Advanced Search
DSpace@MIT

Petrology and geochemistry of pyroxenites in the Lanzo ultramafic massif, Northwestern Italy

Research and Teaching Output of the MIT Community

Show simple item record

dc.contributor.advisor Oliver Jagoutz. en_US
dc.contributor.author Pesce, Kathryn A en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. en_US
dc.coverage.spatial e-it--- en_US
dc.date.accessioned 2012-05-15T21:11:58Z
dc.date.available 2012-05-15T21:11:58Z
dc.date.issued 2012 en_US
dc.identifier.uri http://hdl.handle.net/1721.1/70781
dc.description Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2012. en_US
dc.description "February 2012." Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references (p. 43-45). en_US
dc.description.abstract Combined field, microtextural, and geochemical observations are presented for pyroxenites in the Lanzo ultramafic massif in order to place chemical and petrological constraints both locally on the geologic history of the massif and more generally on the role of magmatic rifting and the rift-to-drift transition in ultraslow-spreading ridge environments. Two separate generations of pyroxenites have been distinguished. A young set of primitive Cr-diopside websterites of MORB affinity are related to melt infiltrations and melt-rock reactions during rifting and Jurassic exhumation, while a much older generation of websterites likely of subcontinental origin were inherited and pre-date continental rifting and exhumation of the massif. The regional compositional and textural variation observed in the latter group of pyroxenites is not due to primary heterogeneities but rather to differences in subsequent metamorphic histories. Pyroxenites from the northern domain experienced a colder exhumation history and physical isolation from the rest of the massif by means of a high temperature shear zone related to the rifting. These websterites preserve garnet pseudomorphs and elevated REE which are textural and geochemical evidence for the prior coexistence of clinopyroxene and garnet. The implications of this study are that the Lanzo massif was indeed subcontinental lithosphere prior its exhumation and existence as an Ocean Continent Transition Zone (OCTZ) and that high temperature shear zones do seem to serve as effective permeability barriers and melt-focusing zones in rifting systems. en_US
dc.description.statementofresponsibility by Kathryn A. Pesce. en_US
dc.format.extent 45, [24] p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri http://dspace.mit.edu/handle/1721.1/7582 en_US
dc.subject Earth, Atmospheric, and Planetary Sciences. en_US
dc.title Petrology and geochemistry of pyroxenites in the Lanzo ultramafic massif, Northwestern Italy en_US
dc.type Thesis en_US
dc.description.degree S.M. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. en_US
dc.identifier.oclc 792739627 en_US


Files in this item

Name Size Format Description
792739627.pdf 9.095Mb PDF Preview, non-printable (open to all)
792739627-MIT.pdf 9.095Mb PDF Full printable version (MIT only)

This item appears in the following Collection(s)

Show simple item record

MIT-Mirage