1. School of Geosciences, China University of Petroleum (East China), 266580 Qingdao, China
2. German Research Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, Germany
3. GEOS4 GmbH, Peter-Huchel-Chaussee 88, 14552 Michendorf, Germany
4. State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou, China