5.3. Implications for other garnet–clinopyroxene rocks from granulite bodies in the Bohemian Massif
The flat patterns of the cores of our garnets indicate that initial UHP garnets were well homogenized before the decompressional reaction. As they JIB-04 were immediately overgrown by a significant amount of new garnet during rapid decompression, they became effectively shielded and their composition was thus preserved despite ultrahigh temperatures persisting at granulite-facies conditions.
5.4. Comparison with other UHP terranes and tectonic interpretation
The UHP rocks from the North Bohemian Massif record the highest peak temperatures compared to other UHP terranes worldwide (Fig. 16). For instance, the diamond-bearing garnet–biotite–(phengite) gneisses, dolomitic marbles and some other rocks from the Kokchetav Massif formed at c. 950–1000 °C at c. 4.5 GPa (Hermann et al., 2001, Schertl and Sobolev, 2013 and Zhang et al., 1997). Based on melting experiments at an ion extreme pressure of 7 GPa, temperatures of 1250 °C were suggested by Massonne and Fockenberg (2012) for the gneisses from the Lake Kumdy–Kol from the Kokchetav Massif. Lower peak temperatures, generally up to 850 °C at 3–4 GPa, were reached by various coesite-bearing, but diamond-free gneisses, marbles, quartzites, amphibolites or eclogites from the Dabie–Sulu UHP terrane (Liou et al., 2009, Liu and Liou, 2011 and Zheng, 2008).
The flat patterns of the cores of our garnets indicate that initial UHP garnets were well homogenized before the decompressional reaction. As they JIB-04 were immediately overgrown by a significant amount of new garnet during rapid decompression, they became effectively shielded and their composition was thus preserved despite ultrahigh temperatures persisting at granulite-facies conditions.
5.4. Comparison with other UHP terranes and tectonic interpretation
The UHP rocks from the North Bohemian Massif record the highest peak temperatures compared to other UHP terranes worldwide (Fig. 16). For instance, the diamond-bearing garnet–biotite–(phengite) gneisses, dolomitic marbles and some other rocks from the Kokchetav Massif formed at c. 950–1000 °C at c. 4.5 GPa (Hermann et al., 2001, Schertl and Sobolev, 2013 and Zhang et al., 1997). Based on melting experiments at an ion extreme pressure of 7 GPa, temperatures of 1250 °C were suggested by Massonne and Fockenberg (2012) for the gneisses from the Lake Kumdy–Kol from the Kokchetav Massif. Lower peak temperatures, generally up to 850 °C at 3–4 GPa, were reached by various coesite-bearing, but diamond-free gneisses, marbles, quartzites, amphibolites or eclogites from the Dabie–Sulu UHP terrane (Liou et al., 2009, Liu and Liou, 2011 and Zheng, 2008).