Grand canyon relative dating exercise
Grand canyon relative dating exercise - call girlsn al quasais
Sediment deposited on steep slopes will be washed away before it is buried and lithified to become sedimentary rock, but sediment deposited in nearly horizontal layers can be buried and lithified.
In order to do so we will have to understand the following: To better understand these concepts, let's look at an archeological example: Imagine we are a group of archeologists studying two different trash pits recently discovered on the Tulane University campus and at the Audubon Zoo (where they all aksed for you).Thus, we know that the dike is younger than the mudstone, sandstone, and shale.Similarly, the rhyolite dike cuts only the mudstone and the sandstone, but does not cut across the shale.A more modern way of stating the same principle is that the laws of nature (as outlined by the laws of chemistry and physics) have operated in the same way since the beginning of time, and thus if we understand the physical and chemical principles by which nature operates, we can assume that nature operated the same way in the past.Principle of Superposition Because of Earth's gravity, deposition of sediment will occur depositing older layers first followed by successively younger layers.Thus, in a sequence of layers that have not been overturned by a later deformational event, the oldest layer will be on the bottom and the youngest layer on top.
This is the same principle used to determine relative age in the trash pits discussed previously.The Grand Canyon is particularly good for this because different sedimentary rocks have different colors.For example, the mudstone, sandstone and shale are cut by the basalt dike, so we know that the mudstone, sandstone, and shale had to be present before the intrusion of the basalt dike.In fact, sedimentary rocks are, in a sense, trash from the Earth's surface deposited in basins.Principle of Original Horizontality Sedimentary strata are deposited in layers that are horizontal or nearly horizontal, parallel to or nearly parallel to the Earth's surface.From the beginning of this course, we have stated that the Earth is about 4.6 billion years old.