Oxygen and carbon isotopic profiles of Recent and Cenozoic mollusks: Growth rates and paleoenvironmental analysis

Oxygen and Carbon stable isotope ratios were used to analyze and compare growth histories of six Recent and fossil genera of mollusks: three genera of gastropods---Triplofusus, Fasciolaria, and Beringius, and three genera of bivalves--- Dosinia, Anadara, and Codakia. Taxa were selected to check for compatibility of results between different fossil genera from the same environment. Comparison between isotopic signatures in recent and fossil congeneric species allowed substantial insight into growth rates. Recent specimens were collected from the Gulf of Aniva, Gulf of California, Bahamas, Florida Keys, and Gulf of Mexico. Fossil specimens were collected from the Middle Miocene of Kamchatka and the Pleistocene of Florida. Oxygen isotope ratios were also used to infer ambient seawater temperatures during the deposition of each shell. The calculated temperatures offer significant insight into the Pleistocene southern Florida embayment and Middle Miocene climatic optimum in the North Pacific.