Abstarct: The Torud–Ahmad Abad magmatic belt is located south-southeast of Shahrood (Esat of Semnan Province) and in the northern part of the Central Iran Structural Zone (CISZ), where a thick sequence of Paleocene to middle Eocene volcanic and volcanosedimentary rocks crop out. This sequence was intruded by numerous dikes, hypabyssal igneous domes and one small gabbro-dioritic intrusion, with compositions ranging from trachybasaltic andesite, trachyandesite, dacite, trachyte, gabbro, diorite and syenite. Various enclaves of different composition, size and shape have been found in these domes and dikes. These enclaves are evidence of magma mixing and crustal contamination. Geochemically, the studied rocks exhibit a calc-alkaline affinity, and they are enriched in LREE and LILE and depleted in HREE and HSFE. Other geochemical characteristics, such as SiO2 varying between 59-63 wt% and 51-59 wt%, Na2O >3wt%, Al2O3 >16 wt%, Yb <1.8 ppm, and Y <18 ppm, makes it possible to classify these rocks as high-silica adakites in the Ahmad Abad region and low-silica adakites in the Sahl-Razzeh region (or at least adakitic-like rocks). Also, depletion of Nb and Ti, and a high enrichment in Rb, Ba, K and Th, implies crustal contamination of the adakitic domes. Petrographical and geochemical data indicate that the magma forming high-silica adakites originated from partial melting of the subducted oceanic slab of Neo-Tethys (Sabzevar–Darouneh branch) in amphibolite to eclogite facies, and the low-silica adakites formed by partial melting of the mextasomatized or modified mantle wedge, above the subduction zone. Gabbroic to syenitic rocks are the products of fractional crystallization of mafic magma which originated from a nearly mantle wedge above the subducted oceanic slab. U-Pb zircon dating of the dacitic and andesitic rocks yielded ages of 41.4±0.3 Ma and 35.5±0.2 Ma, respectively, which is consistent with Middle to Late Eocene. The ratio of 87 Sr/86 Sr (0.703749- 0.705314) and 143 Nd/144 Nd (0.512775-0.512893) suggest that these rocks originated from partial melting of the subducted oceanic slab of Neo-Tethys (Sabzevar–Darouneh branch) and lithospheric mantle source above the subducted oceanic slab of Sabzevar–Darouneh branch. The investigated rocks are mainly composed of pyroxene, amphibole, and plagioclase. Mineral chemical analysis reveals that plagioclase composition varies from albite to labradorite, clinopyroxene varies from diopside to augite, and amphibole varies from Mg-hastingsite to Mg-hornblende. Amphibole geothermobarometry suggests crystallization temperatures of 850–1050ºC, at 2–6 kbar in andesite and 920-970 ºC, at 3- 4.5 kbar in dacite formation. Clinopyroxene crystallized at temperatures of 1020–1170ºC, at 2–10 kbar, indicating crystallization at crustal depths of maximum 30 km for the studied intrusive rocks in the Torud-Ahmad Abad magmatic belt.