James W. Marschalek, Stuart N. Thomson, Claus-Dieter Hillenbrand, Pieter Vermeesch, Christine Siddoway, Andrew Carter, Keir Nichols, Dylan H. Rood, Ryan A. Venturelli, Samantha J. Hammond, Julia Wellner, Tina van de Flierdt
{"title":"从斯怀兹冰川和松树岛冰川之间新发现的西弗岛花岗岩中获得的地质启示","authors":"James W. Marschalek, Stuart N. Thomson, Claus-Dieter Hillenbrand, Pieter Vermeesch, Christine Siddoway, Andrew Carter, Keir Nichols, Dylan H. Rood, Ryan A. Venturelli, Samantha J. Hammond, Julia Wellner, Tina van de Flierdt","doi":"10.1017/s0954102023000287","DOIUrl":null,"url":null,"abstract":"<p>Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛ<span>Nd</span>, <span>87</span>Sr/<span>86</span>Sr and ɛ<span>Hf</span> isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous.</p>","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers\",\"authors\":\"James W. Marschalek, Stuart N. Thomson, Claus-Dieter Hillenbrand, Pieter Vermeesch, Christine Siddoway, Andrew Carter, Keir Nichols, Dylan H. Rood, Ryan A. Venturelli, Samantha J. Hammond, Julia Wellner, Tina van de Flierdt\",\"doi\":\"10.1017/s0954102023000287\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛ<span>Nd</span>, <span>87</span>Sr/<span>86</span>Sr and ɛ<span>Hf</span> isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous.</p>\",\"PeriodicalId\":50972,\"journal\":{\"name\":\"Antarctic Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.8000,\"publicationDate\":\"2024-02-20\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Antarctic Science\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1017/s0954102023000287\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Antarctic Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1017/s0954102023000287","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers
Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛNd, 87Sr/86Sr and ɛHf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous.
期刊介绍:
Antarctic Science provides a truly international forum for the broad spread of studies that increasingly characterise scientific research in the Antarctic. Whilst emphasising interdisciplinary work, the journal publishes papers from environmental management to biodiversity, from volcanoes to icebergs, and from oceanography to the upper atmosphere. No other journal covers such a wide range of Antarctic scientific studies. The journal attracts papers from all countries currently undertaking Antarctic research. It publishes both review and data papers with no limits on length, two-page short notes on technical developments and recent discoveries, and book reviews. These, together with an editorial discussing broader aspects of science, provide a rich and varied mixture of items to interest researchers in all areas of science. There are no page charges, or charges for colour, to authors publishing in the Journal. One issue each year is normally devoted to a specific theme or papers from a major meeting.