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

1996 ◽  
Vol 45 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Hilary H. Birks ◽  
Steinar Gulliksen ◽  
Haflidi Haflidason ◽  
Jan Mangerud ◽  
Göran Possnert
Keyword(s):  
Lake Sediment ◽  
Younger Dryas ◽  
Plant Macrofossils ◽  
Early Holocene ◽  
Radiocarbon Dates ◽  
Terrestrial Plant ◽  
Radiocarbon Age ◽  
The North ◽  
Western Norway ◽  
Ams Dates

AbstractThe 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.).

Implications for the Dating of Wisconsinan (Weichselian) Late-Glacial Events of Systematic Radiocarbon Age Differences between Terrestrial Plant Macrofossils from a Site in SW Ireland

2000 ◽  
Vol 53 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Chris S.M. Turney ◽  
G. Russell Coope ◽  
Doug D. Harkness ◽  
J. John Lowe ◽  
Michael J.C. Walker
Keyword(s):  
Lake Sediment ◽  
Late Glacial ◽  
Plant Macrofossils ◽  
Age Difference ◽  
Organic Detritus ◽  
Radiocarbon Dates ◽  
Terrestrial Plant ◽  
Radiocarbon Age ◽  
Salix Herbacea ◽  
Depth Relationship

AbstractAMS radiocarbon dates were obtained from Salix herbacea leaves, Carex seeds, and bulk organic detritus from a lake sediment profile of Wisconsinan (Weichselian) Lateglacial age in SW Ireland. There is a systematic age difference between the dated series from the two types of macrofossils, with ages obtained from Salix herbacea leaves being 900 to 1500 14C years younger than those obtained from Carex seeds. The latter tend to be more in accord with dates from the total organic detritus in the lake sediment, although the bulk organic fraction invariably registered the older ages. Intact survival of the fragile Salix leaves indicates that they are unlikely to have been physically transferred within the sediment matrix and/or otherwise reworked from the surrounding catchment. Hence, these macrofossils are the more likely to be contemporaneous with the time of deposition. However, there is no significant correlation between measured 14C age and depth in the Salix values, which scatter over a range of 700 14C years. In contrast, the age/depth relationship for Carex shows a significant reversal, possibly reflecting the redeposition of these macrofossils, and therefore giving radiocarbon ages that are anomalously old. The data have important implications for the dating of lake sediment sequences by AMS radiocarbon measurement of terrestrial plant macrofossils.

scholarly journals The Beginning of the Early Bronze Age in the North Jordan Valley: New14C Determinations from Pella in Jordan

Radiocarbon ◽  
2009 ◽  
Vol 51 (3) ◽  
pp. 905-913 ◽  
Author(s):  
Stephen Bourke ◽  
Ugo Zoppi ◽  
John Meadows ◽  
Quan Hua ◽  
Samantha Gibbins
Keyword(s):  
Mass Spectrometry ◽  
Bronze Age ◽  
Early Bronze Age ◽  
Jordan Valley ◽  
Radiocarbon Dates ◽  
The North ◽  
Precursor Phase ◽  
Chalcolithic Period ◽  
Early Phases ◽  
Ams Dates

This article reports on 10 new accelerator mass spectrometry (AMS) radiocarbon dates from early phases of the Early Bronze Age at the long-lived settlement of Pella (modern Tabaqat Fahl) in the north Jordan Valley. The new AMS dates fall between 3400 and 2800 cal BC, and support a recent suggestion that all Chalcolithic period occupation had ceased by 3800/3700 cal BC at the latest (Bourke et al. 2004b). Other recently published Early Bronze Age14C data strongly supports this revisionist scenario, suggesting that the earliest phase of the Early Bronze Age (EBA I) occupied much of the 4th millennium cal BC (3800/3700 to 3100/3000 cal BC). As this EB I period in the Jordan Valley is generally viewed as the key precursor phase in the development of urbanism (Joffe 1993), this revisionist chronology has potentially radical significance for understanding both the nature and speed of the move from village settlement towards a complex urban lifeway.

