Information collected, compiled and correlated regarding Earth history proves irrefutably that its age exceeds 4 billion years (BY), 4.6 BY more accurately. Many lines of evidence in various sciences confirm the very ancient origin of rock. Indelibly carved in stone all around the world is the Earth's story in a book whose pages number in the millions, and which is many miles thick. By reading this book through centuries of difficult field studies and serious inquiry, very useful descriptions of our planet's interior are revealed. As examples, geologists and engineers know where to find oil, gas, groundwater and ore as a result of the study of rocks. Moreover, these are found by logically putting together the evidence of ancient events like mountain building and oceans that dried up. In geology alone, information is gathered from surface exposures, excavations, deep drilling and geophysical imaging, among various means. Other sciences' findings often confirm those of geological discoveries, like DNA studies, as our base of knowledge grows vastly.
The pages of Earth's huge book of stone were written while being created, each page imprinted by the events that caused its very creation. Because the same natural processes were at work in the past as today, reading the pages (layers) is straightforward. Many instances of nature in operation that occur now are also seen in rock layers. Examples include the raising of mountains that slowly erode and deposit sediments around them as well as abrupt volcanic eruptions and also incredible forces pushing and pulling on landmasses. And the processes mentioned here are only a few of those known to occur. Therefore, literally rock-solid evidence persists that indicates not only the same processes go on today as in the past, but also that they have gone on for a very long time.
Radiometric dating methods are not required to reveal our planet's long saga. Simply by noting the variations in the composition of rock strata in extremely deep natural formations, the implications are undeniable. Based solely upon the existence of such very deep and widely extensive layering, the conclusion must be that processes in the past sequentially caused the layers to form. And of course, evidence of each geologic process reflects in the nature of the deposits, such as grain size, composition and fossils. Clearly, based logically on processes that occur every day, Earth's ancient ages are validated. And by way of one corollary, radioactive substances and their respective daughter products in rock strata verifies their extremely ancient origins. By way of such dating techniques, in conjuction with knowledge of how older layers underlie younger ones, events like worldwide glaciation around 1.2 BY and continental origins at 3.8 BY are noted. Of course, repeated verifications by way of actual evidence are required before asserting theories, as is the case for all valid science.