Development of igneous layering during growth of pluton: The Tarcouate Laccolith (Morocco)

摘要

We discuss the significance of igneous layering with respect to pluton growth processes. The case study is the Tarcouate Laccolith (Morocco), whose core consists of modally layered hornblende granodiorites with high amount of monzodioritic enclaves, contrasting with peripheral, non-layered biotite granodiorites with low amount of enclaves. Rhythmic layering, with modal grading, cross-stratification and trough layering is associated with monzodioritic layers and wraps around mafic enclaves. Its steep dips >= 45 degrees result from tilting that occurred above solidus conditions, as indicated by sub-vertical and synmagmatic granite, aplite and monzodiorite dykes cutting across the layering.