科研之友
微信
新浪微博
Facebook
分享链接
摘要
A robust marine radiocarbon (C-14) reservoir correction (Delta R) is essential for calibrating C-14 dates of marine mollusks and fish bones routinely found in archaeological sites as discarded food remains and bones of terrestrial animals (including humans) with an appreciable marine diet. New Delta R values are reported for the atoll archipelago of the Marshall Islands, eastern Micronesia. Atolls consist of biogenetic material-mostly coral and foraminifera-that can be directly dated for establishing sequences of atoll emergence and islet development. After sectioning and examination using scanning electron microscopy (SEM) to screen for sample diagenesis, 6 pristine branch coral samples were selected from the modern oceanside beach, 3 archaeological sites, and islet developmental facies from Ebon Atoll (4 degrees 34'N, 168 degrees 41'E). Each sample was analyzed by U-series and accelerator mass spectrometry (AMS) C-14 showing no substantial temporal Delta R variations and yielding a weighted mean Delta R of 41 +/- 42 yr(1) spanning similar to 500 yr before earliest human colonization (the period when islets first became habitable) through the entire 2000-yr occupation sequence. Reliable published Delta R values for Micronesia and Delta C-14 data for Palmyra Island, together with our results for Ebon Atoll, indicate that the Pacific North Equatorial Counter Current is almost stable for the past 2500 yr.
- 出版日期2018-2
