Accepted Manuscript Holocene tephra from the Chukchi-Alaskan margin, Arctic Ocean: Implications for sediment chronostratigraphy and volcanic history Vera Ponomareva, Leonid Polyak, Maxim Portnyagin, Peter Abbott, Egor Zelenin, Polina Vakhrameeva, Dieter Garbe-Schönberg PII: S1871-1014(17)30140-1 DOI: 10.1016/j.quageo.2017.11.001 Reference: QUAGEO 878 To appear in: Quaternary Geochronology Received Date: 24 August 2017 Revised Date: 30 October 2017 Accepted Date: 2 November 2017 Please cite this article as: Ponomareva, V., Polyak, L., Portnyagin, M., Abbott, P., Zelenin, E., Vakhrameeva, P., Garbe-Schönberg, D., Holocene tephra from the Chukchi-Alaskan margin, Arctic Ocean: Implications for sediment chronostratigraphy and volcanic history, Quaternary Geochronology (2017), doi: 10.1016/j.quageo.2017.11.001. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT 1 Holocene tephra from the Chukchi-Alaskan margin, Arctic Ocean: 2 Implications for sediment chronostratigraphy and volcanic history 3 4 Vera Ponomareva a, Leonid Polyak b, Maxim Portnyagin c, Peter Abbott d 1 , Egor Zelenin e, Polina 5 Vakhrameeva f,g , Dieter Garbe-Schönberg h 6 7 a Institute of Volcanology and Seismology, Piip Boulevard 9, Petropavlovsk-Kamchatsky, 8 683006, Russia. E-mail: [email protected] 9 b Byrd Polar and Climate Research Center, Ohio State University, 108 Scott Hall, 109 Carmack 10 Rd., Columbus, OH 43210, USA. E-mail: [email protected] 11 c GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, 12 Germany. E-mail: [email protected] 13 d Department of Geography, Swansea University, Singleton Park, Swansea, SA2 8PP, UK. E- 14 mail: [email protected] 15 e Geological Institute, Pyzhevsky Lane 7, Moscow, 119017, Russia. E-mail: 16 [email protected] 17 f Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234, 69120 18 Heidelberg, Germany. E-mail: [email protected] 19 g Institute of Earth Sciences, St. Petersburg StateMANUSCRIPT University, Universitetskaya Nab. 7-9, 199034, 20 St. Petersburg, Russia 21 h Institute of Geoscience, Christian-Albrechts-University of Kiel, Ludewig-Meyn-Strasse 10, 22 24118 Kiel, Germany. E-mail: [email protected] 23 24 25 26 Corresponding author: 27 Vera Ponomareva, 28 Institute of Volcanology and Seismology, Piip Boulevard 9, Petropavlovsk-Kamchatsky, 29 683006, Russia. E-mail: [email protected] 30 31 1 Now at: Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, CH-3012 32 Bern, Switzerland,ACCEPTED and School of Earth and Ocean Sciences, Cardiff University, Park Place, 33 CF10 3AT, Cardiff, UK 34 35 1 ACCEPTED MANUSCRIPT 36 Abstract 37 Developing chronologies for sediments in the Arctic Ocean and its continental margins is an 38 important but challenging task. Tephrochronology is a promising tool for independent age 39 control for Arctic marine sediments and here we present the results of a cryptotephra study of a 40 Holocene sedimentary record from the Chukchi Sea. Volcanic glass shards were identified and 41 quantified in sediment core HLY0501-01 and geochemically characterized with single-shard 42 electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP- 43 MS). This enabled us to reveal a continuous presence of glass shards with identifiable chemical 44 compositions throughout the core. The major input of glasses into the sediments is 45 geochemically fingerprinted to the ~3.6 ka Aniakchak caldera II eruption (Alaska), which 46 provides an important chronostratigraphic constraint for Holocene marine deposits in the 47 Chukchi-Alaskan region and, potentially, farther away in the western Arctic Ocean. New 48 findings of the Aniakchak II tephra permit a reevaluation of the eruption size and highlight the 49 importance of this tephra as a hemispheric lateMANUSCRIPT Holocene marker. Other identified glasses likely 50 originate from the late Pleistocene Dawson and Old Crow tephras while some cannot be 51 correlated to certain eruptions. These are present in most of the analyzed samples, and form a 52 continuous low-concentration background throughout the investigated record. A large proportion 53 of these glasses are likely to have been reworked and brought to the depositional site by currents 54 or other transportation agents, such as sea ice. Overall, our results demonstrate the potential for 55 tephrochronology for improving and developing chronologies for Arctic Ocean marine records, 56 however, at some sites reworking and redistribution of tephra may have a strong impact on the 57 record of primaryACCEPTED tephra deposition. 