Petrography, Major and Trace Element Geochemistry of the Discovery Seamounts

Hoffmann, Paulina Ewa (2012) Petrography, Major and Trace Element Geochemistry of the Discovery Seamounts (Master thesis), Christian-Albrechts-Universität, Kiel, 66 pp

[img] Text
HoffmannMasters1012.pdf - Published Version
Restricted to Registered users only

Download (7Mb)


The Discovery Seamounts form a major bathymetric high in the South Atlantic southwestern of South Africa. Until now the seamounts were poorly explored: in two expeditions only five dredges could recover volcanic material from the seafloor. During the cruise MSM 19/3 with R/V Maria S. Merian in December 2011 ten more dredges recovered volcanic material from the seamounts. These samples were petrographically examined and analyzed for major and trace element contents (XRF and ICP-MS). Due to advanced stages of alteration, some of the newly obtained samples are both richer in secondary volatile and P2O5 contents than the previously described samples. The most evolved lavas occur in the northeast (trachybasalts, basaltic trachyandesites, trachyandesites and trachytes), whereas the southwestern part of the Discovery Seamounts is dominated by more primitive lavas with basanitic/tephritic and basaltic compositions. The samples are all alkaline in character, were erupted in an intraplate setting and show a highly enriched OIB-like trace element pattern. Some trace elements even show higher values than other South Atlantic ocean island basalts. The Discovery Seamounts lie within the belt of the Dupal anomaly, whose origin is still a controversy. Different hypotheses on the origin of these anomalous enriched lavas have been published, including the presence of the Discovery Plume causing the enrichment of the magma source region. The enrichment in specific trace elements indicates that the EM1-mantle endmember as a possible source of the magma source region.
The new data contribute to an improved understanding of the petrogenesis and geochemistry of the Discovery Seamounts.

Document Type: Thesis (Master thesis)
Thesis Advisors: Hoernle, Kaj and Hauff, Folkmar
Additional Information: Print-Ausg. in GEOMAR Bibliothek Ostufer vorhanden.
Keywords: Hotspots; South Atlantic; Discovery Seamounts; volcanic material; petrography; MSM 19/3; ANT-XXIII/5
Subjects: Course of study: MSc Geoscience
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Date Deposited: 10 Jan 2013 09:05
Last Modified: 27 Feb 2017 07:18

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...