Book reviews

THE IMPACT OF VOLCANIC HAZARDS AT RABAUL, PAPUA NEW GUINEA (Discussion Paper No. 33) by R. J. Blong and C. Aislabie. 17 × 25 cm, xiv and 207 pages. Institute of National Affairs: Port Morseby 1988 (ISBN 9980 77 086 4).

A PRACTICAL APPROACH TO SEDIMENTOLOGY by R. C. Lindholm. 15 × 23 cm, xviii and 279 pages. Allen & Unwin: London 1987 (ISBN 0 04 551132 2) $A45.00 (soft).

THE ATMOSPHERE AND WEATHER OF SOUTHERN AFRICA by R. A. Preston‐Whyte and P. D. Tyson. 18 × 24 cm, xiii and 375 pages. Oxford University Press: Cape Town 1988 (ISBN 0 19 570 514 9) R56.00 (hard); (ISBN 0 19 570 496 7) R39.14 (soft).

QUATERNARY PALEOCLIMATOLOGY: Methods of Paleoclimatic Reconstruction by R. S. Bradley. 15 × 23 cm, xvii and 472 pages. Allen & Unwin: Boston 1985 (ISBN 0 04 551067 9) $A69.95 (hard); (ISBN 0 04 551068 7) $A39.95 (soft).

PROCESSES IN PHYSICAL GEOGRAPHY by R. D. Thompson, A. M. Mannion, C. W. Mitchell, M. Parry and J. R. Townsend. 24 × 19 cm, xii and 380 pages. Longman: London 1986 (ISBN 0 582 30136) $A44.95.

PERSPECTIVES ON A DYNAMIC EARTH by T. R. Paton. 16 × 24 cm, 142 pages. Allen & Unwin: London 1986 (ISBN 0 04 55 0043 6) $A23.95 (soft).

LAND DEGRADATION AND SOCIETY edited by P. Blaikie and H. Brookfield. 15 × 23 cm. xxiv and 296 pages. Methuen: London 1987 (ISBN 0 416 40150 3) $A32.95 (soft).

THE PENGUIN DICTIONARY OF HUMAN GEOGRAPHY by B. Goodall. 13 × 20 cm, 509 pages. Penguin: Harmondsworth 1987 (ISBN 0 14 051095 8) $A19.95 (soft).

MAKING SENSE OF DEVELOPMENT: An Introduction to Classical and Contemporary Theories of Development and Their Application to South‐east Asia by P. W. Preston. 14 × 22 cm, xxi and 318 pages. Routledge & Kegan Paul: London 1986 (ISBN 0 7102 0813 8) $A87.95 (hard).

THE DEMOGRAPHIC DIMENSION IN INDONESIAN DEVELOPMENT by G. J. Hugo, T. H. Hull, V. J. Hull and G. W. Jones. 16 × 25 cm, xxv and 417 pages. Oxford University Press: Singapore 1987 (ISBN 0 19 582699 X) $A49.95 (hard).

GLOBAL ISSUES AND OUTLOOK IN PULP AND PAPER edited by G. F. Schreuder, 18 × 26 cm, ix and 302 pages. University of Washington Press: Seattle 1988 (ISBN 0 295 96642 4) $US40.00 (hard).

AN HISTORICAL GEOGRAPHY OF MODERN AUSTRALIA: The Restive Fringe (Cambridge Studies in Historical Geography No. 11) by J. M. Powell. 16 × 33 cm, xx and 400 pages. Cambridge University Press: Cambridge 1988 (ISBN 0 521 25619 4) $A39.95 (hard).

HISTORICAL GEOGRAPHY: Progress and Prospect edited by M. Pacione. 14 × 22 cm, 306 pages. Croom Helm: London 1987 (ISBN 0 7099 40467) $A27.50 (hard).

THE ROLE OF THEORY IN URBAN PLANNING: A Study of Metropolitan Planning in Perth, Western Australia (Geowest No. 24) by O. Yiftachel. 21 × 29 cm, 102 pages. Department of Geography, University of Western Australia: Nedlands 1987 (ISBN 0 86422 063 4).

