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Updated: Jul 19, 2026

Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis
Published on: August 15, 2018
Otolith delta 18O record of mid-Holocene sea surface temperatures in Peru
C Fred T Andrus1, Douglas E Crowe, Daniel H Sandweiss
1Department of Geology, University of Georgia, Athens, GA 30602-2501, USA. andrus@gly.uga.edu
Abstract:
Peruvian sea catfish (Galeichthys peruvianus) sagittal otoliths preserve a record of modern and mid-Holocene sea surface temperatures (SSTs). Oxygen isotope profiles in otoliths excavated from Ostra [6010 +/- 90 years before the present (yr B.P.); 8 degrees 55'S] indicate that summer SSTs were approximately 3 degrees C warmer than those of the present. Siches otoliths (6450 +/- 110 yr B.P.; 4 degrees 40'S) recorded mean annual temperatures approximately 3 degrees to 4 degrees C warmer than were measured under modern conditions. Trophic level and population diversity and equitability data from these faunal assemblages and other Peruvian archaeological sites support the isotope interpretations and suggest that upwelling of the Peru-Chile current intensified after approximately 5000 yr B.P.
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