Zn-Rich Spinel in Association with Quartz in the Al-Rich

Al-rich metapelites from the Mashan khondalite series are characterized by the assemblage Spl+Grt+Sil+Crd+Bt+Pl (An₇₂)+Kfs+Quartz+graphite. Large amounts of spinel+quartz assemblages occur as inclusions in garnet and prismatic sillimanite in the Al-rich metapelites of the Mashan complex, NE China. The chemical composition of spinel is characterized by Zn-rich (<i>X</i>_Zn=0.33–0.40. <i>X</i>_Zn=Zn/Zn+Mg+Fe*) (Fe*=Fe²⁺+Fe³⁺) and Fe³⁺ rich (up to 0.31 p.f.u.). The characteristic chemical composition and the mineral association indicated that the formation of spinel and quartz assemblage may be due to the breakdown of Zn-rich staurolite. The geothermobarometers studies show that the peak temperature of the Mashan complex is around 820 ℃ and the peak pressures is 8.0 kbar. The Mashan complex shows a typical orogen style <i>P</i>-<i>T</i> path.

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Zn-Rich Spinel in Association with Quartz in the Al-Rich Metapelites from the Mashan Khondalite Series, NE China

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