SYDNEY INTO ITS THIRD CENTURY: Metropolitan Strategy for the Sydney Region by NSW Department of Environment and Planning. 21 × 29 cm, 72 pages. NSW department of Environment and Planning: Sydney 1988 (ISBN 0 7305 4312 9).

BUS SERVICES IN WESTERN SYDNEY: Private Bus Operators and Government Transport Departments (Monograph Series No. 3) by P. Tranter. 21 × 29 cm, v and 98 pages. Department of Geography and Oceanography, University College, Australian Defence Force Academy: Campbell, ACT 1988 (ISBN 0 7317 0036 8).

AGEING IN VICTORIA: An Electronic Social Atlas by A. L. Howe, P. Newton and P. Sharwood. 30 × 21 cm, 105 pages. National Research Institute for Gerontology and Geriatric Medicine, Mt. Royal Hospital and University of Melbourne: Melbourne 1987 (ISBN 0 958326 6 2) $A10.00 (soft).

READINGS IN AUSTRALIAN GEOGRAPHY: Proceedings of the 21st Institute of Australian Geographers’ Conference, Perth 10–18 May 1986, edited by A. Conacher. 21 × 29 cm, vi and 493 pages. Institute of Australian Geographers (WA Branch) and Department of Geography, University of Western Australia: Perth 1987 (ISBN 0 909678 30 B) $A25.00 (soft).

GEOGRAPHY RESEARCH PROJECTS: A Senior Student's Handbook by H. Binden and H. Williams. 18 × 26 cm, 149 pages. Edward Arnold Australia: Caulfield East 1988 (ISBN 0 7131 8311 X) $A 14.95 (soft).

OUR AMERICAN LAND: 1987 Yearbook of Agriculture, ix and 323 pages. US Government Printing Office, Washington, DC: 1987 $US9.50.

THE ENCYCLOPAEDIC DICTIONARY OF PHYSICAL GEOGRAPHY edited by A. Goudie et al. 17 × 24 cm, xvi and 528 pages. Basil Black‐well: Oxford 1988 (ISBN 0 631 15581 3) $A34.95 (soft).

THE CONSERVATION OF ECOSYSTEMS AND SPECIES by Gareth E. Jones, 14 × 22 cm, 277 pages. Croom Helm: London 1987 (ISBN 0 7099 1463 6) $A87.95 (hard).

SO CAME THEY SOUTH by R. Clancy and A. Richardson. 35 × 35 cm, 176 pages. Shakespeare Head: Sydney 1988 (ISBN 0 7302 0864 8) $A34.95.     

Particle size dependent response of aerosol counters

During an international workshop at the Institute for Experimental Physics of the University of Vienna, Austria, which was coordinated within the Committee on Nucleation and Atmospheric Aerosols (IAMAS-IUGG), 10 instruments for aerosol number concentration measurement were studied, covering a wide range of methods based on various different measuring principles. In order to investigate the detection limits of the instruments considered with respect to particle size, simultaneous number concentration measurements were performed for monodispersed aerosols with particle sizes ranging from 1.5 to 50 nm diameter and various compositions.The instruments considered show quite different response characteristics, apparently related to the different vapors used in the various counters to enlarge the particles to an optically detectable size. A strong dependence of the 50% cutoff diameter on the particle composition in correlation with the type of vapor used in the specific instrument was found. An enhanced detection efficiency for ultrafine hygroscopic sodium chloride aerosols was observed with water operated systems, an analogous trend was found for n-butanol operated systems with nonhygroscopic silver and tungsten oxide particles.     

TRIFFID Photometry of Globular Cluster Cores — I. Photometric Techniques and Variable Stars in M15

The Galway/DIAS Image Sharpening Camera, TRIFFID, has been used to make observations in two colours of the centre of the post-core-collapse globular cluster M15. We present here our analysis of the photometry in B over two seasons. We have combined the complementary qualities of the HST 's high astrometric precision and TRIFFID's extended coverage and photometric precision, to perform crowded-field photometry in the innermost region of M15. Our technique virtually eliminates the problem of extreme crowding which has hitherto hampered studies of the variable star populations in globular cluster cores, and thereby provides an extension of the HST 's capability. Candidate variables detected with the HST have been confirmed and monitored over longer periods. We show that most of these are RR Lyrae stars, and that one is a short-period Type II Cepheid (the third to be discovered in M15). Our photometric study also produced evidence of a similar number of new variables. These also appear to be RR Lyrae stars, except for a possible eclipsing system. Further data from an upgraded version of TRIFFID have recently been obtained to help to refine the light curves of all these objects.     

