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Researcher Li Ni Went to the United States for Exchange Visit

2016/12/30 9:03:16

At the invitation of Professor Anthony Koppers of the Academy of Geology, Oceanography and Atmospheric Sciences, Oregon State University, Researcher Li Ni of IGL went to the Argon Geochronology Laboratory of the Academy in July 2016 for more than two months’ exchange visit.

The volcanic activity age since Cenozoic Era, Late Quaternary in particular has been the focus of our volcanological research and attention all the time. At present, relatively reliable methods for determining the time of recent volcano eruption activities are K-Ar isotope chronology method and Ar-Ar isotope chronology method for testing of volcanic rock samples. Accurate determination of young, like Later Quaternary, volcanic rock samples is always a difficulty of dating research. Professor Anthony Koppers researched and compiled Ar-Ar isotope geological dating software and computing method earlier. At present, he is the Director of Argon Geochronology Laboratory of the Academy.

The purpose of Researcher Li Ni‘s this visit is to complete Ar-Ar dating analysis and electronic probe test of volcanic rock samples of NSFC-funded project “research of mechanism and volcanic clastic rocks of Yunnan Tengchong Daliuchong Volcano” undertaken by him, learn the sample treatment process, and experimental techniques, methods and experience from American laboratories, and know the current new international tendency of dating of volcanic rock samples.

From the short-term exchange visit to Argon Geochronology Laboratory, Oregon State University, Researcher Li Ni learnt the following things: (1) The laboratory has very good rules and regulations, visiting experiment personnel need to receive training, the experimental process is mature and complete, and the pretreatment procedure of rock samples is meticulous and rigorous to assure the reliability of test samples from the source.(2) Crushers, vacuumizers and slicers are all shared by multiple labs. These noisy devices are installed in basement to eliminate dust and noise impact on staffs in the building.(3) The volcanic rock samples for Ar-Ar dating in China usually are fine particles obtained by crushing total rocks, while foreign laboratories usually heat monominerals in rocks by step and stage till they are completely melted. The former tests a mixture of various minerals and matrices.The composition is complex. It is likely that the data and test results cannot be explained. In comparison, the composition of monomineral is relatively simple and the dating result is more convincing and can be more easily explained and accepted.

Photo: Discuss with Laboratory Director Professor Anthony Koppers and Supervisor

Dr. Daniel Miggins

This exchange visit to the United States is fruitful. Researcher Li Ni completed sample pretreatment and young volcanic (clastic) rock Ar-Ar dating and computer analysis and test of some samples in the NSFC-funded project undertaken by Li Ni. It is a great help to the forthcoming establishment of a sample operation room and formulation of a complete chemical treatment process of the volcano laboratory, IGL. Meanwhile, through communication with Professor Anthony Koppers and Dr. Daniel Miggins during this visit, Researcher Li Ni preliminarily studied the mechanism of explosive eruption of intermediate-acidic volcanoes, and also established a tentative intention for further cooperation in the test and research of samples at the latest geologic age.