1. Department of Geology and Geophysics, Yale University, New Haven, Connecticut, 06511, USA
2. NERC Geochronology and Tracers Facility, British Geological Survey, Keyworth NG12 5GG, UK
3. State Key Laboratory of Palaeobiology and Stratigraphy and Center for Excellence in Life and Paleoenvironment, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
4. College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
5. Department of Earth Science, University of California, Santa Barbara, California 93106, USA