Zircon U–Pb age, element and C–O isotope geochemistry of post-collisional mafic-ultramafic rocks from the Dabie orogen in east-central China

Concentrations of the platinum group elements (PGEs), including Ir, Ru, Rh, Pt, and Pd, have been determined for both Raobazhai and Bixiling mafic-ultramafic rocks from the Dabie Orogen by fire assay method. Geochemical compositions suggest that the Raobazhai mafic-ultramafic rocks represent mantle residues after variable degrees of partial melting. They show consistent PGE patterns, in which the IPGEs (i.e., Ir and Ru) are strongly enriched over the PPGEs (i.e., Pt and Pd). Both REE and PGE data of the Raobazhai mafic-ultramafic rocks suggest that they have interacted with slab-derived melts during subduction and/or exhumation. The Bixiling ultramafic rocks were produced through fractional crystallization and cumulation from magmas, which led to the fractionated PGE patterns. During fractional crystallization, Pd is in nonsulfide phases, whereas both Ir and Ru must be compatible in some mantle phases. We suggest that the PGE budgets of the ultramafic rocks could be fractionated by interaction with slab-derived melts and fractional crystallization processes.

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Ultrahigh-pressure eclogite transformed from mafic granulite in the Dabie orogen, east-central China

Journal of Metamorphic Geology ◽

10.1111/j.1525-1314.2007.00739.x ◽

2007 ◽

Vol 25 (9) ◽

pp. 975-989 ◽

Cited By ~ 45

Author(s):

Y.-C. LIU ◽

S.-G. LI ◽

X.-F. GU ◽

S.-T. XU ◽

G.-B. CHEN

Keyword(s):

Central China ◽

Mafic Granulite ◽

Ultrahigh Pressure ◽

Dabie Orogen ◽

East Central

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Precise Re-Os Dating of Molybdenite from the Northern Dabie Molybdenum Belt in Central China and its Geodynamic Implications

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1035 ◽

2012 ◽

Vol 535-537 ◽

pp. 1035-1038

Author(s):

Jun Ping Li ◽

Yong Feng Li ◽

Ke Jia Xie

Keyword(s):

North China ◽

Central China ◽

Metamorphic Belt ◽

Dabie Orogen ◽

East Central ◽

The North ◽

Metallogenic Belt ◽

Vein Type ◽

Granite Porphyries ◽

Granitoid Intrusions

The Dabie orogen of east-central China marks the boundary between the North China and Yangtze Cratons, and is characterized by juxtaposition of the ~400Ma Tongbai metamorphic belt and the ~220Ma South Qinling-Dabie metamorphic belt. The Triassic collision between the North China and Yangtze Cratons which generated numerous granitoid intrusions such as the Shangcheng, Xingxian and Lingshan intrusions, and other small stocks, such as Tangjiaping, Dayinjian, Mushan and so on. Those shallow-emplaced granite porphyries are closely related to porphyry-skarn Mo and Mo-W deposites, forming the Dabie molybdenum metallogenic belt. Molybdenum deposits occur in the endo- and exocontact zones of the porphyry, include with three major types of Mo mineral systems, i.e., porphyry, less porphyry-skarn and vein-type. The ore-forming ages of the molybdenum deposits in Dabie area are mainly cluster 127.8±0.9~113.1±7.9Ma. The pulse is the product of the transformation of the tectonic regime from NS- to nearly EW-directions in East China.

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