Paleoclimatic and paleoenvironmental changes in Amazonian lowlands over the last three millennia
Paleoclimatic and paleoenvironmental changes in Amazonian lowlands over the last three millennia
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DOI：
10.1016/j.quascirev.2022.107383
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发表时间：
2022-03
影响因子：
4
通讯作者：
Marcela Eduarda Della Libera;V. Novello;F. W. Cruz;R. Orrison;M. Vuille;S. Maezumi;J. D. de Souza
中科院分区：
文献类型：
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作者：
Marcela Eduarda Della Libera;V. Novello;F. W. Cruz;R. Orrison;M. Vuille;S. Maezumi;J. D. de Souza
亚马逊盆地在过去的几千年里的古气候和古环境历史以及整个低地的南美季风系统（SAMS）的行为尚未得到彻底的研究，因为缺乏来自盆地中部的记录。在这里，我们讨论了这些过去的变化的基础上新的高分辨率δ 18 O和δ 13 C记录收集在亚马逊盆地西南部，在SAMS的对流活动的核心区域的洞穴。我们证明，从这些新记录的δ 18 O是SAMS变化的代表，这个对流系统提供了独特的降水模式在盆地。SAMS在公元前1000年至公元300年之间处于中性阶段，降水均匀，而在公元700年至公元1200年之间，盆地西侧的干燥条件占主导地位，在公元1450年之后，当我们的研究地点普遍存在潮湿条件时，在亚马逊盆地建立了东西气候偶极子。洞穴沉积物δ 13 C记录表明，在研究期间，除了与中世纪气候异常（MCA）相关的干燥时期外，总体趋势是更潮湿的热带森林。亚马逊西南部的前哥伦布文化的动态似乎与该地区的古气候和环境变化有关。
The paleoclimatic and paleoenvironmental history of the Amazon basin over the last millennia and the behavior of the South American Monsoon System (SAMS) throughout the lowlands have not yet been thoroughly examined due to a lack of records from more central portions of the basin. Here we discuss these past changes based on new high-resolution δ18O and δ13C records from speleothems collected in the southwestern Amazon Basin, at the core region of the convective activity of the SAMS. We demonstrate that the δ18O from these new records is representative of SAMS variations and that this convective system provides distinct precipitation patterns over the basin. The SAMS was in a neutral phase with homogeneous precipitation between 1000 BCE and 300 CE, whereas drier conditions prevailed over the western side of the basin between 700 and 1200 CE and an east-west climatic dipole was established over the Amazon Basin after 1450 CE when wetter conditions prevailed over our study site. The speleothem δ13C record indicates an overall tendency toward a more humid tropical forest during the studied period, except for a drier period which correlates with the Medieval Climate Anomaly (MCA). The dynamics of pre-Columbian cultures from southwestern Amazonia seem to have been related to paleoclimatic and environmental changes reported for the region.