Geologic age dating methods Mature sex cam chat no sign up no upggrade

15 Jan

Some of the isotopes used for this purpose are uranium-238, uranium-235 and potassium-40, each of which has a half-life of more than a million years.

Unfortunately, these elements don't exist in dinosaur fossils themselves.

By using radiometric dating to determine the age of igneous brackets, researchers can accurately determine the age of the sedimentary layers between them.In Grand Canyon, the "date" of metamorphism of the basalt lavas to form these Brahma amphibolites has been determined as 1690-1710 Ma (million years ago), based on U-Pb dating of minerals in the overlying Vishnu Schist and underlying Rama Schist that formed during the metamorphism.It is also claimed that the original basalt lavas were erupted between 17 Ma, based on U-Pb dating of "original" zircon grains in metamorphosed felsic (granitic) volcanic layers within the Brahma and Rama Schists.While the oldest known rocks on Earth are about 3.5 billion years old, researchers have found zircon crystals that are 4.3 billion years old [source: USGS].Based on the analysis of these samples, scientists estimate that the Earth itself is about 4.5 billion years old.