Canberra: a city for the future?     

Ernst Löffler 《Geoforum》1973,4(1):17-29

Present development and future planning of Canberra, the Australian National Capital, is described as an example of modern town planning emphasising the spatial and functional organisation of the urban area. Canberra is a rapidly growing city and is being expanded by the creation of new dispersed satellite towns which are grouped around Inner Canberra in three growth corridors. The towns are structured into a hierarchical order of centers and provide a large range of services and facilities as well as a concentration of employment opportunities. Although the towns are self-supporting to a great degree, they remain integral parts of the metropolis with the City center providing the greatest range of services and facilities, as well as employment. One of the main problems facing the Capital is the inefficiency of public transport and accordingly the strong reliance on private motor vehicles, which will be difficult to overcome If present population densities are not substantially increased.  相似文献   

Paleoenvironments and cultural diversity in late Pleistocene South America     

Alan L. Bryan 《Quaternary Research》1973,3(2):237-256

After a summary assessment of certain selected early man sites in various parts of America, the environment of the Venezuelan coastal plain is discussed in order to evaluate the stratigraphy and radiometric dating of the Taima-Taima site, near Coro, Venezuela, where mammals, many now extinct, were killed by people making El Jobo points about 13,000 years ago.Potentially important areas in Peru, Chile and Brazil are mentioned. Certain problems in the models and interpretation of South American paleoclimates are pointed out.The presence of at least four different bifacially flaked stone projectile point traditions in widely separated and environmentally diverse parts of America between 11,000 and 13,000 yr ago suggests that the immediate cultural antecedents of these traditions were essentially independent of one another. From this it is argued that several early American flaked-stone point traditions developed indigenously in America from technological bases which were present in the Old World Middle Paleolithic.  相似文献   

Über Zersetzungsprodukte von Olivin-Feldspatbasalten     

Dr. Ernst Bolter 《Contributions to Mineralogy and Petrology》1961,8(2):111-140

Zusammenfassung Es wurden die am Kontakt zum Nebengestein, in gangartigen Zersatzzonen und als Zersatzrinden an Basaltblöcken auftretenden Umwandlungserscheinungen von vier Olivin-Feldspat-Basalten optisch, röntgenographisch chemisch und differentialthermoanalytisch untersucht. Die Zersetzung der Minerale erfolgt in der Reihenfolge Olivin, Glas, An-reiche Plagioklase, Pyroxen, Abreiche Plagioklase, K-Analbite, Apatit, Biotit, Erz. Im Anfangsstadium der Zersetzung werden Mg- und Fe-reiche Montmorinminerale gebildet. Bei stärkerer Zersetzung entstehen Kaolin- und Mg- und Fe-reiche Montmorinminerale. Die Kaolinmineralbildung scheint dabei besonders begünstigt zu werden, wenn gute Möglichkeiten einer Wegfuhr von in Lösung gegangenen Elementen vorhanden sind. Außer den Tonmineralen wird noch Goethit neugebildet. Bei der Zersetzung der Pyroxene werden in diesen keine Mineralneubildungen, sondern nur Lösungserscheinungen beobachtet. Im Anfangsstadium der Zersetzung fällt besonders eine starke Oxydation von Fe⁺⁺ zuF+++ und eine deutliche Abnahme des MgO-Wertes auf, während Calcium erst bei stärkerer Zersetzung wegtransportiert wird. Die Alkalien werden bei leichter Zersetzung relativ angereichert. Die stärkste relative Anreicherung wird beim Titan beobachtet. Auch der Al₂O₃-Wert steigt mit zunehmender Zersetzung. Die Änderungen des SiO₂-Wertes sind im Vergleich zu den anderen Elementen gering. Die Zersetzung der untersuchten Basalte erfolgte wahrscheinlich durch mehr oder weniger saure Lösungen. Im Zusammenhang mit der Basaltzersetzung wurde ein Vorkommen von Chloropal untersucht.  相似文献   

A Geochemical and Isotopic Approach to Delineate Landfill Leachates in an RCRA Study     

Steven J. Fritz  Jeffrey D. Bryan  F. Edwin Harvey  Darrell I. Leap 《Ground water》1994,32(5):743-750

  相似文献   

清镇陨石（EH3）硫镁矿微量元素化学特征   总被引：1，自引：0，他引：1  

陈永亨佩里卡  E 《矿物学报》1993,13(3):197-203

本文应用电子探针和中子活化分析方法详细研究了清镇陨石(EH 3)中硫镁矿的化学组成和微量元素分布、硫镁矿携带了部分HREE、高度富集钪等难熔亲石元素,论证了该矿物的高温成因,REE丰度可能与陨硫钙石互补。该矿物含有钠-硒组分,可能是顽火辉石陨石独有的组分。铬归一化的钠-钴(原子比)相关关系具有CI一致的趋势,表明其母体来自太阳组成的气体星云。  相似文献   