58 59 Keywords: Arctic Ocean; Chukchi Sea; marine sediments; cryptotephra; Holocene; volcanic 60 eruption; Aniakchak caldera 61 2 ACCEPTED MANUSCRIPT 62 1. Introduction 63 The Chukchi and Beaufort Seas, which extend from the East Siberian to North American 64 continental margin, are experiencing the highest rate of Arctic sea-ice retreat (e.g., Walsh et al., 65 2016), and thus represent a key area for investigating related processes under both present and 66 past climatic conditions. Several paleoceanographic studies have recently been undertaken on 67 Holocene deposits that accumulated at the Chukchi margin since the last deglaciation and 68 inundation of the shallow shelf (e.g., Keigwin et al., 2006; Darby et al., 2009; Polyak et al., 69 2016). While at some sites these deposits reach a considerable thickness and provide a fairly 70 high centennial to multidecadal-scale temporal resolution for paleoclimatic proxy 71 reconstructions, this advantage cannot be fully exploited due to problems with developing 72 adequate age constraints. For example, biogenic carbonates suitable for radiocarbon age 73 determination are scarce in these sediments due to widespread dissolution, the total organic 74 matter has a high content of terrestrial material potentially having a wide age range, and the 75 reservoir age in different water masses of the westMANUSCRIPTern Arctic is poorly understood (e.g., Faux et 76 al., 2011; Darby et al., 2012; Polyak et al., 2016). Current age models for regional sediment 77 records benefit from the analysis of paleomagnetic secular variations, but the usefulness of this 78 approach varies depending on sedimentation rates and lithology (Barletta et al., 2008; Lisé- 79 Pronovost et al., 2009; Lund et al., 2016). 80 A promising tool for independent age control of sediments in the Chukchi Sea, and in the 81 Arctic Ocean in general, could be tephrochronology. The Chukchi Sea could be especially 82 promising for tephrochronology as this margin is located close to the volcanically active North 83 Pacific region,ACCEPTED which includes the prominent Alaska-Aleutian and Kuril-Kamchatka volcanic 84 arcs. Furthermore, the prevailing direction of winds and currents controls an efficient 85 transportation of suspended sediment and aerosols from this region into and across the Chukchi 86 Sea (e.g., Weingartner et al., 2005; Danielson et al., 2014). As most of the large Holocene 87 tephras from the North Pacific volcanoes have been geochemically fingerprinted and 14 C-dated 3 ACCEPTED MANUSCRIPT 88 (e.g., Kyle et al., 2011; Kaufman et al., 2012; Ponomareva et al., 2015, 2017; Davies et al., 89 2016), their identification in the Arctic sediments will enable accurate correlation to well-dated 90 terrestrial and marine records. Such correlations will provide independent age constraints for 91 Arctic sediment cores and an insight into the marine reservoir effect that impacts 14 C dating. 92 Tephra and cryptotephra occurrences are known from many terrestrial Arctic sites, 93 including Greenland, Svalbard, and northeast Asia (e.g., Abbott and Davies, 2012; Ponomareva 94 et al., 2013a; van den Bogaard et al., 2014; van der Bilt et al., 2017). Visible tephra layers have 95 not been found in Arctic marine sediments, but the presence of cryptotephra in sediments from 96 the Fram Strait connecting the Arctic and Nordic Seas (Zamelczyk et al., 2012), highlights the 97 possibility of finding volcanic deposits in the Arctic Ocean. 98 Indeed, the first ever studies of tephra in Arctic marine sediments, performed recently at 99 two sites in the Chukchi Sea (Fig. 1), both identified abundant cryptotephra related to the ~3.6 ka 100 Aniakchak II caldera-forming eruption (Ponomareva et al., 2014; Pearce et al., 2017). However, 101 these data also highlighted the complexity of MANUSCRIPTthe volcanic signal in the investigated sediments. 102 For example, Pearce et al. (2017) reported a >1.5-m-thick zone of high glass shard 103 concentrations with numerous irregular peaks and minima, rather than a distinct glass shard 104 concentration peak. These results make it difficult to use this cryptotephra as an isochron and 105 pose questions regarding the mechanisms of glass distribution and deposition. 106 In order to further evaluate the potential of tephrochronology for constraining the age of the 107 western Arctic marine sediments and to investigate tephra transport and deposition patterns, we 108 performed a detailed investigation