Tropical Andean climate variations since the last deglaciation

• 成果类型: Article
• 署名作者: Zhao, Boyang; Russell, James M.; Blaus, Ansis; Nascimento, Majoi de Novaes; Freeman, Aaron; Bush, Mark B.
• 署名单位: Brown University; Florida Institute of Technology; University of Amsterdam
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13915
• DOI: 10.1073/pnas.2320143121
• 发表日期: 2024-08-20
• 关键词: hydrogen-isotopic composition; dialkyl glycerol tetraethers; late pleistocene glaciation; be-10 production-rate; stable-isotopes; temperature; precipitation; holocene; variability; record

摘要

Global warming during the Last Glacial Termination was interrupted by millennial- scale cool intervals such as the Younger Dryas and the Antarctic Cold Reversal (ACR). Although these events are well characterized at high latitudes, their impacts at low latitudes are less well known. We present high- resolution temperature and hydroclimate records from the tropical Andes spanning the past similar to 16,800 y using organic geochemical proxies applied to a sediment core from Laguna Llaviucu, Ecuador. Our hydroclimate record aligns with records from the western Amazon and eastern and central Andes and indicates a dominant long- term influence of changing austral summer insolation on the intensity of the South American Summer Monsoon. Our temperature record indicates a similar to 4 degrees C warming during the glacial termination, stable temperatures in the early to mid- Holocene, and slight, gradual warming since similar to 6,000 y ago. Importantly, we observe a similar to 1.5 degrees C cold reversal coincident with the ACR. These data document a temperature change pattern during the deglaciation in the tropical Andes that resembles temperatures at high southern latitudes, which are thought to be controlled by radiative forcing from atmospheric greenhouse gases and changes in ocean heat transport by the Atlantic meridional overturning circulation.