New Radiocarbon Dates for the Vedde Ash and the Saksunarvatn Ash from Western Norway

Abstract

The Vedde Ash Bed (mid-Younger Dryas) and the Saksunarvatn Ash (early Holocene) are important regional stratigraphic event markers in the North Atlantic, the Norwegian Sea, and the adjacent land area. It is thus essential to date them as precisely as possible. The occurrence of the Saksunarvatn Ash is reported for the first time from western Norway, and both tephras are dated precisely by AMS analyses of terrestrial plant material and lake sediment at Kråkenes. The Vedde Ash has been previously dated at sites in western Norway to about 10,600 yr B.P. It is obvious in the Younger Dryas sediments at Kråkenes, and its identity is confirmed geochemically. The mean of four AMS dates of samples of Salix herbacea leaves adjacent to the tephra is 10,310 ± 50 yr B.P. The Saksunarvatn Ash is not visible in the early Holocene lake sediment at Kråkenes. After removal of organic material and diatoms, the identity of the tephra particles was confirmed geochemically, and their stratigraphic concentration was estimated. From curve matching of a series of seven AMS dates of terrestrial plant macrofossils and whole sediment, the radiocarbon age of the ash is 8930–9060 yr B.P., corresponding to an age of 9930–10,010 cal yr B.P. (7980–8060 cal yr B.C.).

Radiocarbon Calibration by Means of Varves Versus 14C Ages of Terrestrial Macrofossils from Lake Gościąż and Lake Perespilno, Poland

“…This layer has been independently dated by 14 C to 10,330 ± 30 BP (based on 11 AMS 14 C ages from Bard et al 1996 andBirks et al 1996), which agrees with the coral date from Tahiti (at 11,930 cal BP) only when R=300 yr is applied (Figures 4 and 5). Table 4 Mean reservoir ages of corals from Barbados and Tahiti and New Guinea (Edwards et al 1993) …”

“…As noted by Bard et al (1998), the GRIP timescale is also confirmed through the Saksunarvatn ash layer, which has been identified in the GRIP core and dated to 10,180 (Grönvold et al 1995). This layer has been independently dated by 14 C to 8960 ± 70 BP (based on three AMS 14 C ages from Birks et al 1996), which perfectly fits the pine calibration curve (Figure 2). …”

Calendar year age estimates of Allerød–Younger Dryas sea‐level oscillations at Os, western Norway

“…This is later than interpreted for the Sotra curve and other sea-level curves in western Norway. We consider this also to be related to the accuracy of the 14C dates, but partly also to the elevations of the investigated basins, and the original estimate of the Vedde Ash Bed Birks et al, 1996), which was 300 yr too old. Another striking effect of the improved chronology is the timing of the major post-glacial regression.…”

“…The Vedde Ash has been dated to ca. 10 300 14C yr BP (Birks et al, 1996) and 11 980+-80 ice-core yr BP (Grønvold et al, 1995). In addition, we use the rise of Betula (birch) pollen that we regard as a reliable, local correlation horizon.…”

Chronology and paleoenvironments during the late Weichselian deglaciation of the southwest Iceland shelf

“…Ingólfsson et al 1997;Geirsdóttir et al 1997). The first observation of Vedde Ash at the base of lithofacies Ssd, the transitional unit between the glacialmarine and postglacial seismic units, provides a maximum age for lithofacies Ssd of 10.3 ka BP (Birks et al 1996). We consider this to be a maximum age because we recognize that the Vedde Ash in lithofacies Ssd may not represent a primary ash-fall deposit.…”