Instrumental Neutron Activation Analysis Of French Geochemical Reference Samples

Instrumental neutron activation analytical data, for eighteen trace elements (Ba, Co, Cr, Cs, Hf, Rb), Sb, Sc, Ta, Th, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu), Hd₂O and Fe₂0₃ in eleven French geoche-mical reference samples are presented and discussed briefly.     

The mineralogy and geochemistry of the sediments of northwestern Lake Victoria

In the nearshore area of northwestern Lake Victoria a thin strip of quartzarenite sand occurs which grades lakeward into silty clay consisting of quartz with subordinate amounts of K-feldspar, plagioclase, kaolinite, illite, vermiculite and organic matter. Varimax matrix determinations of the element concentrations in the lake-bottom sediments extractable by aqua regia indicate that: (1) there is a strong association of Cr, Cu, Zn and Ni; (2) there is a strong association of Fe, Mn and Co; (3) Cu and Ni show moderate to slight associations with organic matter; (4) Ca is relatively independent of the other elements. The general decrease in the pH values of the surface and bottom waters outward from the lake shore, with consistently higher values for the surface water relative to the bottom waters, results from decreasing levels of photosynthetic activity.     

Till body morphology and structure related to glacier flow

Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties associated with glacial transport, and have suffered a minimum of redistribution suhsequent to their release from glacier ice. It is shown that ridges and mounds cannot he explained in terms of preferential till accretion. An alternative mechanism is presented in which form and structurc are a result of redistribution of debris in transport by secondary flows in ice.
Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis.
Debris entrainment by Antarctic cold-based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt-out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water-lain deposits; (3) foliated till with sub-horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica.
Transverse asymmetric ridges are related to till stacking by over-folding in the marginal compressive zone of cold-based glaciers. Plastic deformation of the debris-laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica.     

The Holocene fossil marine macrofauna of the Vestfold Hills, East Antarctica

The Holocene (< 10,000 years old) fossil marine macrofauna (molluscs, polychaetes, mammals and birds) of the Vestfold Hills, Antarctica (68°30'S, 78°00'E) is described. All species are extant, with circumantarctic or wider distributions and wide depth ranges. At Heidemann Bay, Pleistocene-age (> 30 ky old) shell fragments occur in a Holocene moraine. These are interpreted as being glacially reworked fossil shells. Holocene benthic estuarine and coastal molluses and serpulid worm tubes are abundant on the flanks of terraces above saline and hypersaline lakes. Extensive radiocarbon dating gives a chronology of these deposits which were not synchronous. Mummies of seals and penguins, which are concentrated on the shores of the saline lakes and scattered across the Hills, are of no use in dating geomorphological events. Marine fossils in moraines are difficult to interpret because they can be glacially-transported live or fossil shells, or deposited after wind transport. The fossil fauna has such a wide ecological range that it indicates only in general terms that for part of the Pleistocene and most of the Holocene, climatic conditions were broadly similar to the present.     

Current continental palaeoclimatic research in the Nordic region (100 years since Gunnar Andersson 1909) – Introduction

Seppä, H., Birks, H. J. B., Bjune, A. E. & Nesje, A. 2010: Current continental palaeoclimatic research in the Nordic region (100 years since Gunnar Andersson 1909) – Introduction. Boreas, Vol. 39, pp. 649‐654. 10.1111/j.1502‐3885.2010.00170.x. ISSN 0300‐9483.