Himanshu Bali , Anil K. Gupta , Sudheer Joseph , Arun Kaushik
{"title":"探索自渐新世晚期以来东印度洋的深海水团翻转:海洋门户和古气候的意义","authors":"Himanshu Bali , Anil K. Gupta , Sudheer Joseph , Arun Kaushik","doi":"10.1016/j.palaeo.2024.112607","DOIUrl":null,"url":null,"abstract":"<div><div>Tectonically driven adjustments within ocean gateways and their impacts on deep water production, thermohaline circulation, and nutrient distribution are well constrained. With no deep water formation in the modern northern Indian Ocean, this study aims to reconstruct the possible source and pathways of deep circulation since the late Oligocene, altering the water mass properties at study sites in the eastern Indian Ocean. Our benthic foraminifera results suggest that tectonic gateways influenced the deep water masses in the eastern Indian Ocean. Significant changes in deep water masses at the studied sites commenced with a gradual reduction in corrosive deep water in the eastern equatorial Indian Ocean (EIO) due to the inflow of relatively warmer and less corrosive Tethyan Overflow Water (TOW) through the Tethyan Gateway in the late Oligocene (∼24 Ma). The EIO gradually became less corrosive from the late Oligocene to the middle Miocene (∼24 to 14 Ma). This turnover reflects the intrusion of southward-flowing TOW and a reduction in the Antarctic Bottom Water (AABW) between ∼24 and ∼ 14.5 Ma in the Indian Ocean. Hereafter, a significant switch in deep water mass was established, contemporaneous with the expansion of Antarctic ice sheets that led to the enhanced production of cold and corrosive AABW that replaced the warm and less corrosive TOW at ∼14 Ma. Furthermore, between ∼12 and 8 Ma the closure of the Tethys Seaway caused a significant hydrological reorganization, replacing the TOW with the Pacific Deep Water (PDW) and North Component Water (NCW). At ∼8 Ma, the contribution of the PDW diminished and AABW flow increased again after a reduction between 12 and 8 Ma, leading to a gradual increase in corrosive deep water. Since 8 Ma, a circulation pattern resembling the modern framework was established with the intrusion of the North Atlantic Deep Water into the CDW, and this pattern was developed by ∼5.7 Ma. Furthermore, the final closure of the Central American Seaway increased the formation of the NADW and its intrusion into the CDW after ∼3.2 Ma.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"657 ","pages":"Article 112607"},"PeriodicalIF":2.6000,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Exploring the deep water mass turnovers in the Eastern Indian Ocean since the late Oligocene: Significance of ocean gateways and paleoclimate\",\"authors\":\"Himanshu Bali , Anil K. Gupta , Sudheer Joseph , Arun Kaushik\",\"doi\":\"10.1016/j.palaeo.2024.112607\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Tectonically driven adjustments within ocean gateways and their impacts on deep water production, thermohaline circulation, and nutrient distribution are well constrained. With no deep water formation in the modern northern Indian Ocean, this study aims to reconstruct the possible source and pathways of deep circulation since the late Oligocene, altering the water mass properties at study sites in the eastern Indian Ocean. Our benthic foraminifera results suggest that tectonic gateways influenced the deep water masses in the eastern Indian Ocean. Significant changes in deep water masses at the studied sites commenced with a gradual reduction in corrosive deep water in the eastern equatorial Indian Ocean (EIO) due to the inflow of relatively warmer and less corrosive Tethyan Overflow Water (TOW) through the Tethyan Gateway in the late Oligocene (∼24 Ma). The EIO gradually became less corrosive from the late Oligocene to the middle Miocene (∼24 to 14 Ma). This turnover reflects the intrusion of southward-flowing TOW and a reduction in the Antarctic Bottom Water (AABW) between ∼24 and ∼ 14.5 Ma in the Indian Ocean. Hereafter, a significant switch in deep water mass was established, contemporaneous with the expansion of Antarctic ice sheets that led to the enhanced production of cold and