Victorian bluestone : a proposed global heritage stone province from Australia
- Authors: Walter, Susan
- Date: 2020
- Type: Text , Book chapter
- Relation: Geological Society Special Publication p. 7-31
- Full Text: false
- Reviewed:
- Description: Victorian Bluestone is proposed as a Global Heritage Stone Province from Australia. Numerous heritage stones occur within this province and of these Malmsbury Bluestone is suggested as a Global Heritage Stone Resource. Bluestone, an iconic basalt dimension stone from Victoria, is used domestically and internationally with a recognized heritage value. Sources are located in urban and country areas of Victoria some of which are still utilized for dimension stone. In many instances bluestone has superior technical characteristics, including durability, that surpass high-quality commercial sandstones, despite an architectural preference for lighter-coloured stones. These characteristics are matched by the diversity of significant uses for domestic, commercial and infrastructure purposes especially in Victoria. Notable examples include the Spotswood Pumping Station, Malmsbury Viaduct, the Graving Dock (Williamstown), Malmsbury Reservoir, St Patrick's Cathedral (Melbourne), Kyneton Railway Station and Ararat Gaol. If the bluestone used in pavements and drains is also considered, Victorian Bluestone could be described as Australia's most prominent infrastructure heritage stone. Bluestone use in Melbourne dates from the 1840s, in the other states of Australia and in New Zealand from 1873, with international interest from Asia between 1860 and 1880. The stone continues to be utilized widely around Australia and is also exported. © 2018 The Author(s).
Evolution of the boundary between the western and central Lachlan Orogen : Implications for tasmanide tectonics
- Authors: Spaggiari, Catherine , Gray, David , Foster, David , McKnight, Stafford
- Date: 2003
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 50, no. 5 (2003), p. 725-749
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- Description: Differences in oblique overprinting, along-strike complexity as well as structural, metamorphic and timing constraints suggest that the boundary between the western and central subprovinces of the Lachlan Orogen, currently designated by the Governor Fault, cannot be a single structure. Previously limited data on the nature and kinematics of the fault/shear systems defining the boundary have led to varying scenarios for the tectonic evolution of the Lachlan Orogen. These scenarios either involve large-scale strike-slip displacement along the boundary with subsequent overthrusting or convergence of oppositely vergent thrust-systems with limited strike-slip translation. Geometrical constraints, fabric chronology and kinematic indicators in both the Mt Wellington (Melbourne Zone) and Governor (Tabberabbera Zone) Fault Zones indicate that maximum displacements relate to thrusting and duplex formation, followed by minor strike-slip faulting perhaps in response to slightly oblique collision of the Melbourne and Tabberabbera structural zones. Collision of these zones took place between ca 400 and 390 Ma. At Howqua, structural relationships indicate that collision involved northeast-directed thrusting of the Melbourne Zone (Mt Wellington Fault Zone) over the Tabberabbera Zone (Governor Fault Zone), and was followed by regional, northwest-trending, open folding. These structures overprint the dominant fabrics and metamorphic assemblages that are interpreted to relate to disruption and underthrusting of Cambrian oceanic/arc crust during closure of a marginal basin. Major deformation in the Tabberabbera Zone took place from ca 445 Ma and was associated with mélange formation, underplating and imbrication or duplexing (Governor Fault Zone, East Howqua segmennt). At slightly higher crustal levels, and following deposition of Upper Ordovician black shale and chert sequences (ca 440 Ma), Tabberabbera Zone evolution included offscraping of a serpentinite body (Dolodrook segment) that may have been either a Marianas-style seamount or transform fault zone within the Cambrian oceanic/arc crust. Major thrusting in the Mt Wellington Fault Zone was underway sometime after ca 420 Ma, and in contrast to the Governor Fault Zone, no mélange or broken formation was produced, metamorphism was at slightly higher temperatures and deformation probably occurred under higher strain states.
- Description: C1
- Description: 2003000547
Collembola fauna of the South Shetland Islands revisited
- Authors: Greenslade, Penelope
- Date: 2010
- Type: Text , Journal article
- Relation: Antarctic Science Vol. 22, no. (2010), p. 233-242
- Full Text: false
- Reviewed:
- Description: A review of the collembolan fauna of the South Shetland Islands is presented. Cryptopygus nanjiensis Yue & Tamura is synonymized with C. antarcticus Willem. A record of Tullbergia mediantarctica Wise from King George Island is considered a misidentification of Tullbergia mixta Wahlgren and Tillieria penai Weiner & Najt, described from the same island, is synonymized with T. mixta. The current fauna stands at eleven species, of which at least three are introduced. A checklist of Collembola currently considered to occur in the South Shetland Islands is supplied with distributional data.
