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West Antarctic Margin Signatures of Ice Sheet Evolution

Periodic Reporting for period 2 - WAMSISE (West Antarctic Margin Signatures of Ice Sheet Evolution)

Reporting period: 2020-10-31 to 2021-10-30

The evolution of the Antarctic ice sheets has been widely debated. According to several studies a continent-wide ice sheet first developed during the early Oligocene and subsequently it experienced many cycles of advance and retreat. Tectonic, oceanographic, climatic and ice dynamic processes have been pointed to as the primary factors controlling this oscillation. However, their relative influence is still controversial. Middle Miocene growth of the Antarctic ice sheet has been related to intensification of the Antarctic Circumpolar Current. It was followed by warm episodes during the Miocene Climate Optimum (∼17-14 Ma) and during the Pliocene when collapse of the West Antarctic Ice Sheet has been suggested. However, the stratigraphic signature of such a collapse has not been recognized on West Antarctic continental margins. The main aim of WAMSISE is examine the record of ice sheet evolution on West Antarctic continental margins from middle Miocene to present and clarify the factors controlling the major sedimentary changes and their global implications. To date, the research developed under WAMSISE has been focussed on the middle Miocene ice sheet oscillation over the Ross Sea continental shelf. The insights suggest ice sheet advance on the continental shelf during short time intervals prior to the Miocene Climate Optimum, which was followed by widespread marine-based ice sheet advance on the Ross Sea during the Middle Miocene Climate Transition (∼14 Ma). Additional work developed in the Drake Passage and Scotia Sea reveals a link between the regional variability of the bottom-water flows and the Antarctic ice sheets dynamics from late Miocene to present.
This final report of WAMSISE includes an overall summary of the activities developed during the fellowship. WAMSISE had three main phases: 1) secondment at the National Institute of Oceanography and Applied Geophysics (OGS) (Italy); 2) outgoing phase at the Antarctic Research Centre (ARC) (New Zealand); 3) returning phase at British Antarctic Survey (BAS) (UK) mostly developed remotely. The original fellowship plan has been substantially altered after consensus with the EU commission. Major changes include an extended outgoing phase due to COVID-19 global pandemic; and six months remote part-time dedication developed due to the permanent position at GEUS earned by the researcher.

The project database considered under work package (WP) 0 has been compiled including all the seismic profiles along the West Antarctic Margin and the logged physical properties of the sites recovered during IODP, DSDP, ODP and ANDRILL. Two IHS Kingdom projects allowed work on the Ross Sea (WP1) and the Antarctic Peninsula (WP4).

Seismic-stratigraphic analyses and core-log-seismic correlations in the Ross Sea (WP1) have resulted on a scientific paper entitled ‘Early and middle Miocene ice sheet dynamics in the Ross Sea: results from integrated core-log-seismic interpretation’. It was published on the Geological Society of America Bulletin in May 2021. Major insight are the regional transition from growth of isolated ice caps to widespread ice sheets occurred through Miocene. A second Ross Sea manuscript has been submitted for publication to Earth and Planetary Science Letters in January 2022. It presents the correlation of the central and western Ross Sea. The early and middle Miocene evolution of the East Antarctic Ice Sheet is conciliated with the West Antarctic Ice Sheet advance and retreat patterns. In addition, the researcher contributed to the paper ‘A Large West Antarctic Ice Sheet Explains Early Neogene Sea-Level Amplitude’ by Marschalek et al. (2021) published in Nature. She is also co-author in three other Ross Sea manuscripts are currently under development.

A manuscript about the ice sheet dynamics on the Pacific Margin of the Antarctic Peninsula from late Miocene (WP4) is currently under-elaboration. In addition, the researcher has participated as co-author on three chapters of the book ‘Antarctic Climate Evolution’ (Ed. Florindo, et al. 2021). These contributions relate with the overall Miocene evolution of the West Antarctic Ice Sheet (WP1 to WP5).

In addition, the researcher participated in the International Ocean Discovery Program (IODP) Expedition 382 (2019). As a result, a paper entitled ‘Miocene to present oceanographic variability in the Scotia Sea and Antarctic ice sheets dynamics: Insight from revised seismic-stratigraphy following IODP Expedition 382’ was published in Earth and Planetary Science Letters in November 2020. This publication updates the age models of the major events in the Scotia Sea from late Miocene and relates them to regional variability of the oceanic circulation pattern associated with the oscillation of the Antarctic ice sheets (WP5). Sortable silt analyses on IODP Expedition 382 samples have been delayed due to COVID-19 lockdowns. They will provide insights on the regional variability of the bottom flows between late Miocene and the present-day. She is also co-author of the IODP Expedition 382 scientific reports, one published paper and four related manuscripts currently under-review.
The researcher has participated in three in person and five online international conferences. She was scientific committee member in the Early Career Researcher conference from the UKPN (2021). She was convener in two sessions at the XIII International Symposium on Antarctic Earth Sciences (2019, South Korea) and West Antarctic Ice Sheet Workshop (2020, online). She has acted as moderator in APECS-SCAR workshop, SCAR Online (2020, online) and the INStabilities &Thresholds in ANTarctica (INSTANT) kick-off meeting (2021, online). She has been involved in twenty-three conference contributions and lead-authored five of them. The researcher took part on the Mission Specific Platform workshop UK-IODP Online (2021). As a result, she is involved on a drilling proposal in the Amundsen Sea. In addition, she has been invited speaker in seminars at Darwin College, GEUS, University of Manitoba, Woods Hole Oceanographic Institution, Lamont-Doherty Earth Observatory - Columbia University, University of Tasmania, ARC and OGS.

The researcher completed the training on the software Hampson Russell - Emerge and CAT3D during the secondment at OGS. She attended the Petrophysics Summer School at University of Leicester and a course on Petrel software at Royal Holloway University of London in UK. The researcher has obtained the certificate ‘Focus on Peer Review’ from Nature masterclasses. She has completed the BAS mandatory courses. She also attended the Grand Writing Workshop at BAS as well as the ARICE online training on polar operations.

The researcher has been appointed steering committee member of INSTANT, associate researcher at the Darwin College and more recently honorary associated researcher at the BAS. She has been involved in the leadership of the Association of Polar Early Career Scientists as Executive Committee member (2018-2020). She has led the organization of several outreach activities including authorship of five outreach articles. She has mentored early career participants during 2019 AGU Fall Meeting. She has also been part of the Polar Pen Pal UKPN and the early career researchers and women in science events at ARC. She has reviewed eleven manuscripts for international peer-review journals, including Nature, and assessed fellowship applications for five international calls.