High‐resolution diatom δ18O records,from the last 150 years,reflecting changes in amount of winter precipitation in two sub‐Arctic high‐altitude lakes in the Swedish Scandes

Waters from high‐altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high‐altitude lakes have lake water isotopic compositions (δ¹⁸O_lake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water δ¹⁸O. Here we compare two high‐resolution δ¹⁸O_diatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900–1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ¹⁸O_diatom as decreasing trends. Lowest δ¹⁸O_diatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the δ¹⁸O_diatom signal in these sub‐Arctic high‐altitude lakes with short residence times has been changes in amount of winter precipitation and that δ¹⁸O_diatom derived from high‐altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy. Copyright © 2010 John Wiley & Sons, Ltd.     

MicroRaman spectroscopy of diamond and graphite in Almahata Sitta and comparison with other ureilites

This work is the first detailed study of carbon phases in the ureilite Almahata Sitta (sample #7). We present microRaman data for diamond and graphite in Almahata Sitta, seven unbrecciated ureilites, and two brecciated ureilites. Diamond in Almahata Sitta was found to be distinct from that in unbrecciated and brecciated ureilites, although diamond in unbrecciated and brecciated ureilites is indistinguishable. Almahata Sitta diamond shows a peak center range of 1318.5–1330.2 cm^?1 and a full width at half maximum (FWHM) range of 6.6–17.4 cm^?1, representing a shock pressure of at least 60 kbar. The actual peak shock pressure may be higher than this due to postshock annealing, if shock synthesis is the source of ureilite diamonds. Diamond in unbrecciated and brecciated ureilites have peak center wave numbers closer to terrestrial kimberlite diamond, but show a wider range of FWHM than Almahata Sitta. The larger peak shift observed in Almahata Sitta may indicate the presence of lonsdaleite. Alternatively, the lower values in brecciated ureilites may be evidence of an annealing step either following the initial diamond‐generating shock or as a consequence of heating during reconsolidation of the breccia. Graphite in Almahata Sitta shows a G‐band peak center range of 1569.1–1577.1 cm^?1 and a G‐band FWHM range of 24.3–41.6 cm^?1 representing a formation temperature of 990 ± 120 °C. Amorphous carbon was also found. We examine the different theories for diamond formation in ureilites, such as chemical vapor deposition and shock origin from graphite, and explore explanations for the differences between Almahata Sitta and other ureilites.     

Late Weichselian environmental change in Norway,including Svalbard

A synthesis of the principal environmental changes that are inferred to have occurred in Norway and Svalbard (Fig. 1) during the Late-glacial period (14-9 ka BP) is presented. The paper has three sections dealing separately with (I) western Norway, (II) northern Norway and (III) Spitsbergen, Svalbard. The main conditions described include glacial events, sea-level changes, vegetation history and climatic variations. A summary chart of environmental reconstructions is presented for each of the three areas, each including a curve of temperature reconstructions for the Late-glacial period. These indicate some significant regional variations in contemporaneous thermal conditions during the Late-glacial.     

Characteristics of the lithospheric mantle beneath East Serbia inferred from ultramafic xenoliths in Palaeogene basanites

Mantle xenoliths from Paleogene basanites of East Serbia were studied using EMP and LA-ICP-MS techniques in order to better understand mantle characteristics in this region. Five different mantle lithologies have been distinguished: a dunite/harzburgite/lherzolite (D/HZ/L) group, clinopyroxene-rich lherzolites (Cpx-L), clinopyroxene megacrysts (Cpx-M), spinel-rich olivine websterites (OWB₁) and spinel-poor olivine websterites (OWB₂). D/HZ/L xenoliths are the most common and represent normal mantle composed of typical anhydrous spinel peridotites with well equilibrated, unzoned silicates characterized by high Mg# s. Negative correlations between Mg# and TiO₂, Al₂O₃ and CaO wt% in clinopyroxenes (cpx) and orthopyroxenes (opx) and the Cr–Al trend in spinel (sp) suggest depletion via extraction of basaltic melts. The modal composition of D/HZ/L xenoliths and unusual low-Al opx suggest that the lithospheric mantle underneath East Serbia is more depleted than normal European lithosphere. D/HZ/L xenoliths contain numerous pockets and veins filled by Cr-rich cpx, Ti-rich spinel, altered glass, apatite and rare ilmenite and phlogopite. Petrographic observations, supported by major element contents in sp and cpx, and modelling using trace element contents in cpx, indicate that the pockets and veins formed from infiltration of alkaline melts and reaction with peridotite wall-rock causing opx and spinel replacement. The same alkaline melt-related metasomatism gave rise to the Cpx-L and OWB₁ mantle xenoliths and Cpx-M xenocrysts. Trace element contents of cpx in these xenoliths show a distinctively concave downwards REE pattern with a HFSE depletion, very similar to cpx megacrysts from the Pannonian Basin and to vein cpx from Eifel. In contrast, the OWB₂ xenoliths show evidence of precipitation from subduction-related mafic to ultramafic melts, as inferred from their opx-rich lithology and unusual Cr-rich spinels. They are probably related to subduction magmatism during the Late Cretaceous.Milivoje Jovanovi: deceased in April 2004     

