Youhong Gao , Hucai Zhang , Xiaonan Zhang , Lizeng Duan , Huayong Li , Ian R. Hall , Sidney R. Hemming , Leah J. LeVay , Junsheng Nie , Xibin Han
{"title":"IODP U1477遗址晚更新世沉积物物源分析揭示了赞比西河流域的气候和流域动态","authors":"Youhong Gao , Hucai Zhang , Xiaonan Zhang , Lizeng Duan , Huayong Li , Ian R. Hall , Sidney R. Hemming , Leah J. LeVay , Junsheng Nie , Xibin Han","doi":"10.1016/j.gr.2025.05.012","DOIUrl":null,"url":null,"abstract":"<div><div>The provenance of sedimentary material deposited in marginal marine environments offers significant insights into the evolving conditions within adjacent river catchments, thereby revealing the basin dynamics and climate variations. In this study, we used rare earth element (REE) compositions and Sr-Nd-Hf isotope signatures to investigate the provenance of sediments at International Ocean Discovery Program (IODP) Site U1477, located offshore of the Zambezi River mouth, over the past 150 thousand years (ka). These geochemical and isotope proxies indicate that the entire Zambezi River Basin (ZRB) has contributed sediments to the offshore region near the Zambezi River mouth during the last approximately 150 ka. Distinctly unradiogenic ε<sub>Nd</sub> and ε<sub>Hf</sub> signatures coupled with highly radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr values are indicative of sediment input from the middle and lower reaches of the ZRB. Conversely, more radiogenic ε<sub>Nd</sub> and ε<sub>Hf</sub> signatures along with unradiogenic <sup>87</sup>Sr/<sup>86</sup>Sr values suggest sediment contributions from the upper reaches. The geochemical and isotope data from Site U1477 thus reveal that substantial changes in the sediment provenance occurred during the Late Pleistocene. By integrating our findings with other paleoclimate records from marine sediments and paleolake cores, we infer that the increased contribution of the upper Zambezi sediment sources to the offshore deposits from approximately 40 ka onwards reflects the reestablishment of the sediment supply from both the upper and middle Zambezi at this time. These changes were likely associated with shifts in the regional rainfall patterns across the ZRB, as well as modifications of the drainage divides due to varying sediment loads resulting from active bedrock erosion following the tectonic uplift on the Chobe fault near the Chobe–Zambezi confluence. This study offers novel insights into the Late Pleistocene evolution of the Zambezi drainage system and is essential for accurately reconstructing regional climate and environmental changes.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"146 ","pages":"Pages 25-38"},"PeriodicalIF":7.2000,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Provenance analysis of late Pleistocene sediment from IODP site U1477 reveals climate and river basin dynamics in the Zambezi river catchment\",\"authors\":\"Youhong Gao , Hucai Zhang , Xiaonan Zhang , Lizeng Duan , Huayong Li , Ian R. Hall , Sidney R. Hemming , Leah J. LeVay , Junsheng Nie , Xibin Han\",\"doi\":\"10.1016/j.gr.2025.05.012\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The provenance of sedimentary material deposited in marginal marine environments offers significant insights into the evolving conditions within adjacent river catchments, thereby revealing the basin dynamics and climate variations. In this study, we used rare earth element (REE) compositions and Sr-Nd-Hf isotope signatures to investigate the provenance of sediments at International Ocean Discovery Program (IODP) Site U1477, located offshore of the Zambezi River mouth, over the past 150 thousand years (ka). These geochemical and isotope proxies indicate that the entire Zambezi River Basin (ZRB) has contributed sediments to the offshore region near the Zambezi River mouth during the last approximately 150 ka. Distinctly unradiogenic ε<sub>Nd</sub> and ε<sub>Hf</sub> signatures coupled with highly radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr values are indicative of sediment input from the middle and lower reaches of the ZRB. Conversely, more radiogenic ε<sub>Nd</sub> and ε<sub>Hf</sub> signatures along with unradiogenic <sup>87</sup>Sr/<sup>86</sup>Sr values suggest sediment contributions from the upper reaches. The geochemical and isotope data from Site U1477 thus reveal that substantial changes in the sediment provenance occurred during the Late Pleistocene. By integrating our findings with other paleoclimate records from marine sediments and paleolake cores, we infer that the increased contribution