The Geologic Time Scale
The Geologic Time Scale is a system of chronological measurement showing the beginning of time (4.6 bya) to today. It includes Eons, Eras, Periods, Epochs and Pivotal Events. In 1669 Nicolaus Steno created 2 geologic principles, one, that rocks are layered horizontally, and two, that each rock is younger than the one below it and older than the one above it. In 1815 William Smill made a geologic map of England demonstrating the “principle of faunal succession”. In 1913 the first Geologic Time Scale was made by British geologist Arthur Holmes. Nicolaus Steno, William Smill and Arthur Holmes were the 3 biggest contributors to the creation of the Geologic Time Scale. Scientists decide where one era ends and another begins from dramatic changes to fossil assemblage, often caused by climate change.Fossils are the preserved remains of things that used to be alive. They give evidence to what the world used to be like and what animals lived then. The fossil record is ALL the evidence that scientists have gathered over time on living organisms. The Law of Superposition is very good evidence for the Geologic Time Scale because it states that each rock layer is younger than the one below it and older than the one above it, so the different fossils found in different layers are younger or older than each other depending on their location.
The Geologic Time Scale is a system of chronological measurement showing the beginning of time (4.6 bya) to today. It includes Eons, Eras, Periods, Epochs and Pivotal Events. In 1669 Nicolaus Steno created 2 geologic principles, one, that rocks are layered horizontally, and two, that each rock is younger than the one below it and older than the one above it. In 1815 William Smill made a geologic map of England demonstrating the “principle of faunal succession”. In 1913 the first Geologic Time Scale was made by British geologist Arthur Holmes. Nicolaus Steno, William Smill and Arthur Holmes were the 3 biggest contributors to the creation of the Geologic Time Scale. Scientists decide where one era ends and another begins from dramatic changes to fossil assemblage, often caused by climate change.Fossils are the preserved remains of things that used to be alive. They give evidence to what the world used to be like and what animals lived then. The fossil record is ALL the evidence that scientists have gathered over time on living organisms. The Law of Superposition is very good evidence for the Geologic Time Scale because it states that each rock layer is younger than the one below it and older than the one above it, so the different fossils found in different layers are younger or older than each other depending on their location.