Stratigraphical natures for the Hadean: An important clue for understanding of both evolutionary history and palaeogeographical background in forming and initial periods of the Earth

Within the current Precambrian geological time scale,it is an undefined base of the Archean Eon that it is roughly indicated at about 4000 Ma,which results in a use of Hadean is informal as it has not been defined. Two of key advances led to the revision of stratigraphical nature for the Hedean,which as follows:( 1) The discovery of truly ancient zircon crystal in Archean conglomerates at Jack Hills in Western Australia,which extend back to 4404 Ma and contain a wealth of information about conditions on very earlyEarth; ( 2) The discovery of ca. 4030 Ma Acasta Gneiss in northern Canada. These discoveries,together with age dating of the Moon and meteorites,have yielded a great deal of knowledge about the early history of our solar system that is just an important foundation to revise the stratigraphical nature of the Hadean. The knowledge includes the formation of the solar system and the Earth,the important changes and their physical records on very early Earth,the origin of life and its early evolution. This