America's Volcanic Past -
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| "Though few people in the United States may actually experience an erupting volcano, the evidence for earlier volcanism is preserved in many rocks of North America. Features seen in volcanic rocks only hours old are also present in ancient volcanic rocks, both at the surface and buried beneath younger deposits." -- Excerpt from: Brantley, 1994 |
Volcanic Highlights and Features:
[This list is just a sample of
various Florida volcanic features or events and is by no means inclusive.]
Florida's geologic history begins deep beneath its surface where ancient rocks indicate that Florida was once a part of northwest Africa. As ancient supercontinents split apart, collided, and rifted again, a fragment of Africa remained attached to North America. This fragment formed the base for the carbonate buildup which includes the Florida and Bahamas Platforms.
Much of the surface of Florida is covered by sediment
(loose mineral particles, such as quartz sand), or
sedimentary rocks such as limestone and dolostone.
Igneous and metamorphic rocks
do not occur naturally at the surface, but are
found in deep wells reaching
from 3,500 feet to deeper than 18,670 feet below land surface.
Excerpt from: Florida Geological Survey Website, 2001 |
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The Atlantic Plain:3
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| Florida's Basement Rocks |
Florida Platform:2
The Florida Platform lies on the south-central part of the North American
Plate, extending to the southeast from the North American continent
separating the Gulf of Mexico from the Atlantic Ocean. The Florida
Platform, as measured about the 300 foot isopath, spans more than 350
miles at its greatest width and extends southward more than 450 miles at
its greatest length. The modern Florida peninsula is the exposed part of
the platform and lies predominanly east of the axis of the platform.
Most of the State of Florida lies on the Florida Platform; the western
panhandle is part of the Gulf Coastal Plain.
The basement rocks of the Florida Platform include Precambrian-Cambrian
igneous rocks, Ordovician-Devonian Sedimentary rocks, and
Triassic-Jurassic volcanic rocks.
Florida's igneous and sedimentary
foundation separated from what is now the African Plate when the
super-continent Pangea rifted apart in the Triassic (pre-Middle Jurassic?)
and sutured to the North American craton.
| Florida's Igneous Rocks |
Florida's Volcanic Rocks:1
Igneous and metamorphic rocks
do not occur naturally at the surface, but are
found in deep wells reaching
from 3,500 feet to deeper than 18,670 feet below land surface.
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