Collaborative Research: The Ecological Context of Complex Society Emergence

点击翻译按钮获取中文摘要

Paleoclimate research seeks to understand the role of environmental change on human society. Archaeological remains provide a long-term perspective on human-environment interaction not available from other sources. This project will contribute to this interdisciplinary field of science by reconstructing the cultural and environmental factors responsible for a 9000-year vegetation history of a valley in southern Peru. This information will allow scientists to model the effects of future climate change, human impact, and social responses to that change. This research began with a chance finding in 2012 during archaeological excavations in a floodplain in the Chincha valley of southern Peru. While excavating in a farm field near a 2300-year-old archaeological site to better assess prehistoric agricultural practices, researchers found evidence of wet and marshy conditions five kilometers from the ocean during the middle Holocene circa 7000 -1500 years ago. This was quite unexpected because archaeologists and paleo-climate specialists had assumed the area to have been open desert prior to human occupation. Previous scientific consensus was that the desert was irrigated around 3000 years ago by people using canals drawn from the deeply entrenched rivers that course through the valley. Additional work found similar patterns of hydromorphic (waterlogged) soils and evidence of the use of artificial drainage canals. Analyses of ancient seeds, pollen, plant microfossils, and diatoms (fossil algae) confirmed evidence of a lush landscape back to 9000 years ago that included plants such as cattails, sedges, and rushes. This project's systematic scientific research will confirm, modify, or reject the hypothesis of a paleo-wetland. The project incorporates students from two US universities who will work with students in Peru, thereby increasing cross-border training and seeding future collaboration. These early career researchers will learn advanced laboratory techniques to reconstruct past environments, including state-of -the-art techniques in ground-penetrating radar and archaeological methods. Stretching from Chile to California, the Pacific desert watershed is home to very dense human populations today and has provided favored locations to live for millennia. These areas are also some of the richest agricultural lands in the world. A full appreciation of their environmental and cultural histories is vital, not least because fresh water is the limiting factor in population growth and agricultural productivity. To properly understand the intricate history of vegetation, water, irrigation, geology, and human settlement, this project will obtain data from a representative swath of land in the entire Chincha Valley of coastal Peru. The vegetation, geological, and geomorphological history will be meticulously reconstructed. Project participants will measure the ground water levels over millennia. Correlations of cultural and environmental records with El Nino events, tsunamis, tectonic events, and other natural processes will shed light on the relationship between cultural adaptations and environmental change. Buried archeological sites and canals will be detected with ground-penetrating radar. At its conclusion, the project will provide a highly detailed understanding of the human-environment history of a key Pacific watershed drainage.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.