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Late Mesozoic-Cenozoic magmatic rocks constitute the main lithological units of the Lut Block and occur in an area of 60000 km 2. Our field observation from the eastern Lut (Khur region) indicate intrusive rocks occur as dike (granitoid and mafic dikes) and shallow plutons (monzonites) in the Lut Block. Volcanic rocks (basaltic andesites, andesites, trachyandesites, dacites, rhyodacites) are also abundant and are intruded into pyroclastic rocks. U-Pb zircon ages indicate that granitic-dioritic dikes and monzonite were emplaced at 44.97 to 40.86 Ma and 41.11 Ma, respectively. Granitoid dikes are high-K calc-alkaline and metaluminous and geochemically belong to I-type granitoids. Monzonites show I-type (and rarely A-type) signatures, with typical enrichments in alkalis, Zr and Ce, high FeO t /(FeO t +MgO) ratio and depletion in Sr and Nb. Geochemical data, including major and trace elements and Sr-Nd isotopes indicate that the volcanic and intrusive rocks are products of a mantle source, presumably modified by sediment melts/fluids. The genesis of these rocks is suggested to be associated with extension above the subducting Sistan Ocean slab beneath the Lut Block. Subduction-related extension was also responsible for the high magmatic rate during Late Cretaceous-Oligocene and was associated large-scale Cu-Au mineralization in the Lut Block.

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