“…The timing of the marine incursion in the Araripe Basin is extensively debated. Among the proposals, it is considered that the deposits of the Romualdo Formation (calciferous mudstone and sandstone) are the first records of a marine incursion in the Araripe Basin based on the presence of marine fossils (fishes, ostracods, gastropods, dynoflagellates and microforaminiferal linings; Lima, 1978;Arai and Coimbra, 1990;Maisey, 2000;Bruno and Hessel, 2006;Pereira et al, 2016) and facies associations (depositional sequences comprising transgressive and highstand system tracts; Assine, 2007;Rojas, 2009;Assine et al, 2014;Neumann and Assine, 2015;Custódio et al, 2017). Evidence for marine incursion during the deposition of the Ipubi Formation black shales is based on the occurrence of both dynoflagellates (Spinierites and Subtilisphaera; Arai and Coimbra, 1990) and palynoforaminifers (organic linings and allied material; Lima 1978;Arai, 2012;Goldberg et al, 2019), odd-to-even n-alkanes distribution (Silva et al, 2014), N/Vi ratios (0.13-0.49; Lúcio et al, 2016b) and Type II kerogen (Menezes, 2017).…”