Nature of gold mineralisation in the Walhalla Goldfield, southeast Australia
- Authors: Hough, M. A. , Bierlein, Frank , Ailleres, L. , McKnight, Stafford
- Date: 2010
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 57, no. 7 (2010), p. 969-992
- Full Text: false
- Reviewed:
- Description: The Walhalla-Woods Point Goldfield in southeast Australia is characterised by large gold deposits associated with a Late Devonian dyke swarm. The setting of this goldfield is unique because unlike the major gold deposits in Victoria, it occurs close to the eastern margin of the Western Lachlan Orogen, and highlights the disparities between the evolving phases of orogenic gold mineralisation in the Western Lachlan Orogen, and the contrasts between sediment hosted, dyke-associated and dyke-hosted gold mineralisation. This study integrates existing and new data from renewed mapping of the geology and geochemistry of three gold deposits near the township of Walhalla, in the historically important yet under-explored and under-researched Walhalla-Woods Point Goldfield. The ten highest yielding deposits within the goldfield are either hosted within, or adjacent to, intrusions of the Woods Point Dyke Swarm. This is due to the greater chemical reactivity of the calc-alkaline dykes, and the greater rheological contrast between the dykes and surrounding low-grade metasedimentary units, which allowed for the formation of dyke-hosted quartz breccia veins that are consistently favourable sites for gold mineralisation in the Walhalla Goldfield. This is in contrast to historical production, which concentrated on visible gold within the shear zone-hosted laminated quartz veins. Gold and As assay results have highlighted the increased levels of invisible gold disseminated along dyke margins in proximity to shear zones and quartz reefs. The high-yielding gold deposits hosted wholly by the dyke intrusions of the Woods Point Dyke Swarm are orogenic gold deposits, as they are not associated with elevated levels of Bi, W, As, Mb, Te and Sb, typical of intrusion-related gold deposits.
- Description: 2003008285
Leven Star deposit: An example of Middle to Late Devonian intrusion-related gold systems in the western Lachlan Orogen, Victoria
- Authors: Whittam, R. R. , Bierlein, Frank , McKnight, Stafford
- Date: 2006
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 53, no. 2 (2006), p. 343-362
- Full Text:
- Reviewed:
- Description: This study documents an example of atypical gold mineralisation in the central Victorian gold province of the western Lachlan Orogen, Australia. Unlike the vast majority of orogenic gold deposits in this region, the Leven Star deposit at Malmsbury is characterised by a disseminated-stockwork style of mineralisation, a close spatial and temporal association with post-tectonic felsic intrusions, complex alteration characteristics and a Au-As-Sb (±Bi-Te-Cu-Zn-Pb-Sn-W) ore assemblage. In contrast to orogenic-style, metamorphism-related gold mineralisation (ca 440 Ma), which pre-dated magmatism in the western Lachlan Orogen by tens of millions of years, ore formation in the Leven Star deposit was synchronous with, and is paragenetically younger than, Middle to Late Devonian (ca 370 Ma) magmatism. On the basis of these timing relationships, as well as whole-rock geochemistry, and structural, petrographic and fluid-inclusion data, it is suggested that the Leven Star deposit is not orogenic in character and instead should be classified as intrusion-related. © Geological Society of Australia.
- Description: C1
- Description: 2003001628
Significance of monazite EPMA ages from the Quamby Conglomerate, Queensland
- Authors: Evins, P. M. , Wilde, A. R. , Foster, David , McKnight, Stafford , Blenkinsop, T. G.
