Sequence Stratigraphy and Quantitative Relative Sea-Level History for Miocene-Pliocene Ponce Limestone, Puerto Rico

Ponce Limestone exposures in southern Puerto Rico are being used to develop chronostratigraphic and sequence stratigraphic frameworks, and construct rock-based quantitative relative sea-level histories to better evaluate and quantitatively constrain controls on carbonate development in the Caribbean. New strontium isotope absolute age data indicate Middle to Late Miocene ages for three major sequences (DS1, DS2, DS3) and sequence boundaries (SB1, SB2) that developed in response to relative sea-level fluctuations of several 10’s of meters. DS1 is dominated by benthic foraminifera, mollusks, and solitary corals within a subtidal system that contains abundant burrowing and local trough cross bedding indicating intermittent energy. Gradual increase in photosynthetic corals and abrupt change to a Porites-stick dominated reef at the top of DS1 denote a shallow marine environment. The trace of the reef down paleoslope signifies a relative sea-level fall (SB1). Syndepositional faults (approximately 4-6 m displacement) indicate an influence of tectonism on the DS1 system. DS2, dominated by subtidal bioturbated mollusk and benthic foraminifera, represents a relative sea-level rise. A subsequent relative sea-level fall (SB2) is evidenced by subaerial erosion and brecciation. DS3, dominated by subtidal bioturbated mollusk and benthic foraminifera at the base, represents a relative sea-level rise. Coral reefs, oyster banks, Clypeaster cubensis, and articulated red algae at the top of DS3 denote a shallow marine environment in response to relative sea-level fall. This initial work provides the basis for further analyses and quantification of the controls on the carbonate system and comparison to other Caribbean project study sites.