Comparative advantage and distant water fishing fleets: The Australian east coast tuna longline fishery     

HF Campbell  A McIlgorm 《Marine Policy》1997,21(6):493-499

A coastal state benefits from importing the services of a distant water fishing nation (DWFN) fleet if the DWFN has a comparative advantage in exploiting the fishery, based on factors such as market access, costs or technology. The paper compares the activities of the Australian and Japanese vessels in the east coast tuna longline fishery and finds the Australian vessels receive higher prices, have higher costs and use a different technology from the Japanese fleet. These differences suggest a pattern of comparative advantage which can lead to Australia benefitting from importing the services of the Japanese fleet.  相似文献   

Architecture and emplacement of the Nebo–Babel gabbronorite-hosted magmatic Ni–Cu–PGE sulphide deposit,West Musgrave,Western Australia     

Zoran Seat  Stephen W. Beresford  Benjamin A. Grguric  Rob S. Waugh  Jon M. A. Hronsky  M. A. Mary Gee  David I. Groves  Charter I. Mathison 《Mineralium Deposita》2007,42(6):551-581

The Nebo–Babel Ni–Cu–platinum-group element (PGE) sulphide deposit in the West Musgrave Block, Western Australia, is the largest nickel sulphide discovery in the last 10 years. The deposit is hosted within a concentrically zoned, olivine-free, tube-like (chonolithic), gabbronorite intrusion associated with the, approximately, 1,078-Ma Giles Complex-layered intrusions in the Warakurna large igneous province. Emplaced into sulphide-free amphibolite facies orthogneiss, the fault-offset Nebo–Babel chonolith extends for 5 km and has a cross-section of 1 × 0.5 km. Igneous mineralogy, fabrics, and textures are well preserved. The lithostratigraphy includes variably textured leucogabbronorites (VLGN) that form an outer shell around mineralised gabbronorite (MGN), with barren gabbronorite (BGN) and oxide–apatite gabbronorite (OAGN) in the middle and lower parts of the chonolith. Mineral and whole-rock geochemistry indicate that the units become progressively evolved in the order: VLGN, MGN, BGN, and OAGN, and that incompatible trace-element concentrations increase downwards within the MGN and BGN. The mineralisation, which is confined to the early, more primitive units (VLGN and MGN), occurs as massive sulphide breccias and stringers and as disseminated gabbronorite-hosted sulphides. The massive sulphides were emplaced late in the intrusive sequence, have different PGE chemistry and Cu tenor to the disseminated sulphides, and have undergone sulphide fractionation. The distribution of disseminated sulphides, which are primary magmatic in origin, is related to chonolith geometry and magma flow regimes, rather than to gravitational settling. Sulfur-bearing country rocks are absent in the Nebo–Babel deposit area, and thus, local crustal S addition was unlikely to have been the major mechanism in achieving sulphide immiscibility. The Nebo–Babel intrusion is part of an originally continuous magma chonolith with multiple and related magma pulses. The parental magma was medium- to low-K tholeiite with 8–9 wt% MgO. The initial magma pulse (VLGN), the most primitive and sulphide saturated, was probably emplaced along a linear weakness in the country rock. After crystallisation of VLGN, marginally more fractionated, sulphide-saturated magma was injected through the thermally insulated core of the conduit, forming the MGN. Successive pulse(s) of more fractionated magma (BGN) were emplaced in the core of the intrusion. After magma flow ceased, closed system crystal fractionation produced consistent mineral and chemical fractionation trends within BGN and OAGN. After crystallisation, the intrusion was overturned and then offset by the Jameson Fault resulting in the apparent ‘reverse’ chemical and mineral trends in Nebo–Babel.  相似文献   

Internal stratigraphic architecture of the komatiitic dunite-hosted MKD5 disseminated nickel sulfide deposit,Mount Keith Domain,Agnew-Wiluna Greenstone Belt,Western Australia     

