Roberts, Carole Anne;
(2023)
Exploring the nature of climate variability during past warm periods: Palynological insights from the Fucino Basin, central Italy.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Environmental reconstructions of past warm periods enhance knowledge of natural climate variability under conditions of excess warmth. The Last Interglacial (LIG) (129-116 ka) was characterised by a global mean temperature ~0.8˚C warmer than the pre-industrial, pronounced Arctic warming and elevated sea level. Exploring the local expression of LIG climatic changes through vegetation dynamics can strengthen understanding of regional responses to a warmer background state. However, a lack of high-resolution palaeoclimatic archives employing a precise, independent and robust chronological framework remains a primary limitation in investigating climate variability and relating it to changes in other records. This research aims to produce detailed palynological and charcoal analyses combined with isotopic, geochemical and sedimentological proxies of a thick lacustrine sedimentary sequence retrieved from the Fucino Basin, central Italy, covering the period ca. 139 to 107 ka at subcentennial to centennial resolution. High-resolution pollen and charcoal records of the Late Pleniglacial to early Holocene (ca. 18 to 8 ka) are generated from an adjacent sediment core. A crucial aspect of the record is its independent chronology based on direct 40Ar/39Ar dating and geochemical fingerprinting of several tephra layers. Annual and seasonal LIG temperature and precipitation is reconstructed from fossil pollen assemblages as a consensus of three different models. The highly resolved multiproxy records reveal substantial environmental responses to long-term and short-term climate variability. The pollen sequences reveal a succession of arboreal phases, interrupted by centennial- to millennial-scale contractions in temperate vegetation, and demonstrate the importance of the region in hosting significant LIG Fagus populations. Pollenbased climate reconstructions suggest an overall warm and wet LIG climate with peak annual temperatures ~2˚C warmer than present and a strong hydrological seasonal contrast during the early stages. The detection of high-frequency interglacial climate variability confirms a highly interconnected North Atlantic and Mediterranean climate regime. Comparison between the last two glacial-interglacial intervals reveals several contrasting features that can be related to the dynamics of the preceding glacial intervals and orbital forcing mechanisms.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Exploring the nature of climate variability during past warm periods: Palynological insights from the Fucino Basin, central Italy |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10178641 |
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