corrosive AABW that replaced the warm and less corrosive TOW at ∼14 Ma. Furthermore, between ∼12 and 8 Ma the closure of the Tethys Seaway caused a significant hydrological reorganization, replacing the TOW with the Pacific Deep Water (PDW) and North Component Water (NCW). At ∼8 Ma, the contribution of the PDW diminished and AABW flow increased again after a reduction between 12 and 8 Ma, leading to a gradual increase in corrosive deep water. Since 8 Ma, a circulation pattern resembling the modern framework was established with the intrusion of the North Atlantic Deep Water into the CDW, and this pattern was developed by ∼5.7 Ma. Furthermore, the final closure of the Central American Seaway increased the formation of the NADW and its intrusion into the CDW after ∼3.2 Ma.</div></div>\",\"PeriodicalId\":19928,\"journal\":{\"name\":\"Palaeogeography, Palaeoclimatology, Palaeoecology\",\"volume\":\"657 \",\"pages\":\"Article 112607\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-11-15\",\"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/S0031018224005960\",\"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/S0031018224005960","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}
引用次数: 0
摘要
大洋门户内构造驱动的调整及其对深水生成、温盐环流和营养物质分布的影响受到了很好的制约。由于现代北印度洋没有深水形成,本研究旨在重建晚渐新世以来深层环流的可能来源和路径,改变东印度洋研究地点的水团特性。我们的底栖有孔虫研究结果表明,构造门影响了东印度洋的深层水团。研究地点深水水团的显著变化始于赤道印度洋东部(EIO)腐蚀性深水的逐渐减少,这是由于在渐新世晚期(∼24 Ma),相对较暖和腐蚀性较弱的哲罗纪溢流水(TOW)通过哲罗纪门户流入。从渐新世晚期到中新世中期(24 ∼ 14 Ma),EIO 的腐蚀性逐渐减弱。这一变化反映了南流 TOW 的侵入以及印度洋南极底层水(AABW)在 24 至 14.5 Ma 之间的减少。此后,随着南极冰盖的扩张,深层水的质量发生了重大变化,导致冷的和腐蚀性强的南极底层水(AABW)的生成量增加,在 14 Ma ∼时取代了温暖的和腐蚀性较弱的南极底层水(TOW)。此外,在 ∼12 到 8 Ma 之间,特提斯海道的关闭引起了重大的水文重组,太平洋深水(PDW)和北成分水(NCW)取代了 TOW。在 ∼8 Ma 时,PDW 的贡献减少,AABW 流量在 12 至 8 Ma 期间减少后再次增加,导致腐蚀性深水逐渐增加。自 8 Ma 起,随着北大西洋深水侵入 CDW,建立了类似现代框架的环流模式,这种模式在 5.7 Ma 以前得到了发展。此外,中美洲海道的最终关闭增加了北大西洋深水的形成,并在∼3.2Ma之后将其侵入CDW。
Exploring the deep water mass turnovers in the Eastern Indian Ocean since the late Oligocene: Significance of ocean gateways and paleoclimate
Tectonically driven adjustments within ocean gateways and their impacts on deep water production, thermohaline circulation, and nutrient distribution are well constrained. With no deep water formation in the modern northern Indian Ocean, this study aims to reconstruct the possible source and pathways of deep circulation since the late Oligocene, altering the water mass properties at study sites in the eastern Indian Ocean. Our benthic foraminifera results suggest that tectonic gateways influenced the deep water masses in the eastern Indian Ocean. Significant changes in deep water masses at the studied sites commenced with a gradual reduction in corrosive deep water in the eastern equatorial Indian Ocean (EIO) due to the inflow of relatively warmer and less corrosive Tethyan Overflow Water (TOW) through the Tethyan Gateway in the late Oligocene (∼24 Ma). The EIO gradually became less corrosive from the late Oligocene to the middle Miocene (∼24 to 14 Ma). This turnover reflects the intrusion of southward-flowing TOW and a reduction in the Antarctic Bottom Water (AABW) between ∼24 and ∼ 14.5 Ma in the Indian Ocean. Hereafter, a significant switch in deep water mass was established, contemporaneous with the expansion of Antarctic ice sheets that led to the enhanced production of cold and corrosive AABW that replaced the warm and less corrosive TOW at ∼14 Ma. Furthermore, between ∼12 and 8 Ma the closure of the Tethys Seaway caused a significant hydrological reorganization, replacing the TOW with the Pacific Deep Water (PDW) and North Component Water (NCW). At ∼8 Ma, the contribution of the PDW diminished and AABW flow increased again after a reduction between 12 and 8 Ma, leading to a gradual increase in corrosive deep water. Since 8 Ma, a circulation pattern resembling the modern framework was established with the intrusion of the North Atlantic Deep Water into the CDW, and this pattern was developed by ∼5.7 Ma. Furthermore, the final closure of the Central American Seaway increased the formation of the NADW and its intrusion into the CDW after ∼3.2 Ma.
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.