Ar-40/Ar-39 ages of the high-P/T metamorphic rocks of the Heilongjiang Complex in the Jiamusi Massif, northeastern China

作者：Li Weimin^*; Takasu Akira; Liu Yongjiang; Genser Johann; Neubauer Franz; Guo Xinzhuan

来源：Journal of Mineralogical and Petrological Sciences, 2009, 104(2): 110-116.

DOI：10.2465/jmps.081022g

• Ar-40/Ar-39 ages
• Blueschist
• Heilongjiang Complex
• Jiamusi Massif
• Northeastern China

The Heilongjiang Complex in northeastern China is composed mainly of alternating blueschists and pelitic schists which underwent high-P/T type metamorphism of the epidote blueschist facies. Phengites in the pelitic schists from two areas in the Heilongjiang Complex yielded Ar-40/Ar-39 plateau ages of 165 /- 0.8 Ma (Mudanjiang area) and 171 /- 0.7 Ma (Yilan area). Phengites in blueschists from the Yilan area give Ar-40/Ar-39 isochron ages of 145 /- 0.9 Ma and 146 /- 1.3 Ma. The previously reported peak metamorphic temperature of 350-450 degrees C for the Heilongjiang Complex is close to the Lambda r retention temperatures of white mica, suggesting that the ages reported here closely date the metamorphic culmination in this complex. These ages indicate that a widespread high-P/T metamorphism occurred in the Heilongjiang Complex at 165-171 Ma. Subsequent to this period, a similar type of metamorphism continued at least until 145-146 Ma in the Yilian area.

• 出版日期2009-4
• 单位吉林大学