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- Lab number
- GSC-2859
- Material dated
- mammoth bone collagen; collagène osseux de mammouth
- Taxa dated
- Proboscidea, cf. Mammuthus sp. tusk (668 g, id. by C.R. Harington)
- Locality
- Portage Pass, Peace River, British Columbia
- Map sheet
- 94 B/01
- Date submitted
- June 8, 0098
- Date uploaded
- February 14, 2020
- Normalized Age
- 25800 ± 320
- δ13C (per mil)
- -24.1
- Significance
- palaeobiology; paléobiologie
- Context
- large gravel pit used for raw material for the W.A.C. Bennett Dam, terminal moraine, 15 m depth
- Additional information
- This tusk was previously given younger ages by I-2244 and I-2244A.
- Comments
- HaRm-VP, Portage Pass: Two pieces of mammoth tusk, each several feet in length, were found in the terminal moraine of the last glacier to occupy the Peace River valley, during excavations to construct the Portage Mountain (W.A.C. Bennett) Dam. The consulting engineer, Dr. Douglas D. Campbell, of Dolmage, Campbell & Associates in Vancouver, submitted part of the tusk for radiocarbon dating. In response to the article "Elephant-hunting in North America," by C. Vance Haynes that appeared in Scientific American, Campbell wrote on 5 August 1966 to the editors of the magazine, saying that he had acquired a date of 7670 +/- 170 BP (I-2244) on a mammoth tusk, implying that mammoths may have survived in British Columbia to a date later than the 11,000 BP extinction suggested by Haynes. This initial date was based on the carbonate fraction of the tusk, and Campbell's letter was forwarded to Haynes. The date was subsequently published without the dated fraction being identified (Buckley et al., 1968: 263). Campbell wrote directly to Haynes on 25 October 1966 to report that the organic fraction of the tusk had been dated to 11,600 +/- 1000 BP (I-2244A), noting that this date "fits with your theory of the extinction of the elephants extremely well." Campbell also communicated the new finding to the magazine editors. Haynes replied on 1 November, asking for the laboratory number and geographic coordinates, and he sent a copy of his reply to W.H. Mathews. The weight of collagen utilized in I-2244A was so small that no estimate of counting precision could be made and the quoted age "represents a minimum value" (J. Buckley, p.c 1972 to W. Blake, Jr.). The remainder of the tusk was coated with a preservative (Krylon?) and placed on display at the dam. In 1978, W.H. Mathews obtained still another sample from the same tusk, by carefully selecting core material which, although partially imbedded in plaster used to fill the hollow interior, had escaped impregnation by the preservative. Collagen from this sample was dated by GSC-2859 (25,800 +/- 320). Mathews comments (Lowdon and Blake, 1979: 28): A special problem is presented by the two dates GSC-2859 and I-2244A... [GSC-2859], from a proglacial deposit near the Cordilleran ice limit, is difficult to reconcile with the nearly contemporaneous date (GSC-573) from nonglacial sand (Rutter, 1977, p. 19, 20) 135 km to the west and much closer to the source of Cordilleran ice. This discrepancy raised the question of some contamination, notwithstanding the care taken in the latest sampling of the tusk, or even of the remote chance of redeposition of the tusk. Alternatively, however, it raises the possibility that the Cordilleran climax at Portage Mountain was early in Classical Wisconsinan time and that Cordilleran glacial deposits still farther to the east are significantly older. The date, moreover, throws in doubt the previous interpretation that the tusk, the kame-moraine, and the apparently contemporaneous Bessborough stage of Lake Peace were of late Classical Wisconsin age.