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地球学报  1993 

DEEP SEATED XENOLITHS IN KIMBERLITES FROM CHINA
我国金伯利岩中的深源岩石包体

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Abstract:

The ultramafic xenoliths in kimberlites from China have been found from Shengli-1 pipe of Shandong, and No. 50, No. 51, No. 42 pipes of Liao- ning, they are predominatly dunites, garnet Iherzolites, followed by spinel Iherzolites and mica peridotites. The eclogite xenoliths have been found in Hebei kimberlites and Hongqi-2 dike of Shandong. Most of the xenoliths are extensively altered. The form of the xenoliths range from spherical or ellipsoidal to tabular. Their size ranges from less than a centimetre to 15cm in diameter. The xenoliths larger than 15 cm are rare. Dunites and garnet lherzolites are richer in Cr2O3, NiO, and pooer in CaO, CO2, (K2O + Na2O), TiO2 and Al2O3 than those of host kimberlites, and are characterized by simple linear REE distribution pattern showing light REE enrichment.Most of the garnet Iherzolites extend from the depth of 100 - 180km. Spinel Iherzolites occur at depth of 83 - 120 km. Mica-rich peridotites apparently is restricted to the uppermost mantle zone. Eclogite nodules in Hebei kimberlites that formed at the low equilibration temperatures and pressure conditions are believed to have been derived from lower crust. Mica-rich peridotites and spinel lherzolites are accidental xenoliths, but most of garnet lherzolites and dunites are residues during partial melting of upper mantle materials.

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