Major and trace element characterization of Oceanic Anoxic Event 1d (OAE 1d): Insight from the Umbria-Marche Basin, central Italy

First Record of Oceanic Anoxic Event 1d at Southern High Latitudes: Sedimentary and Geochemical Evidence From International Ocean Discovery Program Expedition 369

“…The OAE 1d interval in Hole U1513D is proposed to span from the initial excursion in carbonate δ 13 C values at ∼320 m CSF‐A to ∼300 m CSF‐A where carbonate δ 13 C values start a definitive downward trend (Figure 2). The carbonate δ 13 C excursion and elevated TOC levels observed at Site U1513 are comparable to typical OAE 1d records from the Atlantic/Tethyan basins and surrounding continents (Bornemann et al., 2005, 2017; Gale et al., 2011; Wilson & Norris, 2001; Yao et al., 2021), with the records from the Tethyan Monte Petrano and Le Brecce sections (Gambacorta et al., 2015, 2020) shown for reference (Figure 2). Further, biostratigraphic control including the presence in Hole U1513D, core 26 of Thalmanninella appenninica , a foraminiferal species used for identifying OAE 1d (Table S1 in Supporting Information , Huber et al., 2019), demonstrates chronostratigraphic correlation between the record at Site U1513 and OAE 1d documented elsewhere.…”

“…1d records from the Atlantic/Tethyan basins and surrounding continents (Bornemann et al, 2005(Bornemann et al, , 2017Gale et al, 2011;Wilson & Norris, 2001;Yao et al, 2021), with the records from the Tethyan Monte Petrano and Le Brecce sections (Gambacorta et al, 2015(Gambacorta et al, , 2020 shown for reference (Figure 2). Further, biostratigraphic control including the presence in Hole U1513D, core 26 of Thalmanninella appenninica, a foraminiferal species used for identifying OAE 1d (Table S1 in Supporting Information S1, Huber et al, 2019), demonstrates chronostratigraphic correlation between the record at Site U1513 and OAE 1d documented elsewhere.…”

Assessing controls on organic matter enrichments in hemipelagic marls of the Aptian-Lower Albian Blue Marls of the Vocontian Basin (France): an unexpected variability observed from multiple “organic-rich” levels

“…In the Marnes Bleues Fm., according to our results, surface-water productivity was low to normal. Incidentally, Gambacorta et al (2020) have the same conclusion for an equivalent of OAE1d, namely, the Pialli Level of the Umbria-Marche Basin (central Italy). This basin also accumulated dark grey to black shales under oxic to suboxic conditions.…”

Paleoproterozoic manganese oxide precipitation in oxic seawater surface and reductive enrichment in anoxic seafloor

“…To varying degrees, trace metals and metalloids such as V, Co, As and Ni, exhibit a reasonable covariance with Mn concentrations. Specifically, the reduction of vanadate to vanadyl ions (VO 2-) as well as hydroxyl forms, occur in mildly reducing and non-sulfidic anoxic waters (Algeo and Maynard, 2004;Calvert and Pedersen, 1993;Morford and Emerson 1999;Tribovillard et al, 2006;Gambacorta et al, 2020). Additionally, V 3+ phases are further reduced to insoluble hydroxide forms under strongly reducing conditions when free H2S is present in the euxinic environment (Tribovillard et al, 2006;Takahashi et al, 2014;Zhang et al, 2019).…”