RADIOCARBON-DATES FROM THE ALLEROD SOIL IN KENT

In the 1960s, Kerney reported the widespread occurrence in southern Br itain of a fossil rendzina soil in many chalkland valley sequences of Late-glacial age. He concluded that this soil had formed during the 'A llerod Interstadial', a conclusion partly supported by two conventiona l radiocarbon dates of c. 11 900 yr BP from Dover Hill, Folkestone and from Brook, both in Kent. AMS determinations are reported here from c harcoal from the upper and lower halves of the Dover Hill palaeosol an d from the equivalent horizons at Upper Halling, a previously undated site in north Kent. These determinations are significantly younger tha n the conventional dates and fall in the range 10 900-11 220 yr BP, wh ich are much closer to expected values. In the case of Dover Hill, the discrepancy between the original conventional date and the new AMS da tes has been shown to result largely from a simple error of transcript ion, Q-463 published as 11 934 +/- 210 yr BP, should have been quoted as 11 550 +/- 135 yr BP. This revised date fits perfectly with other A MS dates recently obtained from the same horizon in Holywell Coombe, 2 km west of Dover Hill. Some new dates are also reported from Brook. T wo pairs of determinations have been measured on the 'humic' and 'humi n' fractions from an organic detritus mud from 'Borehole III', previou sly dated at 11 900 +/- 160 yr BP, using both conventional and AMS tec hniques. The results are remarkably consistent and give a pooled mean of 12 190 +/- 30 yr BP. Charcoal from a 'marsh soil' about 15 cm above the organic detritus mud yielded an AMS date of 11 170 +/- 70 yr BP. These results demonstrate that it is the 'marsh soil' that equates wit h the 'Allerod' soils elsewhere in Kent, and not the organic detritus mud, as previously supposed. Another AMS date of 11 575 +/- 75 yr BP w as obtained from the 'Allerod soil' at College Farm, Brook.