Sea Floor Spreading Age Of Rocks

The lithosphere is the outer rock shell of the earth that consists of the crust and the uppermost portion of the underlying mantle.

Sea floor spreading age of rocks.

At a spreading center basaltic magma rises up the fractures and cools on the ocean floor to form new seabed. 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. This has happened many times throughout earth s history. It is called a geomagnetic reversal.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. The mid ocean ridge is where the seafloor spreading occurs in which tectonic plates large slabs of earth s lithosphere split apart from each other. At 280 million years it still pales in comparison to the four billion year old rock that can be found on the continental crust. Past 160 million years by seafloor spreading at the oceanic ridges and the continental lithosphere accumulated over the past 4 billion years.

Hydrothermal vents are common at spreading centers. Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves. 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. Seafloor spreading rates are much more rapid in the pacific ocean than in the atlantic and indian oceans.

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. 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. 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. In this series of 4 investigations they explain how the age of crustal rocks provides evidence of seafloor spreading.

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. Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. 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.