Sea Floor Spreading Age Of Rocks

Students will model core sampling identify patterns in data on the age of the ocean floor use magnetic data to model seafloor spreading and explore the density of oceanic and continental crust.

Sea floor spreading age of rocks. A history of ocean floor mapping and dating the ocean floor is a mysterious place that marine geologists and oceanographers have struggled to fully grasp. At a spreading center basaltic magma rises up the fractures and cools on the ocean floor to form new seabed. Past 160 million years by seafloor spreading at the oceanic ridges and the continental lithosphere accumulated over the past 4 billion years. This has happened many times throughout earth s history.

At spreading rates of about 15 cm 6 inches per year the entire crust beneath the pacific ocean about 15 000 km 9 300 miles wide could be produced in 100 million years. See plate tectonics the largest. Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. How do the ages of the rocks on the ocean floor support the theory of seafloor spreading answers the ages of the rocks become older the farther the way they are the closer they are the younger it.

In this series of 4 investigations they explain how the age of crustal rocks provides evidence of seafloor spreading. Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves. Sea floor spreading a theory thought up by harry hess in the late 1950s was drawn up in relation to the differing ages of rocks which make up oceanic crust ie the ocean floor. Seafloor spreading rates are much more rapid in the pacific ocean than in the atlantic and indian oceans.

The lithosphere is the outer rock shell of the earth that consists of the crust and the uppermost portion of the underlying mantle. It is called a geomagnetic reversal. Basalt the once molten rock that makes up most new oceanic crust is a fairly magnetic substance and scientists began using magnetometer s to measure the magnetism of the ocean floor in the 1950s. 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.

At 280 million years it still pales in comparison to the four billion year old rock that can be found on the continental crust. Older rocks will be found farther away from the spreading zone while younger rocks will be found nearer to the spreading zone. Seafloor spreading is a geologic process where there is a gradual addition of new oceanic crust in the ocean floor through a volcanic activity while moving the older rocks away from the mid oceanic ridge.