Karen Araya , Práxedes Muñoz , Antonio Maldonado , Laurent Dezileau , Lorena Rebolledo , Gloria Sanchez , Gabriel Cantarutti
{"title":"智利Coquimbo湾(30°S)近600年海洋和气候变化的重建","authors":"Karen Araya , Práxedes Muñoz , Antonio Maldonado , Laurent Dezileau , Lorena Rebolledo , Gloria Sanchez , Gabriel Cantarutti","doi":"10.1016/j.margeo.2025.107642","DOIUrl":null,"url":null,"abstract":"<div><div>The upwelling system off Coquimbo (30°S) is strongly influenced by interannual variability driven by the El Niño-Southern Oscillation (ENSO), which decreases primary productivity and increases precipitation during the warm phase (El Niño events). This study examined the historical variations in the primary oceanographic and climatic characteristics of the region based on recent sedimentary records from Coquimbo Bay. In a sediment core (BC117; 83 cm), nine sedimentary units were identified and categorized into two groups: u1, u3, u5, and u9 represent marine sedimentation, as indicated by the major contribution of marine diatoms and higher δ<sup>13</sup>C and δ<sup>15</sup>N values reflecting marine conditions. In contrast, u4, u6 and u7 exhibited more depleted δ<sup>13</sup>C values and an increase in freshwater diatom valves, suggesting a significant continental influence, likely from alluvial events. These units showed elevated concentrations of Fe, K, and Cu and an increase in fine sediment content, likely associated with El Niño-induced heavy rainfall around 1700–1730 CE. This period was followed by a decrease in continental input owing to reduced pluviosity. Spanning from 1403 CE to 1850 CE, the core reflects a period dominated by La Niña-like conditions, sustained by an intensified Southern Oscillation Index (SOI) and diminished Interdecadal Pacific Oscillation (IPO). During this period, the seafloor experienced an increase in reduced conditions, likely leading to anoxic environments, which were subsequently followed by less reduced conditions encompassing the Current Warm Period (CWP) due to enhanced ventilation processes. Nevertheless, increasing proxies for primary productivity have suggested an intensification of upwelling in recent times. Based on the characteristics of the units, three tsunami events were characterized by a significant reduction in total diatom counts contingent on the energy of the event and a sharp basal contact between the lower undisturbed unit and the very disturbed overlying layer (1420, 1471, and 1751 CE).</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"490 ","pages":"Article 107642"},"PeriodicalIF":2.2000,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Reconstruction of oceanographic and climatic changes over the past ∼ 600 years over Coquimbo Bay, Chile (30°S)\",\"authors\":\"Karen Araya , Práxedes Muñoz , Antonio Maldonado , Laurent Dezileau , Lorena Rebolledo , Gloria Sanchez , Gabriel Cantarutti\",\"doi\":\"10.1016/j.margeo.2025.107642\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The upwelling system off Coquimbo (30°S) is strongly influenced by interannual variability driven by the El Niño-Southern Oscillation (ENSO), which decreases primary productivity and increases precipitation during the warm phase (El Niño events). This study examined the historical variations in the primary oceanographic and climatic characteristics of the region based on recent sedimentary records from Coquimbo Bay. In a sediment core (BC117; 83 cm), nine sedimentary units were identified and categorized into two groups: u1, u3, u5, and u9 represent marine sedimentation, as indicated by the major contribution of marine diatoms and higher δ<sup>13</sup>C and δ<sup>15</sup>N values reflecting marine conditions. In contrast, u4, u6 and u7 exhibited more depleted δ<sup>13</sup>C values and an increase in freshwater diatom valves, suggesting a significant continental influence, likely from alluvial events. These units showed elevated concentrations of Fe, K, and Cu and an increase in fine sediment content, likely associated with El Niño-induced heavy rainfall around 1700–1730 CE. This period was followed by a decrease in continental input owing to reduced pluviosity. Spanning from 1403 CE to 1850 CE, the core reflects a period dominated by La Niña-like conditions, sustained by an intensified Southern Oscillation Index (SOI) and diminished Interdecadal Pacific Oscillation (IPO). During this period, the seafloor experienced an increase in reduced conditions, likely leading to anoxic environments, which were subsequently followed by less reduced conditions encompassing the Current Warm Period (CWP) due to enhanced ventilation processes. Nevertheless, increasing proxies for primary productivity have suggested an intensification of upwelling in recent times. Based on the characteristics of the units, three tsunami events were characterized by a significant reduction in total diatom counts contingent on the energy of the event and a sharp basal contact between the lower undisturbed unit and the very disturbed overlying layer (1420, 1471, and 1751 CE).</div></div>\",\"PeriodicalId\":18229,\"journal\":{\"name\":\"Marine Geology\",\"volume\":\"490 \",\"pages\":\"Article 107642\"},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2025-09-15\",\"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/S0025322725001677\",\"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/S0025322725001677","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}
Reconstruction of oceanographic and climatic changes over the past ∼ 600 years over Coquimbo Bay, Chile (30°S)
The upwelling system off Coquimbo (30°S) is strongly influenced by interannual variability driven by the El Niño-Southern Oscillation (ENSO), which decreases primary productivity and increases precipitation during the warm phase (El Niño events). This study examined the historical variations in the primary oceanographic and climatic characteristics of the region based on recent sedimentary records from Coquimbo Bay. In a sediment core (BC117; 83 cm), nine sedimentary units were identified and categorized into two groups: u1, u3, u5, and u9 represent marine sedimentation, as indicated by the major contribution of marine diatoms and higher δ13C and δ15N values reflecting marine conditions. In contrast, u4, u6 and u7 exhibited more depleted δ13C values and an increase in freshwater diatom valves, suggesting a significant continental influence, likely from alluvial events. These units showed elevated concentrations of Fe, K, and Cu and an increase in fine sediment content, likely associated with El Niño-induced heavy rainfall around 1700–1730 CE. This period was followed by a decrease in continental input owing to reduced pluviosity. Spanning from 1403 CE to 1850 CE, the core reflects a period dominated by La Niña-like conditions, sustained by an intensified Southern Oscillation Index (SOI) and diminished Interdecadal Pacific Oscillation (IPO). During this period, the seafloor experienced an increase in reduced conditions, likely leading to anoxic environments, which were subsequently followed by less reduced conditions encompassing the Current Warm Period (CWP) due to enhanced ventilation processes. Nevertheless, increasing proxies for primary productivity have suggested an intensification of upwelling in recent times. Based on the characteristics of the units, three tsunami events were characterized by a significant reduction in total diatom counts contingent on the energy of the event and a sharp basal contact between the lower undisturbed unit and the very disturbed overlying layer (1420, 1471, and 1751 CE).
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.