In coastal and island archaeology, carbonate mollusk shells are often among the most abundant materials available for radiocarbon (14C) dating. The marsh periwinkle (Littorina irrorata) is one of these such species, ubiquitously found along the Atlantic and Gulf coasts of the United States in both modern and archaeological contexts. This paper presents a novel approach to dating estuarine mollusks where rather than attempting to characterize the size and variability of reservoir effects to “correct” shell carbonate dates, we describe a compound-specific approach that isolates conchiolin, the organic matter bound with the shell matrix of the L. irrorata. Conchiolin typically constitutes <5% of shell weight. In L. irrorata, it is derived from the snail’s terrestrial diet and is thus not strongly influenced by marine, hardwater, or other carbon reservoir effects. We compare the carbon isotopes (δ13C and Δ14C) of L. irrorata shell carbonate, conchiolin, and bulk soft tissue from six modern, live-collected specimens from Apalachicola Bay, Florida, with samples that represent possible sources of carbon within their environment including surface sediments, marsh plant tissues, and dissolved inorganic carbon (DIC) in water. Ultimately, this paper demonstrates that samples obtained from wet chemical oxidation of L. irrorata conchiolin produces accurate 14C dates.

中文翻译：

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Marsh Periwinkle (Littorina Irrorata) Conchiolin 中的放射性碳：考古应用

在沿海和岛屿考古学中，碳酸盐软体动物壳通常是可用于放射性碳的最丰富的材料之一。14C) 约会。沼泽长春花 (山茱萸) 是这些物种之一，在现代和考古背景下，在美国大西洋和墨西哥湾沿岸随处可见。本文介绍了一种确定河口软体动物年代的新方法，我们不是试图描述储层效应的大小和可变性以“正确”壳碳酸盐年代，而是描述一种化合物特异性方法，该方法可以分离与壳基质结合的有机物贝壳素的L. irrorata. 贝壳蛋白通常占壳重的 <5%。在L. irrorata，它来自蜗牛的陆地饮食，因此不受海洋、硬水或其他碳储库效应的强烈影响。我们比较碳同位素（δ13C和Δ14三）的L. irrorata来自佛罗里达州阿巴拉契科拉湾的六个现代活体标本的壳碳酸盐、贝壳蛋白和大块软组织，其样本代表了其环境中可能的碳源，包括表面沉积物、沼泽植物组织和溶解的无机碳 (DIC)水。最后，本文证明了从湿法化学氧化获得的样品L. irrorataconchiolin 生产准确14C日期。