The geologic time scale was developed to better explain the earth’s surface from a large-scale to a smaller-scale. Dating methods based on constraining models of strata and age are applied to derive time. This enables researchers to examine the relationship between tectonics, formation of the Earth’s surface, the age of the Earth, and climate. It is used extensively in geology, archaeology, palaeontology, astronomy, and earth sciences.
Geologic time is derived from direct rock records of the Earth’s surface. Over half a million years ago, the most prevalent rocks were metamorphosed or had erupted. The Precambrian includes one of the earliest major rock layers and consists of numerous minor deposits as well as the fossils of pre-homestocene animals. The next important layer, the Paleocene or “aged rock”, consists of older fossils and fine-grained rocks, including the very important sapphire. The latest and youngest stratum, the stratosphere or “ocean” contains the oldest rocks and is composed of dinosaur bone, coral reefs, and other trace fossils. For more information, visit this blog post.
The geologic time scales are broken down into younger and older units, with each unit divided into eras. For instance, the youngest unit, the Cretaceous geological period, comprises a group of hundred to five hundred million years ago, including the dinosaurs. At the same time, the oldest rocks are the Paleocene Eon and the Jurassic period, which feature the very first large dinosaurs. Other significant intervals in earth’s history include the pre-Cylonian era, the Old Stone Age, and the Permian (ages fifty to sixty thousand years ago). In the past few decades, new eras in geologic time have emerged, such as the end-arsity of the dinosaurs, the Mesozoic era, the Permian (ages forty to seventy million years ago), the Triassic period, and the post-Cenozoic era.
Absolute dating methods used today, on the other hand, rely on the precision of fossil evidence and date a specific specimen as close to the actual age of the Earth as possible. In order to be certain that the fossils are really old, a scientific investigation has to be carefully carried out on the rocks. Rocks contain fossils of both plants and animals, as well as shells. These fossilized remains can sometimes be found in combinations or in large groups.
The oldest rocks on Earth have yielded a record of life on Earth. During the study of earth’s history, geologists look for the fossils of animals and plants in rocks, as well as shells and the layers of rock above them. By deducting the right age for an animal or plant from its fossils, geologists can estimate how old it is, how old its shell is, and how old its layers are. They can also determine which layers are younger than others.
Exactly when dinosaurs became extinct, however, is an important subject in geology. The most accepted theory on how this happened is that it was caused by the huge amounts of impact craters that hit the Earth at the end of the Cretaceous geological period. When these massive impact craters formed, they ejected huge amounts of material into the air, including many fossils. Because the Earth was able to produce such huge amounts of impact debris, scientists believe that the Earth’s crust was very porous at that time, allowing liquid to percolate through the rock layers and eventually reach the surface of the planet. This liquid may have been responsible for killing off the dinosaurs, but it is also believed that some catastrophic events caused massive amounts of erosion, causing massive rock layers to form in the Paleocene and Cenozoic eras, along with the eventual decline of the dinosaurs and their surroundings.