GEOL 105L Lecture Notes - Lecture 3: Absolute Time And Space, Unconformity, Absolute Dating
24 Feb 2020
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Only the sequence, not the numeric age. Can determine the absolute time of an event. Within the margin of error of the test. If they aren"t flat, something happened to them. Fractures are younger than the strata they cut across. Fragments of other rocks contained within the body of a rock (xenoliths) are older than the surrounding rock. Parts in a conglomerate rock are older than the conglomerate itself. Represent a time of erosion rather than a deposition. Missing time (usually erosion, sometimes a total halt in deposition) A group of rocks has been tilted and eroded. Sedimentary layers deposited on eroded surface of igneous or metamorphic rock. Igneous or metamorphic on bottom with sedimentary on top. Time it takes to go from 100% parent to 50% parent. The amount of time for half the atoms of a radioactive element to decay.
