Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

David Buriánek, Zdeněk Dolníček

Metamorphic evolution of the contact aureole of the Dipilto Batholith, Eastern Chortis Terrane, Nicaragua

Journal of Geosciences, volume 56 (2011), issue 1, 9 - 26

DOI: http://doi.org/10.3190/jgeosci.084

We examined the tectono-metamorphic evolution of the contact aureole around the Cretaceous Dipilto Batholith in the Eastern Chortis Terrane (Nicaragua, Central America). Three distinct metamorphic phases were distinguished. The first phase represented greenschist-facies regional metamorphism (M₁) accompanied by a prograde deformation (D₁). The Cretaceous contact-metamorphic event (M₂) produced the peak-metamorphic mineral assemblages Wo + Di + Grs + Ves + Qtz + Pl + Kfs in the calc-silicate rocks and Bt + Qtz + Ab + And ± Crd ± Gr ± Chl ± Ms ± Kfs in the metapelites. The estimated P—T conditions near the contact with granitoids are 500—650 °C and ~ 0.2 GPa and coexisting fluids were relatively poor in CO₂ (X_CO2 below 0.15). The emplacement of the Dipilto Batholith at shallow crustal levels was rarely accompanied by weak deformation of the metasediments (D₂). During cooling and exhumation, the contact aureole was locally affected by deformation (D₃₎ and retrograde metamorphism (M₃) again under greenschist-facies conditions.