- Date: 2007
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 54, no. 1 (2007), p. 19-26
- Full Text:
- Reviewed:
- Description: Th-U-Pb electron microprobe (EPMA) dating of mainly detrital monazite from the Quamby Conglomerate in the Eastern Succession of the Mt Isa inlier reveals three distinct monazite growth/recrystallisation events at around 1640, 1580 and 1490 Ma. These ages are particularly significant with respect to the timing of deposition, iron and gold mineralisation, and deformation in the Mt Isa inlier. The oldest age probably represents provenance from igneous rocks. In the sample, the majority of monazite growth occurred at 1580 Ma, coeval with peak metamorphism in the Eastern Succession. The low metamorphic grade of the conglomerate and wide compositional range of monazite bearing this age indicates that the monazite grew elsewhere and was later deposited in the conglomerate. Purple bands in the rock are composed mainly of coarse specular hematite with recrystallised margins that contribute to high (up to 20%) Fe2O3 contents in the conglomerate. Gold is also present in some of the samples. Some of the monazite grains contain small, younger (ca 1490 Ma) domains that may have grown/ recrystallised in situ during a lower grade syn- or post-diagenetic metamorphic/hydrothermal event that may have been related to hematite (re)crystallisation. Together, these ages bracket deposition of the Quamby Conglomerate to between ca 1580 and 1490 Ma, the latter age most likely representing diagenesis. This depositional age also represents a maximum age for north-south-striking, upright folds of the Quamby Conglomerate and implies that significant ductile deformation has affected parts of the Mt Isa inlier after 1580 Ma and probably after 1490 Ma.
- Description: C1
- Description: Creative work
- Description: 2003004832
Grade control geological mapping in underground gold vein operations
- Authors: Dominy, Simon , Platten, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 2 (2012), p. 96-103
- Full Text: false
- Reviewed:
- Description: Grade control is a process of maximising value and reducing risk. It requires the delivery of tonnes at an optimum grade to the mill, via the accurate definition of ore and waste. It essentially comprises data collection, integration and interpretation, local resource estimation, stope design, supervision of mining and stockpile management. The foundation of all grade control programmes should be that of geological understanding led by clear and accurate mapping and representative sampling to drive appropriate estimation strategies and mining. Gold veins show features relating to erratic grade distribution (nugget effect), and variable geometry and internal architecture. These features include variations in dip, strike and width, late-stage faulting/shearing effects and vein continuity and type. Variations generally require close geological understanding to ensure optimum grade, minimal dilution and maximum mining recovery. A welldesigned grade control programme will prove to management and stakeholders that by applying geological knowledge, the mining process can be both efficient and cost effective. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
- Description: 2003010686
Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes
- Authors: Barr, Cameron , Tibby, John , Gell, Peter , Tyler, Jonathan , Zawadzki, Atun , Jacobsen, Geraldine
- Date: 2014
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 95, no. (July 2014 2014), p. 115-131
- Full Text: false
- Reviewed:
- Description: Climates of the last two millennia have been the focus of numerous studies due to the availability of high-resolution palaeoclimate records and the occurrence of divergent periods of climate, commonly referred to as the 'Medieval Climatic Anomaly' and 'The Little Ice Age'. The majority of these studies are centred in the Northern Hemisphere and, in comparison, the Southern Hemisphere is relatively under-studied. In Australia, there are few high-resolution, palaeoclimate studies spanning a millennium or more and, consequently, knowledge of long-term natural climate variability is limited for much of the continent. South-eastern Australia, which recently experienced a severe, decade-long drought, is one such region.Results are presented of investigations from two crater lakes in the south-east of mainland Australia. Fluctuations in lake-water conductivity, a proxy for effective moisture, are reconstructed at sub-decadal resolution over the past 1500 years using a statistically robust, diatom-conductivity transfer function. These data are interpreted in conjunction with diatom autecology. The records display coherent patterns of change at centennial scale, signifying that both lakes responded to regional-scale climate forcing, though the nature of that response varied between sites due to differing lake morphometry. Both sites provide evidence for a multi-decadal drought, commencing ca 650 AD, and a period of variable climate between ca 850 and 1400 AD. From ca 1400-1880 AD, coincident with the timing of the 'Little Ice Age', climates of the region are characterised by high effective moisture and a marked reduction in inter-decadal variability. The records provide context for climates of the historical period and reveal the potential for more extreme droughts and more variable climate than that experienced since European settlement of the region ca 170 years ago.
Sea-level trend analysis for coastal management
- Authors: Parker, Albert , Saad Saleem, Muhammad , Lawson, M.
