Earth Sciences

Mineralogy of glaciomarine sediments from the Prydz Bay–Kerguelen region: relation to modern depositional environments

Andreas Borchers^a1 c1, Ines Voigt^a2, Gerhard Kuhn^a3 and Bernhard Diekmann^a1

^a1 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam Telegrafenberg A43, 14473 Potsdam, Germany

^a2 University of Bremen, Geosciences Postbox 330440, 28334 Bremen, Germany

^a3 Alfred Wegener Institute for Polar and Marine Research, Research Unit Bremerhaven Columbusstrasse, 27568 Bremerhaven, Germany

Abstract

Surface mineralogical compositions and their association to modern processes are well known from the east Atlantic and south-west Indian sectors of the Southern Ocean, but data from the interface of these areas - the Prydz Bay–Kerguelen region - is still missing. The objective of our study was to provide mineralogical data of reference samples from this region and to relate these mineralogical assemblages to hinterland geology, weathering, transport and depositional processes. Clay mineral assemblages were analysed by means of X-ray diffraction technique. Heavy mineral assemblages were determined by counting of gravity-separated grains under a polarizing microscope. Results show that by use of clay mineral assemblages four mineralogical provinces can be subdivided: i) continental shelf, ii) continental slope, iii) deep sea, iv) Kerguelen Plateau. Heavy mineral assemblages in the fine sand fraction are relatively uniform except for samples taken from the East Antarctic shelf. Our findings show that mineralogical studies on sediment cores from the study area have the potential to provide insights into past shifts in ice-supported transport and activity and provenance of different water masses (e.g. Antarctic slope current and deep western boundary current) in the Prydz Bay–Kerguelen region.

(Received May 19 2010)

(Accepted August 31 2010)

(Online publication November 16 2010)

Key words

• bottom water;
• clay minerals;
• East Antarctic Ice Sheet;
• heavy minerals;
• ice rafting;
• Mac. Robertson Land

Correspondence:

^c1 Andreas.Borchers@awi.de