References of "Vander Auwera, Jacqueline"
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See detailThe Sept Iles mafic layered intrusion; an example of ferrobasaltic differentiation
Namur, Olivier ULg; Charlier, Bernard ULg; Higgins, Michael et al

in Geochimica et Cosmochimica Acta (2007), 71(15S), 705

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See detailIlmenite composition in the Tellnes Fe–Ti deposit, SW Norway: fractional crystallization, postcumulus evolution and ilmenite–zircon relation
Charlier, Bernard ULg; Skar, Oyvind; Korneliussen, Are et al

in Contributions to Mineralogy & Petrology (2007), 154(2), 119-134

Major and trace element XRF and in situ LA-ICP-MS analyses of ilmenite in the Tellnes ilmenite deposit, Rogaland Anorthosite Province, SW Norway, constrains a two stage fractional crystallization model of ... [more ▼]

Major and trace element XRF and in situ LA-ICP-MS analyses of ilmenite in the Tellnes ilmenite deposit, Rogaland Anorthosite Province, SW Norway, constrains a two stage fractional crystallization model of a ferrodioritic Fe-Ti-P rich melt. Stage 1 is characterized by ilmenite-plagioclase cumulates, partly stored in the lower part of the ore body (Lower Central Zone, LCZ), and stage 2 by ilmenite-plagioclase-orthopyroxene-olivine cumulates (Upper Central Zone, UCZ). The concentration of V and Cr in ilmenite, corrected for the trapped liquid effect, (1) defines the cotectic proportion of ilmenite to be 17.5 wt% during stage 1, and (2) implies an increase of D VIlm during stage 2, most likely related to a shift in fO2. The proportion of 17.5 wt% is lower than the modal proportion of ilmenite (ca. 50 wt%) in the ore body, implying accumulation of ilmenite and flotation of plagioclase. The fraction of residual liquid left after crystallization of Tellnes cumulates is estimated at 0.6 and the flotation of plagioclase at 26 wt% of the initial melt mass. The increasing content of intercumulus magnetite with stratigraphic height, from 0 to ca. 3 wt%, results from differentiation of the trapped liquid towards magnetite saturation. The MgO content of ilmenite (1.4–4.4 wt%) is much lower than the expected cumulus composition. It shows extensive postcumulus re-equilibration with trapped liquid and ferromagnesian silicates, correlated with distance to the host anorthosite. The Zr content of ilmenite, provided by in situ analyses, is low (<114 ppm) and uncorrelated with stratigraphy or Cr content. The data demonstrate that zircon coronas observed around ilmenite formed by subsolidus exsolution of ZrO2 from ilmenite. The U-Pb zircon age of 920 ± 3 Ma probably records this exsolution process. [less ▲]

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See detailMagma chamber processes in the Tellnes ilmenite deposit (Rogaland Anorthosite Province, SW Norway) and the formation of Fe-Ti ores in massif-type anorthosites
Charlier, Bernard ULg; Duchesne, Jean-Clair ULg; Vander Auwera, Jacqueline ULg

in Chemical Geology (2006), 234(3-4), 264-290

The origin of igneous Fe-Ti oxide ores associated with massif-type anorthosites is investigated through a detailed study of the world-class Tellnes ilmenite deposit, part of the late-Proterozoic (930-920 ... [more ▼]