Geodynamic significance of ultramafic xenoliths from Eastern Serbia: Relics of sub-arc oceanic mantle?

A suite of highly depleted peridotite xenoliths in East Serbian Palaeogene basanites represents the lithospheric mantle beneath the Balkan Peninsula. The xenoliths are harzburgites, clinopyroxene-poor lherzolites and rare dunites. They contain mostly <5 vol.% of modal clinopyroxene and are characterized by high Mg# in silicates (>91), high Cr# in spinel (mostly 0.5–0.7), and by distinctively low Al₂O₃ contents in orthopyroxene (mostly 1–2 wt.%). They have experienced some mantle metasomatism which has slightly obscured their original composition. Nevertheless, the general characteristics of the xenoliths imply a composition which is significantly more depleted than most non-cratonic sub-continental mantle xenolith suites, as well as orogenic peridotites and abyssal peridotites. Geological and compositional evidence suggests that the xenoliths do not represent Archean mantle. The existence of Proterozoic mantle cannot be entirely excluded, although it is in disagreement with geological evidence. On the other hand, the studied xenoliths are compositionally very similar to peridotites of modern oceanic sub-arc settings. The existence of such a depleted lithospheric mantle segment is also inferred from the presence of rare orthopyroxene-rich xenoliths in the same suite. These are interpreted to have originated as lithospheric precipitates of high-Mg, SiO₂-saturated magmas that require a highly depleted mantle source. Such source is typically required by boninitic-like magmas of intraoceanic suprasubduction settings. A proposed geodynamic model to explain these observations involves accretion or underplating of the lower parts of the Tethyan oceanic lithosphere during the Upper Jurassic closure of the eastern branch of the Vardar ocean.     

The Kråkenes late-glacial palaeoenvironmental project

Kråkenes is the site of a small lake on the west coast of Norway that contains a long sequence of late-glacial sediments. The Younger Dryas is well represented, as a cirque glacier developed in the catchment at this time. This site offers unique opportunities to reconstruct late-glacial environments from independent sources of evidence; physical evidence (glacial geomorphology, sedimentology, palaeomagnetism, radiocarbon dating), and biological evidence from the remains of animals and plants derived from both the terrestrial and aquatic ecosystems. This report describes the background to the site, and the international multidisciplinary project to reconstruct late-glacial and early Holocene environmental and climatic changes at Kråkenes.     

Potential Impacts of Climate Change on Tropical Asian Forests Through an Influence on Phenology

Changes in plant phenology will be one of the earliest responses to rapid global climate change and could potentially have serious consequences both for plants and for animals that depend on periodically available plant resources. Phenological patterns are most diverse and least understood in the tropics. In those parts of tropical Asia where low temperature or drought impose a seasonal rest period, regular annual cycles of growth and reproduction predominate at the individual, population, and community level. In aseasonal areas, individuals and populations show a range of sub- to supra-annual periodicities, with an overall supra-annual reproductive periodicity at the community level. There is no evidence for photoperiod control of phenology in the Asian tropics, and seasonal changes in temperature are a likely factor only near the northern margins. An opportunistic response to water availability is the simplest explanation for most observed patterns where water is seasonally limiting, while the great diversity of phenological patterns in the aseasonal tropics suggests an equal diversity of controls. The robustness of current phenological patterns to high interannual and spatial variability suggests that most plant species will not be seriously affected by the phenological consequences alone of climate change. However, some individual plant species may suffer, and the consequences of changes in plant phenology for flower- and fruit-dependent animals in fragmented forests could be serious.     

Book reviews

A WORLD IN CRISIS? Geographical Perspectives (second edition) edited by R. J. Johnston and P. J. Taylor. 15 x 23 cm, x and 371 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 16271 2) $A34.95 (soft).

