129 - Oldest Event Schist @ 440 Ma years form nonconformity...

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Unformatted text preview: Oldest Event Schist @ 440 Ma years form nonconformity form layer 1 form layer 2 form layer 3 form layer 4 fold schist and layers 1-4 weathering to form angular unconformity form layer 5 Dike A @ 360 Ma years form layer 6 form layer 7 form layer 8 form layer 9 Dike B @ 60 Ma years and/or tilting weathering to form angular unconformity form layer 10 form layer 11 form layer 12 form layer 13 erosion & form surface 14 Youngest Event So what about the other events, how do we date them? We need tools Has to be something in the rocks Has to either give an absolute age (i.e., specific age --- 1,485 years ago), Or has to give a relative age (i.e., 1 st millenium) I f w e c a n n o t g e n e r a t e a b s o l u t e a g e s , w e n e e d t o g e n e r a t e r e l a t i v e a g e s FOSSILS can give relative ages Fossils are remains or traces of prehistoric life that have been preserved in rocks (mainly sedimentary, some in volcanic ash) Body Fossils the actual remains of organisms are what we can use to determine relative ages TYPES OF BODY FOSSILS Original remains- original material created by the life form e.g. shells, skeletons, pollen maybe original mineralogy or an altered one, but form is preserved Molds sediment retains an impression of an organism that it once encased Casts sediment or minerals fill a mold of the organism, forming a replica of the original fossil Impressions of soft parts Carbonization- organism compressed flat & dehydrated leaving a thin film of carbon (text includes as a form of impression)...
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129 - Oldest Event Schist @ 440 Ma years form nonconformity...

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