The origin of igneous Fe-Ti oxide ores associated with massif-type anorthosites is investigated through a detailed study of the world-class Tellnes ilmenite deposit, part of the late-Proterozoic (930-920 Ma) AMC series of the Rogaland Anorthosite Province (SW Norway). More than 100 samples from drill cores reveal significant petrographical and compositional variations within the ore body. Four zones are defined, based on variations in modal proportions and cumulus mineral assemblages: the Lower and Upper Central Zones and the Lower and Upper Marginal Zones. Plagioclase and whole-rock compositions discriminate the zones and display patterns interpreted as a result of mixing of either plagioclase-ilmenite or plagioclase-ilmenite-orthopyroxene-olivine cumulates with a melt of ferrodioritic (jotunitic) composition with a content decreasing from 80 to 20% from the margins to the central part of the ore body. Phase diagrams for a jotunitic parental magma reproduce the crystallization sequence at 5 kb. The orthopyroxene-olivine liquidus boundary is a peritectic in the Bjerkreim-Sokndal layered intrusion and a cotectic in Tellnes and this explains the differences in the sequence of crystallization of the two intrusions. The high concentration of ilmenite, well above cotectic proportions, resulted from gravity-sorting in the Tellnes ore body, which represents the lower part of a larger magma chamber. Uniform Sr isotope ratios do not support magma mixing. The cryptic layering of the ore body precludes injection as a crystal mush but favours in situ crystallization from an evolving magma in a sill-like magma chamber. The present trough-shape and mineral orientations result from deformation during gravity-induced subsidence and by up-doming of the anorthosite. Fractional crystallization of a TiO2-rich magma with ilmenite as an early liquidus mineral and plagioclase buoyancy are the principal mechanisms responsible for the formation of Fe-Ti deposits in Proterozoic massif-type anorthosites. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMarginal mafic intrusions as indicators of downslope draining of dense residual melts in anorthositic diapirs?
Vander Auwera, Jacqueline ULg; Weis, Dominique; Duchesne, Jean-Clair ULg

in Lithos (2006), 89(3-4), 329-352

Geochemical and isotopic investigation of three small mafic intrusions (Loyning: 1250 X 150 m, Hogstad: 2000 X 200 m, Koldal: 1250 X 500 m) in the marginal zones of the Egersund-Ogna (Loyning, Koldal) and ... [more ▼]

Geochemical and isotopic investigation of three small mafic intrusions (Loyning: 1250 X 150 m, Hogstad: 2000 X 200 m, Koldal: 1250 X 500 m) in the marginal zones of the Egersund-Ogna (Loyning, Koldal) and Ana-Sira massif-type anorthosites (Hogstad) (Rogaland Anorthositic Province, south Norway: 930 Ma) provides new insights into the late evolution of anorthositic diapirs. These layered mafic intrusions are essentially of norite, gabbronorite as well as leuconorite and display conspicuous evidence of subsolidus recrystallization. In Loyning and Hogstad, the modal layering is parallel to the subvertical foliation in the enclosing anorthosite. The northern part of the Koldal intrusion cuts across the foliation of the anolthosite, whereas in its southern part the subvertical layering is parallel to the anorthosite's foliation. The regularity of the layered structures suggests that the layering was initially acquired horizontally and later tilted during the final movements of the diapirs. The least differentiated compositions of plagioclase and otthopyroxene in the three intrusions (An(59)-En(68) in Loyning, An(49)-En(64) in Hogstad and An(44)-En(61) in Koldal) and the REE contents in apatite (Hogstad) indicate that their parent magmas were progressively more differentiated in the sequence Loyning-Hogstad-Koldal. Isotopic data (Loyning: Sr-87/Sr-86: 0.70376-0.70457, epsilon(Ndt): +6.8 to +2.7; Hogstad: Sr-87/Sr-86: 0.70537-0.70588, epsilon(Ndt): +2.1 to -0.5; Koldal: Sr-87/Sr-86: 0.70659-0.70911, epsilon(Ndt): +3.5 to - 1.6) also indicate that in this sequence, parent magmas were characterized by a progressively more enriched Sr and Nd isotopic signature. In Loyning, the parent magma was slightly more magnesian and anorthitic than a primitive jotunite; in Hogstad, it is a primitive jotunite; and, in Koldal, an evolved jotunite. Given that plagioclase and orthopyroxene of the three intrusions display more differentiated compositions than the orthopyroxene and plagioclase megacryts of the enclosing anorthosites, it is suggested that the parent magmas of the small intrusions are residual melts after anorthosite formation which were entrained in the anorthositic diapir during its rise from lower crustal chambers. Calculated densities of primitive jotunites (2.73-2.74 at FMQ, 0.15% H2O, 200 ppm CO2, 435 ppm F, 1150 degrees C, 3 kb) and evolved jotunites (2.75-2.76 at FMQ, 0.30% H2O, 400 ppm CO2, 870 ppm F, 1135 degrees C, 3 kb) demonstrate that they are much denser than the plagioclase of the surrounding anorthositic crystal mush (2.61-2.65). Efficient migration and draining of dense residual melts through the anorthositic crystal mush could have taken place along sloping floors (zones of lesser permeability in the mush), which occur along the margins of the rising anorthositic diapirs. This process takes into account the restricted occurrence of the mafic intrusions in the margins of the massif anorthosites. In a later stage, when the anorthosite was nearly consolidated, the residual melts were more differentiated (evolved jotunites) and could have been extracted into extensional fractures in the cooling and contracting anorthositic body in a similar way as aplitic dikes are emplaced in granitic plutons. As in the Rogaland Anorthositic Province, these dikes are much more abundant than the small mafic intrusions, collection and transport along dikes was probably more efficient than draining through the crystal mush. (C) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailPhase equilibria of the Lyngdal granodiorite (Norway): Implications for the origin of metaluminous ferroan granitoids
Bogaerts, Michel; Scaillet, Bruno; Vander Auwera, Jacqueline ULg

