Seafloor Spreading Theory Year

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.

Seafloor spreading theory year.

Sea floor spreading powerpoint 1. Supporters of continental drift originally theorized that the continents moved drifted through unmoving oceans. The ocean plates spread and grow in opposite directions so rocks that are equidistance from the center have the same magnetic polarity and age. That is it explains why the age thickness and density of the oceanic crust increases with distance from the mid oceanic ridge.

At spreading rates of about 15 cm 6 inches per year the. Arthur holmes in 1930s discussed the possibility of convection currents. As the magma and lava cool at seafloor spreading centers whatever magnetic field is present get ingrained into the rock. Seafloor spreading helps to explain continental drift in the theory of plate tectonics.

The mid ocean ridge curves like the seams of a baseball along the sea floor extending into all of earth s oceans. Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch. Seafloor spreading theory that oceanic crust forms along submarine mountain zones known collectively as the mid ocean ridge system and spreads out laterally away from them. Seafloor spreading rates are much more rapid in the pacific ocean than in the atlantic and indian oceans.

It leads to the formation of new material on the ridge. To understand the concept of seafloor spreading we must first understand some basic concepts that form the cornerstones for the concept of seafloor spreading. The motivating force for seafloor spreading ridges is tectonic plate slab pull at subduction zones rather than magma pressure although there is typically. Evidence of sea floor spreading.

Convection current theory convection current theory is the soul of seafloor spreading theory. When oceanic plates diverge tensional stress causes fractures to occur in the lithosphere. Seafloor spreading proves that the ocean itself is a site of tectonic activity. These cornerstones are convectional current theory and paleomagnetism.

These age data also allow the rate of seafloor spreading to be determined and they show that rates vary from about 0 1 cm 0 04 inch per year to 17 cm 6 7 inches per year. As per seafloor spreading theory the mid oceanic ridge is the region where at the crest of oceanic ridges through the rupture of the oceanic crust and the crack continuous new lava eruption thrusts into it consequently pushing the oceanic crust on either side. Harry hess s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. The theory of sea floor spreading states that new oceanic crust is being formed continuously at mid oceanic ridges while the older rocks move away from the ridge.

Most of the mountains in the mid ocean ridge lie hidden under hundreds of meters of. Mapping the mid ocean ridge the east pacific rise is just one part of the mid ocean ridge the longest chain of mountains in the world.