The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
The regular order of occurrence of fossils in rock layers was discovered around 1800 by William Smith.
Free 5-day trial Discover how geologists study the layers in sedimentary rock to establish relative age.
Learn how inclusions and unconformities can tell us stories about the geologic past.
The Story That Rocks Can Tell By using prior knowledge of sedimentary rock formation and the agents of erosion and deposition, students use a set of rock samples and the principle of superposition to make observations and inferences. They will also consider the bedrock and glacial history of the area and weave a coherent story for the finding of the set of fossils.
The Gaia Theory Use the data above to construct a graph of the changing percentage composition of Earth's atmosphere since the formation of the Earth.
The Permian through Jurassic stratigraphy of the Colorado Plateau area of southeastern Utah is a great example of Original Horizontality and the Law of Superposition, two important ideas used in relative dating.
These strata make up much of the famous prominent rock formations in widely spaced protected areas such as Capitol Reef National Park and Canyonlands National Park.
Imagine that you're a geologist, studying the amazing rock formations of the Grand Canyon.Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique.Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate.Fossilization usually can only happen to hard parts of the organism's body, so that is another obstacle in the way of making fossils.It is possible that some traces of organisms, like footprints, can become imprint fossils if they are filled with sediments, but these are rare. That organism normally needs to be near an area with a lot of water, like a lake or river.From top to bottom: Rounded tan domes of the Navajo Sandstone, layered red Kayenta Formation, cliff-forming, vertically jointed, red Wingate Sandstone, slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and white, layered Cutler Formation sandstone.