From Migmatites to Plutons: Power Law Relationships in the Evolution of Magmatic Bodies

Соэсоо, Алвар; Bons, Paul D.

doi:10.1007/s00024-014-0995-4

Cited by 10 publications

(16 citation statements)

References 72 publications

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“…A preliminary length vs volume plot for all the plutons is approximately linear (Fig. 13), suggesting that the derived dimensions are relatively correct (cf Soesoo and Bons, 2015).…”

Section: Tectonic Setting and Emplacement Of The Plutonsmentioning

confidence: 94%

Configuration of Late Archaean Chilimanzi and Razi Suites of Granites, South-Central Zimbabwe Craton, From Gravity Modelling: Geotectonic Implications

Ranganai

Gwavava

Ebinger

et al. 2019

Pure Appl. Geophys.

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The subsurface geometry of five representative late Archaean 'Chilimanzi and Razi' suite plutons in the Zimbabwe craton (ZC) has been investigated by gravity modelling constrained in part by surface geology, density measurements and seismic information, to determine their 3D configuration and infer tectonic context of emplacement. The generally K-rich, massive, homogeneous monzogranites are characterised by large Bouguer gravity lows (up to-30 mGal amplitude) whose gradients outline their spatial extent well. The southernmost plutons and their anomalies have general trends paralleling the North Marginal Zone (NMZ) of the Limpopo orogenic belt (LB). Predictive gravity models indicate that the density contrast of the Chivi batholith (CB) adjacent to the 'volcanic arclike' Belingwe greenstone belt extends to a depth of about 13 km. The nearby Razi pluton (RP) which intrudes the ZC-LB boundary appears to have been emplaced at shallower depths/levels. The gravity model suggests a thickness of about 5 to 6 km, and a moderate to shallow dip to the southeast under the NMZ, compatible with syn-kinematic intrusion during overthrust of the LB over the ZC. The smallest Nalatale granite (Ng) is on average 2.5 km thick under the Fort Rixon greenstone belt but includes a root up to 4.5 km thick under the anomaly peak, and a steep contact with the tonalite/gneiss to the east. These granites follow the general power-law for pluton dimension and are similar in this respect to the classical wedge-shaped plutons, extending largely in one direction, with large aspect ratios (Length(L)/Thickness(T)>7). However, the overall shape of the RP is typical of a diapir (Width(W)5; L/T>15). Overall, the CB and the ZG are interpreted as massive, deeprooted batholithic intrusions (L/T10), contrary to some geological interpretations of these late, post-kinematic intrusions as sheet-like bodies emplaced at relatively shallow levels in the crust. On the other hand, the ChB appears to be a tabular intrusion, probably fed by dykes; it exhibits a lateral extent much greater than the vertical one, outlining a sheeted geometry (W/T>7; L/T>18). The geophysical evidence, together with geological and fabric data, support and/or confirm the two main granite configurations: sheets and batholith; and thus also confirm the two main modes of emplacement: dyke and diapirism or ballooning plutonism. This is con...

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“…A preliminary length vs volume plot for all the plutons is approximately linear (Fig. 13), suggesting that the derived dimensions are relatively correct (cf Soesoo and Bons, 2015).…”

Section: Tectonic Setting and Emplacement Of The Plutonsmentioning

confidence: 94%

Configuration of Late Archaean Chilimanzi and Razi Suites of Granites, South-Central Zimbabwe Craton, From Gravity Modelling: Geotectonic Implications

Ranganai

Gwavava

Ebinger

et al. 2019

Pure Appl. Geophys.

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“…Leucosome size distributions in migmatites have been shown to follow power-laws in many migmatite areas: the Paleoproterozoic in Finland (Bons et al, 2004;Bons et al, 2009;Soesoo and Bons, 2015), Estonia (Bons et al, 2004;Soesoo et al, 2004;Urtson and Soesoo, 2007;Urtson and Soesoo, 2009;Soesoo and Bons 2015) and Arizona (Bonamici and Duebendorfer, 2010), and the Paleozoic in Namibia (Hall and Kisters, 2012), Portugal (Urtson and Soesoo, 2009;Soesoo and Bons, 2015) and West Antarctica (Yakymchuk et al, 2013). Many of these distributions follow single untruncated or truncated power-law functions, resulting in shapes as seen in Figures 1A,B.…”

