Collaborative Research: High-resolution, Multi-proxy Reconstruction of Holocene Climate Variability in West Asia

University Of Miami, Coral Gables FL

Investigators

Abstract

Since the beginning of the Neolithic Era, ca. 9500 B.P., some of the first and most outstanding human civilizations rose across the Fertile Crescent, extending between northern Persian Gulf in Iran and the eastern Mediterranean Sea. Evidence is mounting from paleoclimate proxy records around the globe that human societies have been impacted by abrupt climate shifts throughout the Holocene. Very few studies, however, have been conducted in West Asia that document climate variability at interannual to centennial time scales, which are most relevant to the flourishing and diminishing of human societies. This project establishes the first chronologically-robust records of interannual atmospheric dust deposition originating in the African-Asian 'dust belt,' and centennial reconstruction of paleo-moisture based on organic biomarkers, from two rain-fed peat mires in NW Iran. A significant transformative aspect of this project is the combination of organic and inorganic geochemical proxies, which allows documentation of a detailed history of atmospheric exchange between West Asia, the North Atlantic and the African-Asian monsoon system, and their influence on the dominant climate regime in West Asia. Unraveling the role of mid-latitude westerlies, the Siberian Anticyclone and the Indian Ocean summer monsoon (IOSM) in shaping the Holocene climate in this region has major implications for modern societies, as well as ancient civilizations. If, for instance, the insolation-induced intensification of the IOSM coincided with expansion of dry climate over West Asia during the early Holocene, similar conditions can be expected from changes in IOSM intensity from anthropogenically enhanced global warming, with potentially dire socio-economical consequences across the Middle East. High-resolution records from this study also present a rare opportunity to examine possible links between solar activity and changes in mid-latitude atmospheric circulation pattern on interannual to millennial time scales. Broader Impacts: The project is part of a 5-year endeavor by an early-career PI to establish a Holocene Climate Laboratory. Paleoclimate research in this lab will foster international collaborations among researchers from RSMAS Climate Studies, Virginia Institute of Marine Science, Texas A&M University, Institut méditerranéen d'écologie et de paléoécologie (France), the Iranian National Center for Oceanography and the University of Tehran, Iran. The lab encourages enthusiastic undergraduate students to participate in paleoclimate-related research using clean-lab geochemical methods. This project provides opportunities for at least three undergraduate students to receive practical training in this facility. Undergraduate students are involved in sample preparation and analytical measurements performed using a new state-of-the-art Neptune High-resolution Multi-collector Inductively Coupled Plasma Mass Spectrometer. In addition, a new course on the historical and modern impact of Holocene climate change on human societies will be taught. The material and data collected during the course of this NSF-funded project is used in this and other paleoclimate courses. Traditionally, organic and inorganic geochemical proxies have been utilized independently in paleoclimate studies. This is because few investigators have had the opportunity to receive training in these two areas of paleoclimate research. This collaboration between an inorganic paleoclimatologist and an organic geochemist will equip a new generation of students with expertise in the combined use of inorganic and organic paleo proxies to explore new frontiers in the broad field of paleoclimate research.