ABSTRACT

The Khur region is located in the Late Mesozoic-Cenozoic volcanic-plutonic rocks of the Lut Block, eastern Iran. There are several outcrops of subvolcanic rocks in the region which occur mainly as dike (granitoid and mafic dikes) and stock (monzonite porphyry). Volcanic rocks (basaltic andesites, andesites, trachyandesites, dacites and rhyodacites) are also abundant and cover pyroclastic rocks. U–Pb zircon ages indicate that granitic-dioritic dikes and monzonite porphyries 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 the I-type granitoids. Monzonite porphyries 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. Primitive magmas of dikes, stocks and acidic volcanic rocks have formed in the lower crust and have undergone different degrees of AFC, while primitive magmas of mafic volcanic rocks have formed in the mantle and have presumably been modified by melts/fluids. Moreover, a syn to post-collision-related zone is responsible for the high magmatic rate during the Middle Eocene in the Lut Block.

摘要

库尔地区位于伊朗东部卢特地块的晚中新生代火山-深成岩中。该地区有若干次火山岩露头，主要以岩脉（花岗岩和镁铁质岩脉）和岩脉（二长斑岩）的形式出现。火山岩（玄武安山岩、安山岩、粗安山岩、英安岩和流纹英安岩）也很丰富，覆盖着火山碎屑岩。U-Pb 锆石年龄表明花岗闪长岩脉和二长斑岩分别位于 44.97 至 40.86 Ma 和 41.11 Ma。花岗岩脉脉是高钾钙碱性和金属铝质岩脉，地球化学上属于I型花岗岩。二长斑岩显示 I 型（很少是 A 型）特征，典型的富集碱、Zr 和 Ce，高 FeO _t /(FeO _t+MgO) 比率和 Sr 和 Nb 的耗尽。岩脉、岩浆和酸性火山岩的原始岩浆在下地壳形成并经历了不同程度的AFC，而基性火山岩的原始岩浆则在地幔中形成并可能被熔体/流体改造。此外，Lut 地块中始新世的高岩浆速率与碰撞后相关区域的同步。