N. M. Rosengren  B. A. Grguric  S. W. Beresford  M. L. Fiorentini  R. A. F. Cas 《Mineralium Deposita》2007,42(8):821-845

The MKD5 nickel deposit is hosted by the Mount Keith Ultramafic Complex (MKUC), a dunite body of komatiitic affinity located in the Agnew-Wiluna Greenstone Belt, Western Australia. The internal architecture of the MKUC comprises seven distinct internal units that range from extreme adcumulate dunite to relatively fractionated pyroxenitic and gabbroic horizons. The MKUC is divided into three packages of units. The main adcumulate domain (MAD), which is situated in the lower portion of the complex, contains the bulk of disseminated nickel sulfide and is dominated by coarse adcumulate olivine textures. Overlying the MAD is an upper fractionated zone, which is dominated by mesocumulate-to-orthocumulate peridotite with domains containing oikocrystic pyroxenite and gabbroic lenses. An aerially restricted unit comprising texturally and chemically distinct olivine cumulate rocks is known as the western mineralized zone (WMZ). The fractionation trend between the MAD and UPZ indicates a westerly facing for the MKUC, conformable with the bounding stratigraphy. In the MKUC, truncation of some of the uppermost internal stratigraphic units by the hangingwall contact indicates that the unit has undergone structural modification since its emplacement and suggests that a proportion of the upper section has been removed by faulting. Furthermore, vertical and lateral textural transitions within the internal stratigraphy suggest that the MKUC (excluding the WMZ) was emplaced from an essentially continuous magma flow, with the MAD representing the period of highest magma flux and the major constructional period of emplacement. Conversely, the WMZ is interpreted to represent a later pulse of ultramafic magma, emplaced stratigraphically above the main MKUC. Comparison of the MKUC with other komatiitic dunites from both within the Agnew-Wiluna Greenstone Belt and worldwide indicates that despite apparent geometrical differences between lens and sheet komatiitic dunites, a broad facies architecture can be defined. We suggest that the differences in geometry are related to differing degrees of flow localization within dunitic units and are a function of both differences in the thermal characteristics and the degree of litho-facies heterogeneity of the enclosing lithologies.  相似文献   

东澳大利亚南悉尼盆地二叠系与地震沉积有关的软沉积变形构造   总被引：18，自引：3，他引：18       下载免费PDF全文

杜远生  G.SHI  龚一鸣  徐亚军 《地质学报》2007,81(4):511-520

悉尼盆地位于澳大利亚东部,Lachlan褶皱带和New England褶皱带之间。悉尼盆地从晚石炭世末到中三叠世经历了弧后扩张到前陆盆地的不同阶段:弧后扩张阶段(石炭纪)、被动热沉降阶段(早、中二叠世Berry组)和挤压挠曲负载阶段(中二叠世Broughton组—三叠纪)。此时位于悉尼盆地东侧的New England褶皱带为岛弧背景。因此,二叠纪处于弧后盆地的南悉尼盆地受弧后扩张和东侧弧前海沟俯冲的影响地震活动强烈,发育一系列与地震有关的震积岩,形成多种类型的与地震活动有关的软沉积物变形构造。南悉尼盆地二叠系的软沉积物变形包括地裂缝、震褶层、液化脉、沙火山、负荷构造、火焰构造、枕状构造、球状构造、枕状层、滑塌构造、角砾岩化等。其中地裂缝、震褶层是地震颤动直接引起的断裂和褶皱;枕状层是地震颤动引起的砂层脱水、下沉形成的;液化脉、沙火山为液化的砂层穿入地震形成的裂隙形成的;负荷构造、火焰构造、枕状构造、球状构造是受地震颤动在砂、泥岩界面上由于砂层下沉、泥层上穿形成的;滑塌构造和角砾岩化是地震引起的重力滑塌或泥石流形成的。地裂缝、震褶层、液化脉、沙火山、负荷构造、火焰构造、枕状构造、球状构造、枕状层相当于原地震积岩,而滑塌构造和角砾岩化属于异地震积岩。  相似文献   

Numerical simulation of the summer wake of Rottnest Island, Western Australia     

Majid Jandaghi Alaee  Charitha Pattiaratchi  Greg Ivey 《Dynamics of Atmospheres and Oceans》2007,43(3-4):171-198

During the summer, a northward, wind-driven current dominates the Rottnest Island region in southwestern Australia. Field studies have shown that the interaction between Rottnest Island and the northward current generates upwelling at the western end of the island, which is advected downstream, resulting in isotherm doming in the wake region. Flow curvature-induced secondary circulation has been proposed as the dominant mechanism responsible for this upwelling. Here, a three-dimensional numerical model, together with field observations, was used to undertake a detailed investigation of the three-dimensional flow structure in the wake region. Comparison of the observed upwelling pattern and the simulated flows revealed the island's dominant role in generating upwelling. This result was confirmed with the use of idealized numerical experiments. The modeling results confirmed the presence of secondary circulation, generated as a result of flow curvature at the western end of the island, which caused strong upwelling and extended downstream.  相似文献   

Catchment-scale (dis)connectivity in sediment flux in the upper Hunter catchment, New South Wales, Australia   总被引：3，自引：1，他引：3  

Kirstie A. Fryirs  Gary J. Brierley  Nicholas J. Preston  John Spencer 《Geomorphology》2007,84(3-4):297

