Carbonate Clumped Isotope-derived Climate Records of the Early Paleogene from Ellesmere Island and Axel Heiberg Island, Nunavut, Arctic Canada
Abstract
Developing accurate records of paleoclimate and paleoenvironments during past warm periods like the early Paleogene is necessary to predict potential consequences of future anthropogenic warming, particularly in polar regions that may experience dramatic responses to climate change due to their role in carbon storage and surface albedo feedbacks. However, data for sensitive polar regions like the Canadian Arctic during past warm intervals are limited and terrestrial proxy records suggest that global marine records and model simulations may underestimate the severity and rate of change during past climate events. Ellesmere and Axel Heiberg islands in the Canadian Arctic preserve long-term paleoclimate archives in terrestrial fluvio-deltaic, floodplain, and paludal deposits spanning the early Paleogene (earliest Paleocene to middle Eocene). Our work expands on existing stratigraphic and paleontological work from the Canadian Arctic Archipelago through the addition of stable (δ13C, δ18O) and clumped (Δ47) isotope analyses on floodplain carbonates. δ13C isotope values range from -5.0 to +12.5‰ (VPDB), δ18O isotope values range from -23.4 to -15.5‰ (VPDB), with calculated δ18Osw values from -18.0 to -5.1‰. Samples were classified into three fabric types: micritic, mixed, and sparry, with averages of 4.0‰ (δ13C) and -17.7‰ (δ18O), 5.1‰ (δ13C) and -17.4‰ (δ18O), and 1.4‰ (δ13C) and -20.32‰ (δ18O), respectively. Clumped (Δ47) values range from 0.448 to 0.585‰ (CDES) with resulting temperature estimates from 32 to 96 °C. Isotopic values and carbonate fabrics indicate early-stage diagenesis for some samples, and possible solid-state reordering of clumped isotopes during burial; however, primary samples appear to show stable Paleocene climate conditions with a distinct shift to increased temperature and precipitation during the early Eocene. Paired with other Eocene records, warm, wet conditions extending into the arctic during a period with high atmospheric carbon dioxide concentrations may have important implications for understanding polar amplification and terrestrial climate sensitivity.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP51E1176P
- Keywords:
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- 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 4936 Interglacial;
- PALEOCEANOGRAPHY