Pauline Corentin , Emmanuelle Pucéat , Pierre Pellenard , Michel Guiraud , Justine Blondet , Germain Bayon , Thierry Adatte
{"title":"通过矿物学和 HfNd 同位素代用指标证明白垩纪晚期冷却过程中西非克拉通的侵蚀和硅酸盐风化加剧","authors":"Pauline Corentin , Emmanuelle Pucéat , Pierre Pellenard , Michel Guiraud , Justine Blondet , Germain Bayon , Thierry Adatte","doi":"10.1016/j.margeo.2024.107374","DOIUrl":null,"url":null,"abstract":"<div><p>The evolution of oceanic temperatures between the Turonian and the K/T boundary indicates a long-term cooling coincident with a decrease of atmospheric CO<sub>2</sub> levels, yet the cause of climate cooling at that time still remains debated. In this study, we evaluated the possible implication of enhanced silicate weathering as a sink for atmospheric CO<sub>2</sub> by applying paired Nd<img>Hf isotope measurements to detrital clay records from the West African margin. The use of this novel proxy for chemical weathering intensity (Δɛ<sub>Hf(<em>t</em>)clay</sub>) was complemented by additional mineralogical and major-trace element analyses in order to investigate the variability of mechanical erosion patterns and further explore potential linkages between tectonics, weathering and climate during the late Cretaceous.</p><p>Our Δɛ<sub>Hf(<em>t</em>)clay</sub> data suggest more intense silicate weathering on the West African Craton during the Santonian to the middle Campanian period, coincident with enhanced physical erosional inputs as inferred from higher Quartz/Clays and Feldspar/Clays ratios. This observation suggests that the shift towards intensified chemical weathering at that time was driven by enhanced mechanical erosion, possibly related to a moderate tectonic event on the West African craton. Evidence for increasing kaolinite contents and higher Δɛ<sub>Hf(<em>t</em>)clay</sub> values during the Maastrichtian point towards more hydrolysing conditions, inducing either destabilization of older Mesozoic lateritic material or favouring the development of kaolinite-rich soils.</p><p>Overall, this study was compared with several new data of chemical weathering evolution along the south Atlantic margins, adding new insights on tectonic-weathering-climate interactions during the late Cretaceous, suggesting a possible link between silicate weathering feedbacks and global cooling at that time.</p></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"476 ","pages":"Article 107374"},"PeriodicalIF":2.6000,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Enhanced erosion and silicate weathering of the West African craton during the late Cretaceous cooling evidenced by mineralogical and HfNd isotope proxies\",\"authors\":\"Pauline Corentin , Emmanuelle Pucéat , Pierre Pellenard , Michel Guiraud , Justine Blondet , Germain Bayon , Thierry Adatte\",\"doi\":\"10.1016/j.margeo.2024.107374\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The evolution of oceanic temperatures between the Turonian and the K/T boundary indicates a long-term cooling coincident with a decrease of atmospheric CO<sub>2</sub> levels, yet the cause of climate cooling at that time still remains debated. In this study, we evaluated the possible implication of enhanced silicate weathering as a sink for atmospheric CO<sub>2</sub> by applying paired Nd<img>Hf isotope measurements to detrital clay records from the West African margin. The use of this novel proxy for chemical weathering intensity (Δɛ<sub>Hf(<em>t</em>)clay</sub>) was complemented by additional mineralogical and major-trace element analyses in order to investigate the variability of mechanical erosion patterns and further explore potential linkages between tectonics, weathering and climate during the late Cretaceous.</p><p>Our Δɛ<sub>Hf(<em>t</em>)clay</sub> data suggest more intense silicate weathering on the West African Craton during the Santonian to the middle Campanian period, coincident with enhanced physical erosional inputs as inferred from higher Quartz/Clays and Feldspar/Clays ratios. This observation suggests that the shift towards intensified chemical weathering at that time was driven by enhanced mechanical erosion, possibly related to a moderate tectonic event on the West African craton. Evidence for increasing kaolinite contents and higher Δɛ<sub>Hf(<em>t</em>)clay</sub> values during the Maastrichtian point towards more hydrolysing conditions, inducing either destabilization of older Mesozoic lateritic material or favouring the development of kaolinite-rich soils.</p><p>Overall, this study was compared with several new data of chemical weathering evolution along the south Atlantic margins, adding new insights on tectonic-weathering-climate interactions during the late Cretaceous, suggesting a possible link between silicate weathering feedbacks and global cooling at that time.</p></div>\",\"PeriodicalId\":18229,\"journal\":{\"name\":\"Marine Geology\",\"volume\":\"476 \",\"pages\":\"Article 107374\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-08-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Marine Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0025322724001580\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Marine Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0025322724001580","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Enhanced erosion and silicate weathering of the West African craton during the late Cretaceous cooling evidenced by mineralogical and HfNd isotope proxies
The evolution of oceanic temperatures between the Turonian and the K/T boundary indicates a long-term cooling coincident with a decrease of atmospheric CO2 levels, yet the cause of climate cooling at that time still remains debated. In this study, we evaluated the possible implication of enhanced silicate weathering as a sink for atmospheric CO2 by applying paired NdHf isotope measurements to detrital clay records from the West African margin. The use of this novel proxy for chemical weathering intensity (ΔɛHf(t)clay) was complemented by additional mineralogical and major-trace element analyses in order to investigate the variability of mechanical erosion patterns and further explore potential linkages between tectonics, weathering and climate during the late Cretaceous.
Our ΔɛHf(t)clay data suggest more intense silicate weathering on the West African Craton during the Santonian to the middle Campanian period, coincident with enhanced physical erosional inputs as inferred from higher Quartz/Clays and Feldspar/Clays ratios. This observation suggests that the shift towards intensified chemical weathering at that time was driven by enhanced mechanical erosion, possibly related to a moderate tectonic event on the West African craton. Evidence for increasing kaolinite contents and higher ΔɛHf(t)clay values during the Maastrichtian point towards more hydrolysing conditions, inducing either destabilization of older Mesozoic lateritic material or favouring the development of kaolinite-rich soils.
Overall, this study was compared with several new data of chemical weathering evolution along the south Atlantic margins, adding new insights on tectonic-weathering-climate interactions during the late Cretaceous, suggesting a possible link between silicate weathering feedbacks and global cooling at that time.
期刊介绍:
Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.