- Date: 2013
- Type: Text , Journal article
- Relation: Ocean and Coastal Management Vol. 73, no. (2013), p. 63-81
- Full Text: false
- Reviewed:
- Description: A proper coastal management requires an accurate estimation of sea level trends locally and globally. It is claimed that the sea levels are rising following an exponential growth since the 1990s, and because of that coastal communities are facing huge challenges. Many local governments throughout Australia, including those on the coast, have responded to the various warnings about changes in climate and increases in sea levels by undertaking detailed climate change risk management exercises. These exercises, which use projections passed on by the relevant state bodies, are expensive, but still a fraction of the cost of the capital works that they recommend. Several councils have complained to an Australian Productivity Commission report on climate change adaptation they do not have the money for the capital works required. It is shown here that the exponential growth claim is not supported by any measurement of enough length and quality when properly analysed. The tide gauge results do not support the exponential growth theory. The projections by the relevant state bodies should therefore be revised by considering the measurements and not the models to compute the future sea level rises for the next 30 years following the same trend experienced over the last 30 years. © 2012 Elsevier Ltd.
Earth fissures triggered by groundwater withdrawal and coupled by geological structures in Jiangsu Province, China
- Authors: Wang, Guang-ya , You, Greg , Shi, Bin , Yu, Jun , Li, H. Y. , Zong, K. H.
- Date: 2008
- Type: Text , Journal article
- Relation: Environmental Geology Vol. , no. (2008), p. 1-8
- Full Text:
- Reviewed:
- Description: Earth fissures in Jiangsu Province, China have caused serious damages to properties, farmlands, and infrastructures and adversely affected the local or regional economic development. Under the geological and environmental background in Jiangsu Province, this paper presents the earth fissures caused by excessive groundwater withdrawal and coupled by distinctive geological structures such as Ancient Yellow River Fault in Xuzhou karst area, and Ancient Yangtze River Course and bedrock hills in Suzhou, Wuxi, and Changzhou area. Although all the earth fissures are triggered by groundwater exploitation, the characteristics are strongly affected by the specific geological and hydrogeological settings. In particular, in the water-thirsty Xuzhou city, the cone of depression caused by groundwater extraction enlarged nearly 20 times and the piezometric head of groundwater declined 17 m over a decade. As groundwater is extracted from the shallowly buried karst strata in the Ancient Yellow River Fault zone, the development of earth fissures is highly associated with the development of karstic cavities and sinkholes and their distribution is controlled by the Ancient Yellow River Fault with all the 17 sinkholes on the fault. On the other hand, in the rapidly developing Southern Jiangsu Province, groundwater is mainly pumped from the second confined aquifer in the Quaternary, which is distributed neither homogeneously nor isotropically. The second confined aquifer comprises more than 50 m thick sand over the Ancient Yangtze River Course, but this layer may completely miss on the riverbank and bedrock hills. With a typical drawdown rate of 4-6 m per annum, the piezometric head of groundwater in the second confined aquifer has declined 76 m at Maocunyuan since 1970s and 40 m at Changjing since mid-1980s, and a large land subsidence, e.g., 1,100 mm at Maocunyuan, is triggered. Coupled with the dramatic change of the bedrock topography that was revealed through traditional geological drilling and modern seismic reflection methods, the geological-structure-controlled differential settlement and earth fissures are phenomenal in this area. © 2008 Springer-Verlag.
The effect of prescribed fluid consumption on physiology and work behavior of wildfire fighters
- Authors: Raines, Jenni , Snow, Rodney , Petersen, Aaron , Harvey, Jack , Nichols, David , Aisbett, Brad
- Date: 2013
- Type: Text , Journal article
- Relation: Applied Ergonomics Vol. 44, no. 3 (2013), p. 404-413
- Full Text: false
- Reviewed:
- Description: The purpose of this study was to examine 1) wildfire fighters' ability to consume the prescribed fluid volume (1200 mL h-1), 2) the effect of fluid intake on plasma sodium and hydration, and 3) the effect of fluid intake on firefighters' heart rate, core temperature and activity during emergency suppression shifts. Methods: Thirty-four firefighters were divided into ad libitum (AD, n = 17) and prescribed (PR, n = 17) drinking groups. Results: PR drinkers did not meet the prescribed fluid target, yet consumed over double the volume of AD drinkers. No differences between groups in plasma sodium or hydration were noted. PR drinking resulted in lower core temperature between 2 and 6 h. This did not coincide with reduced cardiovascular strain, greater work activity or larger distances covered when compared to AD drinkers. Conclusion: Extra fluid consumption (above AD) did not improve firefighter activity or physiological function (though PR firefighters core temperature was lower earlier in their shift). Firefighter can self-regulate their fluid consumption behavior and work rate to leave the fireground euhydrated. © 2012 Elsevier Ltd and The Ergonomics Society.
