Ocean-rafted pumice constrains postglacial relative sea-level and supports Holocene ice cap survival

QUATERNARY SCIENCE REVIEWS

卷:250

Article

Farnsworth, W. R.^1,2,3  Blake, W., Jr.⁴  Gudmundsdottir, E. R.^1,3,5  Ingolfsson, O.⁵  Kalliokoski, M. H.¹  Larsen, G.^1,5  Newton, A. J.⁶  Oladottir, B. A.^5,7  Schomacker, A.³ 

[1] Univ Iceland, Nord Volcanol Ctr, Sturlugata 7, IS-101 Reykjavik, Iceland

[2] Univ Ctr Svalbard UNIS, Arctic Geol Dept, N-9171 Longyearbyen, Norway

[3] UiT Arctic Univ Norway, Dept Geosci, POB 6050, N-9037 Langnes, Norway

[4] Geol Survey Canada, 601 Booth St, Ottawa, ON, Canada

[5] Univ Iceland, Inst Earth Sci, Sturlugata 7, IS-101 Reykjavik, Iceland

[6] Univ Edinburgh, Sch GeoSci, Drummond St, Edinburgh EH8 9XP, Midlothian, Scotland

[7] IMO Iceland Meteorol Off, Bustaoavegur 7-9, IS-105 Reykjavik, Iceland

关键词: Tephrochronology;    Holocene thermal maximum;    Iceland;    Svalbard;    Katla;   

DOI  :  10.1016/j.quascirev.2020.106654

来源: Elsevier

【 摘 要 】

Distally deposited tephra from explosive volcanic eruptions can be a powerful tool for precise dating and correlation of sedimentary archives and landforms. However, the morphostratigraphic and chronological potential of ocean-rafted pumice has been under-utilized considering its long observational history and widespread distribution on modern and palaeo-shorelines around the world. Here we analyze the geochemical composition and elevation data of 60 samples of ocean-rafted pumice collected since 1958 from raised beaches on Svalbard. Comparison of pumice data with postglacial relative sea-level history suggests eight distinct pumice rafting events throughout the North Atlantic during the Middle and Late Holocene. Analyzed ocean-rafted pumice exhibit consistent silicic composition characteristic of deposits from Iceland's volcanic system, Katla. Eruption-triggered jokulhlaups are key drivers of the transport of pumice from the Katla caldera to beyond the coast of Iceland and into the surface currents of the North Atlantic Ocean. Thus, the correlation of distinct, high-concentration pumice horizons from Katla deposited along raised Middle Holocene beach ridges in Svalbard further advocates for the persistence of the Myrdalsjokull ice cap through the Holocene thermal maximum. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

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