The goal of this research is to reevaluate the reservoir effect in Peru and calculate an improved deltaR correction than those currently used. The new deltaR correction will be based on Protothaca asperima and Semele corrugata shells, collected in Paracas, and Donax obesulus collected in Puerto Salaverry and Puerto Pariñas. These shells were collected before any nuclear weapons testing and were archived in museums; therefore they are not affected by anthropogenic radiocarbon, and were collected on known dates, so decay since death can be calculated. Other species may be added if suitable specimens are found in museums.
    Each of those shells will produce at least 10 sequential samples depending on their size. The samples will be extracted through each shell’s ontogeny. Samples will weigh approximately 4mg and will be analyzed for ¹⁴C using an Accelerator Mass Spectrometer (AMS) at the University of Arizona. Each sample will be milled consecutively parallel to the shell’s growth lines from edge to umbo. Shells are thought to be between one and two years at death. Based on that age, the sample resolution varies between one and two months. Other species may produce a longer record. 
    These shell species will also be evaluated to assess their possible use as sea surface temperature (SST) proxies. Field work in Peru was conducted in summer 2006 and modern shells specimens were collected. Also water samples from the sites of collection were acquired. These shells will be analyzed for d¹⁸O using an isotope ratio mass spectrometer (IRMS) at high resolution through ontogeny. These measurements will be compared to instrumental SST in the areas.  It is hoped that each shell will thus contain two independent proxies for both SST and upwelling.

Study Area

Related Publications

2006. ETAYO-CADAVID, Miguel F, ANDRUS, C. Fred T., HODGINS, Gregory W. L., and JONES, Kevin, Geosciences ONTOGENETIC RADIOCARBON VARIATION IN MODERN PRE-BOMB PERUVIAN MOLLUSK SHELLS AS A PROXY FOR UPWELLING Paper 202-1. GSA, Philadelphia Annual Meeting

2006. JONES, Kevin,  HODGINS, Gregory, ANDRUS, C. Fred T.,  and ETAYO-CADAVID, Miguel F., RADIOCARBON AND STABLE ISOTOPE VARIATION IN PRE-BOMB ARGOPECTEN SHELLS FROM PERU: IMPLICATIONS FOR CHRONOMETRY AND THE MARINE RESERVOIR CORRECTION Paper 202-2. GSA, Philadelphia Annual Meeting

Related Publications

Geological Society of America, Annual Meeting, Philadelphia, PA, October 22-25, 2006 (see abstract above)