More evidence for a glacial world prior to the middle Miocene oxygen-isotope enrichment event: resolution of early Miocene glacioeustatic sea-level cyclicity from North Carolina

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6322986

Synder, S W; Synder, S W; Waters, V J; Steinmetz, J C; Hine, A C; Riggs, S R

Benthic delta/sup 18/O analyses from DSDP sites worldwide have documented a positive excursion (similarly ordered + 1.5%) through the early-middle Miocene. These data are traditionally interpreted as marking the transition from an ice-free world to one that was extensively glaciated. Recently, however, this doctrine has been challenged, and an alternative hypothesis suggests the benthic delta/sup 18/O excursion primarily reflects a temperature drop within a previously glaciated world. Within the North Carolina continental margin, a chronostratigraphic framework consisting of 6 discrete early Miocene depositional sequences was established via stratigraphic interpretations from over 21,000 Km of high-resolution seismic reflection profiles. Each sequence is bound by unconformities which were mapped throughout the continental margin. Biostratigraphic analyses of 140 vibracores penetrating these sequences demonstrate that each sequence is a consequence of 4th-order (10/sup 5/yrs) sea-level cyclicity, similar in duration (100-300 Ka) and amplitude (100-150 m) to the glacioeustatic sea-level fluctuations of the Quaternary Epoch. Recognition of late Burdigalian high-frequency (4th-order) sea-level cyclicity demonstrates that continental ice-sheets were large enough during the early Miocene to drive eustatic sea-level fluctuations with Milankovitch-type periodicities. This further supports Matthews (1984) hypothesis that continental ice-caps existed on Antarctica PRIOR to the well-documented middle Miocene benthic delta/sup 18/O global enrichment event.

• Research Organization: Univ. South Florida, St. Petersburg (USA)
• OSTI ID: 6322986
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CONTINENTAL MARGIN
STRATIGRAPHY
EARTH PLANET
PALEOCLIMATOLOGY
NORTH CAROLINA
SEDIMENTARY ROCKS
ISOTOPE RATIO
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CLIMATE MODELS
CLIMATES
GEOCHEMISTRY
GLACIERS
GLOBAL ASPECTS
MIOCENE EPOCH
OXYGEN 18
SEA LEVEL
TEMPERATURE MEASUREMENT
VARIATIONS
CENOZOIC ERA
CHEMISTRY
EVEN-EVEN NUCLEI
FEDERAL REGION IV
GEOLOGIC AGES
GEOLOGY
ISOTOPES
LEVELS
LIGHT NUCLEI
MATHEMATICAL MODELS
NORTH AMERICA
NUCLEI
OXYGEN ISOTOPES
PALEONTOLOGY
PLANETS
ROCKS
STABLE ISOTOPES
TERTIARY PERIOD
USA
580100* - Geology & Hydrology- (-1989)
580400 - Geochemistry- (-1989)