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Mineralogical and Geochemical Indicators of Subaerial Weathering in the Pozzolane Rosse Ignimbrite (Alban Hills Volcanic District, Italy)

The Pozzolane Rosse ignimbrite [PR] (457±4 ka) in the Alban Hills Volcanic District, Rome, Italy was exposed ~ 40 ka prior to a subsequent volcanic event which coverd it entirely. XRF, XRD, and clay separation results from PR samples from INGV and CA1 boreholes and Castel di Leva quarry show evidence of paleopedogenesis. All locations display loss of base cations, loss of K is consistent with XRD datat showing dissolution or alteration of leucite to analcime. Accumulation of Al and high L.O.I. support XRD evidence of 1:1 clay species at upper depth. Data suggest alteration extent can be determined by geochemistry. Hydrothermal alteration is assessed from geochemistry showing significant leaching of major and trace elements, primary mineralogy loss and iron sulfide and sulfate mineral development. Deep samples of PR may show groundwater influenced alteration with the presence of expandable 2:1 clays, zeolites, and possible mixing with the underlying Vallerano Lava.

Identiferoai:union.ndltd.org:GEORGIA/oai:digitalarchive.gsu.edu:geosciences_theses-1022
Date27 April 2010
CreatorsDickie, Jennifer M.
PublisherDigital Archive @ GSU
Source SetsGeorgia State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceGeosciences Theses

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