Quaternary Glaciers and Climate on Cerro Chirripó, Costa Rica

2000 ◽  
Vol 54 (1) ◽  
pp. 24-37 ◽  
Author(s):  
Kenneth H. Orvis ◽  
Sally P. Horn
Keyword(s):  
Costa Rica ◽  
High Altitude ◽  
Central America ◽  
Younger Dryas ◽  
Glacial Geomorphology ◽  
Radiocarbon Dates ◽  
Tropical Glaciers ◽  
The North ◽  
Organic Sediments ◽  
Lower Limits

Glacial lake sediments and glacial geomorphology in Valle de las Morrenas, a glacial trough on the north face of Cerro Chirripó, Costa Rica, provide evidence on high-altitude Pleistocene conditions in Central America. The most recent glacier in the valley (Chirripó stage I) receded very rapidly near the end of the Younger Dryas chronozone. Radiocarbon dates on basal organic sediments from lakes beneath upper, middle, and lower limits of that glacier fall close together, and two-sigma calibrated ages overlap for the period 9700–9600 cal yr B.P. Earliest datable transition sediments from the central lake date to 12,360–11,230 cal yr B.P. Larger, older moraines, and associated trimlines, allowed reconstruction of three paleoglaciers (Chirripó stages II, III, and IV). Computer analysis of hypsometry using published tropical-glacier vertical mass balance profiles yields ELAs of 3506–3523, 3515–3537, and 3418–3509 m, respectively; Chirripó II ELA-estimate positions applied to Chirripó I yield an ELA of 3538–3546 m. We infer minimal temperature depressions of 7.4–8.0°C for the Chirripó I–IV stages. Modeling the behavior of modern tropical glaciers yields basinwide net accumulation estimates of 440–620, 550–830, and 960–1760 mm yr−1 for the Chirripó II, III, and IV stages.

Stratigraphy, Paleontology, and Age of Lake Algonquin Sediments in Southwestern Ontario, Canada

1975 ◽  
Vol 5 (1) ◽  
pp. 49-87 ◽  
Author(s):  
P.F. Karrow ◽  
T.W. Anderson ◽  
A.H. Clarke ◽  
L.D. Delorme ◽  
M.R. Sreenivasa
Keyword(s):  
Lake Michigan ◽  
Critical Evaluation ◽  
Plant Macrofossils ◽  
Supporting Evidence ◽  
Radiocarbon Dates ◽  
Southern Ontario ◽  
Alluvial Sediments ◽  
The North ◽  
Lake Algonquin ◽  
Water Stage

AbstractMolluscs, ostracodes, diatoms, pollen, plant macrofossils, peat, and wood have been found in glacial Lake Algonquin sediments, and estuarine-alluvial sediments of the same age, in southern Ontario. Molluscs and ostracodes are particularly abundant and widespread. Pollen analysis of Lake Algonquin sediments, bogs on the Algonquin terrace, and upland bogs above the Algonquin terrace, indicate that Lake Algonquin was still in existence at the time of the spruce-pine pollen transition, previously dated at an average of 10,600 yr BP at a number of sites in Michigan, Ohio, and southern Ontario. Wood in estuarine-alluvial sediments graded to the Algonquin level is of similar radiocarbon age. Evidence from several sites in the eastern Great Lakes area suggests the presence of a preceding low-water stage (Kirkfield outlet stage); drowned and alluviated valleys and fining-upward sediment sequences have been identified in this study as further supporting evidence. Lake Algonquin drained from the southern sites by isostatic tilting and eventual opening of the “North Bay outlet” some time shortly after 10,400 yr BP.Our radiocarbon dates suggest the low-water stage has an age of about 11,000 yr BP, and that Lake Algonquin drained 10,000–15,000 y. a. Dates previously published for the Lake Michigan basin are generally too young in comparison with ours, and dates on the Champlain Sea are generally too old. More critical evaluation of all dating results is desirable.From fossil remains we suggest a rapidly expanding fauna in the waters of Lake Algonquin. The spruce pollen period was a time of rapid faunal and floral migration, when the ice front was retreating from Kirkfield to North Bay, Ontario. Diversity of some species and fossil numbers increased substantially at the transition from spruce to pine just before Lake Algonquin drained.