in Journal of Petrology (2006), 47

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See detailGeochemistry of cumulates from the Bjerkreim-Sokndal layered intrusion (S. Norway). Part II. REE and the trapped liquid fraction
Charlier, Bernard ULg; Vander Auwera, Jacqueline ULg; Duchesne, Jean-Clair ULg

in Lithos (2005), 83(3-4), 255-276

Rare earth elements in bulk cumulates and in separated minerals (plagioclase, apatite, Ca-poor and Ca-rich pyroxenes, ilmenite and magnetite) from the Bjerkreim-Sokndal layered intrusion (Rogaland ... [more ▼]

Rare earth elements in bulk cumulates and in separated minerals (plagioclase, apatite, Ca-poor and Ca-rich pyroxenes, ilmenite and magnetite) from the Bjerkreim-Sokndal layered intrusion (Rogaland Anorthosite Province, SW Norway) are investigated to better define the proportion of trapped liquid and its influence on bulk cumulate composition. In leuconoritic rocks (made up of plagioclase, Ca-poor pyroxene, ilmenite, magnetite, olivine), where apatite is an intercumulus phase, even a small fraction of trapped liquid significantly affects the REE pattern of the bulk cumulate, together with cumulus minerals proportion and composition. Contrastingly, in gabbronoritic cumulates characterized by the presence of cumulus Ca-rich pyroxene and apatite, cumulus apatite buffers the REE content. La/Sm and Eu/Eu* VS. P2O2 variations in leuconorites display mixing trends between a pure adcumulate and the composition of the trapped liquid, assumed to be similar to the parental magma. Assessment of the trapped liquid fraction in leuconorites ranges from 2 to 25% and is systematically higher in the north-eastern part of the intrusion. The likely reason for this wide range of TLF is different cooling rates in different parts of the intrusion depending on the distance to the gneissic margins. The REE patterns of liquids in equilibrium with primitive cumulates are calculated with mass balance equations. Major elements modelling (Duchesne, J.C., Charlier, B., 2005. Geochemistry of cumulates from the Bjerkreiin-Sokndal layered intrusion (S. Norway): Part I. Constraints from major elements on the mechanism of cumulate formation and on the jotunite liquid line of descent. Lithos. 83, 299-254) permits calculation of the REE content of melt in equilibrium with gabbronorites. Partition coefficients for REE between cumulus minerals and a jotunitic liquid are then calculated. Calculated liquids from the most primitive cumulates are similar to a primitive jotunite representing the parental magma of the intrusion, taking into account the trapped liquid fraction calculated from the P2O5 content. Consistent results demonstrate the reliability of liquid compositions calculated from bulk cumulates and confirm the hypothesis that the trapped liquid has crystallized as a closed-system without subsequent mobility of REE in a migrating interstitial liquid. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailA tribute to Jean Clair Duchesne
Vander Auwera, Jacqueline ULg

in Vander Auwera, Jacqueline (Ed.) Lithos (2005)

