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  • 1
    Electronic Resource
    Electronic Resource
    Source of Pb in orogenic lode-gold mineralisation: Pb isotope constraints from deep crustal rocks from the southwestern Archaean Yilgarn Craton, Australia (1999)
    Springer
    Mineralium deposita 34 (1999), S. 366-381 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Southern Cross was one of the earliest gold mining centres in Western Australia. Over 142 tonnes of gold have been produced from the district, and, on a gold per hectare basis, the Southern Cross greenstone belt in the southwestern Yilgarn Craton is the most productive of Western Australia's Archaean greenstone belts. The SW Yilgarn Craton is characterised by high-grade (amphibolite- to granulite-facies) metamorphism, extensive granitoid magmatism and older greenstone volcanism ages, compared to the well-known greenschist-facies metamorphism and younger (2.7 Ga) eruption ages which dominate in the Eastern Goldfields Province. The Pb-isotope compositions of deep-seated granitoids in the SW Archaean Yilgarn Craton, which were emplaced coeval with a craton-wide major orogenic lode-gold mineralization event at about 2.64–2.63 Ga, have been determined for 96 whole-rock and 24 K-feldspar samples. The Pb isotope data of the granitoids are consistent with a crustal origin for their genesis, probably by reworking (partial melting) of older continental crust. The Pb isotope composition of greenstones, which are the main host rocks for gold mineralisation, and pyrites from the komatiite-hosted syngenetic Ni deposits in the amphibolite-facies Forrestania greenstone belt, have also been determined, with initial Pb-isotope ratios higher than that for the Eastern Goldfields Province. The Pb isotopic character of the orogenic lode-gold deposits in the region is intermediate between coeval granitoid and greenstone Pb, indicating that the ore fluids contained metals from both reservoirs. The Pb in the ore fluid of the most deeply formed deposit, Griffin's Find, overlaps the isotopic composition of coeval granitoids, indicating the deep-seated granitoid magmatism was the primary source for Pb in the ore fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001260050210
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  • 2
    Electronic Resource
    Electronic Resource
    Pb isotope fingerprinting of mesothermal gold deposits from central Victoria, Australia: implications for ore genesis (1998)
    Springer
    Mineralium deposita 33 (1998), S. 633-638 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract New Pb isotope data from three major mesothermal lode gold deposits (Ballarat West, Tarnagulla, Maldon) in central Victoria support a model whereby the metals derived from a large reservoir with a long residence time in the crust below the Palaeozoic Lachlan Fold Belt. The Pb isotopic ratios of least radiogenic samples from these deposits are in close agreement with published Pb signatures for turbidite-hosted gold deposits, and for Devonian granites, elsewhere in the Lachlan Fold Belt. Despite their spatial distribution and variations in the geological setting, the Pb signatures point to the extraction and transport of metals from a crustal source area by long-lasting, large-scale hydrothermal systems, resulting in the prominent homogenisation of Pb isotopic ratios. The enduring interaction between large hydrothermal systems and an extensive crustal source reservoir were a vital pre-requisite in the formation of the Victorian gold province. In this regard, the prospectivity of Victoria is analogous to world-class ore provinces elsewhere, such as the Archaean Yilgarn Block in Western Australia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001260050178
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  • 3
    Electronic Resource
    Electronic Resource
    Archaean Au−Ag mineralisation at Racetrack, near Kalgoorlie, Western Australia: a high crustal-level expression of the Archaean composite lode-gold system (1993)
    Springer
    Mineralium deposita 28 (1993), S. 375-387 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Racetrack Au−Ag deposit, in the Archaean Yilgarn Block, Western Australia, is hosted by a porphyritic basalt in a low greenschist facies setting and is associated with a brittle strike-slip fault system. Three distinct and successive stages of hydrothermal activity and late quartz-carbonate veining resulted in multiple veining and/or brecciation: Stages I and II are Au-bearing, whereas Stage III and late veins are barren. The ore shows features of both classic epithermal and mesothermal deposits. Alteration assemblages, typified by sericitization, carbonization, silicification and chloritization, are similar to those of mesothermal gold deposits, wheras the quartz vein-textures including comb, rosette, plumose and banded, ore mineralogyof arsenopyrite, pyrite, chalcopyrite, sphalerite, galena, freibergite, tetrahedrite, tennantite, fahlore, electrum and gold, and metal associations (Cu, As, Ag, Sn, Sb, W, Au and Pb) are more characteristics of epithermal deposits. Fluid inclusions related to Stage II are two phase and aqueous with 1–8 (average 4) wt. % NaCl equiv. and CO2 content of 〈0.85 molal. Pressure-corrected homogenisation temperatures range from 190°C to 260°C. Mineral assemblages indicate that ore fluid pH ranged between 4.2 and 5.3, fO 2 between 10−38.8 and 10−39.6 bars, and mΣs between 10−3.2 and 10−3.6. Calculated chemical and stable isotope compositions require a component of surface water in the ore fluid depositing the mineralisation, but evidence for deep crustal Pb indicates that deeply sourced fluids were also involved. The deposit is interpreted to have formed in a shallow environment via mixing of deeply sourced fluids, from at least as deep as the base of the greenstone belt, with surface waters. It therefore represents the upper crustal end-member of the crustal depth spectrum of Archaean lode-gold mineralisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431597
