Strontium isotope geochronology of selected intervals within the Florida Neogene
- Univ. of Florida, Gainesville, FL (United States). Dept. of Geology
The Neogene stratigraphic record of Florida reveals many richly fossiliferous (both invertebrate and vertebrate), shallow-marine deposits whose ages are poorly constrained, despite over a century of paleontological investigation. Chronostratigraphic analyses are frequently hampered by a general absence of age-diagnostic fossils (micro- or nannofossils in particular), laterally discontinuous sedimentary units, and an overall lack of natural exposure. Consequently, temporal correlations among many of Florida's Neogene units as well as with the global geomagnetic polarity timescale (GPTS) remain tenuous. Strontium isotope ([sup 87]Sr/[sup 86]Sr) geochronology offers considerable potential as an independent method for correlating these deposits with one another as well as with the GPTS. Portions of the Miocene and Pliocene as well as most of the Pleistocene were characterized by rapid increases in the global [sup 87]Sr/[sup 86]Sr of seawater. Marine carbonates formed within these intervals are therefore particularly amenable to investigation by Sr isotope techniques. Ratios ([sup 87]Sr/[sup 86]Sr) from mollusk shells collected throughout Florida within stratigraphic context ranged from 0.70785 which roughly correspond to the interval 30 Ma (late Oligocene) to 1 Ma (late Pleistocene). The data suggest that many accepted correlations based on lithologic and/or faunal similarities within Florida's Miocene and Plio-Pleistocene strata are improbable. While additional sampling is in order, improved correlation between vertebrate and invertebrate biochronologies has already resulted from the stratigraphic based upon this approach.
- OSTI ID:
- 6078549
- 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
Similar Records
Geochemistry and origin of the West Florida Shelf phosphorites: Genetic relationships among Neogene phosphorites of the southeastern Atlantic continental shelf
Neogene evolution of northern Mahakam Delta, East Kalimantan, Indonesia
Related Subjects
FLORIDA
GEOLOGIC FORMATIONS
AGE ESTIMATION
STRATIGRAPHY
ISOTOPE DATING
ISOTOPE RATIO
PALEONTOLOGY
SEAWATER
STRONTIUM 86
STRONTIUM 87
TERTIARY PERIOD
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
CENOZOIC ERA
DEVELOPED COUNTRIES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
GEOLOGY
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NORTH AMERICA
NUCLEI
OXYGEN COMPOUNDS
RADIOISOTOPES
STABLE ISOTOPES
STRONTIUM ISOTOPES
USA
WATER
580000* - Geosciences