Documentation of Graf-Wilczek-Knoll

During Leg ANT-XXIII/9 on the 31st March 2007 the German research vessel Polarstern mapped a significant bathymetric feature with its swath sonar system at the north-west margin of the Kerguelen Plateau. Due to the fact, that the feature was discovered just a month after the third IPY 2007/2008 has started, it was named after Graf Wilczek who, together with Carl Weyprecht, had promoted the first IPY. The undersea feature name proposal was officialy accepted by the GEBCO Sub-Committee on Undersea Feature Names (SCUFN) at its 20th meeting in late July and was added to the GEBCO Gazetteer of UFN (http://www.iho.shom.fr/COMMITTEES/GEBCO/SCUFN/scufn_intro.htm). ______________ Graf Hans Wilczek (Notation of the name from the book of Wilczek's daughter Elisabeth Kinsky- Wilczek). The Austrian naval hero Tegetthoff in 1871 planned an expedition to the southern hemisphere. The geophysicist G. Neumayer (1826-1909) already was selected as its chief scientist. Also the naval officer Carl Weyprecht (1838-1881) and the mountaineer Julius Payer (1841-1915) were to participate. Because of the sudden death of Tegettoff the project came to a halt and eventually was cancelled. By support of the well known geographer August Petermann (1822-1878) Weyprecht and Payer made a voyage into the Barents Sea which made them believe having seen the "open polar sea". An additional undertaking to confirm and to extend the find was obvious. At this stage of the affair count Hans Wilczek (1837-1922) got involved. He not only fostered a new expedition with a considerable sum of money, but he participated in commanding a support vessel to Novaya Zemlya. Wilczek managed to get home but the expedition vessel under Weyprecht's command became imprisoned in the pack for two years and at least had to be abandoned. After an adventurous trip back to civilisation Weyprecht changed his mind in what he considered the best way of polar research. Together with Wilczek in 1875 he started the promotion of international station-based polar exploration - the IPY was born. Wilczek guaranteed the constitution of an Austrian station on Novaya Zemlya and was ready to winter over there personally. Because of several political and other obstructions the beginning of the IPY was delayed till 1882. Wilczek's friend Weyprecht had passed away already. The command of the Austrian station, eventually erected on Jan Mayen, was given to Emil v. Wohlgemuth (1843-1896). Wilczek financed the main part of the Austrian IPY participation. Wilczek is described as honest and popular. On the one hand acquainted with the most prominent persons of his days, he respected everybody and had many relationships with scientists and artists. There is a kind of autobiography under the title: Hans Wilczek erzählt seinen Enkeln Erinnerungen aus seinem Leben (Hans Wilczek tells his grandchildren reminiscences from his life); edited by his daughter Elisabeth Kinsky-Wilczek, Graz 1933, 502 p. The book is available in an English version: Happy Retrospect - the Reminiscences of Count Wilczek 1837-1922, Bell and Sons, London 1934, 295 p.

Middle Miocene mineralogical events of Marion Plateau, northeast of Australia

Three ODP sites located on the Marion Plateau, Northeast Australian margin, were investigated for clay mineral and bulk mineralogy changes through the early to middle Miocene. Kaolinite to smectite (K/S) ratios, as well as mass accumulation rates of clays, point to a marked decrease in accumulation of smectite associated with an increase in accumulation of kaolinite starting at ~15.6 Ma, followed by a second increase in accumulation of kaolinite at ~13.2 Ma. Both of these increases are correlative to an increase in the calcite to detritus ratio. Comparison of our record with published precipitation proxies from continental Queensland indicates that increases in kaolinite did not correspond to more intense tropical-humid conditions, but instead to periods of greater aridity. Three mechanisms are explored to explain the temporal trends in clay on the Marion Plateau: sea-level changes, changes in oceanic currents, and denudation of the Australian continent followed by reworking and eolian transport of clays. Though low mass accumulation rates of kaolinite are compatible with a possible contribution of eolian material after 14 Ma, when Australia became more arid, the lateral distribution of kaolinite along slope indicates mainly fluvial input for all clays and thus rules out this mechanism as well as oceanic current transport as the main controls behind clay accumulation on the plateau. We propose a model explaining the good correlation between long-term sea-level fall, decrease in smectite accumulation, increase in kaolinite accumulation and increase in carbonate input to the distal slope locations. We hypothesize that during low sea level and thus periods of drier continental climate in Queensland, early Miocene kaolinite-rich lacustrine deposits were being reworked, and that the progradation of the heterozoan carbonate platforms towards the basin center favored input of carbonate to the distal slope sites. The major find of our study is that increase kaolinite fluxes on the Queensland margin during the early and middle Miocene did not reflect the establishment of a tropical climate, and this stresses that care must be taken when reconstructing Australian climate based on deep-sea clay records alone.

