Poo Core Slice (IMAGE) American Geophysical Union Caption Thin slices of the bat guano core from Home Away from Home Cave, Jamaica, were analyzed for radioisotopes, metals, stable isotopes of carbon and nitrogen, and biochemical markers. Radiocarbon analysis dated the oldest layers at 4,300 years. Credit Chris Grooms Usage Restrictions include image credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.