Stratigraphy,pollen analysis and paleoclimatic interpretation of Mowrray and Rroadmeadows Swamps,North Western Tasmania

Sedimentary, palynologic and ¹⁴C analysis of marls and swamp‐peats, formed under fluctuating artesian spring conditions, provide climate and vegetation records from >52,000 to 0 yr BP at Mowbray, and 30,000 to 0 yr BP at Broadmeadows. Before about 65,000 yr BP conditions at Mowbray were relatively dry and the vegetation was Leptospermum shrubland. After 65,000 and before 55,000 yr BP moist conditions produced Cyperaceae swamps. Between 55,000 and 45,000 yr BP the climate was relatively dry, and between 45,000 and 35,000 yr BP relatively moist. Leptospermum shrubs were dominant in both periods. The climate was moist between 35,000 and 22,000 yr BP and sedge swamps formed. Between 22,000 and 11,000 yr BP the climate was relatively dry and grasses were important. Postglacial climate (11,000–0 yr BP) was warm and moist, and Melaleuca‐Leptospermum forest and shrubland flourished. The climatic changes suggested for north western Tasmania seem to compare broadly with changes suggested for Tasmanian and for other southern Australian sites, but the correlation is limited by imprecise dating.     

Late glacial and Holocene vegetation history at Poets hill lake,western Tasmania

Pollen analysis of 3.25 m of late glacial and Holocene sediments gives a mid‐altitude (600 m) record of vegetation development after the last or Margaret Glaciation. Alpine herbfield, coniferous heath and Nothofagus gunnli scrub developed on the moraines until 11,400 BP. Wet montane forest and heath then developed with Phyllocladus aspleniifolius, Nothofagus cunninghamii and Eucalyptus until c. 10,000 BP. After 10,000 BP a mosaic of N. cunninghamii rainforest, Myrtaceae and Proteaceae scrub and Sprengelia incarnata heath occurred. The development of the vegetation from alpine communities to temperate rainforest, which is near its limit at 600 m, occurred under the influence of improving climatic conditions with rapid upslope migration or local expansion of taxa during the late glacial. Temperatures were warm enough for the development of rainforest at 600 m by 10,000 BP, if not earlier. The development of a mosaic of rainforest, scrub and heath vegetation rather than extensive rainforest after 10,000 BP reflects the influence of poor soils, bad drainage and fires. Comparison with similar pollen diagrams from western Tasmania suggests that the development of pollen/vegetation associations was time transgressive with altitude during the late glacial when climatic influences and migration rates were important, and that the mosaic of vegetation communities became more complex during the Holocene because of adjustment to or control by local ecological factors.     

Studies of Cainozoic environmental change in Tasmania and coastal East Antarctica: a review

Observational studies on Cainozoic environmental changes in both Tasmania and East Antarctica have led to important modifications in the accepted interpretation of the history of glaciation for each area. Many contributors have played an important role in the processes of investigation leading to the present state of knowledge. A crucial role has been played by the integration of the methods of glacial geomorphology, stratigraphy, sedimentology and dating methods. From studies based on combinations of these approaches, a model of multiple glaciations has been developed to explain observed features in Tasmania. This model is complemented by studies of vegetation history, largely through pollen analysis. A less complete picture of the history of ice‐sheet fluctuations in East Antarctica is beginning to emerge from similar applications of cross‐disciplinary studies.     