of the upper Zambezi sediment sources to the offshore deposits from approximately 40 ka onwards reflects the reestablishment of the sediment supply from both the upper and middle Zambezi at this time. These changes were likely associated with shifts in the regional rainfall patterns across the ZRB, as well as modifications of the drainage divides due to varying sediment loads resulting from active bedrock erosion following the tectonic uplift on the Chobe fault near the Chobe–Zambezi confluence. This study offers novel insights into the Late Pleistocene evolution of the Zambezi drainage system and is essential for accurately reconstructing regional climate and environmental changes.</div></div>\",\"PeriodicalId\":12761,\"journal\":{\"name\":\"Gondwana Research\",\"volume\":\"146 \",\"pages\":\"Pages 25-38\"},\"PeriodicalIF\":7.2000,\"publicationDate\":\"2025-06-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gondwana Research\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1342937X25001625\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gondwana Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1342937X25001625","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Provenance analysis of late Pleistocene sediment from IODP site U1477 reveals climate and river basin dynamics in the Zambezi river catchment
The provenance of sedimentary material deposited in marginal marine environments offers significant insights into the evolving conditions within adjacent river catchments, thereby revealing the basin dynamics and climate variations. In this study, we used rare earth element (REE) compositions and Sr-Nd-Hf isotope signatures to investigate the provenance of sediments at International Ocean Discovery Program (IODP) Site U1477, located offshore of the Zambezi River mouth, over the past 150 thousand years (ka). These geochemical and isotope proxies indicate that the entire Zambezi River Basin (ZRB) has contributed sediments to the offshore region near the Zambezi River mouth during the last approximately 150 ka. Distinctly unradiogenic εNd and εHf signatures coupled with highly radiogenic 87Sr/86Sr values are indicative of sediment input from the middle and lower reaches of the ZRB. Conversely, more radiogenic εNd and εHf signatures along with unradiogenic 87Sr/86Sr values suggest sediment contributions from the upper reaches. The geochemical and isotope data from Site U1477 thus reveal that substantial changes in the sediment provenance occurred during the Late Pleistocene. By integrating our findings with other paleoclimate records from marine sediments and paleolake cores, we infer that the increased contribution of the upper Zambezi sediment sources to the offshore deposits from approximately 40 ka onwards reflects the reestablishment of the sediment supply from both the upper and middle Zambezi at this time. These changes were likely associated with shifts in the regional rainfall patterns across the ZRB, as well as modifications of the drainage divides due to varying sediment loads resulting from active bedrock erosion following the tectonic uplift on the Chobe fault near the Chobe–Zambezi confluence. This study offers novel insights into the Late Pleistocene evolution of the Zambezi drainage system and is essential for accurately reconstructing regional climate and environmental changes.
期刊介绍:
Gondwana Research (GR) is an International Journal aimed to promote high quality research publications on all topics related to solid Earth, particularly with reference to the origin and evolution of continents, continental assemblies and their resources. GR is an "all earth science" journal with no restrictions on geological time, terrane or theme and covers a wide spectrum of topics in geosciences such as geology, geomorphology, palaeontology, structure, petrology, geochemistry, stable isotopes, geochronology, economic geology, exploration geology, engineering geology, geophysics, and environmental geology among other themes, and provides an appropriate forum to integrate studies from different disciplines and different terrains. In addition to regular articles and thematic issues, the journal invites high profile state-of-the-art reviews on thrust area topics for its column, ''GR FOCUS''. Focus articles include short biographies and photographs of the authors. Short articles (within ten printed pages) for rapid publication reporting important discoveries or innovative models of global interest will be considered under the category ''GR LETTERS''.