Volume 18, Issue 48 (2-2007)
Abstract
Shekarnab intrusion is a part of an extensive magmatism in the Central Alborz Tectonic Zone of Iran. This intrusive body, which is mostly composed of monzonitic, gabbroic and syenitic lithologies, was intruded within green tuffs of the Karaj formation. These plutonic rocks show geochemical alkaline-potassic affinity and in the case of aluminum saturation index, they could be classified as meta-aluminous rocks. These rocks show Nb negative anomaly, enrichment of LILE and are depleted in HFSE. The spider and discrimination diagrams demonstrate that the parent magma of the plutonic intrusion could be related to a subduction zone and have emplaced in an active continental margin. Based on geochemical analysis of trace and major elements, as well as field and petrographical studies, it could be suggested that crystal differentiation has played an important role in lithological diversity of this intrusive body.