Calcareous nannofossil abundance and datums of ODP Hole 194-1193A sediments, Marion Plateau, Australia

During Leg 194, a series of eight sites was drilled through Oligocene-Holocene mixed carbonate and siliciclastic sediments on the Marion Plateau, northeast Australia. The major objective was to constrain the magnitude and timing of sea level changes in the Miocene. Site 1193, located on the Marion Plateau in 348 m of water ~80 km from the south central Great Barrier Reef margin, is probably the most important site for constraining the major middle to late Miocene sea level drop and reconstructing the evolution history of the Marion Plateau during the Miocene (Isern, Anselmetti, Blum, et al., 2002, doi:10.2973/odp.proc.ir.194.2002). However, there is no biostratigraphic or other chronological data for the critical interval between 36 and 211 meters below seafloor (mbsf) (virtually the entire late and middle Miocene) due to poor core recovery and a virtual absence of planktonic microfossils in the core catcher samples examined aboard the ship (Isern, Anselmetti, Blum, et al., 2002, doi:10.2973/odp.proc.ir.194.2002). The main purpose of this report is to refine the shipboard nannofossil biostratigraphy through examination of new samples and more detailed examination of those samples reported on board the ship. This results in a refinement for most of the nannofossil datums and provides some useful age information to fill the critical data gap for the middle Miocene. Previous Neogene nannofossil biostratigraphic studies of the Marion Plateau and Queensland Plateau include Gartner et al. (1993, doi:10.2973/odp.proc.sr.133.213.1993) and Wei and Gartner (1993, doi:10.2973/odp.proc.sr.133.216.1993).

(Table 2) 230Th, 230Th xs and 232Th concentrations in dissolved, particulate and total (dissolved+small particles) for all KEOPS stations, Marion Dufresne cruise MD145

In the context of the KErguelen Ocean and Plateau compared Study (KEOPS, 19 January-13 February 2005), particle dynamics were investigated using thorium isotope measurements over and off the Kerguelen plateau. Dissolved and particulate 230Th and 232Th samples were collected at nine stations. Dissolved excess 230Th concentrations (230Thxs) vary from 0.5 to 20.8 fg/kg and particulate 230Thxs concentrations from 0.1 to 10.0 fg/kg. Dissolved and particulate 232Th concentration ranges are 16.8-450.2 pg/kg and 3.8-502.8 pg/kg, respectively. The 230Thxs concentrations increase linearly with depth down to the bottom at most of the plateau stations and down to 1000 m at the off-plateau stations. This linear trend is observed down to the bottom (1550 m) at Kerfix, the open-ocean "upstream" station located west of the Kerguelen plateau. A simple reversible scavenging model applied to these data allowed the estimation of adsorption rate constant (k1~=0.2-0.8 per year), desorption rate constant (k-1~=1-8 per year) and partition coefficients (average K=0.16±0.07). Calculated particle settling velocities S deduced from this simple model are ca. 500 m/year at most of the plateau stations and 800 m/year at all the off-plateau stations. The plateau settling velocities are relatively low for such a productive site, compared to the surrounding HNLC areas. The difference might reflect the fact that lateral advection is neglected in this model. Taking this advection into account allows the reconstruction of the observed 230Thxs linear distributions, but only if faster settling velocities are considered. This implies that the 1D model strongly underestimates the settling velocity of the particles. In the deep layers, the occurrence of intense boundary scavenging along the escarpment due to bottom sediment re-suspension and interaction with a nepheloid layer, yielding a removal of ?50% of the Th stock along the northwestward transect, is suggested.

Iron and aluminium and hydrogen peroxide measured on water bottle samples during Marion Dufresne cruise ANTARES-II

Total dissolvable iron (TDFe), particulate iron (PFe) and hydrogen peroxide (H2O2 measurements were performed along a N-S transect in the upper 250 m in the Southern Ocean (62°00E/66°42S - 49°00S, ANTARES II cruise, February 1994). TDFe was organically extracted (APDC/DDDC-chloroform) and analysed by Graphite Furnace Atomic Absorption Spectrometry (GFAAS), PFe was analysed by GFAAS following a strong mixed-acid leach, and H2O2 was analysed on board by fluorometry. The respective detection limits are equal to 0.13 nmol/kg, 0.02 nmol/kg, and 3.0 nmol/kg. TDFe concentrations vary from 0.4 to 6.2 nmol/kg and profiles are not completely depleted in the surface. PFe concentrations vary from 0.02 to 0.2 nmol/kg. Iron/carbon (Fe/C) uptake ratios for phytoplankton were calculated either from seawater or particle measurements. They are variable along the transect but are consistent when they could be compared. All the observed ratios are within the range of values proposed for the Fe/C uptake ratios by phytoplankton. Using our uptake ratio calculated in the Permanent Open Ocean Zone (4 x 10**?6 mol/mol), we estimate that the primary production which can be supported by the iron input flux into the surface waters is two times higher than the measured primary production in the same area. In the surface waters, H2O2 concentrations vary from 5.0 to 19.7 nmol/kg. Such low concentrations are due to strong vertical mixing, low dissolved organic matter concentrations and the latitude of the site.

Study of the fronts of Johnsons and Hurd Glaciers (Livingston Island, Antarctica) from 1957 to 2013, with links to shapefiles

The study of glacier fronts combines different geomatics measurement techniques as the classic survey using total station or theodolite, technical GNSS (Global Navigation Satellite System), using laser-scanner or using photogrammetry (air or ground). The measure by direct methods (classical surveying and GNSS) is useful and fast when accessibility to the glaciers fronts is easy, while it is practically impossible to realize, in the case of glacier fronts that end up in the sea (tide water glaciers). In this paper, a methodology that combines photogrammetric methods and other techniques for lifting the front of the glacier Johnsons, inaccessible is studied. The images obtained from the front, come from a non-metric digital camera; its georeferencing to a global coordinate system is performed by measuring points GNSS support in accessible areas of the glacier front side and applying methods of direct intersection in inaccessible points of the front, taking measurements with theodolite. The result of observations obtained were applied to study the temporal evolution (1957-2014) of the position of the Johnsons glacier front and the position of the Argentina, Las Palmas and Sally Rocks lobes front (Hurd glacier).