Identification of observed factors that predict bather water-immersions at beaches
- Authors: Morgan, Damian , Ozanne-Smith, Joan
- Date: 2013
- Type: Text , Journal article
- Relation: Ocean and Coastal Management Vol. 84, no. (2013), p. 180-183
- Full Text: false
- Reviewed:
- Description: Coastal managers require accurate and relevant visitor information to manage visitor's leisure and recreation experiences. The study reports the development of a predictive model of bather water-immersions at selected beaches in Victoria, Australia for the daily peak-bathing period. Criterion variable data were collected over two summer periods to provide external validation. Predictor variables were observed on site or from secondary data. Results showed a statistically significant model meeting the required assumptions: Adjusted R2 = 0.65: F2, 292 = 270.50, p < 0.001; R2 95% CI: 0.58 to 0.71. Significant predictor variables were daily maximum air temperature and level of service (no service, toilet/water, or kiosk/club). Further research is required to assess the model generalisability to other beach locations and time frames
Approaches to reporting grade uncertainty in high nugget gold veins
- Authors: Dominy, Simon , Edgar, W.
- Date: 2012
- Type: Text , Journal article
- Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 1 (2012), p. 29-42
- Full Text: false
- Reviewed:
- Description: High nugget effect gold veins are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of reserves at production start-up. Despite the well-known risks, these deposits are often high grade and have a grade upside which makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The quoting of the estimated grade within a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion-based through to data-based estimates and geostatistical conditional simulation. Whichever approach is used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
- Description: 2003010578
Controls on the rate of ureolysis and the morphology of carbonate precipitated by S. Pasteurii biofilms and limits due to bacterial encapsulation
- Authors: Cuthbert, M. , Riley, Michael , Handley-Sidhu, Stephanie , Renshaw, Joanna , Tobler, Dominique , Phoenix, Vernon , Mackay, Rae
- Date: 2012
- Type: Text , Journal article
- Relation: Ecological Engineering Vol. 41, no. (2012), p. 32-40
- Full Text: false
- Reviewed:
- Description: Despite the potential contribution of microbially induced carbonate precipitation (MICP) to a range of environmental technologies, little is known about the controls on the rate of ureolysis and precipitate size and morphology using attached bacterial communities. This paper presents results of experiments using Sporosarcina pasteurii biofilms, of varying density, grown on perspex and granite surfaces then immersed in fluids comprising calcium chloride and urea of varying concentrations. Denser biofilms resulting from higher nutrient conditions led to faster nucleation of calcite and higher rates of ammonium production found to be related to crystal size via a power law. The observed morphology of the precipitates was variable depending on precipitation rates and nucleation of calcite was independent of the substrate mineralogy. In some cases the calcite layer became non-porous, and the bridging of pores within the granite was also observed. We show how ureolysis is limited eventually by the encapsulation of the biofilm by calcite and present a novel model that enables the reaction to be optimised to yield maximum calcite precipitation over a desired timescale. Slower reaction rates may in some circumstances be desirable for maximum reaction efficiency. The results have important implications for the design of engineering solutions involving MICP
A legacy of climate and catchment change: the real challenge for wetland management
- Authors: Gell, Peter , Mills, Keely , Grundell, Rosie
- Date: 2013
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 708, no. 1 (May 2013), p. 133-144
- Full Text: false
- Reviewed:
- Description: Wetland managers are faced with an array of challenges when restoring ecosystems at risk from changing climate and human impacts, especially as many of these processes have been operating over decadal-millennial timescales. Variations in the level and salinity of the large crater lakes of western Victoria, as revealed over millennia by the physical, chemical and biological evidence archived in sediments, attest to extended periods of positive rainfall balance and others of rainfall deficit. The recent declines in the depth of these lakes have been attributed to a 15% decline in effective rainfall since AD 1859. Whilst some sites reveal state shifts following past droughts, the response of most wetlands to millennial-scale climatic variations is muted. Regional wetland condition has changed comprehensively, however, since European settlement, on account of extensive catchment modifications. These modifications appear to have reduced the resilience of wetlands limiting their capacity to recover from the recent 'big dry'. These sedimentary archives reveal most modern wetlands to be outside their historical range of variability. This approach provides a longer-term context when assessing wetland condition and better establishes the restoration challenge posed by the impact of climate change and variability and human impacts.