Three-Dimensional Structural Geological Modeling Using Graph Neural Networks     

Hillier  Michael  Wellmann  Florian  Brodaric  Boyan  de Kemp  Eric  Schetselaar  Ernst 《Mathematical Geosciences》2021,53(8):1725-1749

Mathematical Geosciences - Three-dimensional structural geomodels are increasingly being used for a wide variety of scientific and societal purposes. Most advanced methods for generating these...  相似文献   

Fast 3-D simulation of transient electromagnetic fields by model reduction in the frequency domain using Krylov subspace projection   总被引：3，自引：0，他引：3  

Ralph-Uwe Börner  Oliver G. Ernst  Klaus Spitzer 《Geophysical Journal International》2008,173(3):766-780

  相似文献   

Effect of trench-outer rise bending-related faulting on seismic Poisson's ratio and mantle anisotropy: a case study offshore of Southern Central Chile     

Eduardo Contreras-Reyes  Ingo Grevemeyer  Ernst R. Flueh  Martin Scherwath  Joerg Bialas 《Geophysical Journal International》2008,173(1):142-156

  相似文献   

From intrabasinal volcanism to far-field tectonics: causes of abrupt shifts in sediment provenance in the Devonian–Carboniferous Drummond Basin,Queensland     

K. Sobczak  S. E. Bryan  C. R. Fielding  M. Corkeron 《Australian Journal of Earth Sciences》2019,66(4):497-518

The Drummond Basin of central Queensland preserves a large-volume succession of little studied, predominantly fluviatile, coarse-grained sedimentary rocks of mid-Mississippian age. The stratigraphy of the basin has been subdivided into three sedimentary cycles. The Cycle 1/Cycle 2 boundary records a distinct, but poorly understood change in provenance from a volcanic-dominated succession related to initial basin rifting (Cycle 1) to a quartz-rich, craton-derived succession (Cycle 2). Cycle 3 has been thought to mark a resumption of intrabasinal volcanism and related sedimentation. The purpose of this study was to enhance the understanding of the basin-wide siliciclastic sedimentation of Cycles 2 and 3, and causes for the changes in sediment provenance. This objective was achieved by constraining large-scale spatial and temporal depositional trends and investigating sediment transport pathways into and through the basin. Petrographic, QFL, paleocurrent and conglomerate clast analyses were undertaken. The observations presented here have several implications relevant to understanding the stratigraphy of the Drummond Basin and regional tectonic events at this time. Cycle 3 is revised here primarily to be a continuation of Cycle 2-style basement-derived sedimentation, rather than recording a resumption of volcanism in the area, as per prevailing models. Quartz-rich sedimentation in the Drummond Basin was, therefore, more long-lived than previously envisaged, and once established, was not significantly disrupted by volcanism. Cycle 2 formation thicknesses appear highly variable across the basin. This is unlikely to be a result of pre-existing rift-related topography as suggested in previous models. The thickness variations are more likely related to sediment bypassing and post-depositional deformation in the area. The distinctive coarse-grained, relatively quartz-rich sedimentation of Cycles 2 and 3 is unusual in its volume and extent. The sediment was transported into the basin from its southern/southwestern margin, implying long-distance transport and extrabasinal sediment supply. While the specific source terrain(s) remain unknown, one plausible tectonic driver was far-field influence of the intraplate Alice Springs Orogeny.  相似文献   

Estimating parameters of the channel width–flow discharge relation using rill and gully channel junction data     

M. Pilar Salvador Sanchis  Dino Torri  Lorenzo Borselli  Rorke Bryan  Jean Poesen  Marta S. Yañez  Cati Cremer 《地球表面变化过程与地形》2009,34(15):2023-2030

Eroding channels can usually be characterized by a power relationship between channel width (W) and channel discharge (Q). This paper examines the WQ relation using a recently developed channel junction approach to extend the validity of the WQ relation and to develop a procedure for estimating the WQ exponent and proportionality coefficient. Rill and gully channel data from the literature, and new data collected in different badland areas and in a few forest mountain streams, are analysed. Analysis shows that the WQ relation for channel width collected in badlands and forests agrees with trends observed for cropland. The exponent increases with increasing channel width in a continuous fashion rather than in a step‐like way and tends to a maximum whose value ranges between 0·5 and 0·6. The proportionality coefficient can be split into two terms, one expressing the case in which an eroding channel can broaden, the other reflecting the difficulties in removing the less erodible clods or rock fragments from the channel bed. Its splitting allows the development of a more correct form of the WQ relation in agreement with modern approaches of channel geometry: one part has the dimension of a discharge and makes the power base dimensionless, while the other brings the dimension of a length, needed for the channel width, into the WQ relation. The interpretation of the two constants is supported by data collected in rainfall‐runoff simulation experiments conducted in the field. Values characterizing the two constants in some environments are also given. Nevertheless the approach is not sufficiently parameterized yet to be of practical use (e.g. in models or for estimating peak discharge in areas where rill channels have formed). Copyright © 2009 John Wiley & Sons, Ltd.  相似文献