Radiocarbon in Melanopsis Gastropodes

Lilach Lev's MSc project

Partners:

Moti Stein, Geological Survey of Israel

Elisabetta Boaretto, Weizmann Institute of Science

Radiocarbon is one of the tools often used for dating geological sites and events up to ca 40,000 yrs. The method suffers many inaccuracies due to parameters that change the concentration of the radiocarbon in the atmosphere and in the samples to be dated. Thus, every age we receive has to be calibrated. The most popular materials to be dated are charcoal and bones. One of the problems is that they are not found in lacustrine environments very often.

The Melanopsis shells, which are made of aragonite, might provide a tool for dating lake and other continental environments.

Melanopsis is a fresh water gastropod (snail), common in the Kinneret and the surrounding water sources. It is also a common fossil in lake and alluvial deposits. Previous age determinations of living and fossil specimens reveal large anomalies, suggesting that we do not yet understand the C14 systematics in these creatures. The aim of my work is to create a new calibration curve for dating these Melanopsis. In order to achieve this goal, I will measure the isotopic composition of recent shells, compare the results with the isotopic composition of the water and understand the carbon system in the Melanopsis’ shells. I will then compare dates of fossil Melanopsids to ages determined by other independent methods.

We wish to thank Prof. Joseph Heller for sharing his knowledge on the biology of the Melanopsides.

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