Start Meteroites carbon dating

Meteroites carbon dating

Some can be distinguished from terrestrial rocks by their metal content, which is high enough to attract a magnet.

The compositions of processed meteorites are similar to the crusts, mantles or cores of the terrestrial planets.

Thus, they must be fragments of larger asteroids whose interiors melted so that the heavier metals sank to the center and the lighter rocks rose to the surface.

Lead isotopes are commonly used in dating rocks and provide some of the best evidence for the Earth's age.

In order to be used as a natural clock to calculate the age of the earth, the processes generating lead isotopes must meet the four conditions of a natural clock: an irreversible process, a uniform rate, an initial condition, and a final condition.

Second, using two isotopes of the same element makes the sample immune to chemical fractionation during a post-crystallization disturbance (Dalrymple 208). This model ultimately led to the development of isochrons, in which two isotopes are plotted against each other to calculate an age for the mineral or rock.

The commonly accepted 4.5 billion year age of the earth is derived from radiometric dating of lunar rocks and meteorites in addition to dating methods based on the Gerling-Holmes-Houtermans model. Those who developed the method utilized Pb, lead isotopes that are the product of radioactive decay, normalized to 204Pb.

Processed meteorites apparently once were part of a large object that “processed” the original material of the solar nebula into another form.

Radiometric dating shows that these meteorites are generally younger than the primitive meteorites.

SUMMARY: Primitive meteorites are remnants of the solar nebula, containing intermixed rock and metal flakes.

Processed meteorites are fragments of larger asteroids and therefore can be metallic like a planet's core or rocky like its mantle or crust.

The use of lead isotope ratios makes this isochron self-checking.