Response of alluvial fan systems to Quaternary climate changes (Case study: Persian alluvial fan system in northern slope of Keyamaki mount in northwest of Iran)

Parsian alluvial fan system is a part of Asyab-Kharabeh fluvial system that Response it to Quaternary climate changes is the main goal of this study. For this aim, climatic proxies and traces in alluvial fan structure were investigated based on four categories: aggradation and degradation phases, debris flows, size changes in deposited materials and formation of alluvial fan tufas. Primary information of these investigations were obtained via field studies and reconstruction of palaeo environments based on relative chronology. On the basis of this study, Parsian alluvial fan system in addition to enjoyment of special properties such as having a catchment by the same lithology, excess of alluvial fan area relative to catchment area, establishment of carbon cycle and tectonic tranquility in Quaternary is influenced on it’s evolution in Quternary from climatic changes and their proxies in various forms are seen on the different parts of the alluvial fan. Formation of alluvial fan tufas, intensify of debris flows and sediment variations in alluvial fan structure are the most important effects of climatic changes at Quaternary in study area. In this paper, climatic change proxies such as tufa formation phases and their alternation by conglomerate deposits relatively compared to calendar of these changes in Quqternary. Consequently, life of the Parsian alluvial fan system is guaranteed by existing closely interaction between climate, alluvial fan and tufa deposits in study area. Therefore, every development planning must consider the dimentions of this interaction and otherwise, may result ecosystem destruction.