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  • 4
    Electronic Resource
    Electronic Resource
    The source of lead in Archaean lode gold deposits of the Menzies-Kalgoorlie-Kambalda region, Yilgarn Block, Western Australia (1993)
    Springer
    Mineralium deposita 28 (1993), S. 495-502 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Archaean greenstone terrane between Menzies and Kambalda exhibits a coherent, although deformed, stratigraphic sequence intruded by granitoids and bounded by major NNW-trending shear and/or fault zones. The greenstone terrane hosts a large number of lode gold prospects and deposits, including the giant Kalgoorlie deposits. The initial Pb isotope compositions of lode gold deposits, as determined from ore related galena and pyrite, vary systematically in a linear trend on a207Pb/204Pb versus206Pb/204Pb diagram which reflects crustal heterogeneity at the time of mineralisation. Deposits hosted within a 90 km section of the Menzies-Boorara Shear Zone have a uniform, radiogenic initial Pb isotope composition irrespective of temperature of mineralisation and proximity to granitoid-gneiss in plan view. The Pb in these deposits is considered to be derived largely from older felsic crust underlying the greenstone belt and was accessed via this major shear-zone system. Deposits in a transect unrelated to a major shear zone show a systematic correlation between initial Pb isotope compositions and proximity to granitoid-gneiss and/or to mineralisation temperature. These compositions are less radiogenic than those within the Menzies-Boorara Shear Zone, but trend on a207Pb/204Pb versus606Pb/204Pb diagram between this isotope signature and the uniform Pb isotope signature which characterises the 〉100 km greenstone transect from the Mt Pleasant area through Kalgoorlie to Kambalda. These data are interpreted to reflect Pb derivation from discrete crustal segments within and below the greenstones, and require that mineralisation was related to crustal-scale hydrothermal systems that accessed both sialic mid- to lower-crust and the greenstone succession.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431605
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  • 5
    Electronic Resource
    Electronic Resource
    Collateral specific long term potentiation of the output of field CA3 of the hippocampus of the rat (1986)
    Springer
    Experimental brain research 62 (1986), S. 250-258 
    Details
    ISSN: 1432-1106
    Keywords: Longterm potentiation ; Hippocampus ; Collateral specificity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long term potentiation (LTP) in response to brief high frequency trains has been reported for many pathways in the hippocampus. The mechanisms involved are still unclear. The present experiments set out to confirm reports in the literature that LTP of output from CA3 neurons can be specific to particular collaterals. Single pulses delivered to area CA3 produced field responses nearly simultaneously in area CA1 and in the lateral septum (LS). High frequency stimulation of CA3 produced long term potentiation of CA1 but not LS responses. The CA1 response to stimulation of the contralateral hippocampus did not potentiate when the CA1 response to CA3 stimulation showed long term potentiation. The CA1 and LS responses to CA3 stimulation showed similar strength-duration, strength-amplitude and frequency following characteristics. Their latencies were comparable to the latencies of antidromic activation of CA3 cells from CA1 and LS. Movement of stimulating electrodes to the region of the Schaffer collaterals increased the latency of the LS response and decreased the latency of the CA1 response but left the sum of these latencies unchanged. It was concluded that the CA3 and Schaffer stimulation were activating LS and CA1 collaterals of the same CA3 neurons. CA1 and LS responses to CA3 stimulation showed somewhat different paired pulse and frequency potentiation characteristics. These data confirm reports in the literature that long term potentiation is both input-specific and collateral-specific. The mechanisms of long term potentiation are likely, therefore, to be limited to changes at specific synaptic junctions, e.g. changes in sensitivity of specific postsynaptic receptor sites or changes in transmitter release, which can depend on functional or organisational differences between two collaterals of the same neuron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238844
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  • 6
    Electronic Resource
    Electronic Resource
    Medial septal projections to the dentate gyrus of the rat: electrophysiological analysis of distribution and plasticity (1984)
    Springer
    Experimental brain research 56 (1984), S. 243-256 
    Details
    ISSN: 1432-1106