Stratigraphy,pollen analysis,and paleoclimatic interpretation of Pulbeena Swamp,northwestern Tasmania

Sedimentary, palynologic, and ¹⁴C analysis of 480 cm of freshwater marl and swamp-peat deposits, formed under the influence of fluctuating artesian springs, provides a paleoenvironmental and paleoclimatic record of approximately 65,000 yr for northwestern Tasmania.The Holocene (Pollen Zone 1, 11,000-0 yr B.P.) climate was warm and moist, and forest vegetation was dominant throughout the area. During the later part of the last glacial stage (Pollen Zone 2, 35,000–11,000 yr B.P.) the climate was generally drier, and grassy open environments were widespread. The driest part of this period occurred between 25,000 to 11,000 yr B.P., when temperatures in western Tasmania were markedly reduced during the last major phase of glaciation. Prior to 35,000 yr B.P. (Pollen Zones 3–9) a long “interstadial complex” dating to the middle of the last glacial stage is recognized. During this period the climate was generally moist, and forest and scrub communities were more important than during the later part of the last glacial stage, except during Pollen Zone 5 when high Gramineae plus Compositae values suggest drier conditions. High Gramineae and Compositae values also occur in Pollen Zone 10 at the base of the diagram. They suggest that a phase of drier and cooler climatic conditions occurred during the early part of the last glacial stage.     

Glaciations of the West Coast Range,Tasmania

Geomorphic, stratigraphic, palynologic and ¹⁴C evidence indicates that the West Coast Range, Tasmania, was glaciated at least three times during the late Cenozoic. The last or Margaret Glaciation commenced after 30,000 yr B.P., culminated about 19,000 yr B.P., and ended by 10,000 yr B.P. During this period a small ice cap, ca. 250 m thick, and cirque and valley glaciers covered 108 km². The glacial deposits show little chemical weathering or erosional dissection. The snow line ranged from 690 to 1000 m with an average of 830 m for the ice cap. Mean temperature was 6.5°C below the present temperature. During the preceding Henty Glaciation a 300- to 400-m-thick ice cap and outlet glaciers exceeded 1000 km². The glacial deposits are beyond ¹⁴C assay. They are more weathered chemically and more dissected than Margaret age deposits, and the degree suggests a pre-last interglaciation age (> 130,000 yr B.P.). The snow line of the ice cap lay at 740 m, and annual temperature was reduced by 7°C. Ice of the earliest Linda Glaciation slightly exceeded that of the Henty Glaciation but had a similar distribution. The glacial deposits are intensely weathered, have reversed magnetization, and overlie a paleosol containing pollen of Tertiary type. An early Pleistocene or Tertiary age is indicated.     

Investigating a time‐shift extended imaging condition in a Kirchhoff pre‐stack depth migration algorithm

Extracting true amplitude versus angle common image gathers is one of the key objectives in seismic processing and imaging. This is achievable to different degrees using different migration techniques (e.g., Kirchhoff, wavefield extrapolation, and reverse time migration techniques) and is a common tool in exploration, but the costs can vary depending on the selected migration algorithm and the desired accuracy. Here, we investigate the possibility of combining the local‐shift imaging condition, specifically the time‐shift extended imaging condition, for angle gathers with a Kirchhoff migration. The aims are not to replace the more accurate full‐wavefield migration but to offer a cheaper alternative where ray‐based methods are applicable and to use Kirchhoff time‐lag common image gathers to help bridge the gap between the traditional offset common image gathers and reverse time migration angle gathers; finally, given the higher level of summation inside the extended imaging migration, we wish to understand the impact on the amplitude versus angle response. The implementation of the time‐shift imaging condition along with the computational cost is discussed, and results of four different datasets are presented. The four example datasets, two synthetic, one land acquisition, and a marine dataset, have been migrated using a Kirchhoff offset method, a Kirchhoff time‐shift method, and, for comparison, a reverse time migration algorithm. The results show that the time‐shift imaging condition at zero time lag is equivalent to the full offset stack as expected. The output gathers are cleaner and more consistent in the time‐lag‐derived angle gathers, but the conversion from time lag to angle can be considered a post‐processing step. The main difference arises in the amplitude versus offset/angle distribution where the responses are different and dramatically so for the land data. The results from the synthetics and real data show that a Kirchhoff migration with an extended imaging condition is capable of generating subsurface angle gathers. The same disadvantages with a ray‐based approach will apply using the extended imaging condition relative to a wave equation angle gather solution. Nevertheless, using this approach allows one to explore the relationship between the velocity model and focusing of the reflected energy, to use the Radon transformation to remove noise and multiples, and to generate consistent products from a ray‐based migration and a full‐wave equation migration, which can then be interchanged depending on the process under study.