South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center 1 article published in JoVE Environment Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS Zhiyong Lin1,3, Xiaoming Sun1,2,3,4, Jörn Peckmann5, Yang Lu2,3, Harald Strauss6, Li Xu2,3, Hongfeng Lu7, Barbara M.A. Teichert6 1School of Earth Sciences and Engineering, Sun Yat-sen University, 2School of Marine Sciences, Sun Yat-sen University, 3Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 5Institut für Geologie, Universität Hamburg, 6Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, 7Guangzhou Marine Geological Survey Analyses of the sulfur isotopic composition (δ34S) of pyrite from methane-bearing sediments have typically focused on bulk samples. Here, we applied secondary ion mass spectroscopy to analyze the δ34S values of various pyrite generations to understand the diagenetic history of pyritization.