Reconstruction of Holocene Climate Changes in Southwestern Iran using Modern Pollen Rain Analysis

The basis of estimating the future climate is the evidence of today’s climate. The more stable the evidences, the more accurate the perceptions will be. Reconstructing the past climate of hundreds to millions years ago, paleoclimatology can help reconstructing the future climate. In this research, 120 surface samples were used to analyze modern pollen rain and determine the relationship between pollen and climatic variables. Extraction of pollen from surface samples was done using a combination of standard methods of Faegri and Iverson (1975) and Moore et al. (1991). To reconstruct climatic variables, MAT method in PAST software was used as an environmental transfer function. By implementing the results of modern pollen rain analysis on the fossil pollens of Parishan Lake, the climatic variables of the region were reconstructed during the Holocene. The results showed that since about 10,000 years ago, temperature and precipitation have fluctuated a lot in southwest Iran. At this time, the rainfall fluctuated between 316 and 750 mm. There has been three periods of heavy rainfalls in southwest Iran: 8000-9500, 6200-6800, and 2200-4500-years ego. In all the periods, the rainfall average had been more than today’s rainfall average. The minimum rainfall was 550 and the maximum was 750 mm. In all the periods with an increase in precipitation, the temperature has decreased, and there is a strong inverse relationship between them; the greater the decrease of temperature, the greater the increase of precipitation. The decrease of temperature in the Holocene occurred at least up to 19 degrees Celsius and increased up to 26 degrees at the maximum. The temperature increase that matches with the decrease of precipitation occurred in three periods: The early Holocene to 9500 years ago, 6800-8000 years ago, and 4500-6200 years ago.