GEOL 11042 Lecture Notes - Lecture 21: Sea Level Rise, Devonian, Paleozoic
8 Nov 2020
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Document Summary
Following the devonian period, the mississippian and pennsylvanian periods included the gradual formation of the supercontinent pangaea, composed of gondwanaland to the south (africa, south america, antarctica, india, australia) and laurentia and eurasia. Immense forests were the sources of the great coal beds of these two periods: additionally, extensive glaciation occurred, which resulted in sea level drop. Sea level rise and fall as a response to glacial-interglacial cycles at this time produced facies changes in the sediments in the shallow seas of the flooded mid- continents. These facies packages are cyclothems: cyclothems have a standard sequence-first, nonmarine sediments, then grading to shallow marine and then back to nonmarine sediments. This is a facies change: cyclothems are found in the missippian and pennsylvanian periods worldwide. Mississippian and pennsylvanian time also was a time of the third and final orogenic event that built the appalachian mountains.
