| Abstract |
A geology-based classification of geothermal resources can significantly help required exploration and utilization strategies and overall management of the geothermal fields/projects. Although Iran owes its high geothermal potential to its special geological characteristics and active volcanic-tectonic nature, but none of geothermal prospecting studies consider geological environments and features of the proposed geothermal areas. The eighteen previously introduced geothermal areas of Iran are situated in different sedimentary basins and tectonic zones. By comparing the general but remarkable geological signatures of each structural zone and by applying the most important geological parameters, including geological environments, geological features, crustal heat source, resource category and rock type, a geology-based classification of geothermal areas is proposed. In this scheme, the geothermal areas can be categorized based on their geological features into at least five groups; a) Quaternary Volcanoes-associated geothermal prospects, including Sabalan, Sahand, Khoy-Maku, Taftan-Bazman areas/volcanoes all belonging to the UDMA. b) Quaternary Volcanics-Major Faults- associated geothermal prospects, including Damavand, Ferdows, Tabas, Takab-Bijar, Kashmar areas that except Damavand area that is Quaternary volcano in Alborz zone and formed in an transformational regiment and pull-apart basin, are all pertinent to the transformational tectonic regimen and their related young volcanism predominantly in Central Iran/Domain and Eastern Iran zones, c) Faults-associated geothermal prospects, including Khur-Biabanak, Avaj, Amol, Baft areas that except Amole, all the remained areas are located in the faulted and fractured regions in different tectonic zones, d) Thrust-Fold Belt-associate geothermal prospects, including Minab, Kazeroon, Lar-Bastak areas that are situated in the Zagros Fold Belt and tightly engaged with deep thrust faults, and e) Plutons-associated geothermal prospects, including Ramsar and Isfahan-Mahalat areas which have no relationship with young volcanism, but are relevant to local and regional buried intrusions. Thrust-Fold Belt-associate geothermal prospects are the only ones that geologically occurred in inter-plate environment, whereas all the other areas and classes belong to plate margin environment. In other scope, proposed geothermal prospects can be classified on the basis of nature and geological settings, where Quaternary Volcanoes-associated geothermal prospects, in addition to Damavand area from Quaternary Volcanics-Major Faults- associated geothermal prospects group are volcanic type of geothermal systems and are high-temperature resources, while Khur-Biabanak, Avaj, Amol, Minab, Kazeroon, Lar-Bastak, Ramsar and Isfahan-Mahalat, Kashmar areas are convective systems. Other areas, including Tabas, Ferdows, Takab-Bijar and Baft could be derived from a combination of both volcanic and convective geothermal systems. |