Jian Chen , YueHan Lu , YongGe Sun , Nicholas Hogancamp , Man Lu
{"title":"泥盆纪晚期弗拉斯年-法门年生物危机和安努拉塔生物事件期间大陆风化和涌入造成的大洋优氧和海底氧合作用","authors":"Jian Chen , YueHan Lu , YongGe Sun , Nicholas Hogancamp , Man Lu","doi":"10.1016/j.chemgeo.2024.122213","DOIUrl":null,"url":null,"abstract":"<div><p>Oceanic anoxia is regarded as the immediate cause of the Late Devonian Frasnian–Famennian (F–F) bio-crisis and Annulata bio-event. The oceanic anoxia has been linked to continental weathering and input. However, some previous findings indicate oxic marine environments during the F–F bio-crisis. Moreover, the relative impact of terrestrial input on the Late Devonian oceanic redox conditions, when comparing a bio-crisis and a bio-event, remains unknown . Here, we present a decoupled oceanic redox model suggesting the redox conditions were different between shallow and deep water columns during the F–F bio-crisis, i.e., intensified euxinia in the photic zone and a more oxygenated condition at the seafloor. Geochemical (biomarker and trace metal) and sedimentologic evidence from the Late Devonian Seaway, eastern U.S., indicate that the shallow-deep decoupled oceanic redox conditions were regulated by terrestrial weathering and input. During the F–F bio-crisis, land nutrient input intensified photic zone euxinia through eutrophication, while hyperpycnal flows oxygenated seafloors. After the F–F bio-crisis, the seafloor redox conditions shifted from oxygenation to silled euxinia, and the watermass became hydrographically restricted. During this post-F–F interval, the euxinia at the seafloor intensified due to land nutrient runoff during the Annulata bio-event. Importantly, the land weathering and input during the F–F bio-crisis were more prominent than during the Annulata bio-event. This resulted in widespread and intense photic zone euxinia during the F–F bio-crisis, relative to the seafloor euxinia that developed in restricted areas during the Annulata bio-event. Our decoupled oceanic redox model may explain the preferential decimation of shallow-water organisms during the F–F bio-crisis. The seafloor euxinia during the Annulata bio-event may provide a niche for the turnover of benthic faunas adapting to low oxygen levels. This study suggests that continental weathering and influxes played an important role in regulating oceanic oxygen evolution and impacting life evolution and bio-diversity.</p></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":null,"pages":null},"PeriodicalIF":3.6000,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Oceanic euxinia and seafloor oxygenation linked to continental weathering and influxes during the Late Devonian Frasnian–Famennian bio-crisis and Annulata bio-event\",\"authors\":\"Jian Chen , YueHan Lu , YongGe Sun , Nicholas Hogancamp , Man Lu\",\"doi\":\"10.1016/j.chemgeo.2024.122213\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Oceanic anoxia is regarded as the immediate cause of the Late Devonian Frasnian–Famennian (F–F) bio-crisis and Annulata bio-event. The oceanic anoxia has been linked to continental weathering and input. However, some previous findings indicate oxic marine environments during the F–F bio-crisis. Moreover, the relative impact of terrestrial input on the Late Devonian oceanic redox conditions, when comparing a bio-crisis and a bio-event, remains unknown . Here, we present a decoupled oceanic redox model suggesting the redox conditions were different between shallow and deep water columns during the F–F bio-crisis, i.e., intensified euxinia in the photic zone and a more oxygenated condition at the seafloor. Geochemical (biomarker and trace metal) and sedimentologic evidence from the Late Devonian Seaway, eastern U.S., indicate that the shallow-deep decoupled oceanic redox conditions were regulated by terrestrial weathering and input. During the F–F bio-crisis, land nutrient input intensified photic zone euxinia through eutrophication, while hyperpycnal flows oxygenated seafloors. After the F–F bio-crisis, the seafloor redox conditions shifted from oxygenation to silled euxinia, and the watermass became hydrographically restricted. During this post-F–F interval, the euxinia at the seafloor intensified due to land nutrient runoff during the Annulata bio-event. Importantly, the land weathering and input during the F–F bio-crisis were more prominent than during the Annulata bio-event. This resulted in widespread and intense photic zone euxinia during the F–F bio-crisis, relative to the seafloor euxinia that developed in restricted areas during the Annulata bio-event. Our decoupled oceanic redox model may explain the preferential decimation of shallow-water organisms during the F–F bio-crisis. The seafloor euxinia during the Annulata bio-event may provide a niche for the turnover of benthic faunas adapting to low oxygen levels. This study suggests that continental weathering and influxes played an important role in regulating oceanic oxygen evolution and impacting life evolution and bio-diversity.</p></div>\",\"PeriodicalId\":9847,\"journal\":{\"name\":\"Chemical Geology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.6000,\"publicationDate\":\"2024-06-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Chemical Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0009254124002936\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0009254124002936","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Oceanic euxinia and seafloor oxygenation linked to continental weathering and influxes during the Late Devonian Frasnian–Famennian bio-crisis and Annulata bio-event
Oceanic anoxia is regarded as the immediate cause of the Late Devonian Frasnian–Famennian (F–F) bio-crisis and Annulata bio-event. The oceanic anoxia has been linked to continental weathering and input. However, some previous findings indicate oxic marine environments during the F–F bio-crisis. Moreover, the relative impact of terrestrial input on the Late Devonian oceanic redox conditions, when comparing a bio-crisis and a bio-event, remains unknown . Here, we present a decoupled oceanic redox model suggesting the redox conditions were different between shallow and deep water columns during the F–F bio-crisis, i.e., intensified euxinia in the photic zone and a more oxygenated condition at the seafloor. Geochemical (biomarker and trace metal) and sedimentologic evidence from the Late Devonian Seaway, eastern U.S., indicate that the shallow-deep decoupled oceanic redox conditions were regulated by terrestrial weathering and input. During the F–F bio-crisis, land nutrient input intensified photic zone euxinia through eutrophication, while hyperpycnal flows oxygenated seafloors. After the F–F bio-crisis, the seafloor redox conditions shifted from oxygenation to silled euxinia, and the watermass became hydrographically restricted. During this post-F–F interval, the euxinia at the seafloor intensified due to land nutrient runoff during the Annulata bio-event. Importantly, the land weathering and input during the F–F bio-crisis were more prominent than during the Annulata bio-event. This resulted in widespread and intense photic zone euxinia during the F–F bio-crisis, relative to the seafloor euxinia that developed in restricted areas during the Annulata bio-event. Our decoupled oceanic redox model may explain the preferential decimation of shallow-water organisms during the F–F bio-crisis. The seafloor euxinia during the Annulata bio-event may provide a niche for the turnover of benthic faunas adapting to low oxygen levels. This study suggests that continental weathering and influxes played an important role in regulating oceanic oxygen evolution and impacting life evolution and bio-diversity.
期刊介绍:
Chemical Geology is an international journal that publishes original research papers on isotopic and elemental geochemistry, geochronology and cosmochemistry.
The Journal focuses on chemical processes in igneous, metamorphic, and sedimentary petrology, low- and high-temperature aqueous solutions, biogeochemistry, the environment and cosmochemistry.
Papers that are field, experimentally, or computationally based are appropriate if they are of broad international interest. The Journal generally does not publish papers that are primarily of regional or local interest, or which are primarily focused on remediation and applied geochemistry.
The Journal also welcomes innovative papers dealing with significant analytical advances that are of wide interest in the community and extend significantly beyond the scope of what would be included in the methods section of a standard research paper.