- Description: C1
Paleoclimate studies and natural-resource management in the Murray-Darling Basin II: unravelling human impacts and climate variability
- Authors: Mills, Keely , Gell, Peter , Gergis, Joelle , Baker, Patrick J. , Finlayson, C. Max , Hesse, Paul , Jones, R. , Kershaw, Peter , Pearson, Stuart , Treble, Pauline , Barr, Cameron , Brookhouse, Matthew , Drysdale, Russell , McDonald, Janece , Haberle, Simon , Reid, Michael , Thoms, M. , Tibby, John
- Date: 2013
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 60, no. 5 (2013), p. 561-571
- Full Text: false
- Reviewed:
- Description: The management of the water resources of the Murray-Darling Basin (MDB) has long been contested, and the effects of the recent Millennium drought and subsequent flooding events have generated acute contests over the appropriate allocation of water supplies to agricultural, domestic and environmental uses. This water-availability crisis has driven demand for improved knowledge of climate change trends, cycles of variability, the range of historical climates experienced by natural systems and the ecological health of the system relative to a past benchmark. A considerable volume of research on the past climates of southeastern Australia has been produced over recent decades, but much of this work has focused on longer geological time-scales, and is of low temporal resolution. Less evidence has been generated of recent climate change at the level of resolution that accesses the cycles of change relevant to management. Intra-decadal and near-annual resolution (high-resolution) records do exist and provide evidence of climate change and variability, and of human impact on systems, relevant to natural-resource management. There exist now many research groups using a range of proxy indicators of climate that will rapidly escalate our knowledge of management-relevant, climate change and variability. This review assembles available climate and catchment change research within, and in the vicinity of, the MDB and portrays the research activities that are responding to the knowledge need. It also discusses how paleoclimate scientists may better integrate their pursuits into the resource-management realm to enhance the utility of the science, the effectiveness of the management measures and the outcomes for the end users.
- Description: C1
The aerial invertebrate fauna of subantarctic Macquarie Island
- Authors: Hawes, Timothy , Greenslade, Penelope
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Biogeography Vol. 40, no. 8 (2013), p. 1501-1511
- Full Text: false
- Reviewed:
- Description: Aim: The extent and diversity of invertebrate aerial dispersal both on remote islands and in polar regions has long been of interest to biogeographers. We therefore monitored the airborne dispersal of insects and other micro- and macroinvertebrates to and on Macquarie Island in order to assess (1) the magnitude and composition of local aerial dispersal activity by the island's invertebrate fauna, and (2) the potential for exotic arrival and establishment. Location: Macquarie Island. Methods: Two robust wind-traps were run year-round on Macquarie Island from 1991 to 1994 to collect airborne insects and other micro- and macroinvertebrates. Results: More than 3000 invertebrates were caught in these traps over the sampling period in the most comprehensive aerial survey of subantarctic invertebrates to date. Representatives of seven orders of Insecta were captured: Psocoptera, Thysanoptera, Hemiptera, Coleoptera, Diptera, Lepidoptera and Hymenoptera. Other taxa captured included other arthropods (Arachnida and Collembola) but also terrestrial Gastropoda. Evidence of possible long-distance dispersal (LDD) was limited to two exotic catches (one species of Collembolon, and one species of Thysanoptera). The abundance and composition of indigenous invertebrates caught in the traps indicates that the frequency of short-distance dispersal (SDD) movements on the island far exceeds that which had previously been realized. Main conclusions: More than half the total catch (53%) was of flightless (i.e. passively dispersed) invertebrates, with 84% of them flightless in one of the two traps. The extent of passive dispersal movements is consistent, with most invertebrates being widely distributed at a whole-island scale. Aerial dispersal may act as a conduit for non-indigenous arrivals but this occurs infrequently. Other explanations for exotic species in traps are equally likely. The implications of these findings are discussed in relation to terrestrial invertebrate biogeography. © 2013 Blackwell Publishing Ltd.