    Keywords: Medial septum ; Hippocampus ; Dentate gyrus ; Evoked potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous electrophysiological experiments in rabbits have suggested that medial septal stimulation activates dentate granule cells and evokes an associated negative field response at the granule cell layer, without an associated “dendritic” response. Anatomical studies have suggested that septal input to the granule cells may be to stratum moleculare, or close to the cell layer, or may not exist at all. The present experiments confirmed in rats anaesthetised with urethane that medial septal stimulation elicits single action potentials from cells in the granule layer. The associated negative field potential was maximal in the granule cell layer and there was no sign of a separate dendritic potential. The fibres responsible for this potential travel to the dorsal hippocampus in the fornix superior rather than the fimbria, taking the same course as the fibres which contribute to the dense cholinesterase staining just above the granule cell layer. Stimulation at 100 Hz for 1 s of either medial septal, or perforant path, input to the dentate granule cell layer produced long term potentiation of the subsequent evoked field responses to the stimulated pathway. The responses to the non-stimulated pathway were unchanged. Paired pulse stimulation produced both homosynaptic and heterosynaptic potentiation. These data suggest that medial septal input synapses close to granule cell bodies and produces a negative field potential which is a combination of dendritic and population spike potentials. Medial septal input also appeared to produce direct activation of hilar neurones, some of which may be basket cells or other interneurones. The data also show that long term potentiation is specific to this input, perhaps dependent on presynaptic mechanisms. Paired pulse potentiation, at least in the heterosynaptic case appears to depend on postsynaptic mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236280
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  • 7
    Electronic Resource
    Electronic Resource
    Alzheimer's dementia produces a loss of discrimination but no increase in rate of memory decay in delayed matching to sample
    Amsterdam : Elsevier
    Neuropsychologia 30 (1992), S. 133-143 
    Details
    ISSN: 0028-3932
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Psychology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0028-3932(92)90023-F
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  • 8
    Electronic Resource
    Electronic Resource
    Thermal erosion by komatiites at Kambalda, Western Australia and the genesis of nickel ores (1986)
    [s.l.] : Nature Publishing Group
    Nature 319 (1986), S. 136-139 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Schematic representation (not to scale) of: a, Relationships in the lower part of the Kambalda komatiite pile emphasizing embay-ment (trough) structures and showing hanging-wall ores (adapted from rf. 23); and ², relationships between massive ores, interspinifex ores and komatiite flow-tops ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/319136a0
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  • 9
    Electronic Resource
    Electronic Resource
    The age and origin of younger granitic plutons of the Shaw Batholith in the Archaean Pilbara Block, Western Australia (1989)
    Springer
    Contributions to mineralogy and petrology 101 (1989), S. 361-376 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The whole-rock Pb-Pb method has been used to date four of the younger, mainly adamellite, late-tectonic plutonic phases within the ca. 3.5 Ga Shaw Batholith of the Archaean east Pilbara Block. Three suites give ages within error of 2966 Ma (Porphyritic Granites at 2948±50 Ma, Leuco-adamellites at 2943±46 Ma and Garden Creek Adamellite at 3007±48 Ma). The post-tectonic Cooglegong Adamellite gives an age of 2847±34 Ma. The Sm-Nd model isotopic systematics of all four suites indicate derivation from crust ranging between ca. 3200 and 3600 Ma in age. The sources for these four younger plutonic phases were heterogeneous and, although exhibiting some isotopic characteristics of the older (3.5−3.3 Ga) calc-alkali plutonic suites, were more depleted in the LIL elements Rb, U and Th. In addition, the Garden Creek Adamellite and the Cooglegong Adamellite lack the very fractionated and HREE-depleted REE patterns characteristic of both the older calc-alkali plutonic rocks and the Porphyritic Granites and Leuco-adamellites. The crust underlying the Shaw Batholith at ca. 2950 Ma must have been both markedly heterogeneous and variably depleted, a conclusion consistent with the complex tectonic and plutonic evolution of this region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375320
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  • 10
    Electronic Resource
    Electronic Resource
    Record of emergent continental crust ∼3.5 billion years ago in the Pilbara craton of Australia (1995)
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 574-577 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The unconformity is best exposed in the Pilgangoora syncline between 21° 05' S, 119° 13' E and 21° 07' S, 118° 59' E, although it crops out over a strike length of at least 75 km (Fig. 1). Previously recognized as a minor disconformity12'13, it is ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/375574a0
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