Abstract
dc:description.abstractTwo magmatic systems were investigated using different petrological tools: 1) Origin of Ponza trachyte was studied combining data from MI with trends predicted by thermodynamic modeling. MI data were compared with known phase relations in the ternary feldspar and anorthite-diopside-albite systems to constrain the parameters used in the modeling. MI data are consistent with melt evolution from a basaltic parent via a fractional crystallization mainly of pyroxene and feldspars. These data and the results from the modeling, suggest a genetic link between the Ponza trachyte and coeval alkali olivine basalts on the nearby Ventotene Island. 2) We evaluated the range of magmatic temperatures within the crystallization interval for a basanite with different olivine-spinel geothermometers. While olivine spinel pair records the evolution of the basanite during crystallization, low temperatures calculated with the geothermometers are unrealistic. This is likely due to the presence of significant amounts of Ti in our magmatic spinels. Indeed Ti is not taken into account in the geothermometers. We tested the possibility of accounting for the presence and effects of Ti using a linear correction for the Fe+2 content in our spinels. While this generated more realistic temperatures at the low end of the range, it also increased the dispersion in the data, suggesting that spinel behavior is more complex and that the presence of Ti affects content and site occupancy of other elements as well.
Degree
thesis:*- Name thesis:degree_name
- Ph. D.
- Level thesis:degree_level
- doctoral
- Discipline thesis:degree_discipline
- Geological Sciences
- Department dc:contributor.department
- Geological Sciences
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2002
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Fedele, Luca
- Chair dc:contributor.committeechair
-
- Bodnar, Robert J.
- Committee members dc:contributor.committeemember
-
- Belkin, Harvey
- Beard, James S.
- De Vivo, Benedetto
- Tracy, Robert J.
- Webster, James
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-05242002-120716
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/27869