Holocene floodplain aggradation in the central Grampian Highlands, Scotland

Figures & data

Figure 1. Location of the sampling sites for radiocarbon dating of sub-terrace and supra-terrace organic material. Also shown are the locations of the high-level (∼500 m) blanket peat pollen sampling sites of Binney (1997; pollen site 1) and Paterson (2011; pollen site 2).

Table 1. Radiocarbon ages relating to the Main Holocene Terrace, central Grampians.

Sample number	OS Grid reference (NN)	Laboratory code	Sample depth (cm)	Sample type	Radiocarbon age (^14C a BP)	Calibrated age range (b2k) ± 2σ
Upper Edendon Valley: base of peat overlying floodplain terrace
ES-1	715770	SRR-5947	–	4 mm thick peat sample	2340 ± 45	2727–2213
EN-2	715770	SRR-5940	–	4 mm thick peat sample	2490 ± 45	2775–2421
Upper Edendon Valley: sub-terrace sample
EN-1	715770	SRR-5941	29	4 mm thick peat sample	2645 ± 40	2856–2775
Upper Glen Feshie: buried soil marking the surface of a fan terrace
GF-3	841905	–	–	Soil humic A horizon	3150 ± 60	3532–3264
Upper Glen Feshie: sub-terrace samples
GF-1	844917	Har-4535	95	Charcoal in buried soil	3620 ± 50	4140–3783
GF-2	845920	–	45	Charcoal in buried soil	3480 ± 70	4014–3618
Glen Feshie: Allt Fhearghan (GF4) and Allt Mharcaidh (GF5) fans, sub-terrace samples
GF-4	855971	–	73	Soil humic A horizon	3570 ± 60	4130–3744
GF-5	879049	–	44	Soil humic A horizon	3740 ± 60	4341–3956
Upper Glen Tromie: Allt Domhainn fan, sub-terrace samples
GT-1	765827	–	34	Soil humic Bh horizon	875 ± 200	1297–572
GT-2	765827	–	59	Soil humic A horizon	3820 ± 50	4459–4139

Sample depth is depth below terrace surface. Age calibration is based on the IntCal20 calibration curve (Reimer et al., 2020) and OxCal version 4.4 (Bronk Ramsey, 2009); b2k: before AD 2000. Samples EN1, EN2 and ES1are from Ballantyne and Whittington (1999); Sample GF1 is from Robertson-Rintoul (1986). Samples without codes were analysed at the Godwin Laboratory, University of Cambridge.

Figure 2. Oblique view of upper Glen Feshie, viewed from the south, showing the sampling locations of samples GF-1, GF-2 and GF-3. GF-3 (56.9976°N, 3.9046°W) is approximately 1.2 km upvalley from GF-1. MHT: Main Holocene Terrace (Google Earth^TM image).

Figure 3. Sections showing the stratigraphic context of the Glen Feshie and Glen Tromie samples; note the differences in vertical scale. The stratigraphy of the Edendon Valley sampling sites is illustrated in Ballantyne and Whittington (1999).

Figure 4. Oblique view of the Allt Domhainn Fan (56.9925°N, 4.0269°W) viewed from the southwest in 2005, showing the location of the site from where samples GT-1 and GT2 were obtained. The distance from the apex of the fan to its toe is 350 m. The toe of the fan is partly truncated by the Allt Gharbh Ghaig, a tributary of the River Tromie (Google Earth^TM image).

Figure 5. Environmental changes in the study area, 4.5–2.0 cal ka. (a) Maximal ages for floodplain and fan aggradation (upticks) and incision (downticks) as represented by the sub-terrace and supra-terrace radiocarbon ages obtained in Glen Feshie and Glen Tromie (top) and the Edendon Valley (bottom). The ticks represents the median calibrated radiocarbon age. (b) The trajectory of decline in pine woodland cover as represented by Pinus sylvestris pollen as a percentage of total land pollen; 30% approximates the point at which only isolated stands of pine occurred at the pollen sites. Curve 1 (dashed line) is for 500 m in Glen Einich, based on data in Binney (1997); curve 2 is for 510 m at Geldie Lodge, based on data in Paterson (2011). (c) Standardised records of periods of increased wetness (below the line) and dryness (above the line) at Mallachie Moss (Langdon & Barber, 2005).

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