Ar-40-Ar-39 dating and its tectonic significance of the Hulan Group at the northern margin of the North China Plate

作者：Liu ZhiHong^*; Wang Chao; Song Jian; Gao Xiang; Sun LiNan

来源：Acta Petrologica Sinica, 2016, 32(9): 2757-2764.

• Muscovite Ar-40-Ar-39 age
• Tectonic significance
• Hulan Group
• Northern margin of the North China Plate

The Hulan Group, outcropped along the northern margin of the North China Plate in Hongqiling-Hulan area of central Jilin Province, consists mainly of felsic volcanic and sedimentary rocks with low greenschist to amphibolite facies metamorphism and multiple phases of deformation. Most parts of the stratigraphic sequence of the Hulan Group were severely damaged. The observed "bedding" in the field is actually mostly foliation formed by displacement. The majority of the lithologic boundaries are in fact structural interface. The Hulan Group is possibly a suit of m lange consisting of a series of mutual tectonic slices in a stacked configuration. Hulan Group underwent two stages of ductile deformations: the early stage showed thrusting from NNE to SSW in the NNE-SSW trending compression; the late stage showed mainly dip-slip from SW to NE in the NE-SW extension. We have acquired Ar-40-Ar-39 plateau ages of 220. 23 +/- 2. 15Ma and 221. 31 +/- 2. 6Ma for muscovite from the muscovite-quartz schist and garnet-muscovite schist, respectively, in strong deformation zone in the Hongqiling area. Consequently, the age of similar to 220Ma could represent the postorogenic extension time for the collision orogenic belt at the northern margin of the North China plate.

• 出版日期2016-9
• 单位吉林大学