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- Lab number
- GSC-12202
- Field number
- 68/GS-51
- Material dated
- mastodon femur bone (collagen?)
- Taxa dated
- Mammut americanum (id. by C.S. Churcher)
- Locality
- modern floodplain of the Middle River, 2.5 km south-southeast of Middle River bridge, near Lower Middle River, Cape Breton Island, Nova Scotia
- Map sheet
- 011 K/02
- Submitter
- D.R. Grant
- Date submitted
- December 31, 0087
- Measured Age
- 31 ± 500
- Normalized Age
- 31300 ± 500
- δ13C (per mil)
- -19.8
- Significance
- nonglacial; palaeoenvironment; paleobiology
- Context
- 12 cm (5") depth in recent alluvium
- Associated taxa
- Mammalia: Mammut americanum
- Additional information
- Apatite pre-treatment, then residue burned.
- Comments
- CaCf-VP: A mastodon femur was plowed up by Alexander MacRae in 1834 and is now the property of the Nova Scotia museum. Because the bone had some cemented mineral matter attached, presumably from earlier enclosing sediment, the sample site may be a placer deposit derived from older sediments. In addition to the standard collagen pre-treatment used for GSC-1220, two ages were measured from a second preparation of material. The first attempt used an extended (overnight) base treatment and yielded an age of 31,600 +/- 690 BP. The second attempt (GSC-1220-2) entailed pre-treatment to eliminate apatite (bone mixed with water and acetic acid) with the residue (collagen?) being burned to produce the sample. D.R. Grant comments that this mastodon femur is one of several Quaternary fossils that have been solicited from Maritimes museums for the purpose of chronostratigraphic development. The age and sedimentary context suggests that the fossil has been reworked by fluvial action, and perhaps also by glaciers, from a pre-existing deposit, probably within a few kilometres of the site judging by the lack of wear on the bone. The site is believed to lie beyond the limit of Late Wisconsinan glaciers. If the agreement in ages obtained by different preparation methods means little or no contamination, the date can be considered finite as determined. Unless the bone was transported into Cape Breton by a glacier, an ice-free interval during Middle Wisconsinan time is indicated. Whether there was subsequent glacial cover is not yet resolved on stratigraphic grounds. The bone has a darkened ferruginous stain, and pore spaces have calcite fillings suggesting lengthy burial below the water table. Cemented organic detritus (dung?) adhering to bone cavities was analyzed for pollen. This material contained "a rather large hardwood component compared to the modern boreal forest" (J. Terasmae, pers. comm. to D.R. Grant, 1970). Hence it is possible that the bone dates from an earlier, more temperate nonglacial period (an interglacial stage), and the date is therefore minimal.