Oligocene reef deposits linked to ODP Site 999 with strontium isotope stratigraphy

Author(s): Johnson, Claudia C.; Ramírez, Wilson R.; Leckie, R. Mark; Hernandez, Sonya Y.; Barrow, Erica A.; Hegewald, Morgan; Velez, Jorge
Author Affiliation(s): Primary:
Indiana University, Department of Geological Sciences, Bloomington, IN, United States
University of Puerto Rico, Puerto Rico
University of Massachusetts, United States
Volume Title: Geological Society of America, 2006 annual meeting
Source: Abstracts with Programs - Geological Society of America, 38(7), p.557; Geological Society of America, 2006 annual meeting, Philadelphia, PA, Oct. 22-25, 2006. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Lithologic units transitional from the San Sebastian Formation to Lares Limestone were examined in northern Puerto Rico. As in previous studies, stratigraphic, sedimentologic and paleontologic data allowed for interpretation of marginal marine to reef depositional environments as part of a marine transgression, but detailed data further define changes in relative water depth within the Lares Limestone. Fossils in the lower transitional units are identified as abundant plant material, bivalves of the families Pectinidae, Osteridae and Arcidae, gastropods of the families Naticidea, Cypraeidae and Volutidae, and partial specimens of foraminifera of the Miliolidae. Massive corals, robust erect bryozoa and abundant foraminifera of the Miliolidae dominate the upper units. Common coral genera include Porites, Goniopora, Cladocora, Alveopora, Antiguastrea, Acropora, Montastrea, Colpophyllia, Favites and Leptoseris among others. Calcified siphon sheaths of Kuphus bivalves extracted from stratigraphic units containing reef-building corals yielded 87Sr/86Sr isotope values ranging from .708087 to 708108 within the Lares Limestone and identify the age of reef building at approximately 27my within the Chattian stage of the Oligocene. The San Sebastian and Lares formations of Puerto Rico have been identified in earlier publications as Eocene to Oligocene based predominantly on foraminifera. The strontium chemostratigraphic marker correlates to Oi2b via the 27my date obtained from tephra in ODP site 999, thereby allowing for correlation of deep water tropical events with shallow, reef-building episodes. Isotope data extracted from foram shells allow for determination of ice volume and sea surface temperatures for the tropical Atlantic for this time period. Abstract 113587 modified by on 7-11-2006
Year of Publication: 2006
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Anthozoa; Antilles; Atlantic Ocean; Bivalvia; Bryozoa; Caribbean Sea; Caribbean region; Cenozoic; Chemostratigraphy; Cnidaria; Colombian Basin; Depositional environment; Foraminifera; Fossils; Greater Antilles; Invertebrata; Isotope ratios; Isotopes; Lares Limestone; Leg 165; Marine environment; Metals; Microfossils; Mollusca; North Atlantic; Northern Puerto Rico; ODP Site 999; Ocean Drilling Program; Oligocene; Paleogene; Protista; Puerto Rico; Reefs; San Sebastian Formation; Sea-level changes; Sea-surface temperature; Sr-87/Sr-86; Stable isotopes; Strontium; Tertiary; Transgression; West Indies
Coordinates: N124437 N124437 W0784422 W0784422
Record ID: 2010031506
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