(Dis)connectivity within and between landscape compartments affects the extent and rate of transfer of energy and matter through catchments. Various landforms may impede sediment conveyance in a river system, whether laterally to the channel (termed buffers) or longitudinally along the channel itself (termed barriers). A generic approach to analysis of landscape (dis)connectivity using slope threshold analysis in GIS, tied to air photograph interpretation and field mapping of buffers and barriers, is tested in the upper Hunter catchment, Australia. Under simulated conditions, effective catchment area, which is a measure of the proportion of a catchment that has the potential to contribute sediment to the channel network, varies from 73% to just 3% of the total catchment area for differing subcatchments in the upper Hunter. This variability can be explained by the spatial distribution and assemblage of buffers and barriers in each subcatchment. Multiple forms of disconnectivity are evident in some subcatchments, such that when one buffer or barrier is breached, other features still impede sediment transfer within the system. The importance of the position of buffers and barriers within any given subcatchment is emphasised. Spatial variability in valley width exerts a critical control on catchment connectivity, with more efficient sediment conveyance in narrow valleys relative to wider valleys characterised by piedmonts, terraces, fans and extensive floodplains in which conveyance is impeded. This variability reflects the landscape history and geological setting of each subcatchment. The framework developed in this paper can be used to assess the impact of natural or human-induced buffers and barriers on catchment-scale sediment flux in any landscape setting, providing a physical template atop which other biogeochemical fluxes could be examined.  相似文献   

Gleaning from Gluttony: an Australian youth subculture confronts the ethics of waste     

Ferne Edwards 《The Australian geographer》2007,38(3):279-296

As part of the global ‘rights to the city’ movement and mounting concern over food waste, results are presented here of an ethnographic study of young people in Australia who choose to glean food from supermarket ‘dumpster bins’ and open markets primarily for political reasons. These youth form part of an international ‘freegan’ subculture: the belief in ‘minimising impact on the environment by consuming food that has literally been thrown away’ (Macmillan English Dictionary Online 2002). The study explores the emergence of two related subcultures: ‘Dumpster Diving’ (the act of procuring food from a supermarket dumpster bin for individual consumption) and ‘Food Not Bombs’ (a global-spanning group who collect left-over food from markets to cook and serve to people on the street). The analysis focuses on the ethics embedded within their alternative consumption diets. These findings are analysed in terms of the creation of their alternative identities performed on temporal–spatial terrains, exemplifying the role of the contemporary activist's use of space, place and culture in relation to social issues.  相似文献   

Channel response to a new hydrological regime in southwestern Australia     

J.N. Callow  K.R.J. Smettem 《Geomorphology》2007,84(3-4):254

The Kent River flows from semi-arid headwaters in the agricultural (wheatbelt) region of Western Australia to a wetter and forested lower-catchment. It is set in an atypical fluvial environment, with rainfall decreasing inland towards a low-relief upper catchment. Replacement of native deep-rooted perennial vegetation with shallow-rooted seasonal crops has altered the hydrology of the upper catchment. Clearing for agriculture has also increased recharge of regional groundwater systems causing groundwater to rise and mobilise salt stores. This has increased stream salinity which has degradation riparian vegetation and decreased flow resistance. Elevated groundwater has also affected streamflow, increasing flow duration and annual discharge. The altered hydrological regime has affected geomorphic stability, resulting in channel responses that include incision and removal of uncohesive material. Channel response is variable, showing a high dependence on channel morphotype, channel boundary material and severity of salinity (degree of vegetation degradation). Response in confined reaches bounded by sandy material has been characterised by minor lateral bank erosion. In the fine-grained, wider, low-gradient reaches, mid-channel islands have been stripped of sandy sediment where vegetation has degraded. Following an initial period of high erosion rates in these reaches, the channel is now slowly adjusting to a new set of boundary conditions. The variable response has significant implications for management of salt affected rivers in southwestern Australia.  相似文献   

澳大利亚西澳州2004-2005年度矿产勘探综述   总被引：1，自引：0，他引：1  

张金昌 《地质通报》2007,26(3):361-365

介绍了澳大利亚西澳州2004—2005年度金、镍、铁、钛、锆、金刚石矿床的勘探情况和取得的找矿成果。简述了2004—2005年度西澳州矿产勘探(包括石油勘探)消费支出、不同矿产品所占勘探支出的份额、钻探、矿山土地复垦及环境保护的情况。  相似文献   

Assessing the threat to Western Australia from tsunami generated by earthquakes along the Sunda Arc   总被引：1，自引：1，他引：1  

David Burbidge  Phil Cummins 《Natural Hazards》2007,43(3):319-331

A suite of tsunami spaced evenly along the subduction zone to the south of Indonesia (the Sunda Arc) were numerically modelled in order to make a preliminary estimate of the level of threat faced by Western Australia from tsunami generated along the Arc. Offshore wave heights from these tsunami were predicted to be significantly higher along the northern part of the west Australian coast than for the rest of the coast south of the town of Exmouth. In particular, the area around Exmouth may face a higher tsunami hazard than other areas of the West Australian coast nearby. Large earthquakes offshore of Java and Sumbawa are likely to be a greater hazard to WA than those offshore of Sumatra. Our numerical models indicate that a magnitude 9 or above earthquake along the eastern part of the Sunda Arc has the potential to significantly impact a large part of the West Australian coastline. The Australian government reserves the right to retain a non-exclusive, royalty free license in and to any copyright.  相似文献