Data

Copy and paste the text below. It is read-only. Select All

Relative Dating Means placing rocks in their proper sequence of formation (first, second, third). It doesn't tell dates or lengths of time but which event preceded another event. Law of Superposition In an undeformed sequence of sedimentary rock, each bed is older than the one about it and younger than the one below it Principle of Original Horizontality Layers of sediments are generally deposited in a horizontal position. If we see rock layers that are flat, it means they have not been disturbed and thus still have their original horizontality. Principle of Cross-cutting relationships When a fault is younger than the rock through which it cuts Inclusions Pieces of one rock unit that are contained within another. The rock mass containing the conclusions is the younger of the two. Conformable Rocks that have been undisturbed Unconformity A long period of time during which deposition of a rock layer ceased and erosion removes previously formed rocks and then deposition of new layers form; essentially missing a layer. Three types: angular conformity, disconformity and non conformity Angular conformity Tilted or folded sedimentary rocks that are then overlain by younger flat laying layers Disconformity Like an angular unconformity but the layers are parallel to the overlain strate Nonconformity the break seperates older metamorphic or instrusive igneous rock from younger sedimentary strata.