Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-Cretaceous to other Mesozoic events by Percival, L, Jenkyns, H, Mather, T, Dickson, A, Batenburg, S, Ruhl, M, Hesselbo, S, Barclay, R, Jarvis, I, Robinson, S, Woelders, L