Research

Sedimentary provenance studies:

Tracing ice rafted detritus in the ocean :                                                                     

Antarctica

(Trevor Williams, Elizabeth Pierce, Tina van de Flierdt, Sidney Hemming, Steven Goldstein)

IRD from East Antarctica

North Atlantic                                                           

(Sidney Hemming, Elizabeth Pierce )                                                       

Tracing till dispersal :

           IRD from East Antarctica    (photo E. Pierce)

Canadian shield

(Sidney Hemming, Martin Roy)

Tracing ocean currents :

The isotopic signature of terrigenous material on the sea floor carries information on its source and can therefore be used to trace changes in the flow path of past ocean currents.

Agulhas Current

(Allison Franzese, Sidney Hemming, Steven Goldstein) ( Franzese et al., 2006 )

Antarctic Circumpolar Current

(Sidney Hemming, Steven Goldstein) ( Hemming et al., 2007 ).

Antarctic Bottom Water formation

(Tina van de Flierdt, Sidney Hemming)

The authigenic Nd and Hf isotope systematics around Antarctica provide constraints on bottom water formation ( van de Flierdt et al., 2006 ).

Antarctica's geologic history:

Radiogenic isotopes in proximal terrigenous sediments around Antarctic reflect its bedrock geology ( Roy et al., 2007 ), and provide insights into the isotope systematics of Hf in the oceans ( van de Flierdt et al., 200 7).

The Roy et al. survey shows that large portions of East Antarctica saw high grade metamorphism/plutonism during pan-African orogenesis; however, sediments off of Wilkes Land (Pierce et al., 2008) and the Eastern Weddell Sea ( Steponaitis et al., 2008 ) contain hornblende grains with much older ages, potentially providing important constraints on Antarctica’s role in continental cycles

View of Antarctic Penninsula from the LM Gould (photo E. Pierce)

Sectors survey

(Sidney Hemming, Steven Goldstein, Stefanie Brachfeld, Tina van de Flierdt)

Prydz Bay/Gamburtsev Mountains

(Sidney Hemming, Steven Goldstein, Tina van de Flierdt, Elizabeth Pierce, Stephen Cox, Trevor Williams,  Arizona group)

Terrigenous sediments provide constraints on the origin of the Gamburtsev Subglacial Mountains ( van de Flierdt et al., 2006; Cox et al., 2008 ).

The regional variability of geological history allows using terrigenous sediment provenance to understand past ice sheet dynamics (Williams et al., 2007; Pierce et al., 2008 )

Wilkes Land and Weddell Sea/Droning Maud Land

(Elizabeth Pierce, Sidney Hemming, Steven Goldstein, Trevor Williams, Tina van de Flierdt, Elena Steponaitis)
Sediments off of Wilkes Land ( Pierce et al., 2008 ) and the Eastern Weddell Sea ( Steponaitis et al., 2008 ) contain hornblende grains that are much older than the pan-African orogenesis in portions of East Antarctica ( Roy et al., 2007 ), potentially providing important constraints on Antarctica’s role in continental cycles.

 

Nd isotopes as water-mass tracer:

The distinct Nd isotopic signature of different water masses in the ocean provides a great tool to reconstruct past changes in water-mass mixing and hence changes in ocean circulation.

NADW history in the SE Atlantic

(Alex Piotrowski, Steven Goldstein, Sidney Hemming, Alison Hartman) ( Piotrowski et al., 2004, 2005, 2008 )                                                                                           

 Fish teeth from the South Atlantic (photo A. Hartman)

Intermediate water changes in the Atlantic

(Katharina Pahnke, Steven Goldstein, Sidney Hemming) ( Pahnke et al., 2008 )

South Atlantic εNd survey - Holocene vs. LGM

(Katharina Pahnke, Steven Goldstein, Sidney Hemming)

The use of Nd isotopes as water mass tracer relies on a limited amount of seawater Nd isotope data and paleo-studies. A comprehensive mapping of sediment surface εNd and comparison with seawater εNd, supports the notion that eNd in Fe-Mn oxides in marine sediments reflects the εNd of overlying deep water. This study also aims at comparing the Holocene to the last glacial maximum (LGM) εNd distribution in the South Atlantic that will give further insight into the distribution of water masses during the LGM.

Nd isotopes in seawater and sediments around South Africa, Agulhas Current

(Kevin Jones, Steven Goldstein, Sidney Hemming)

Nd isotope distribution in the ocean using an ocean general circulation model

(Kevin Jones, Steven Goldstein, Sidney Hemming) ( Jones et al., 2008 ).

 

Chemical Oceanography:

The study of eNd and REE in the ocean is crucial for the understanding of their sources, sinks and internal cycling.  

Nd isotopes and REE concentrations in the ocean (part of GEOTRACES)

(Katharina Pahnke, Tina van de Flierdt, Kevin Jones, Steven Goldstein, Sidney Hemming)

Seawater Nd isotope profiles in the Agulhas Current region, south of Africa

(Kevin Jones, Steven Goldstein, Sidney Hemming)

 

Mantle Geochemistry:

The Tristan-Gough plume sources and contraints on the composition of recyled sediment

(C. Class, A. P. Le Roex (UCT, South Africa), D. Long (UCT, South Africa), S. L. Goldstein, Y. Cai, T. van de Flierdt)  

 Class and le Roex 2008

Shona and Discovery Seamount Chains, South Atlantic

(C. Class, A. P. Le Roex (UCT), J. O'Connor (Vrij U, Amsterdam), W. Jokat (AWI Bremerhaven, Germany)

Grande Comore lavas: a new extreme among a spectrum of EM-type mantle endmembers

( Class et al. 2005; Class et al. 2009 )

Evolution of Helium Isotopes in the Earth's Mantle

(C. Class, S. L. Goldstein, A. W. Hofmann) ( Class and Goldstein 2005 )

Images of the Azores (photos C. Class)

                 

 

Subduction Zone Processes:

Reconstructing Slab and Mantle Fluxes During th Eocene-Oligocene Evolution of the Izu-Bonin Volcanic Arc

(S. Straub, S. L. Goldstein, C. Class) (Straub et al. 2009 )

Melting of carbonate-bearing sediments in subduction zone

(R. Dasgupta (Rice U) and C. Class)