Section: Power-law Behavior and Self-organization In Migmatitesmentioning

confidence: 99%

“…Many of the migmatites where leucosome distribution has been measured are stromatic, as this kind of migmatite consists of elongated parallel leucosomes and is therefore easy to measure with simple line transects perpendicular to the leucosome stripes (Marchildon and Brown, 2003;Bons et al, 2004;Soesoo et al, 2004;Urtson and Soesoo, 2007;Urtson and Soesoo, 2009;Bonamici and Duebendorfer, 2010;Yakymchuk et al, 2013;Soesoo and Bons, 2015). Some non-stromatic migmatites (Tanner, 1999), as well as granitic intrusions on a 1-100 km scale (Soesoo and Bons, 2015), also show power-law distributions. Spacing of leucosomes in migmatites has also been shown to display power-law distributions (Soesoo et al, 2004;Bonamici and Duebendorfer, 2010).…”

Section: Power-law Behavior and Self-organization In Migmatitesmentioning

confidence: 99%

Double Power-Law in Leucosome Width Distribution: Implications for Recognizing Melt Movement in Migmatites

Saukko

Ahläng²,

Nikkilä

et al. 2020

Front. Earth Sci.

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“…The rheology and strength of partially molten rocks change significantly at two thresholds that are relevant for most migmatite terranes [11,25,85], including the Yunkai region. The first is known as the melt connectivity transition (MCT) [86][87][88][89], which is generally thought to occur at 7 vol.% melt in a static system [88]. A second threshold is known as the solid-to-liquid transition (SLT) [88], which is similar to the rheologically critical melt percentage (RCMP), and is characterized by the less-pronounced aggregate strength drop at a melt fraction around 40 vol.% [90][91][92].…”

Section: Rheology Of the Yunkai Region During The Wuyi-yunkai Orogenymentioning

confidence: 99%

Partial Melting and Crustal Deformation during the Early Paleozoic Wuyi–Yunkai Orogeny: Insights from Zircon U-Pb Geochronology and Structural Analysis of the Fuhuling Migmatites in the Yunkai Region, South China

et al. 2019

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：Migmatites record crucial information about the rheology and tectonothermal evolutionof the deep crust during orogenesis. In the Wuyi–Yunkai orogen in South China, migmatites at Fuhuling record Early Paleozoic high temperatures and associated partial melting. However, the absolute timing and implications for the rheology of the deep crust during orogenesis are poorly constrained. In this contribution, we used spatial analysis of migmatitic leucosomes, structural analysis, and U-Pb geochronology of zircon to elucidate the absolute timing of crustal partial melting, the degree of partial melting, and the role of partial melting on the rheology of the crust during the Wuyi–Yunkai orogeny. Partial melting of the Fuhuling migmatites occurred at c. 440 Ma during Early Paleozoic Wuyi–Yunkai orogenesis. Subsequent lower temperature metamorphism associated with Indosinian movement that caused minor zircon recrystallization was temporally associated with the crystallization of nearby biotite monzogranites, but it did not influence the morphology of the Fuhuling migmatites. The migmatites preserve a morphological transition from metatexite to diatexite with an increasing proportion of leucosome. This transition preserves different structural characteristics that represent the response of the solid framework and melt network to variable melt fractions during partial melting. The large proportion of in situ or in source leucosome in the Fuhuling migmatites suggests that it was a melt-rich crustal horizon during orogenesis, and that a substantial proportion of anatectic melt was retained in the deep crust. The rheological transition documented in the Fuhuling migmatites was caused by changes in the melt fraction, and it is an analogue for the rheological transition characteristics of melt-rich crustal horizons in the Yunkai region during Early Paleozoic Wuyi–Yunkai orogenesis and subsequent orogenic collapse.

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From Migmatites to Plutons: Power Law Relationships in the Evolution of Magmatic Bodies

Cited by 10 publications

References 72 publications

Configuration of Late Archaean Chilimanzi and Razi Suites of Granites, South-Central Zimbabwe Craton, From Gravity Modelling: Geotectonic Implications

Configuration of Late Archaean Chilimanzi and Razi Suites of Granites, South-Central Zimbabwe Craton, From Gravity Modelling: Geotectonic Implications

Double Power-Law in Leucosome Width Distribution: Implications for Recognizing Melt Movement in Migmatites

Partial Melting and Crustal Deformation during the Early Paleozoic Wuyi–Yunkai Orogeny: Insights from Zircon U-Pb Geochronology and Structural Analysis of the Fuhuling Migmatites in the Yunkai Region, South China

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