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Science Frontiers ONLINE No. 57: May-Jun 1988 |
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Florida More Exotic Than The Travel Agents Promise
Anyone who has visited Florida knows that it differs in several ways from the rest of North America. Now we find that Florida doesn't even belong to North America; it is an interloper, an "exotic terrane."
How does one know this? Three facts hint that Florida doesn't belong:
- When pre-Cenozoic land masses are fitted together, assuming the truth of continental drift, an awkward overlap arises that suggests that Florida was not always where it is today;
- The latest paleomagnetic measurement of Florida's Paleozoic latitude is consistent with it being part of Gond wanaland rather than at its present latitude;
- Radiometric dating of zircons retrieved from a core extracted from Northern Florica yield an age of 16501800 million years. There are no known source rocks in the southeastern U.S. that old; Africa and South America are likely sources of such zircons.
"These (latter) two new lines of geologic data provide strong evidence confirming previous suggestions that Florida was part of Gondwana during the early Paleozoic and that its current configuration is that of an exotic terrane sutured to North America during the fragmentation of Pangea."
(Opdyke, Neil D., et al; "Florida as an Exotic Terrane: Paleomagnetic and Geochronologic Investigation of Lower Paleozoic Rocks from the Subsurface of Florida," Geology, 15:900, 1987.)
Comment. Other exotic terranes have been found in western North America, making the continent a veritable pastiche.