Scientific Reports 6: Article number: 24639; published online: 19 April 2016; updated: 03 November 2016

In this Article, Aifang Chen is incorrectly affiliated with ‘Department of Earth Sciences, University of Gothenburg, Gothenburg 450 30, Sweden’ The correct affiliation is listed below:

Department of Earth Sciences, University of Gothenburg, Gothenburg 405 30, Sweden.