Renan F. dos Santos , Pierre Sansjofre , Afonso C.R. Nogueira , Simon V. Hohl , Marlone H.H. Bom , Ailton S. Brito , Flavia Callefo , Stefan V. Lalonde
{"title":"Puga cap碳酸盐中的后Marinoan古氧化还原和古生产率记录:亚马逊克拉通边缘海沿岸生物殖民化的影响","authors":"Renan F. dos Santos , Pierre Sansjofre , Afonso C.R. Nogueira , Simon V. Hohl , Marlone H.H. Bom , Ailton S. Brito , Flavia Callefo , Stefan V. Lalonde","doi":"10.1016/j.palaeo.2024.112600","DOIUrl":null,"url":null,"abstract":"<div><div>The geochemical signatures in cap carbonate successions are critical records of paleoceanographic conditions following Snowball Earth events. These deposits offer insight into the shifts in redox conditions and the re-establishment of biogeochemical cycles during postglacial periods, providing a window into the evolving marine environments and potential drivers of early oxygenation. To track redox changes during this transition, we present improved high-resolution analyses of redox proxies across Puga cap carbonate (∼ 635 Ma) on the Southern Amazon Craton, Brazil, allowing for the identification of temporal redox transitions during the post-Marinoan transgression. The depletion of trace elements, particularly redox-sensitive elements (RSEs), such as Mo, U, and V in microbialites formed in basal cap dolostone, was deposited under oxic conditions. Following the initial melting of Marinoan glaciers, microbial mats flourished and grew in a semi-restricted shallow marine environment in the coastal paleoenvironment along the Amazon cratonic margin, where nutrient-rich surface waters fueled primary productivity. In contrast, the increase in RSEs in upper wave-dominated dolostone facies indicates predominantly dysoxic conditions in continuous sea level rise, resulting in the drowning of these early microbial environments and the precipitation of cap limestones. The sequential oxic-dysoxic redox marks the transition from shallow sea to deepening CaCO<sub>3</sub>-oversaturated platform conditions. These results demonstrate an unequivocal synchronous relationship between the initial oxygenation of the Amazon margin and the local microbial mat flourishment shortly after the Marinoan glaciation.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"657 ","pages":"Article 112600"},"PeriodicalIF":2.6000,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Post-Marinoan paleoredox and paleoproductivity record in Puga cap carbonate: Implication for coastal life colonization at the Amazon Craton marginal Sea\",\"authors\":\"Renan F. dos Santos , Pierre Sansjofre , Afonso C.R. Nogueira , Simon V. Hohl , Marlone H.H. Bom , Ailton S. Brito , Flavia Callefo , Stefan V. Lalonde\",\"doi\":\"10.1016/j.palaeo.2024.112600\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The geochemical signatures in cap carbonate successions are critical records of paleoceanographic conditions following Snowball Earth events. These deposits offer insight into the shifts in redox conditions and the re-establishment of biogeochemical cycles during postglacial periods, providing a window into the evolving marine environments and potential drivers of early oxygenation. To track redox changes during this transition, we present improved high-resolution analyses of redox proxies across Puga cap carbonate (∼ 635 Ma) on the Southern Amazon Craton, Brazil, allowing for the identification of temporal redox transitions during the post-Marinoan transgression. The depletion of trace elements, particularly redox-sensitive elements (RSEs), such as Mo, U, and V in microbialites formed in basal cap dolostone, was deposited under oxic conditions. Following the initial melting of Marinoan glaciers, microbial mats flourished and grew in a semi-restricted shallow marine environment in the coastal paleoenvironment along the Amazon cratonic margin, where nutrient-rich surface waters fueled primary productivity. In contrast, the increase in RSEs in upper wave-dominated dolostone facies indicates predominantly dysoxic conditions in continuous sea level rise, resulting in the drowning of these early microbial environments and the precipitation of cap limestones. The sequential oxic-dysoxic redox marks the transition from shallow sea to deepening CaCO<sub>3</sub>-oversaturated platform conditions. These results demonstrate an unequivocal synchronous relationship between the initial oxygenation of the Amazon margin and the local microbial mat flourishment shortly after the Marinoan glaciation.</div></div>\",\"PeriodicalId\":19928,\"journal\":{\"name\":\"Palaeogeography, Palaeoclimatology, Palaeoecology\",\"volume\":\"657 \",\"pages\":\"Article 112600\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-11-10\",\"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/S0031018224005893\",\"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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Palaeogeography, Palaeoclimatology, Palaeoecology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0031018224005893","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}
Post-Marinoan paleoredox and paleoproductivity record in Puga cap carbonate: Implication for coastal life colonization at the Amazon Craton marginal Sea
The geochemical signatures in cap carbonate successions are critical records of paleoceanographic conditions following Snowball Earth events. These deposits offer insight into the shifts in redox conditions and the re-establishment of biogeochemical cycles during postglacial periods, providing a window into the evolving marine environments and potential drivers of early oxygenation. To track redox changes during this transition, we present improved high-resolution analyses of redox proxies across Puga cap carbonate (∼ 635 Ma) on the Southern Amazon Craton, Brazil, allowing for the identification of temporal redox transitions during the post-Marinoan transgression. The depletion of trace elements, particularly redox-sensitive elements (RSEs), such as Mo, U, and V in microbialites formed in basal cap dolostone, was deposited under oxic conditions. Following the initial melting of Marinoan glaciers, microbial mats flourished and grew in a semi-restricted shallow marine environment in the coastal paleoenvironment along the Amazon cratonic margin, where nutrient-rich surface waters fueled primary productivity. In contrast, the increase in RSEs in upper wave-dominated dolostone facies indicates predominantly dysoxic conditions in continuous sea level rise, resulting in the drowning of these early microbial environments and the precipitation of cap limestones. The sequential oxic-dysoxic redox marks the transition from shallow sea to deepening CaCO3-oversaturated platform conditions. These results demonstrate an unequivocal synchronous relationship between the initial oxygenation of the Amazon margin and the local microbial mat flourishment shortly after the Marinoan glaciation.
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.