Artículos de revistas
Coexistence of halloysite and iron-bearing clays in an altered ignimbrite, Patagonia, Argentina
Fecha
2014-06Registro en:
Cravero, Maria Fernanda; Marfil, Silvina Andrea; Ramos, Cinthia Paula; Maiza, Pedro Jose; Coexistence of halloysite and iron-bearing clays in an altered ignimbrite, Patagonia, Argentina; Mineralogical Soc; Clay Minerals (print); 49; 3; 6-2014; 429-441
0009-8558
CONICET Digital
CONICET
Autor
Cravero, Maria Fernanda
Marfil, Silvina Andrea
Ramos, Cinthia Paula
Maiza, Pedro Jose
Resumen
The Mamil Choique halloysite deposits of Patagonia, Argentina, contain randomly distributed green clay inclusions and patches within the halloysite mass. Halloysite has been formed from the thorough alteration of rhyolitic to dacitic ash fall tuffs and ignimbrites of the Huitrera Formation, Eocene age, under ambient conditions. The smectites present in the clay inclusions have been determined as ferruginous beidellites with variables amounts of Fe3+ in octahedral sites. The weathering activity that caused the formation of halloysite was also responsible for the genesis of the iron-bearing clay minerals, the formation of which was controlled mainly by permeability. Textural variations within the rock indicate favourable local geochemical environments for the formation of the green clay minerals.