scholarly journals Radiocarbon Age of the Laacher See Tephra: 11,230 ± 40 BP

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Irena Hajdas ◽  
Susan D. Ivy-Ochs ◽  
Georges Bonani ◽  
André F. Loiter ◽  
Bernd Zolitschka ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Younger Dryas ◽  
Cold Event ◽  
Time Marker ◽  
Terrestrial Plant ◽  
Plant Macrofossil ◽  
Radiocarbon Age ◽  
Ash Layer ◽  
Laacher See Tephra

The Laacher Sec Tephra (LST) layer provides a unique and invaluable time marker in European sediments with increasing importance because it occurs just before the onset of the Younger Dryas (YD) cold event. As the YD begins ca. 200 calendar years after the LST was deposited, accurate determination of the radiocarbon age of this ash layer will lead to a more accurate age assignment for the beginning of the YD. On the basis of 12 terrestrial plant macrofossil 14C ages derived from sediments from Soppensee, Holzmaar and Schlakenmehrener Maar, we found an age of at least 11,230 ± 40 bp for the LST event. This is ca. 200 yr older than the often reported age of 11,000 ± 50 bp (van den Bogaard and Schmincke 1985).

scholarly journals Paleośrodowiskowe znaczenie zmian tempa i charakteru sedymentacji osadów jeziora Jelonek w Borach Tucholskich = Paleoenvironmental significance of changes in the rate and type of sedimentation in Lake Jelonek within Poland’s Tuchola Pine Forest (Bory Tucholskie)

2020 ◽  
Vol 92 (3) ◽  
pp. 409-422
Author(s):  
Mateusz Kramkowski
Keyword(s):  
Sedimentation Rate ◽  
Sediment Cores ◽  
Rapid Change ◽  
Lacustrine Sediments ◽  
Younger Dryas ◽  
Pine Forest ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
The North ◽  
High Sedimentation

This paper presents the matter of the environmental reconstruction of laminated lacustrine sediments from the Younger Dryas through to the present day, in particular in respect of microlithofacial analysis and sedimentation rate. Lake Jelonek is located within the Tuchola Pine Forest of northern Poland (at 53°45’58N, 18°23’30E). It occupies a subglacial channel immediately adjacent to the Wda Valley. The lake covers 19.9 ha and has a maximum depth of 13.8 m. In 2014, overlapping sediment cores JEL14 (14.23 m) were collected from that deepest part, in order for a full sediment profile including the younger Dryas and the Holocene to be created. Most of the sediment is found to be laminated. Sedimentation rate was reconstructed for the lake, along with microlithofacial variability of different sections of the sediment. The results obtained were related to an age depth model based on 14 AMS radiocarbon dates, varve chronology and the Askja AD 1875 cryptotephra; and was correlated with pollen profiles. The Holocene sediment record of Lake Jelonek exhibits differences between low and high sedimentation rate intervals and varved and non-varved intervals. From the beginning of the Holocene through to the Subatlantic period, sedimentation proved to be a stable phenomenon. However, in the Subatlantic period, the average sedimentation rate increased to 7.7 mm per year from 2.2 mm, with maximum rates even reaching 15.3 mm/year. This period is reflected in a lack of lamination and the appearance of redeposited deposits. These changes prove particularly sensitive to local impact, with distinct alternations of low and high sedimentation rates and varved and non-varved intervals. The most probable drivers for the observed variability reflect a combination of changes of climate plus anthropogenic deforestation during periods of settlement that enhanced the sensitivity of the lake to wind stress. A summary of all analyses allowed for the identification of periods of rapid change in sedimentation, and – indirectly – for the reproduction of changes in the water level and anthropopressure in and around Lake Jelonek. Such results contribute to a better understanding of local influences on fluctuations in lake sedimentation processes characteristic for the north of Poland, but also Central Europe more widely.

scholarly journals Radiocarbon Age of Vertisols and Its Interpretation Using Data on Gilgai Complex in the North Caucasus

