Geochemical provenance of Florida basement components
- Univ. of Florida, Gainesville, FL (United States). Dept. of Geology
- Univ. of Georgia, Athens, GA (United States). Dept. of Geology
The pre-Cretaceous basement of Florida is generally considered to be exotic with respect to Proterozoic Laurentia. Paleontologic and paleomagnetic evidence have suggested a Gondwanan provenance for the Floridan basement, as either a peri-Gondwanide terrane or as a rifted block of the West African craton. The report of generally similar lithologic sequences and a record of similar Ar-Ar cooling ages in some Floridan and West African lithologic units has led to very specific correlations between these units. U-Pb, Sm-Nd, and Rb-Sr geochronologic studies as well as isotopic and elemental abundance data have been used to evaluate the validity of these correlations. Results indicate: (1) geochemical similarities between volcanic rocks of northeastern Florida and a Pan-African metavolcanic sequence (Niokola-Koba group) exposed in Senegal; (2) an absence of a Grenvillian-age (i.e., Laurentian) component in zircons separated from a Paleozoic Suwanee basin sandstone; and (3) whole-rock Sm-Nd and U-Pb zircon evidence for an Archean ([approximately]3.0 Ga) component in the neo-Proterozoic Osceola granitoid(s). Although silicic rocks from throughout Florida have Nd model ages (T[sub DM]) that are predominantly Grenvillian (1.1--1.4 Ga), the absence of a Grenvillian component in zircons separated from granite and sandstone suggests that the model ages represent a mixture of older and younger components. Overall, the evidence for Birimian ([approximately]2.1 Ga) and Liberian ([approximately]3.0 Ga) age components in the Florida basement are consistent with its origin as a rifted block of cratonic Gondwana. In addition to demonstrating a strong affinity between the Florida basement and cratonic West Africa/northern South America, these data provide a basis for comparison with other circum-Atlantic terranes traditionally described as Avalonian/Cadomian, etc.
- OSTI ID:
- 5950793
- Report Number(s):
- CONF-9304188-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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