Andes mountains south american mountain chain formed by subduction of converging south american and nazca plates.
The seafloor spreading hypothesis states that.
Based on the work of previous scientists who had theorized about horizontal movement of the continents.
Plate tectonics a theory that states earth s surface is made up of giant moving slabs called tectonic plates.
Image of sea floor spreading 1.
When oceanic plates diverge tensional stress causes fractures to occur in the lithosphere.
Dietz american geophysicist and oceanographer who set forth a theory of seafloor spreading in 1961.
After serving as an officer in the u s.
Marie tharp s incredible maps were integral to the acceptance of the plate tectonic theory.
A change of the magnetic poles resulting in a pattern that provides evidence for seafloor spreading and plate tectonics.
Seafloor spreading occurs at divergent plate boundaries.
Dietz was educated at the university of illinois b s 1937.
The anomalously high values are considered to reflect the intrusion of molten material near the crests of the ridges.
One important way in which dietz s theory of sea floor spreading differed from hess was that dietz correctly surmised that the lithosphere was moving on top of the plastic asthenosphere with the convection currents where as hess suggested the the base of the crust was moving with currents.
Seafloor spreading explains how the continents moved to complete wegener s continental drift theory.
Studies conducted with thermal probes for example indicate that the heat flow through bottom sediments is generally comparable to that through the continents except over the mid ocean ridges where at some sites the heat flow measures three to four times the normal value.
Eventually the crust cracks.
As tectonic plates slowly move away from each other heat from the mantle s convection currents makes the crust more plastic and less dense.
The acceptance of continental drift and seafloor spreading.
A veritable legion of evidence supports the seafloor spreading hypothesis.
State of the science and events.
Continental drift was a revolutionary scientific theory developed in the years 1908 1912 by alfred wegener 1880 1930 a german meteorologist climatologist and geophysicist that put forth the hypothesis that the continents had all originally been a part of one enormous landmass or supercontinent about 240 million years ago before breaking apart and drifting to their current locations.
Seafloor spreading helps explain continental drift in the theory of plate tectonics.
The less dense material rises often forming a mountain or elevated area of the seafloor.
