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  • 1
    Electronic Resource
    Electronic Resource
    Petrogenesis of Archaean Tonalites (1982)
    Springer
    International journal of earth sciences 71 (1982), S. 328-346 
    Details
    ISSN: 1437-3262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract The Archean tonalitic magma series is characterized by a high Al2O3 and Na2O content. Tertiary tonalites with similar major element composition have been generated in subduction zones. It is therefore suggested that the Archean tonalites was generated in relation to subduction zones, the primary magma of the series being of dioritic composition. The generation of the primary magma occurred at about 15 kbar, while the recent generation of andesite occur at about 30 kbar. The higher frequency of generation in the Archean, and the relatively small depth of geneeration is related to the slightly higher temperatures of the mantle in the Archean.
    Abstract: Résumé La série des magmas tonalitiques de l'Archéen est caractérisée par une haute teneur en Al2O3. Les tonalites tertiaires, de même composition quant aux éléments majeurs, ont été engendrées dans des zones de subduction. C'est pourquoi il est suggéré que les tonalites archéennes aient été engendrées en relation avec des zones de subduction, le magma primaire de la série étant de composition dioritique. La genèse du magma primaire se fit sous environ 15 kbar, tandis que la genèse récente des andésites se fait à 30 kbar. La fréquence élevée de la formation dans l'Archéen et la profondeur relativement faible de cette formation est en liaison avec les températures légèrement plus élevées du manteau dans l'Archéen.
    Notes: Zusammenfassung Die tonalitische Magmenfolge des Archäikum wird durch hohe Al2O3- und Na2O-Gehalte gekennzeichnet. Tertiäraltrige Tonalite mit ähnlicher Hauptelement-Zusammensetzung entstanden in Subduktionszonen. Deshalb wird vorgeschlagen, daß die archäischen Tonalite im Zusammenhang mit Subduktionszonen entstanden, wobei das primäre Magma der Folge dioritischer Zusammensetzung war. Das primäre Magma entstand unter einem Druck von etwa 15 kbar; in jüngster Zeit entsteht aber Andesit bei etwa 30 kbar. Die höhere Entstehungsrate im Archäikum wird, so wie auch die verhältnismäßig geringe Entstehungstiefe, zu den etwas höheren Manteltemperaturen im Archäikum in Beziehung gesetzt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01825045
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  • 2
    Electronic Resource
    Electronic Resource
    Geochemical aspects of some accumulation models for primary magmas (1986)
    Springer
    Contributions to mineralogy and petrology 93 (1986), S. 449-458 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The compositions of primary magmas depend to some degree on the dynamic processes occurring in the partially molten region of the mantle. The compositional dependence is estimated for three models which assume either accumulation from a migmatized source region or accumulation entirely by the interstitial flow of magma. Accumulation from a migmatised region results in magmas with higher concentrations of incompatible elements than does batch melting, whereas accumulation by interstitial flow results in magmas with lower concentrations of these elements. The concentrations of refractory elements are almost independent of both the accumulation process and the degree of partial melting and are therefore usefull for the identification of primary magmas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371715
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  • 3
    Electronic Resource
    Electronic Resource
    Delayed fractionation of basaltic lavas (1988)
    Springer
    Contributions to mineralogy and petrology 98 (1988), S. 401-407 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The phenocryst cores of the basaltic lavas from Jan Mayen and Hawaii display a range in compositions. The textural features of the phenocrysts also vary, both euhedral and skeletal phenocrysts are present in the same thin section. Apparently the basaltic magmas underwent crystallization within a temperature interval of 50–200° C before they became fractionated. The fractionates of basaltic lavas are therefore average compositions of the phenocryst assemblages rather than liquidus compositions. This type of fractionation is called delayed fractionation. It is considered that most tholeiitic and alkalic basaltic lavas undergo delayed fractionation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372360
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  • 4
    Electronic Resource
    Electronic Resource
    Population density and zoning of olivine phenocrysts in tholeiites from Kauai, Hawaii (1989)
    Springer
    Contributions to mineralogy and petrology 101 (1989), S. 176-186 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The population density of olivine phenocrysts of the tholeiites display an exponential variation, which is typical of igneous as well as contact metamorphic rocks. The exponential variation is explained by a new growth probability model, which is consistent with experimental work. The forsterite content of the olivine phenocrysts decreases with decreasing size. Various phenocryst features suggest that the tholeiites first crystallized slowly in a magma chamber, after which they underwent crystallization for a short period of time in a feeder dyke before eruption took place.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375304
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  • 5
    Electronic Resource
    Electronic Resource
    Water content of a granite magma deduced from the sequence of crystallization determined experimentally with water-undersaturated conditions (1975)
    Springer
