Geochemistry, petrogenesis and tectono-magmatic setting of the basic magmatism in Ardekan and Isfahan, Central Iran

• Data on Paleozoic magmatism in Central Iran are limited, due to their rare occurrence.
• The igneous rocks were generated in a continental rift in an extensional regime.
• This regime related to the tensional movements in Central Iran during the Paleozoic.
• These extensional–compressional movements are comparable with Hercynian orogeny.
• Partial melting is the most important factor in magma evolution.

In this paper, the basic magmatism in northeast of Ardekan and northeast of Isfahan are described. Both areas are located in Central Iran. In Ardekan, the studied section is composed of a late Devonian- carbonate and terrigenous succession. There are some volcanic horizons in this section which represent basic submarine volcanic activities. In northeast of Isfahan (Zefreh–Bagherabad), small intrusive (hypabyssal) bodies intruded into the late Devonian succession. The geochemical characteristics suggest that magma was produced by partial melting of a garnet-lherzolite zone. Of course the role of partial melting of a plagioclase-bearing source shouldn’t be ignored. Based on clinopyroxenes analysis, magma in the storage region crystallized in relatively low pressure conditions. The evidences of crustal contamination are not significant, which can be attributed to the rapid ascent of the parental magma. Based on geochemical and tectonic data, these rocks are of alkaline to tholeiitic affinity and were created in a continental rift in an extensional regime probably related to the tensional movements in Central Iran during the Paleozoic.