Investigating geochemical characteristics and tectonic environment of Quaternary Sablan adakites

Quaternary volcanic activity, as the last magmatic effort in Iran, is the evolution of large volcanic cones such as Damavand, Sahand, Sablan, Taftan and Bazman, as well as lava flows such as Mako basalts and Lot block. Sablan, a young member of the Cenozoic volcanic complex, belongs to the Alborz magmatic arc (AMA). In Sablan Mountain, there is a collection of volcanic rocks with the composition of andesite, basaltic andesite, dacite, rhyodacite and trachy andesite. The texture of these rocks is mostly porphyritic with microlithic clay, porous porphyritic, sometimes glomeroporphyric, sieve and trachytic. Among the main minerals, plagioclase and one or more mafic minerals such as hornblende and pyroxene can be mentioned. Secondary minerals include opaque minerals, edengsite, chlorite and calcite. In the normalized multi-element diagrams, relative enrichment of K, Ba, Rb and relative depletion of Ti, Ta, and Nb indicate magmatism affected by subduction processes. In terms of the chemical composition of these rocks, the main elements such as K2O, Na2O, MgO, Al2O3, SiO2 Mg# and K2O/Na2O and the composition of rare elements such as Cr, Ni, Yb, Y, Sr, Rb Sr/Y and La/Yb are in the range Adakite stones are placed. In addition, the geochemistry of these rocks, including the concentration of Cr, MgO, Th, Rb, Th/Ce, and K2O/Na2O, is in better agreement with the adakites derived from partial melting of the subducted oceanic sheet. According to the petrographic diagrams, the adakitic magma forming these rocks was formed from the partial melting of an eclogitic source rock or amphibolite garnet resulting from the metamorphism of the subducted Neotethys oceanic plate under Central Iran. Keywords: petrology, PULL PARAT, petrogenesis, Iran.