Shenandoah National Park and Florida Geologic Setting
Florida and Shenandoah National Park have many commonalities as well as differences that makes each of these geologic setting unique. Though North America looks like Florida and Shenandoah National Park never seemed to collide with one another, Shenandoah has a rock record of being about 1 billion years old that constructed the North American continent and a building block that formed the Appalachians through orogenies. Florida falls about 300 million years old with the North American plate, however findings that were part of Gondwana provides evidence of the origin of Florida. With a vast time difference of these rock records, what can be furthered analyzed of what the…show more content… Rodinia started to rift around 750 to 600 million years ago and the Iapetus Ocean opening up as seen in Figure 1, the Swift Run Formation with Grenville, volcanic debris and ash material produced the Catoctin Formation that contains flood basalts supporting Shenandoah. With modern day East Africa rift and Red Sea curst stretched, this allowed flood basalts and rhyolite seep through the ocean floor and eventually made its way to the surface. Florida didn’t really start until Rodinia started to break apart through rifting and seafloor spreading. This rifting and seafloor spreading ripped apart the eastern part of North America and made shorelines that are smaller than coves and high lands near the surface of the ocean (M.C. Smith, written communication, 2017). This created a conjugate margin that made North America wait for Gondwana where orogenic belts can be created.
Just like Shenandoah the Iapetus ocean started to open separating land masses Laurentia and Gondwana as Florida’s basement rock comes from the Gondwana region. Within the Neoproterozoic there is granitoids and igneous rocks that are found in central and northeastern part of Florida as evidence of Florida being part of Gondwana(M.C. Smith, written communication, 2017). In Figure 2, Findings of minerals such as schists and quartz