Fruit carbonate in archaeological sites: a new proxy for reconstructing agricultural systems of early societies

考古植物组合中的碳酸果具有迄今为止被低估的考古研究潜力。与常见的烧焦的考古植物大残骸相比，富含caco3的水果含有相对较高的氧和锶。这些结果适用于估算古气候参数（delta 18O, delta 47）和物源分析（87Sr/86Sr），为更好地了解早期农业动态提供了基础。该项目的中心目标是为使用水果碳酸盐岩作为早期农业生态系统的古环境代用品奠定基础。项目设计包括两个研究阶段。将对收集的现代材料取样并在实验室实验中生长进行试点研究。本研究将完成以下任务：(1)评估果实碳酸盐14c测年的潜在储层效应；(2)揭示果实碳酸盐δ 18O值与当地气候参数（降水和温度）的相关性；(3)建立果实碳酸盐δ 47值（“团块同位素测温”）对当地温度的依赖关系；(4)评估果实碳酸盐87Sr/ 86sr比值与生长地点土壤的关系。在主要研究中，建立的地球化学关系将应用于考古植物材料。水果碳酸盐岩必须作为古环境的代用物来解决近东考古中的两个关键问题：(1)以前的水分有效性（气候还是灌溉？）和(2)以前植物生长地点的定位导致耕种区域的重建。分析这一多功能代理的预期结果将为考古学和地球科学提供广泛的应用。

Fruit carbonate in archaeobotanical assemblages bears a hitherto underestimated potential for archaeological research. In contrast to common charred archaeobotanical macroremains, the CaCO3-enriched fruits contain relatively high amounts of oxygen and strontium. These are suitable for estimating paleoclimate parameters (delta 18O, Delta 47) as well as provenance analysis (87Sr/86Sr), providing a basis for better understanding the early agricultural dynamics. The central goal of this project is to create foundations for the use of fruit carbonate as a palaeoenvironmental proxy of early agroecosystems. The project design involves two research phases. A pilot study will be performed on modern material sampled in collections and grown in laboratory experiments. This study will fulfill the following tasks: (1) to assess potential reservoir effects in 14C-dating of fruit carbonate, (2) to reveal the correlation between delta 18O values of fruit carbonate and local climate parameters (precipitation and temperature), (3) to establish the dependence of Delta 47-values of fruit carbonate ('clumped isotope thermometry') on local temperatures, (4) to evaluate the relationship between 87Sr/86Sr-ratios of fruit carbonate and those of soils at growing locations.In the main study, the established geochemical relationships will be applied to archaeobotanical material. The fruit carbonate has to serve as a palaeoenvironmental proxy to approach two key questions in Near Eastern archaeology: (1) the former moisture availability (climate or irrigation?) and (2) localization of the former sites of plant growth leading to reconstruction of the cultivation areas. The expected results from analyzing this multifunctional proxy will provide a broad spectrum of applications for archaeology and the geosciences.