Eastern Junggar of Xinjiang Uygur Autonomous Region is an important area of the Central Asian Orogenic belt

where the Siberia and Kazakhstan plates collided. Late Carboniferous granites are widespread in this area

among which alkali granites in Yundukala are investigated and studied in this paper. Yundukala alkali granites are characterized by high SiO

2

(72.40%-74.17%)

high alkaline (Na

2

O+K

2

O=8.41%-10.40%)

low TiO

2

(0.20%-0.40%) and low CaO(0.38%-0.70%) contents. They are significantly enriched in high field strength elements like Zr

Th

and Y

and exhibit highly differentiated REE patterns

showing right dipping lines with strong negative Eu anomaly

whilst their obvious depletion of Sr

Ba and Ti might have resulted from fractional crystallization of feldspar and Ti-oxides. These geochemical characteristics indicate they are typical A-type granites and may be the product of partial melting of the predominantly subducted oceanic crust or Nbrich basalt in the lower crust. The formation of these A-type granites infers that collisional orogenesis ended during late Carboniferous.