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See detailInefficiency of magma mixing and source heterogeneity in the genesis of granitoids: the example of the Farsund body (southern Norway)
Dupont, Alain; Vander Auwera, Jacqueline ULg; Paquette, Jean-Louis et al

in Geophysical Research Abstracts (2005), 7

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See detailModelling of Magma Chambers
Vander Auwera, Jacqueline ULg

in Lithos (2005), 83

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See detailREE in bulk cumulates and the trapped liquid shift in the Bjerkreim-Sokndal layered intrusion (Norway)
Charlier, Bernard ULg; Vander Auwera, Jacqueline ULg; Duchesne, Jean-Clair ULg

in Geochimica et Cosmochimica Acta (2004, June), 68(11, Suppl. S), 632

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See detailSimilar sources for the Apuseni Mts and Banat (Romania) Late Cretaceous Banatitic magmatism
Vander Auwera, Jacqueline ULg; Berza, T.; Marincea, Stefan ULg et al

in Geochimica et Cosmochimica Acta (2004, June), 68(11, Suppl. S), 684

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See detailDerivation of the 1.0-0.9 Ga ferro-potassic A-type granitoids of southern Norway by extreme differentiation from basic magmas
Vander Auwera, Jacqueline ULg; Bogaerts, Michel; Liégeois, Jean-Paul ULg et al

in Precambrian Research (2003), 124(2-4), 107-148

Major and trace elements, Sr and Nd isotopic data as well as mineral compositions are presented for a selection of the 1.0 - 0.9 ferro-potassic A-type granitoids (Bessefjellet, Rustfjellet ... [more ▼]

Major and trace elements, Sr and Nd isotopic data as well as mineral compositions are presented for a selection of the 1.0 - 0.9 ferro-potassic A-type granitoids (Bessefjellet, Rustfjellet, Verhuskjerringi, Valle, Holum, Svöfjell, Handeland-Tveit, Åseral, Lyngdal gabbronorites) that occur close to the Mandal-Ustaoset Line of southern Norway. These hornblende biotite granitoids (HBG) define an extensive differentiation trend ranging from gabbronorites (50 wt % SiO2) to granites (77 wt % SiO2). This trend is interpreted as resulting from extreme fractional crystallization of several basaltic magma batches with similar major and trace elements compositions. At 930 Ma, the HBG suite displays a narrower range in ISr (0.7027 - 0.7056) than in Nd(t) (+1.97 down to -4.90) suggesting some assimilation of a Rb-depleted lower crust (AFC process) or/and source variability. An age of 929 ± 47 Ma is given by a Rb-Sr isochron on the Holum granite (Sri = 0.7046 ±0.0006, MSWD = 1.7). Geothermobarometers indicate a low pressure of emplacement (1.3-2.7 kbar) and an oxygen fugacity close to NNO. High liquidus temperatures are given by the apatite saturation thermometer (1005°C to 1054 °C) and are in agreement with results from other studies. The basaltic parent magmas of the HBG suite are partial melts of an hydrous mafic, potassic source lying either in the lithospheric upper mantle or in the mafic lower crust derived from it. This contrasts with the 930 Ma anorthosite-mangerite-charnockite suite (AMC) of the Rogaland Province for which a depleted lower crustal anhydrous gabbronoritic source has been indicated. The present data imply the penecontemporaneous melting of two contrasting sources in southern Norway. The source duality could result from an increasing degree of metamorphism (amphibolite to granulite) from East to West, an horizontal stratification of the lower crust or from the stratification of the lithosphere (melting of the lower crust or upper mantle). It may also indicate that the AMC and HBG suites formed in two distinct crustal segments. The linear alignment of the HBG suite along the Mandal-Ustaoset shear zone suggests that a linear uprise of the asthenosphere, following a lithospheric delamination under this structure, could be the vector of the mantle heat. [less ▲]

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See detailPetrology of the Lyngdal granodiorite (southern Norway) and the role of fractional crystallization in the genesis of Proterozoic rapakivi-like granites
Bogaerts, Michel; Scaillet, Bruno; Liégeois, Jean-Paul ULg et al

in Precambrian Research (2003), 124(2-4), 149-184

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See detailOrigin and evolution of Precambrian Anorogenic Magmatism
Vander Auwera, Jacqueline ULg; Martin, Hervé; Rämö, Tapani

in Precambrian Research (2003), 124(2-4), 105-344

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See detailOrigin and evolution of Proterozoic Anorogenic Magmatism
Vander Auwera, Jacqueline ULg; Martin, Hervé; Rämö, Tapani

in Vander Auwera, Jacqueline; Martin, Hervé; Rämö, Tapani (Eds.) Lithos (2003)

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See detailSmall mafic intrusions as indicators of downslope draining of dense residual liquids in anorthositic diapirs
Vander Auwera, Jacqueline ULg; Ernst, Gérald; Weis, Dominique et al

in Geophysical Research Abstracts (2003), 5

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