Sea Floor Spreading Freeboard

Freeboard tectonics and mantle temperature.

Sea floor spreading freeboard.

Seafloor spreading theory that oceanic crust forms along submarine mountain zones and spreads out laterally away from them. The maximum age of the ocean basins is made 150 ma representing a slightly faster rate of seafloor spreading than today appropriate for a time of decreased freeboard. The regions that hold the unique record of earth s magnetic field lie along the mid ocean ridges where the sea floor is spreading. Spreading of the sea floor offers the less radical answer t h a t the earth s volume has re mained constant.

The process of sea floor spreading. Carey s 9 tectonic analysis has resulted in the need for a twenty fold increase in volume of the earth. Strong evidence of seafloor spreading and plate tectonics. This idea played a pivotal role in the development of the theory of plate tectonics which revolutionized geologic thought during the last quarter of the 20th century.

Spreading is then doubled in this triangular ocean for a period of 5 m y and the change in o 2 relative sfs rate e 200 o d a c ioc o a. The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid ocean ridge is the spreading half rate and is equal to half of the spreading rate. Longer and faster spreading ridges provide a means to inflate the seafloor and thus present an appealing way to maintain a uniform continental freeboard when the volume of continents was less and the surface area of the oceans was greater fig. Seafloor spreading occurs along mid ocean ridges large mountain ranges rising from the ocean floor.

The formation of the new crust is due to the rising of the molten material magma from the mantle by convection current. Spreading rates determine if the ridge is fast intermediate or slow. The mid atlantic ridge for instance separates the north american plate from the eurasian plate and the south american plate from the african plate the east pacific rise is a mid ocean ridge that runs through the eastern pacific ocean and separates the pacific plate from the north american. When the production of new sea.

And planetary science letters v. To account for sea floor rifting heezen 8 for example has advocated an expanding earth a doub ling of the diameter. Paleomagnetism led the revival of the continental drift hypothesis and its transformation into theories of sea floor spreading and plate tectonics. It takes the sea floor spreading oceanic crust subduction and transform fault as main active forms and mantle convection as an original dynamic.

Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. The oceanic crust is composed of rocks that move away from the ridge as new crust is being formed.