and waves. Seamount never made it to the surface and kept its mountain like shape. Evolution of The Ocean Basins Through Plate Movement  Evolution of The Ocean Basins Through Plate Movement Through most of geologic time, probably extending back 2 million years ago, the ocean basins have both grown and been consumed as plate tectonics continued on Earth. The latest phase of ocean basin growth began just less than 200 million years ago with the breakup of the supercontinent Pangaea, the enormous landmass composed of nearly all the present-day continents.  Evolution of The Ocean Basins Through Plate Movement The oldest known oceanic crust is located in the far western equatorial Pacific, east of the Mariana Island arc. The Pacific Ocean floor at this site was generated during seafloor spreading from a pattern of ridges and plates that had existed for some unknown period of time.  Evolution of The Ocean Basins Through Plate Movement The seafloor in the western portion of the Philippine Sea developed between 60 and 35 million years ago in the east it was formed by back arc spreading from 30 million years ago. Quiz NO CHEATING (Kaya di ka crinacrushback e :P ) 1) What is 70% of the planet’s surface is made up of ________. a) Oceanic Basins c) Crust b) Tectonic Plates d) Cuteness ni ano :P 2) What do call a large submerged volcanic mountain rising from the ocean floor? a) Oceanic Basins C) Mid Oceanic Ridge b) seamount D) Guyot  True or False (Tulad ng feelings mo sakanya kunwari false pero true naman :P) 3)All Guyot's are once a seamount.  Identification (Identify mo san ka nagkulang :P) 4)What is a small elevated landform that "Rises" from the depth of the ocean? 5) ________ is a structure in the ocean on which it didn't reach the surface and kept it's mountain like shape  Identification Last na to pramis :DD 6) It's similar to a seamount, but it is a submerged volcanic mountain with a flat top.  Describe the process Char lang xDD For 7-8 How does guyot's gets it's flat top? Note: okay lang ket di super accurate lel