Scaggion Cinzia, Giovanardi Tommaso, Loponte Daniel, Carbonera Mirian, Armaroli Elena, Bernardini Sara, Benazzi Stefano, Gascue Andrés, Acosta Alejandro, Marciani Giulia, Bortolini Eugenio, Cipriani Anna, Lugli Federico
Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto Nacional de Antropología y Pensamiento Latinoamericano (INAPL), Buenos Aires, Argentina.
PLoS One. 2025 Jul 15;20(7):e0326047. doi: 10.1371/journal.pone.0326047. eCollection 2025.
Bioavailable strontium (Sr) isoscapes are essential tools in studies on environmental processes, animal and human mobility and provenance. The success of these studies relies on the comparison between the measured 87Sr/86Sr isotope ratios of specimens and the spatial distribution of environmental bioavailable Sr isotopic signatures across geographical regions. A critical step of this process is the construction of reference maps that integrate environmental Sr isotopic data with geographical information. Here, we present a new bioavailable Sr dataset of 113 environmental samples, including plants and malacological samples collected from center-east Argentina (Paraná Delta, Pampa and Entre Ríos plains) as well as adjacent Uruguay, covering an area of approximately 122,500 km2. This dataset is further integrated with archaeological bioapatite data from the literature to construct the first random forest-based Sr isoscape of the region. Notably this area is on recent Quaternary (fluvial, marine and aeolian) sediments derived from the erosion of magmatic and metamorphic terrains with different Sr isotope composition from low 87Sr/86Sr ratios (about 0.706) to highly radiogenic signatures (>0.71), and heterogeneously transported in the Delta area by the rivers and in the high plains by wind and rivers. This isoscape offers a unique perspective on the Sr isotope distribution in a lithologically homogeneous region characterized by relatively young sedimentary sequences. This work represents a significant advancement in the development of Sr isoscapes, providing a fundamental tool for environmental and archaeological applications in South America.
生物可利用锶（Sr）等时线是环境过程、动物和人类迁移及来源研究中的重要工具。这些研究的成功依赖于所测标本的87Sr/86Sr同位素比值与地理区域内环境生物可利用Sr同位素特征的空间分布之间的比较。这一过程的关键步骤是构建将环境Sr同位素数据与地理信息相结合的参考地图。在此，我们展示了一个包含113个环境样本的新的生物可利用Sr数据集，这些样本包括从阿根廷中东部（巴拉那三角洲、潘帕斯和恩特雷里奥斯平原）以及相邻的乌拉圭采集的植物和贝类样本，覆盖面积约122,500平方公里。该数据集进一步与文献中的考古生物磷灰石数据相结合，构建了该地区首个基于随机森林的Sr等时线。值得注意的是，该地区位于源自具有不同Sr同位素组成的岩浆岩和变质岩地形侵蚀的全新世（河流、海洋和风成）沉积物上，其Sr同位素比值从低87Sr/86Sr比值（约0.706）到高放射性特征（>0.71）不等，并在三角洲地区由河流以及在高平原地区由风和河流进行非均匀输送。这条等时线为一个以相对年轻的沉积序列为特征的岩性均匀区域内的Sr同位素分布提供了独特视角。这项工作代表了Sr等时线发展的重大进展，为南美洲的环境和考古应用提供了一个基础工具。
