The geology of the Aracruz pluton (Espírito Santo, Brazil), a Cambrian post-orogenic intrusion in the aftermath of Gondwana amalgamation

Abstract

We present the first geological map of the Aracruz pluton (Espírito Santo, Brazil), which belongs to the late Cambrian post-orogenic suite that intruded the Nova Venécia metapelites and Ediacaran syn-orogenic S-type granites of the Araçuaí belt. Our mapping coupled with airbone magnetic and radiometric observations reveals that the pluton is not regularly zoned. It is composed of porphyric alkali feldspar granites, into which charnockite and quartz-diorite bands intruded as several pulses while the granites were a deforming crystal mush, and an undeformed central norite emplaced when most movement of the host magma had ceased. Steep-dipping concentric magmatic foliation, magmatic foliation parallel to tectonic foliation in the country rock, the noritic core, and the irregular charnockite and quartz-diorite band alignment suggest buoyancy-driven diapirism as emplacement mechanism. The Aracruz pluton is a superb example of mantle-derived post-orogenic intrusion attesting for the production of continental crust during the final stages of a Wylson cycle.

Keywords

• Geological map
• aracruz pluton
• araçuaí belt
• Post-collisional magmatism