INTEGRATED RURAL DEVELOPMENT PROGRAMMES IN PAPUA NEW GUINEA: External Aid and Provincial Planning (IASER Monograph No 28) by R. Crittenden and D. A. M. Lea, 17 x 24 cm, xv and 132 pages. Papua New Guinea Institute of Applied Social and Economic Research and Department of Geography and Planning, University of New England: Armidale 1989 (ISBN 9980 75 018 9).

ACCOMMODATING INEQUALITY: Gender and Housing by Sophie Watson. 14 x 21 cm, x and 157 pages. Allen & Unwin: Sydney 1988 (ISBN 0 04 320209 2) $A 14.95 (soft).

A SHORT HISTORY OF GEOMORPHOLOGY by K. J. Tinkler. 14 x 22 cm, xviii and 317 pages, Croom Helm: London 1985 (ISBN 0 7099 2441 0) $A49.95 (hard).

PATHWAYS IN GEOLOGY: Essays in Honour of

Edwin Sherbon Hills edited by R. W. Le Mai‐

tre. 25 x 19 cm, viii and 463 pages. Basil

Blackwell: Melbourne 1989 (ISBN

0731682416) $A110.00 (hard).

CHANGING THE FACE OF THE EARTH: Culture, Environment, History by I. G. Simmons. 17 x 24 cm, xiii and 487 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 16351 4) $A49.95 (soft).

PLANNED TO DEATH: The Annihilation of a Place Called Howdendyke by J. D. Porteous. 16 x 24 cm, xiii and 254 pages. Manchester University Press: Manchester 1989 (ISBN 0 7190 2831 0) £35.00 (hard).

A SOCIAL ATLAS OF DARWIN: 1986. Census of Population and Housing by J. Taylor and D.

Jaensch. 21 x 29 cm, and 66 pages. Australian Bureau of Statistics and North Australia Research Unit: Darwin 1989 (ISBN 0 642 143322 6).

ATLAS OF DEMOGRAPHIC CHANGE IN THE SOUTH EAST REGION OF NEW SOUTH WALES 1861–1991 by Terry G. Birtles and Jane E. Gordon. 21 x 29 cm, v and 141 pages. Canberra College of Advanced Education: Belconnen 1989 (ISBN 0 85889 355 5 $A40.00 (soft).

LABOUR ADJUSTMENT IN METROPOLITAN REGIONS by P. S. Morrison 15 x 21 cm, ix and 254 pages. Victoria University Press: Wellington 1989 (ISBN 0 86473 190 6) SA25.00 (soft).

AUSTRALIAN REGIONAL DEVELOPMENTS: Readings in Regional Experiences, Policies and Prospects (Australian Regional Developments No. 10) edited by B. Higgins and K. Zagorski. 17 x 25 cm. xi and 260 pages. AGPS Press: Canberra 1989 (ISBN 0 644 0935).

SOUTH AUSTRALIAN MANUFACTURING IN TRANSITION edited by T. J. Mules. 15 x 21 cm, vii and 188 pages. Wakefield Press (for Centre of South Australian Economic Studies): Adelaide 1989 (ISBN 909591 74 1) $A24.95 (soft).

COUNTERURBANIZATION: The Changing Pace’ and Nature of Population Deconcentration edited by A. G. Champion. 16 x 24 cm, xxii and 266 pages. Edward Arnold: London 1989 (ISBN 0 7131 6614 2) £27.00 (hard).

THE HUMANE CITY: Cities as if People Matter by J. R. Short. 15 x 22 cm, 167 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 15824 3) $A27.95 (soft).

THE TORRES STRAIT: People and History (revised edition) by J. Singe. 13 x 19 cm, xviii and 261 pages. University of Queensland Press: St Lucia 1989 (first published in 1979) (ISBN 0 7022 2232 1) $A19.95 (soft).

HAWKE'S LAW: The Politics of Mining and Aboriginal Land Rights in Australia by R. T. Libby. xxvii and 175 pages. University of Western Australia Press: Nedlands 1989 (ISBN 085564 301 1) $A25.00.

THE THIRD WORLD: States of Mind and Being edited by J. Norwine and A. Gonzales. 15 x 23 cm, xi and 275 pages. Unwin Hyman: Boston 1989 (ISBN 0 04 910121 8) $A39.95 (soft).

IRELAND: A Contemporary Geographical Perspective edited by R. W. G. Carter and A. J. Parker. 14 x 22 cm, xiv and 486 pages. Routledge: London 1989 (ISBN 0 415 00486 3) $A 120.00 (hard).