{"title":"Meteorological influences on marine chemistry during the Cryogenian Sturtian glaciation","authors":"","doi":"10.1016/j.palaeo.2024.112573","DOIUrl":null,"url":null,"abstract":"<div><div>The Cryogenian Sturtian glaciation (717–660 Ma) represents the most extreme icehouse climate condition in Earth's history, during which the global ocean was completely frozen, known as the Snowball Earth event. It is widely accepted that such a global freeze could result in persistent anoxic and ferruginous marine conditions. Here, we report on a Sturtian-aged storm-prone shelf (ca. 678 Ma) in South China, characterized by dynamic fluctuations in marine redox conditions. We observe a sequence of transitions from euxinic (anoxic and H<sub>2</sub>S-enriched) to ferruginous (anoxic but iron-rich), and finally to oxic conditions on this shelf. The euxinic deposits frequently exhibit hummocky/swaley cross-bedding structures (HCS/SCS) and contain high levels of authigenic francolite. In contrast, the ferruginous interval displays rare occurrences of HCS/SCS and lower amounts of authigenic francolite. Conversely, the oxic deposits show no evidence of storm activity. These results suggest that the strong storm waves played a crucial role in facilitating the upwelling of phosphorus-enriched deep water, thereby creating favorable nutrient conditions that stimulated primary productivity and microbial sulfate reduction (MSR). These findings underscore the significant influence of local meteorological conditions, particularly storm activity, on marine redox changes. Furthermore, dynamic storm-induced currents combined with marine redox conditions indicate the presence of an unfrozen sea with active biogeochemical cycles during the Cryogenian Sturtian glaciation. This study confirms the complex interactions among meteorology, oceanography, and Earth's climate system during extreme glacial events.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Palaeogeography, Palaeoclimatology, Palaeoecology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0031018224005625","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOGRAPHY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The Cryogenian Sturtian glaciation (717–660 Ma) represents the most extreme icehouse climate condition in Earth's history, during which the global ocean was completely frozen, known as the Snowball Earth event. It is widely accepted that such a global freeze could result in persistent anoxic and ferruginous marine conditions. Here, we report on a Sturtian-aged storm-prone shelf (ca. 678 Ma) in South China, characterized by dynamic fluctuations in marine redox conditions. We observe a sequence of transitions from euxinic (anoxic and H2S-enriched) to ferruginous (anoxic but iron-rich), and finally to oxic conditions on this shelf. The euxinic deposits frequently exhibit hummocky/swaley cross-bedding structures (HCS/SCS) and contain high levels of authigenic francolite. In contrast, the ferruginous interval displays rare occurrences of HCS/SCS and lower amounts of authigenic francolite. Conversely, the oxic deposits show no evidence of storm activity. These results suggest that the strong storm waves played a crucial role in facilitating the upwelling of phosphorus-enriched deep water, thereby creating favorable nutrient conditions that stimulated primary productivity and microbial sulfate reduction (MSR). These findings underscore the significant influence of local meteorological conditions, particularly storm activity, on marine redox changes. Furthermore, dynamic storm-induced currents combined with marine redox conditions indicate the presence of an unfrozen sea with active biogeochemical cycles during the Cryogenian Sturtian glaciation. This study confirms the complex interactions among meteorology, oceanography, and Earth's climate system during extreme glacial events.
期刊介绍:
Palaeogeography, Palaeoclimatology, Palaeoecology is an international medium for the publication of high quality and multidisciplinary, original studies and comprehensive reviews in the field of palaeo-environmental geology. The journal aims at bringing together data with global implications from research in the many different disciplines involved in palaeo-environmental investigations.
By cutting across the boundaries of established sciences, it provides an interdisciplinary forum where issues of general interest can be discussed.