An annually resolved climate record for MIS 11 from Marks Tey, eastern England: Investigating landscape response to abrupt events during the closest climatic analogue to the Holocene

摘要

Climatic and environmental reconstructions from previous interglacial episodes of the Quaternary Period are of significant interest, as previous interglacials may have the potential to act as analogues for the Holocene. Based on the similarity in long-term insolation patterns during both interglacials, Marine Isotope Stage 11 (MIS 11, ca. 410,000 yrs BP.) is widely considered to offer the best orbital analogue for the Holocene. The palaeo-lake sequence at Marks Tey, eastern England, represents one of the key MIS 11 sites in the UK and Europe because not only does it record a full vegetation succession for the interglacial at a single site, the sediments are also purportedly annually-laminated (varved) in parts of the sequence (Turner, 1970). Furthermore, the vegetation succession is interrupted during full interglacial conditions by an abrupt event (the Non-Arboreal Pollen (NAP) phase), which may be analogues to the 8.2 ka event that punctuated the early Holocene (Koutsodendris et al., 2012).This thesis presents a re-examination of the early Hoxnian (MIS 11) sequence from a new core drilled at Marks Tey in 2010, providing discussion of: 1) Micro-facies analysis of the laminated sediments preserved during the early part of MIS 11; to demonstrate the annual nature of sedimentation and produce a varve chronology; 2) Results of stable oxygen and carbon isotopic analysis from authigenic carbonate laminations that occur throughout the core section studied and their environmental significance; and 3) Combining the varve chronology and stable isotope results with other proxy evidence to investigate the timing and forcing mechanism for, as well as the rate of proxy response during the NAP phase.