Supplemental material: Environmental changes in the Late Ordovician–early Silurian: Review and new insights from black shales and nitrogen isotopes M.J. Melchin et al. 10.1130/2013352 https://gsapubs.figshare.com/articles/journal_contribution/Supplemental_material_Environmental_changes_in_the_Late_Ordovician_early_Silurian_Review_and_new_insights_from_black_shales_and_nitrogen_isotopes/12530336 GSA Data Repository Item 2013352, GSA Bulletin. File size: about 1494 KB. 2013-01-01 00:00:00 Geoscience