Ghal-é blockstream on Northern slope of Keyamaky Mount. in the northwest of Iran: implications for Holocene climatic changes



In recent years there has been studies concerning the investigation of macro-scale geomorphic proxies of Quaternary climatic changes in the study area. Without detail analysis of slope geomorphic features, there can be little progress on expanding the knowledge of past slope development in the northwestern Iran high mountain environments. Consequently, the information pertaining to these Quaternary environments has remained rather rudimentary. Block streams are among landforms that relate to past climatic changes on Northern slope of Keyamaky Mount. The paper describes the Ghal-é blockstream as the most important and complete blockstream in study area with dimensions in 630m. longitude and meanly 80m. width. In this study, Holocene climatic changes evaluation is based on data gained from field studies and interpretation of Ghal-é blockstream characteristics. Botanical development and rehabilitation of small trees around blockstream, blockstream structure and existence of three distinct layers are reliable proxies for Holocene climatic changes. The results showed that the characteristics described for Ghalee blockstream closely resemble those of other areas in the world. This blockstream is among low altitude and steep slope blockstreams that settled on superficial slope deposits containing blocks. In spite of insignificant climatic changes in Holocene, the existence of factors such as fit conditions for bedrock weathering, activity of rock avalanches and frost-coated clast flows as transportation mechanisms, and activity of frost and melt process have been result severe blockstream activity in study area. However, four periods including present warm period, little ice age synchronous period, upper Holocene warm period, and iron epoch synchronous cold period are recognizable based on blockstream characteristics.