Oxidized intervals of five organic‐rich Madeira Abyssal Plain (MAP) turbidites deposited during the Miocene, Pliocene, and Pleistocene all displayed comparable major loss of total organic carbon (TOC) (84 ± 3.1%) accompanied by a negative isotopic (δ¹³C) shift ranging from −0.3 to −2.9‰. Major but significantly lower loss of total nitrogen...