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 603-610 ◽  
Author(s):  
Irina Kovda ◽  
Warren Lynn ◽  
Dewayne Williams ◽  
Olga Chichagova
Keyword(s):  
Parent Material ◽  
North Caucasus ◽  
Radiocarbon Dates ◽  
Radiocarbon Age ◽  
The North ◽  
The World ◽  
Soil Complex ◽  
Using Data ◽  
Sampling Procedures ◽  
Different Parts

Radiocarbon dates were analyzed to assess Vertisols age around the world. They show an increase of radiocarbon age from mainly modern–3000 BP in 0–100 cm layer up to 10,000 BP at a depth 100–200 cm. Older dates reflect the age of parent material. The inversion of 14C dates seems to be a frequent phenomenon in Vertisols. A series of new dates of Vertisols from gilgai microhigh, microslope and microlow in the North Caucasus was done in order to understand the nature of this inversion. 14C age in the gilgai soil complex ranges from 70 ± 45 BP in the microlow to 5610 ± 180 BP in the microhigh. A trend of similar depths being younger in the microslope and microlow was found. We explain this by intensive humus rejuvenation in the microlows due to water downward flow. The older date in the microhigh represents the old humus horizon sheared laterally close to the surface and preserved by impermeable water regime. We explain inversions of 14C age-depth curves by the sampling procedures. In a narrow pit, genetically different parts of former gilgai could easily be as a genetically uniform soil profile. Because of this strong microvariability, Vertisols require sampling in a trench accounting for gilgai elements, even when gilgai are not obvious.

Marine reservoir corrections for bowhead whale radiocarbon age determinations

1996 ◽  
Vol 33 (12) ◽  
pp. 1628-1637 ◽  
Author(s):  
Arthur S. Dyke ◽  
Roger N. McNeely ◽  
James Hooper
Keyword(s):  
Canadian Arctic ◽  
Bowhead Whale ◽  
Bone Collagen ◽  
Radiocarbon Dates ◽  
Marine Molluscs ◽  
Terrestrial Plant ◽  
Radiocarbon Age ◽  
Raised Beaches ◽  
Eastern Canadian Arctic ◽  
Age Determinations

Twenty-two pairs of radiocarbon dates on driftwood and bowhead whale (Balaena mysticetus) bones from raised beaches, dates on whale bone and terrestrial plant detritus from a stratigraphie section, and 25 additional dates on whale bones from the lowest (≤1 ka BP) raised beaches in the eastern Canadian Arctic suggest that a marine reservoir correction of about −200 years is appropriate for normalized age determinations on bone collagen from the bowhead whale in this region. This is less than the correction (−400 years) normally applied to carbonate shells of marine molluscs from this region. The carbon in bowhead collagen appears to be derived from the whales' zooplankton food rather than from marine bicarbonate.

Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses

1991 ◽  
Vol 36 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Scott A. Elias ◽  
Paul E. Carrara ◽  
L. J. Toolin ◽  
A. J. T. Jull
Keyword(s):  
Bark Beetles ◽  
Coniferous Forest ◽  
Plant Macrofossils ◽  
Early Holocene ◽  
San Juan ◽  
Radiocarbon Dates ◽  
San Juan Mountains ◽  
Cast Doubt ◽  
Organic Sediments ◽  
Insect Fossils

AbstractPrevious radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al., 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early Holocene age, rather than a late Pleistocene age, for the basal sediments of Lake Emma. These new radiocarbon ages suggest that by at least 10,000 yr B.P. deglaciation of the San Juan Mountains was complete. The insect and plant macrofossils from the basal organic sediments indicate a higher-than-present treeline during the early Holocene. The insect assemblages consisted of about 30% bark beetles, which contrasts markedly with the composition of insects from modern lake sediments and modern specimens collected in the Lake Emma cirque, in which bark beetles comprise only about 3% of the assemblages. In addition, in the fossil assemblages there were a number of flightless insect species (not subject to upslope transport by wind) indicative of coniferous forest environments. These insects were likewise absent in the modern assemblage.

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