This vast length of time, lasted for over 4.06 Billion Years - the large majority of all Earth's existence. Beginning in the Hadean Eon, 4.6 Billion years ago, and ending at the end of the Proterozoic Eon 540 million years ago, it is an almost incomprehendably long time for anyone to fully appreciate. This then, is why Palaeontologists and Geologists, have divided the massive Super-Eon, into three EPrecambrian 'Super-Eon', represents one of the greatest Palaeontological mysteries of all - it spanned such a great time, surely the formation for the foundations for the advancement of evolution as we recognise it from our Phanerozoic Eon arising, and yet we have only the faintest glimpses of the shrouded time that we have unearthed. There may well, in all likelihood, be a vast seam of Palaeontological evidence, in the form of fossils (skeletal, trace and indeed microorganisms, to name a few) to be studied yet. The Precambrian is a relatively 'unchartered' time, getting less and less clear the further back into its epic duration we go. In a sense, The Precambrian is a hazey prologue to the mighty and much more 'interesting and active' (yet considerably younger, by over 3.5 Billion Years) events and animalistic Dynasties of The Phanerozoic Eon. Nevertheless, there is a great deal we have yet to learn about the 4 Billion and 60 Million Year old 'Super-Eon'. Zircon crystals have been analysed and indicate that the Earth indeed is at least 4.4 Billion Years Old. The 4.6 Billion total Earth age agreed by most scientific circles, is the most educated and argued (and arguably correct to many) number. To just even consider the vastness of this 'Super-Eon's' constituent Eons, let alone the full informal Precambrian 'Super-Eon', is a very much demanding task for many people. Thousands of millions of years simply goes beyond the comprehensions of reality for many, not least of which the Creationists - who still regard the Religious study of the Bible, to be evidence enough to believe that the Earth was created at around 4004 BC; claiming, then, that Planet Earth is a mere 6,013 Years Old (as of 2009 now) Nevertheless, specifically Geological research has now quite recently, put an amazingly highly precise number to the age of the Earth; 4,567 Million Years...not quite 4,600 Million, but this general figure is still widely acceptable. No matter how accurate and clever we would like to be when it comes to pin-pointing the exact time of Old Earth's first years of existence, it is not so informal as to opt for a more conservative approach.
The Hadean Eon The Archaean Eon The Proterozoic Eon The Phanerozoic Eon The Palaeozoic Era The Cambrian Period The Ordovician Period The Silurian Period The Devonian Period The Carboniferous Period The Permian Period The Mesozoic Era The Triassic Period The Jurassic Period The Cretaceous Period The Cenozoic Era The Tertiary Period The Palaeocene Epoch The Eocene Epoch The Oligocene Epoch The Miocene Epoch The Pliocene Epoch The Quaternary Period The Pleistocene Epoch The Holocene Epoch