- Description: 2003011217
Disturbance and the role of refuges in mediterranean climate streams
- Authors: Robson, Belinda , Chester, Edwin , Mitchell, Bradley , Matthews, Ty
- Date: 2013
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 719, no. 1 (2013), p. 77-91
- Full Text: false
- Reviewed:
- Description: Refuges protect plant and animal populations from disturbance. Knowledge of refuges from disturbance in mediterranean climate rivers (med-rivers) has increased the last decade. We review disturbance processes and their relationship to refuges in streams in mediterranean climate regions (med-regions). Med-river fauna show high endemicity and their populations are often exposed to disturbance; hence the critical importance of refuges during (both seasonal and supraseasonal) disturbances. Disturbance pressures are increasing in med-regions, in particular from climatic change, salinisation, sedimentation, water extraction, hydropower generation, supraseasonal drought, and wildfire. Med-rivers show annual cycles of constrained precipitation and predictable seasonal drying, causing the biota to depend on seasonal refuges, in particular, those that are spatially predictable. This creates a spatial and temporal mosaic of inundation that determines habitat extent and refuge function. Refuges of sufficient size and duration to maintain populations, such as perennially flowing reaches, sustain biodiversity and may harbour relict populations, particularly during increasing aridification, where little other suitable habitat remains in landscapes. Therefore, disturbances that threaten perennial flows potentially cascade disproportionately to reduce regional scale biodiversity in med-regions. Conservation approaches for med-river systems need to conserve both refuges and refuge connectivity, reduce the impact of anthropogenic disturbances and sustain predictable, seasonal flow patterns. © 2012 Springer Science+Business Media Dordrecht.
- Description: C1
Paleoclimate studies and natural-resource management in the Murray-Darling Basin I: past, present and future climates
- Authors: Mills, Keely , Gell, Peter , Hesse, Paul , Jones, R. , Kershaw, Peter , Drysdale, Russell , McDonald, Janece
- Date: 2013
- Type: Text , Journal article
- Relation: Australian Journal of Earth Sciences Vol. 60, no. 5 (2013), p. 547-560
- Full Text: false
- Reviewed:
- Description: This paper provides an incisive review of paleoclimate science and its relevance to natural-resource management within the Murray-Darling Basin (MDB). The drought of 1997-2010 focussed scientific, public and media attention on intrinsic climate variability and the confounding effect of human activity, especially in terms of water-resource management. Many policy and research reviews make statements about future planning with little consideration of climate change and without useful actionable knowledge. In order to understand future climate changes, modellers need, and demand, better paleoclimate data to constrain their model projections. Here, we present an insight into a number of existing long-term paleoclimate studies relevant to the MDB. Past records of climate, in response to orbital forcing (glacial-interglacial cycles) are found within, and immediately outside, the MDB. High-resolution temperature records, spanning the last 105 years, exist from floodplains and cave speleothems, as well as evidence from lakes and their associated lunettes. More recently, historical climate records show major changes in relation to El Niño-Southern Oscillation cycles and decadal shifts in rainfall regimes. A considerable body of research currently exists on the past climates of southeastern Australia but, this has not been collated and validated over large spatial scales. It is clear that a number of knowledge gaps still exist, and there is a pressing need for the establishment of new paleoclimatic research within the MDB catchment and within adjacent, sensitive catchments if past climate science is to fulfil its potential to provide policy-relevant information to natural-resource management into the future. © 2013 Copyright Taylor and Francis Group, LLC.
- Description: C1
Gold mineralisation and ore controls at the Clogau mine, Dolgellau, north Wales, United Kingdom
- Authors: Dominy, Simon , Platten, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 1 (2012), p. 12-28
- Full Text: false
- Reviewed:
- Description: At a recorded production of 2·5 t Au and mill recovered grade of 17 g/t Au, Clogau is the largest and richest mine in the Dolgellau gold-belt and is the most prolific gold producer in the United Kingdom. The main period of production commenced in 1861 and ended in 1911, with intermittent production between 1983 and 2007. The principal gold-quartz bearing Main reef can be traced for about 3 km along strike, trending approximately NE-SW and dipping between 60uSE and 90uSE. The reef system pinches and swells, changes strike, and splits into a number of major and minor branches. Reef width is variable, ranging from 6 m to a few centimetres. The reef is internally complex and composed of swarms of narrow sub-parallel quartz veins separated by sheets of country rock. The gold-bearing vein segments within the composite reef package are discontinuous, though may locally possess bonanza grades running at 1000s g/t Au. The predictability of the gold-rich segments is poor, but has been shown to be related to presence of the Clogau Formation (black-shale), interactions of the reef fault with greenstone sills, and/or reef splitting to form discrete ore shoots. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
- Description: 2003010576