The Role of rock weathering processes on climate Pltyr models in Iran

Weathering happens with the breaking and transformation of ground surface stones, due to physical, chemical or biological processes. Wind, water, climate, plant and animal factors can cause weathering. The present study is performed based on Louis Peltier models in which two variables of average temperature and precipitation were used. Applying these two variables, Peltier distinguished 7 models which can describe different forms of weathering. Among these, two models of weathering regimes and morphogenetic regimes were investigated in Iran and related regimes of each station were determined based on the related graphs. To study and investigate weathering and geomorphologic areas across the country, climatic data including average annual precipitation and temperature were collected from 143 stations in Meteorological Organization portal with appropriate data and statistical period. The collected data were registered in a GIS database. After investigating the temperature and precipitation trend of the country, the regime of each station was determined using Peltier models and a weight was assigned to it. Then, they were registered into the mentioned database and related maps were produced in Arcmap. Results indicate that 5 of 9 morphogenetic situations of Peltier models occur in Iran climatic situation, so the central plateau, east and west of the country are mostly located in arid zone. Mountainous areas, Zagros and Alborz elevations have semi-arid regime, and stations located in southern coasts of the Caspian Sea and western hillsides of Zagros have a mild regime. Regarding weathering, areas in the central plateau and southern part of the country have a very low level of weathering, mountainous areas like Zagros and Alborz elevations and North West of the country have a weak level of mechanical weathering. Some stations in Northern Alborz and western hillsides of Zagros have average chemical weathering with frost and in some stations on the southern coasts of the Caspian Sea, severe chemical weathering occur.