GEO 103 Lecture 20: Paleozoic Era
28 Mar 2017
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Document Summary
Geologic history of north american carton may be divided into two parts. Relatively stable continental interior over which epeiric seas transgressed and regressed. L. sloss (american, 1963) divided n. american sedimentary record into 6 cratonic sequences. Large-scale lithostratigraphic unit representing major transgressive-regressive cycle bounded by craton-wide unconformities. Six unconformities extend across various north american cratonic basins into marginal mobile belts. Aka there is a layer of conformity between each chunk or block of sediments. The left column represents the periods where the craton has gone through mountain building. The middle column shows a cross section of the continental craton where the brown sections show where unconformities are located. The edges have less brown showing that there are fewer periods of time where there was an unconformity while the middle is exposed to the surface more often and have longer periods of unconformities. The pinching going upwards of unconfirmity is the transgression (sea level covering the land in.
