MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
Suplementary Material to Gürer et al. 2015b. Structure and evolution of volcanic plumbing systems in fold-and-thrust belts: a case study at the Cerro Negro de Tricao Malal, Neuquén Province, Argentina
GURER,DERYA; GALLAND, OLIVIER; FERNANDO CORFU; LEANZA HÉCTOR A.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
GEOLOGICAL SOC AMER, INC
Lugar: Boulder; Año: 2015 p. 1 - 1
The subvolcanic rocks of the Cerro Negro intrusive complex were characterizedas (hornblende) andesites based on qualitative petrographic observations of mineralsand textures and especially based on their major element geochemistry (Figures 1 and2, Table 1 (Supplementary material)).Hand-specimen of all samples are fine-grained, mesocratic and consist ofplagioclase and one or more mafic minerals, mostly of amphibole of variable size andcolor. The variance in color (grey-green to orange-red) is due to variations incomposition, degree of alteration and variation in grain size. Some samples have darkinclusions consisting of hornblende. In thin section, all samples contain phenocrystsof plagioclase (plag), hornblende (hbl), orthopyroxene (opx), clinopyroxene (cpx), Fe-Ti oxides as well as minor amounts of secondary biotite (bt) and chlorite (chl)growing at the expense of plagioclase and pyroxene. Accessory phases include zircon(zr), and apatite (ap) (Figure 1). In general, being intermediate in composition(chemically more evolved than basalts), andesites have lower solidus and liquidustemperatures than basalts. The presence of primary hornblende and possibly biotite