    Contributions to mineralogy and petrology 52 (1975), S. 175-191 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The sequence of crystallization in a biotite-granite from the Bohus batholith of Norway and Sweden, deduced from its texture, was magnetite, plagioclase, microcline, quartz, and finally biotite. Several sequences of crystallization were determined experimentally at 2 kb in the presence of varying only for H2O contents below 1.2% by weight. The rock was fused to a homogeneous glass, and each experiment included samples of finely crushed rock and glass. The samples were reacted in Ag-Pd capsules with measured H2O content in coldseal pressure vessels with NNO buffer. With excess H2O (more than 6.5%) the crystallization interval extends from 865° C to 705° C. In the H2O-deficient region, the solidus temperature remains unchanged as long as a trace of vapor is present, but the liquidus temperature increases as H2O content decreases; with 0.8 % H2O the liquidus temperature is 1125° C, the crystallization interval is 420° C, and a separate aqueous vapor phase is evolved only a few degrees above the solidus at 705° C. The biotite phase boundary increases slightly from 845° C with excess H2O to 875° C with 1% H2O, and it intersects the steep phase boundaries for quartz and feldspars; the sequence of crystallization changes at each intersection point. Similar diagrams at various pressures for related rock compositions involving muscovite, biotite and amphibole will provide grids useful in defining limits for the water content of granitic and dioritic magmas. Applications are considered for the Bohus batholith, other granitic rocks, and rhyolites. The Bohus magma could have been formed by crustal anatexis as a mobile assemblage of H2O-undersaturated liquid and residual crystals with initial total H2O content less than 1.2%, or it could have been derived by fractionation of a more basic parent with low H2O content from mantle or subduction zone, but it could not have been derived from a primary andesite generated from mantle peridotite. We consider it unlikely that the H2O content of large granitic magma bodies exceeds about 1.5% H2O; these magmas are H2O-undersaturated through most of their histories. Uprise and progressive crystallization of magma bodies produces H2O-saturation around margins and in the upper regions of magma chambers. H2O-saturated rhyolitic and dacitic magmas with phenocrysts can be tapped from the upper parts of the magma chambers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00457293
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  • 6
    Electronic Resource
    Electronic Resource
    The major element composition of the upper mantle estimated from the composition of lherzolites (1977)
    Springer
    Contributions to mineralogy and petrology 63 (1977), S. 161-173 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The compilation of analyses of continental and oceanic spinel Iherzolites show that these two types of Iherzolites have very similar compositions. Their composition range differ from that of African garnet Iherzolites, and the data suggest that the mantle beneath Africa has an anomalous composition. If the composition of the upper mantle may be estimated from that of Iherzolites, the compositions of spinel Iherzolite should form the basis for this estimate. It is suggested that the compositions of spinel Iherzolite represent both undepleted and depleted compositions, and a representative composition for the primitive mantle is proposed on this basis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398777
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  • 7
    Electronic Resource
    Electronic Resource
    Olivine phenocrysts of Hawaiian olivine tholeiite and oceanite (1982)
    Springer
    Contributions to mineralogy and petrology 81 (1982), S. 203-211 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Olivine phenocrysts of Hawaiian tholeiites display a variety of textures and a variation in composition which is due to supercooled crystallization. The highest forsterite content measured is 91%, and the highest magnesia content estimated for a tholeiitic liquid is 17%, using the olivine geothermometer. The liquid of this composition may be either a primary magma or a primitive magma. It is not yet possible to specify any particular composition range for the primary Hawaiian tholeiites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371297
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  • 8
    Electronic Resource
    Electronic Resource
    The permeability controlled accumulation of primary magma (1982)
    Springer
    Contributions to mineralogy and petrology 81 (1982), S. 350-357 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The initial accumulation of primary magma occurs just after the mantle has become permeable. The accumulation is caused by the compaction of the residuum, which either may be controlled by the rate of creep, or by the rate of flow of the interstitial melt. Experimental results suggest that the rate of compaction is controlled by the permeability, and a model for the accumulation process is worked out on this basis. The compaction causes the formation of a lower compaction boundary and an upper layer of melt. The ascending mantle of plumes and convection currents will form layers of melt situated 20–100 m apart. The type of partial melting for this accumulation is critical melting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371689
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  • 9
    Electronic Resource
    Electronic Resource
    The generation and shape of feeder dykes from mantle sources (1987)
    Springer
    Contributions to mineralogy and petrology 96 (1987), S. 47-55 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The criterion for fracture propagation suggests that the primary magma generated in the mantle ascends in a stepwise fashion. Initially a pulse of magma forms a dyke above the mantle source and ascends for some distance, whereafter it stops. A subsequent pulse of magma joins the first one, and the ascent of the accumulating body of magma continues for some distance each time a new pulse of magma reaches the body of magma situated in the top of the dyke. In this manner a dyke is formed that may extend either partly or the whole way from the mantle source to the surface. This model may explain the large pressures, up to 2000 bars, that prevail during basaltic eruptions. The calculated shape of the ascending pulses of magma suggests that their heights and widths are similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375524
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