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T3
Chironomid-Inferred Lateglacial Interstadial Temperatures from Muir Park, southern
Scotland
K. Mather 1 *, I.P. Matthews 1 , and S.J Brooks 2
1 Centre for Quaternary Research, Department of Geography, Royal Holloway, University of London,
Egham
2 Life Sciences Department, Aquatic Invertebrates Division, Natural History Museum, London
Currently there are ten published Lateglacial chironomid-inferred mean July air
temperature (C-IT) records in Britain and Ireland, which are all broadly similar to oxygen
isotope data from Greenland ice-core records. However, due to local and regional factors,
poor chronological controls, and in-lake variability, differences exist. Ice-cores provide a
highly resolved record of climate change during the Last Glacial-Interglacial Transition
(LGIT), but additional independent, high resolution climate records are required to
determine any differences in the magnitude and timing of climatic trends on local and
regional scales in NW Europe. Chironomidae (non-biting midges) provide high resolution,
quantitative, low-error summer temperature data and are used here to provide a new
Lateglacial Interstadial (14.7 – 12.9 ka BP) C-IT record from Muir Park, Scotland.
Preparation and identification of chironomid head capsules follows Brooks et al. (2007)
and mean July air temperature was reconstructed using a modern Norwegian training set
and 2-component weighted averaging partial least squares inference model (Brooks and
Birks, 2000; Heiri et al., 2011; Self et al., 2011). Two previously identified cryptotephras,
the Borrobol and Penifiler tephra, are used to provide a chronology and isochronous
marker (Cooper, 1999; Roberts, 1997; Royal Holloway Tephra Laboratory). C-ITs indicate
a thermal maximum of 13.2 °C at the Lateglacial Interstadial onset, which correlates to GI-
1e. Temperature then declines to 10.6 °C, which is interpreted as GI-1d, due to
stratigraphic proximity to the Penifiler tephra. Temperature then oscillates between 12.4
°C and 10.7 °C, with two smaller cold events, of 10.7 °C and 10.8 °C, which is interpreted
as GI-1c. This is followed by a temperature reduction to 10.2 °C, which is the coldest
recorded temperature in the sequence, and is interpreted as GI-1b. Finally, temperature
rises to 12 °C which is interpreted as GI-1a. C-ITs from this study are linked to previously
reconstructed C-ITs from Muir Park, which add data from the Younger Dryas and early
Holocene (Davies, 2010), and as a result completes the Lateglacial C-IT record at Muir
Park. C-IT trends from this study are similar to C-IT from other sites in Britain, Ireland, and
NW Europe, and to records based on other proxies in Britain during the Lateglacial.
However, differences exist, notably that GI-1b is inferred as being cooler than GI-1d at
Muir Park, whereas in most other British records a reverse trend is evident, which
suggests regional factors and localised climate forces may be influencing the Muir Park
record.
Keywords: chironomidae; Diptera; Invertebrates; Lateglacial; LGIT; Scotland
Brooks, S. J., Langdon, P. G. and Heiri, O. (2007) The identification and Use of Palaearctic
Chironomidae Larvae in Palaeoecology. Quaternary Research Association Technical Guide no. 10.
Brooks, S. J. and Birks, H. J. B. (2000) ‘Chironomid-inferred Late-glacial air temperatures at Whitrig
Bog, southeast Scotland’, Journal of Quaternary Science, 15(8), pp. 759 – 764.
Cooper, R. (1999) Lithostratigraphy and tephrochronology of sediments spanning the time interval of
the Last Glacial-Interglacial Transition at Muir Park Reservoir, Scotland and Sluggan Moss, Northern
Ireland. Unpublished BSc Thesis, University of London.
Davies, K. L. (2010) The Younger Dryas-Holocene Transition: A Chironomid-Inferred Temperature
Reconstruction, Muir Park Reservoir, Scotland. Unpublished MSc Thesis, Royal Holloway, University of
London.
Heiri, O., Brooks, S. J., Birks, H. J. B. and Lotter, A. F. (2011) ‘A 274-lake calibration data-set and
inferences model for chironomid-based summer air temperature reconstruction in Europe’, Quaternary
Science Reviews, 30, pp. 3445 – 3456.