%0 Journal Article
%T Parag¨¦nesis de zeolitas alcalinas en un afloramiento de basaltos oliv¨ªnicos amigdaloides de Jun¨ªn de Los Andes, Neuqu¨¦n, Patagonia, Argentina
%A Vattuone
%A Mar¨ªa E.
%A Leal
%A Pablo R.
%A Crosta
%A Sabrina
%A Berbeglia
%A Yanina
%A Gallegos
%A Ernesto
%A Mart¨ªnez-Dopico
%A Carmen
%J Revista mexicana de ciencias geol¨®gicas
%D 2008
%I Universidad Nacional Aut¨®noma de M¨¦xico
%X the optical characteristics, x-ray diffraction, unit cell, chemistry and crystallization conditions of an alkaline zeolite assemblage -were studied. the zeolites have been found infilling amygdales and in the matrix of tertiary olivine basalts from junin de los andes, patagonia. the secondary minerals (albite, pumpellyite, interestratified chlorite/smectite (c/s), smectite, iddingsite, magnetite and hematite) are replacing phenocrysts ofplagioclase, olivine and the matrix of the rocks. zeolites are sodic, calcosodic and potassic in composition. na-chabazite, analcime, ca-k phillipsite and paulingite are the first zeolites that crystallized. they were followed by acicular-fibrous zeolites as natrolite/nagonnardite, thomsonite, mesolite and scolecite. the formation of the first zeolites is consistent with low temperature (<100 ¡ãc), low pressure (<0.1 gpa) and alkaline (ph 9-10) hydrothermal/geothermal meteoric fluids, which were favored by tensional fractures. the activity of si decreased during the alteration process and the temperature increased toward 200 ¡ãc allowing the analcime formation followed by the equilibrium assemblage natrolite/nagonnardite-thomsonite-scolecite and mesolite.
%K alkaline zeolites
%K basalts
%K jun¨ªn de los andes
%K patagonia.
%U http://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S1026-87742008000300008&lng=en&nrm=iso&tlng=en