Precipitation of Secondary Phases from the Dissolution of Basaltic Glasses. (4118)
Authors:
D.C. Golden - NASA / Hernandez Eng. Inc.
D.W. Ming* - NASA-Johnson Space Center
Abstract:
Basaltic and anorthositic glasses were subjected to aqueous weathering conditions in the laboratory where the variables were pH, temperature, glass composition, solution composition, and time. Leached layers formed at the surfaces of glasses were followed by the precipitation of X-ray amorphous iron and titanium oxides in acidic and neutral solutions at 25°C over time. Basaltic glass under oxidative
hydrothermal treatments at 150°C yielded a three-layered surface; which included an outer smectite layer, a Fe-Ti oxide layer and an innermost thin leached layer.
The introduction of Mg into hydrothermal solutions facilitated the formation of phyllosilicates. Aqueous hydrothermal treatment of anorthositic glasses (high Ca, low Ti) at 200°C readily formed smectite, whereas, the basaltic glasses (high Ti) were more resistant to alteration and smectite was not observed. Alkaline
hydrothermal treatment of all glasses at 200°C produced zeolites and smectites.
These mineralogical changes, although observed under controlled conditions, have direct applications in interpreting planetary (e.g., meteorite parent bodies) and terrestrial aqueous alteration processes.
Speaker Information: Douglas Ming, NASA-Johnson Space Center, Douglas. W.
Ming ARES Bldg. 31, Room 120 NASA Johnson Space Center, Houston, TX 77058;
Phone: 281 480 4805; E-mail: [email protected]
Session Information: Tuesday, November 2, 2004, 2:00 PM-4:00 PM Presentation Start: 2:00 PM (Poster Board Number: 1748)
Keywords: Glass dissolution; Aqeous alteration; Soil formation; Mineral precipitation
