Postdoctor SU Benxun and his teachers compile the published and unpublished major and trace element data of global garnet peridotites occurring as xenoliths in the off-craton and on-craton and fragments in orogenic belts and try to understand their different evolution by compositional and tectonic comparisons.

The petrologic comparisons between 231 garnet peridotite xenoliths and 198 orogenic garnet peridotites revealed that (1) bulk-rock REE (rare earth element) concentrations in xenoliths are relatively high, (2) clinopyroxene and garnet in orogenic garnet peridotites show a highly fractionated REE pattern and Ce-negative anomaly, respectively, (3) Fo contents of olivines for off-cratonic xenolith are in turn lower than those of orogenic garnet and cratonic xenolith but mgnumber of garnet for orogenic is less than that of off-cratonic and on-cratonic xenolith, (4) Al2O3, Cr2O3, CaO and Cr# of pyroxenes and chemical compositions of whole rocks are very different between these garnet peridotites, (5) orogenic garnet peridotites are characterized by low T and high P, off-cratonic by high T and low P, and cratonic by medium T and high P and (6) garnet peridotite xenoliths are of Archean or Proterozoic origin, whereas most of orogenic garnet peridotites are of Phanerozoic origin.

Su et al. Geochemical syntheses among the cratonic, off-cratonic and orogenic garnet peridotites and their tectonic implications. International Journal of Earth Sciences, 2011, 100(4): 695-715 （Download Here）

Fig. Distributions of global garnet peridotite xenoliths and orogenic garnet peridotites (SU modified after Kerrich and Polat 2006)

Fig. Garnet peridotite occurrences and their possibly related tectonic setting (Image by SU)