Abstract. 

"The Rare Earth Element (REE) systematics of the post-Marinoan cap dolostones reflect the marine redox conditions and chemistry in the immediate aftermath of the snowball Earth. Rare earth elements and yttrium (REY) compositions in the Doushantuo cap dolostones that directly overlie Nantuo glacial diamictites in south China are determined from the inner shelf to the slope. In general, shale-normalized REY patterns (REYSN) of the cap dolostones show significant fractionations that are characterized by light REE depletion, slight middle REE enrichment relative to the light and heavy REEs, positive Eu anomalies, and slightly super-chondritic Y/Ho ratios. [...]".

Source: Science Direct
Authors: Min Ren & Ruifan Li
DOI: https://doi.org/10.1016/j.sedgeo.2023.106343

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Abstract. 

"Deep water freshening beneath pan-Arctic ice shelves has recently been proposed based on the absence of excess thorium in glacial Arctic sediments. This profound proposal requires scrutiny of Arctic paleohydrology during past glacial periods. Here, we present structural and geochemical results of inorganic authigenic carbonates in deep-sea glacimarine sediments from the Mendeleev Ridge, western Arctic Ocean over the last 76 kyr. Our results suggest that Polar Deep Water in the western Arctic became brackish and anoxic during stadial periods. We argue that sediment-laden hyperpycnal meltwater discharged from paleo-ice sheets filled much of the water column [...]".

Source: Nature 
Authors: Kwangchul Jang et al.
DOI: https://doi.org/10.1038/s43247-023-00708-6

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Abstract. 

"Mesozoic oceanic anoxic events are recognized as widespread deposits of marine organic-rich mudrocks temporally associated with mass extinctions and large igneous province emplacement. The Toarcian Oceanic Anoxic Event is one example during which expanded ocean anoxia is hypothesized in response to environmental perturbations associated with emplacement of the Karoo–Ferrar igneous province. However, the global extent of total seafloor anoxia and the relative extent of euxinic (anoxic and sulfide-rich) and non-euxinic anoxic conditions during the Toarcian Oceanic Anoxic Event are poorly constrained. [...]".

Source: Nature
Authors: Alexandra Kunert & Brian Kendall
DOI: https://doi.org/10.1038/s41467-023-36516-x

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Abstract. 

"Despite carbon-cycle perturbations at a global scale during the early Toarcian, the extent of anoxia during the ∼182-Ma Toarcian Oceanic Anoxic Event (T-OAE) remains in debate. A common factor in the development of oceanic anoxia is watermass restriction, which is thought to have been important in the NW European Seaway, but whose influence elsewhere is relatively unstudied. Here, we analyze Mo/TOC (a proxy for watermass restriction) and redox proxies (e.g., Corg/P) in two sections of the Asturian Basin (northern Iberian Paleomargin), and we integrate these results with data from a suite of global Toarcian sections in order to reassess [...]".

Source: Science Direct 
Authors: Javier Fernández-Martínez et al.
DOI: https://doi.org/10.1016/j.gloplacha.2022.104026

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Abstract.

"Before the Quaternary, the Earth experienced a series of environmental perturbations. The causal links between large volcanic events, extreme climatic change, and ocean anoxia have been examined in the context of these perturbations. However, to date, the correlation between oceanic anoxia and large volcanic activity in the Pleistocene remains poorly constrained. Identifying the physical processes that can control changes to the marine osmium, uranium, and sulfur isotope ratios is critical to understanding how volcanic activity, climate changes, and ocean anoxia have coevolved throughout the Quaternary. [...]".

Source: Science Direct 
Authors: Wenlong Pei et al. 
DOI: https://doi.org/10.1016/j.palaeo.2022.111360

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Abstract. 

"The impact of global climate events on local ecosystems can vary spatially. Understanding this potential heterogeneity can illuminate which environments will be most impacted and the proximal drivers of ecosystem responses. Cenomanian–Turonian marine deposits of the Western Interior Seaway (WIS) record paleoceanographic changes associated with the Greenhorn transgression and the onset of Oceanic Anoxic Event 2 (OAE2). They provide an ideal setting to study basin-wide paleoecological responses during a global perturbation. [...]".

Source: Cambridge University Press
Authors: Raquel Bryant & Christina L. Belanger
DOI: https://doi.org/10.1017/pab.2022.47

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Abstract. 

"Climate change is undermining the health and integrity of seafloor ecosystems, with declines in bioturbation expected to impact future ecosystem functioning. We explored changes in the nature and degree of bioturbation during Early Jurassic global warming and ocean deoxygenation. Understanding how these communities responded can help anticipate how bioturbation and ecosystem functioning might change over large spatial and temporal scales. Trace and body fossils from outcrop and core in the Cleveland Basin, UK show how healthy seafloor communities deteriorated through the Pliensbachian spinatum Zone, and macroinfaunal behaviour [...]".

Source: Geological Society of London
Authors: Bryony A. Caswell & Liam Herringshaw
DOI: https://doi.org/10.1144/SP529-2022-226

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Abstract.

"A Tremadocian (Early Ordovician, base Stairsian North American Stage) mass extinction event is recorded globally in rocks from several ancient continents and is accompanied by a globally correlated positive carbon isotope excursion (CIE; the largest during the Early Ordovician). In this study, elemental concentrations and uranium isotope compositions (δ238U) were measured for carbonate samples from three sections (along a proximal-to-distal transect: Ibex area, Shingle Pass, Meiklejohn Peak, respectively) in the Great Basin to test the role of ocean anoxia/euxinia on the base Stairsian mass extinction event. [...]".

Source: Science Direct 
Authors: Xinze Lu et al. 
DOI: https://doi.org/10.1016/j.gca.2022.11.028

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Abstract. 

"Early animals experienced multiple-phase radiations and extinctions from the late Ediacaran to early Cambrian. Oxygen likely played an important role in these evolutionary events, but detailed marine redox evolution during this period remains highly debated. The emerging vanadium (V) isotope system can better capture short-term perturbations to global ocean redox conditions. In this study, we analyzed V isotope compositions [...]".

Source: Science Direct 
Authors: Wei Wei et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117942

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Abstract.

"The late Pliensbachian to early Toarcian was characterized by major climatic and environmental changes, encompassing the early Toarcian Oceanic Anoxic Event (T-OAE, or Jenkyns Event, ∼183 Ma) and the preceding Pliensbachian–Toarcian boundary event (Pl/To). Information on seawater redox conditions through this time interval has thus far come mainly from European sections deposited in hydrographically restricted basins, and hence our understanding of the redox evolution of the open ocean (and in particular Panthalassa – the largest ocean to have existed) is limited. [...]".

Source: Science Direct 
Authors: Wenhan Chen et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117959

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