Relationship Between Solidification Depth of Granitic Rocks and Formation of Hydrothermal Ore Deposits

Uchida, Etsuo; Endo, Shunsuke; Makino, Mitsutoshi

doi:10.1111/j.1751-3928.2006.00004.x

Cited by 206 publications

(117 citation statements)

References 14 publications

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“…Depth of formation of the Wmineralized granites are considered to be 6 -9 km (0.2 -0.3 GPa) by the biotite geobarometer (Uchida et al, 2007). Ryoke metamorphism has been considered regional in scale, and intruded granitoids also emplaced in a deep level around the time of the metamorphism (Ishihara, 1973).…”

Section: Relation To Mineralizationsmentioning

confidence: 99%

Chemical compositions of the late Cretaceous Ryoke granitoids of the Chubu District, central Japan – Revisited

Ishihara¹

2007

Bull. Geol. Surv. Japan

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Late Cretaceous plutonic rocks of 6 gabbroids, and 75 granitoids, all belonging to ilmenite series, were re-examined by polarized XRF method. The gabbroids are relatively abundant in the south of the studied region, implying more in-put of heat and mafic magmas from the upper mantle to the lower crust. The MgO/Fe2O3 ratio of the gabbroids reveal regional variation being MgO-rich to the south, which would reflect generation depth of the mafic magmas. The granitoids are classified into I type and S type. The I-type granitoids occur most widely and divided into five zones. Their average silica contents vary from the Median Tectonic Line to the north as follows: Shinshiro-Shitara zone (60.1 % SiO2), Asuke zone (64.2 %), Toyota-Akechi zone (70.0 %), Sanagesan-Obara zone (73.9 %) and Seto zone (75.2 %). This regional variation was considered to reflect chemical heterogeneity of the infracrustal source rocks, rather than the magmatic differentiation.Granitoids of the Okazaki-Busetsu zone, represented by garnet-bearing muscovite-biotite granites, occur in the highest metamorphic grade zone, and is felsic (average SiO2 70.2 %), peraluminous (A/CNK over 1.1), and thus be called S type. Because of the highest heat flow rate in the OkazakiBusetsu zone, even supracrustal rocks were converted to magmas and formed the S-type granites. Both I and S type granitoids are often heterogeneous in the foliated parts, as compared with massive granitoids of non-metamorphic terrains. The heterogeneity can be considered due to different original compositions of the source materials and/or formed by differential regional stress during the flow movement of the solidifying magmas. Lack of hydrothermal mineralization in the south where metamorphic roof-pendent still remain, can be explained by a deep emplacement level ( 15 km) and small degree of fractionation of these granitic magmas.

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Section: Relation To Mineralizationsmentioning

confidence: 99%

Chemical compositions of the late Cretaceous Ryoke granitoids of the Chubu District, central Japan – Revisited

Ishihara¹

2007

Bull. Geol. Surv. Japan

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“…Presenting such a highly oxidized state for host rocks of biotite illustrates a typical potential for mineralization (especially for Cu-Mo-Au porphyry deposits) in these subduction-related I-type granitoids. On the other hand, according to Uchida et al (2007), all of our studied intrusions have a characteristic potential for mineralization (Al total < 3.2 apfu), in view of the maximum and minimum values of Al total content of biotites, which are 2.82 and 2.23apfu, respectively (Table 1).…”

Section: Discussionmentioning

confidence: 99%

Metallogenic implications of biotite chemical composition: Sample from Cu-Mo-Au mineralized granitoids of the Shah Jahan Batholith, NW Iran

