| 1. |
- Bentley, Michael J., et al.
(författare)
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A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 100, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets and recent decades have seen an upsurge in such data gathering around the continent and Sub-Antarctic islands. Here, we report a new synthesis of those datasets, based on an accompanying series of reviews of the geological data, organised by sector. We present a series of timeslice maps for 20 ka, 15 ka, 10 ka and 5 ka, including grounding line position and ice sheet thickness changes, along with a clear assessment of levels of confidence. The reconstruction shows that the Antarctic Ice sheet did not everywhere reach the continental shelf edge at its maximum, that initial retreat was asynchronous, and that the spatial pattern of deglaciation was highly variable, particularly on the inner shelf. The deglacial reconstruction is consistent with a moderate overall excess ice volume and with a relatively small Antarctic contribution to meltwater pulse la. We discuss key areas of uncertainty both around the continent and by time interval, and we highlight potential priorities for future work. The synthesis is intended to be a resource for the modelling and glacial geological community.
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| 2. |
- Hodgson, Dominic A., et al.
(författare)
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Terrestrial and submarine evidence for the extent and timing of the Last Glacial Maximum and the onset of deglaciation on the maritime-Antarctic and sub-Antarctic islands
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 100, s. 137-158
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Tidskriftsartikel (refereegranskat)abstract
- This paper is the maritime and sub Antarctic contribution to the Scientific Committee for Antarctic Research (SCAR) Past Antarctic Ice Sheet Dynamics (PAIS) community Antarctic Ice Sheet reconstruction. The overarching aim for all sectors of Antarctica was to reconstruct the Last Glacial Maximum (LGM) ice sheet extent and thickness, and map the subsequent deglaciation in a series of 5000 year time slices. However, our review of the literature found surprisingly few high quality chronological constraints on changing glacier extents on these timescales in the maritime and sub Antarctic sector. Therefore, in this paper we focus on an assessment of the terrestrial and offshore evidence for the LGM ice extent, establishing minimum ages for the onset of deglaciation, and separating evidence of deglaciation from LGM limits from those associated with later Holocene glacier fluctuations. Evidence included geomorphological descriptions of glacial landscapes, radiocarbon dated basal peat and lake sediment deposits, cosmogenic isotope ages of glacial features and molecular biological data. We propose a classification of the glacial history of the maritime and sub Antarctic islands based on this assembled evidence. These include: (Type I) islands which accumulated little or no LGM ice; (Type II) islands with a limited LGM ice extent but evidence of extensive earlier continental shelf glaciations; (Type III) seamounts and volcanoes unlikely to have accumulated significant LGM ice cover; (Type IV) islands on shallow shelves with both terrestrial and submarine evidence of LGM (and/or earlier) ice expansion; (Type V) Islands north of the Antarctic Polar Front with terrestrial evidence of LGM ice expansion; and (Type VI) islands with no data. Finally, we review the climatological and geomorphological settings that separate the glaciological history of the islands within this classification scheme. (C) 2014 The Authors. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Holmes, Emily A., et al.
(författare)
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Positive interpretation training : Effects of mental imagery versus verbal training on positive mood
- 2006
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Ingår i: Behavior Therapy. - : ELSEVIER INC. - 0005-7894 .- 1878-1888. ; 37:3, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- Therapists often assume a special association between mental imagery and emotion, though empirical evidence has been lacking. Using an interpretation training paradigm, we previously found that imagery had a greater impact on anxiety than did verbal processing of the same material (Holmes & Mathews, 2005). Although the finding of a differential impact of imagery versus verbal processing of negative material was replicated, findings did not extend to benign material. Results therefore left open the question of whether there may be a special association between imagery and positive emotion. The current experiment examined positive interpretation training. Numerous scenarios were presented with initial ambiguity as to positive outcome or not, with final information then yielding consistently positive resolutions. Participants were asked to either imagine these positive events or to listen to the same descriptions while thinking about their verbal meaning. Those participants in the imagery condition reported greater increases in positive affect and rated new descriptions as being more positive than did those in the verbal condition. Results suggest that positive training can be enhanced through imagery as opposed to verbal processing. This study also provides the first test of a standardized intervention using an "interpretive bias training" paradigm to improve positive mood.
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| 4. |
- Holmes, Emily A., et al.
(författare)
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The causal effect of mental imagery on emotion assessed using picture-word cues
- 2008
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Ingår i: Emotion. - : AMER PSYCHOLOGICAL ASSOC. - 1528-3542 .- 1931-1516. ; 8:3, s. 395-409
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that mental imagery is more likely to elicit emotion than verbal processing of the same material was investigated in two studies. Participants saw a series of pictures, each accompanied by a word, designed to yield a negative or benign meaning when combined. Participants were either free to combine the picture and word as they wished (Experiment 1) or instructed to integrate them using either a descriptive sentence or a mental image (Experiment 2). Emotional response was consistently greater following imagery than after producing a sentence. Experiment 2 also demonstrated the causal effect of imagery on emotion and evaluative learning. Additional participants in Experiment 2 described aloud their images/sentences. Independent ratings of descriptions indicated that, as well as being more emotional, images differed from sentences elicited by identical cues by greater similarity to memories, and greater involvement of sensations and specific events. Results support the hypothesis that imagery evokes stronger affective responses than does verbal processing, perhaps because of sensitivity of emotional brain regions to imagery, the similarity of imagery to perception, and to autobiographical episodes.
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