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

• Published in: Journal of geosciences (Prague) 2011-01, Vol.56 (1), p.9-26
• Main Authors: Buriánek, D., Dolníček, Z.
• Format: Article
• Language: English
• Subjects: Coastal plains; Geology; Metamorphic rocks
• ISSN: 1802-6222; 1803-1943
• DOI: 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 (M^sub 1^) accompanied by a prograde deformation (D^sub 1^). The Cretaceous contact-metamorphic event (M^sub 2^) 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^sub CO2^ below 0.15). The emplacement of the Dipilto Batholith at shallow crustal levels was rarely accompanied by weak deformation of the metasediments (D^sub 2^). During cooling and exhumation, the contact aureole was locally affected by deformation (D^sub 3^) and retrograde metamorphism (M^sub 3^) again under greenschist-facies conditions. [PUBLICATION ABSTRACT]