Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by GIORGETTI, G. Articles by LUCCHETTI, G. Search for Related Content GeoRef GeoRef Citation

Clay mineral mixtures as alteration products in pillow basalts from the eastern flank of Juan de Fuca Ridge: a TEM-AEM study

¹ Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, 53100 Siena, Italy, and ² Dipartimento per lo Studio del Territorio e delle sue Risorse, C.so Europa, 26, 16132, Genova, Italy

^* E-mail: giorgettig{at}unisi.it

(Received 8 March 2000; revised 16 August 2000)

Transmission electron microscope-analytical electron microscope analyses have been carried out on secondary minerals from pillow basalts with various degrees of alteration from the Juan de Fuca Ridge (ODP Leg 168). The electron microscopic data indicate that the alteration products consist mainly of phyllosilicate mixtures. The least altered sample shows poorly crystalline phyllosilicates occurrring as flakes with 10 Å-spaced lattice fringes. They have compositions of celadonite mixed with smectite and/or Fe oxyhydroxides and Mg-rich smectite. Proceeding towards older, more altered basalts, the alteration products consist of: (1) poorly crystalline celadonite mixtures and Mg-rich smectite; and (2) phyllosilicates with a higher degree of crystallinity, showing lattice fringes with 9.1 Å-spacing and with a talc-like composition. Changes in phyllosilicate association occur as the type of alteration changes from an oxidizing, water-dominated system (occurrence of celadonite mixtures with Fe hydroxides) to a reducing, rock-dominated system (occurrence of Fe-smectite and talc-like mixtures).

KEYWORDS: clay minerals, basalt alteration, TEM-AEM, Juan de Fuca Ridge

This article has been cited by other articles:

				G. Giorgetti, T. Monecke, R. Kleeberg, and M. D. Hannington LOW-TEMPERATURE HYDROTHERMAL ALTERATION OF SILICIC GLASS AT THE PACMANUS HYDROTHERMAL VENT FIELD, MANUS BASIN: AN XRD, SEM AND AEM-TEM STUDY Clays and Clay Minerals, April 1, 2006; 54(2): 240 - 251. [Abstract] [Full Text] [PDF]

				M. D. BUATIER, A. M. KARPOFF, and D. CHARPENTIER Clays and zeolite authigenesis in sediments from the flank of the Juan de Fuca Ridge Clay Minerals, March 1, 2002; 37(1): 143 - 155. [Abstract] [Full Text] [PDF]