The USGS admits that they were unable to find any rock that had not been altered by the Earths tectonic plates, so the age of the Earth could be refined in the future.When the gasses of the early solar nebula began to cool, the first materials to condense into solid particles were rich in calcium and aluminum.The United States Geological Survey(USGS) website has a lot of indepth material about how the age of the Solar System was determined.The basics of it are that all material radioactively decays into a stable isotope.The the Allende meteorite of 1969 was the first to show inclusions that were extremely rich in calcium and aluminum.It took 40 years for the spectra of the inclusions to be discovered and then extrapolates to very old asteroids still in orbit around the Sun.By 1907 study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool.As radioactive Parent atoms decay to stable daughter atoms (as uranium decays to lead) each disintegration results in one more atom of the daughter than was initially present and one less atom of the parent.
In addition to the ages of Earth, Moon, and meteorites, radiometric dating has been used to determine ages of fossils, including early man, timing of glaciations, ages of mineral deposits, recurrence rates of earthquakes and volcanic eruptions, the history of reversals of Earth's magnetic field, and the age and duration of a wide variety of other geological events and processes.
Eventually solid particles of different elements clumped together to form the common building blocks of comets, asteroids, and planets.
Astronomers have long thought that some of the Solar System’s oldest asteroids should be more enriched in calcium and aluminum, but, none had been identified until recently.
The Solar System was formed around 4.6 billion years ago, out of the collapse of a dense cloud composed of dusts and gases.
Meteorites, which are the very components of our planets (through the process of accretion), are the remnants of the Solar System’s origins.