“Tali Glaciation” on Massif Diancang

The term of ''Tali Glaciation'' is nominated from Massif Diancang in Yunnan Province. The confusing process of the term''s being put forward is confirmed through literature checking. Based on several times of field trip, the glacial landforms in this region are studied in detail, and the magnitude of the glaciation was determined. According to the numerical ages from TL, AIMS ^(14)C and OSL dating, the earliest glacial advance on Massif Diancang occurred at 30—40 ka BP, followed by the advances at the last stage of the last glaciation, the late glacial and neoglations in turn, until glaciers vanished at 1.2—1.5 ca. a BP in this region. It can be concluded that glaciers were limited above 3600 m a.s.l., and no glaciers existed on the lower part and adjacent mountains since the last glaciation.

New Zircon U-Pb Geochronology of the Post-kinematic Granitic Plutons in the Diancang Shan Metamorphic Massif along the Ailao Shan-Red River Shear Zone and Its Geological Implications

The Ailao Shan-Red River fault zone is the boundary between the Yangtze block to the northeast and the Indochina block to the southwest.It is an important tectonic zone due to its role in the southeastward extrusion of the Indochina block during and subsequent to the Indian-Eurasian collision.Diancang Shan（DCS） high-grade metamorphic complex,located at the northwest extension along the Ailao Shan-Red River（ASRR） shear zone,is a representative metamorphic complex of the ASRR tectonic belt.Structural and microstructural analysis of sheared rocks in the high-grade metamorphic rocks reveals that they are coherent with solid-state high-temperature ductile deformation,which is attributed to left-lateral shearing along the ASRR shear zone.New LA-ICP-MS zircon U-Pb geochronological and microstructural studies of the post-kinematic granitic plutons provide a straightforward time constraint on the termination ductile left-lateral shearing and exhumation of the metamorphic massif in the ASRR shear zone.It is suggested that the left-lateral shearing along the ASRR shear zone ended at ca.21 Ma at relative lower-temperature or decreasing temperature conditions.During or after the emplacement of the young dikes at ca.21 Ma,rapid brittle deformation event occurred,which makes the DCS massif start fast uplift/exhumation and cooling to a shallow crustal level.

点苍山大理冰期研究回顾、讨论与展望

大理冰期作为第四纪末次冰盛期,在了解历史环境变化方面具有很高的研究价值,多年来中国学者用各种传统研究方法对大理冰期的起源地——点苍山的末次冰期进行了研究,并获取了大量科学成果。回顾这一历史进程,重点对航空遥感、地质地貌结构、冰川地貌特征、区域尺度等方面的研究方法及结果进行了总结。并在此基础上讨论了一些存疑,分析了运用3S技术进行冰川研究和古冰川模型重建的基础问题及可行性。