Zakeri¹,

Malek-Ghasemi²,

Jahangiri³

et al. 2011

Central European Geology

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Igneous biotite has been analyzed from three I-type calc-alkaline intrusives of the Shah Jahan Batholith in NW Iran, which host several Cu-Mo-Au prospects. The X Mg (Mg/Mg+Fe) value of biotite is the most significant chemical factor and the relatively high value of X Mg corresponds to relatively high oxidation states of magma (estimated ƒ O2 is mostly 10 -12.5 to 10 -7.5 bars), which is in good agreement with their host intrusions' setting and related ore occurrences. Based on criteria of Al IV and Al VI values, all studied biotites are primary (Al VI = 0), and based on Al total values (2.23-2.82 apfu) are in distinctive ranges of mineralized granitoid (Al total =3.2 apfu).The maximum F content of biotite from the Shah Jahan intrusions is moderately higher than those from some other calc-alkaline intrusions related to Cu-Mo porphyries in the world, and in contrast, Cl content is relatively lower. It is likely a result of primary magmatic vs. secondary hydrothermal origin, as well as the Mg-rich characteristics of the biotite in Shah Jahan. X Mg values do not correlate with F and Cl contents of biotite, suggesting that biotite records changes in the F/OH and Cl/OH ratios in coexisting melt/fluids. It is consistent with F-compatible and Cl-incompatible behavior during fractional crystallization of wet calc-alkaline I-type granitoid magma generated at subduction related arc settings. The fugacity ratios of (H 2 O/HF), (H 2 O/HCl) and (HF/HCl) magmatic solutions coexisting with biotite illustrate similar trends in the three intrusions, which can be due to parental magma sources and/or indicate occurrence of similar magmatic processes prior to or contemporaneous with exsolution of fluids from melt. The observed trends caused F-depletions and Cl-enrichments within developed magmatic-hydrothermal systems which are one of the essential characteristics of potential Cu-Mo-Au mineralized I-type granitoids.

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“…The granitic rocks analyzed for this study are from the same 15 areas studied by Uchida et al [3] (Figure 1). Table 1 lists the names of the areas and mining districts from which the samples were collected, rock type, age, associated metal type, and sample number for the samples.…”

Section: Granitic Intrusions Investigatedmentioning

confidence: 99%

Major and Trace Element Chemical Compositional Signatures of Some Granitic Rocks Related to Metal Mineralization in Japan

Uchida¹,

Osada²,

Nakao³

2017

OJG

Self Cite

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We analyzed the major and trace element chemical compositions of 66 granitic rocks from 15 different areas in Japan. The intrusions from which the samples were collected were associated with Pb-Zn, Mo, Cu-Fe, Sn, or W mineralization and, for comparison, samples were also collected from intrusions not associated with any metal mineralization. The analyses indicated that the granitic rocks associated with Pb-Zn, Mo, or Cu-Fe mineralization were granites, granodiorites, or diorites, and that they were all I-type and formed in a volcanic arc tectonic setting. The granitic rocks associated with Sn or W mineralization and barren granitic rocks were classified as granites and as I-type with the exception of a few S-type granitic rocks. Most of the Sn-or W-associated granitic rocks and barren granitic rocks are thought to have formed in a volcanic arc tectonic setting. The Pb-Zn-, Mo-, or Cu-Fe-associated granitic rocks rarely shows negative Eu anomalies and a few of them are adakitic rocks, whereas all of the Sn-or W-associated granitic rocks and barren granitic rocks show negative Eu anomalies. For these Japanese granitic rocks, the contents of K 2 O, La, Y, Rb, Ta, Pb, Th, U, and REEs other than Eu increase with increasing SiO 2 . Conversely, the contents of major components other than Na 2 O and K 2 O and the trace components V, Zn, Sr, Eu, and Sc decrease with increasing SiO 2 . The Zr, Sn, and Hf abundances increase with increasing SiO 2 up to 70 wt%, but their abundances decrease when the SiO 2 exceeds 70 wt%. This suggests that granitic magma is saturated with these elements at 70 wt% of SiO 2 , approximately.

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Relationship Between Solidification Depth of Granitic Rocks and Formation of Hydrothermal Ore Deposits

Cited by 206 publications

References 14 publications

Chemical compositions of the late Cretaceous Ryoke granitoids of the Chubu District, central Japan – Revisited

Chemical compositions of the late Cretaceous Ryoke granitoids of the Chubu District, central Japan – Revisited

Metallogenic implications of biotite chemical composition: Sample from Cu-Mo-Au mineralized granitoids of the Shah Jahan Batholith, NW Iran

Major and Trace Element Chemical Compositional Signatures of Some Granitic Rocks Related to Metal Mineralization in Japan

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