A disastrous date

Antiquity ◽  
2014 ◽  
Vol 88 (339) ◽  
pp. 288-289 ◽  
Author(s):  
J. Alexander MacGillivray

Paolo Cherubini and colleagues have demonstrated convincingly that the identification of olive wood tree-rings from Santorini is ‘practically impossible’. Thus, the single piece of evidence that might have persuaded some archaeologists to support the ‘high’ 1613±13 BC date for the Theran eruption is hors de combat. The Theran olive-tree branch has gone the way of the Greenland Ice Core results of similar date and which enjoyed a similar devoted following until shown to be from a different eruption. Taken with Malcolm Wiener's explicit exposé of the myriad shortcomings of 14C dating, especially for this time period and event, these results take us back to where we were before the ‘radiocarbon revolution‘, when the largest Holocene eruption in the ancient world happened as Minoan Crete enjoyed wideranging influence, perhaps even control, over the Aegean, when Late Minoan IA pottery styles proliferated, and Egypt was in the early stages of its New Kingdom period (Wiener 2012, 2013).

Antiquity ◽  
2014 ◽  
Vol 88 (339) ◽  
pp. 277-282 ◽  
Author(s):  
Manfred Bietak

The criticism of the date of the olive tree branch from Thera offered by Cherubini et al. (above) has to be fully supported. The attribution of the branch in question to the late part of the seventeenth century BC is by itself not unexpected, as most of the other radiocarbon dates of short-lived samples from the site of Akrotiri fall into the second half of that century. The attempt to produce a wiggle-match drawn from a succession of non-existent tree-rings in this branch, and to fit such a result into the general calibration curve to give the illusion of precision, however, does not pass the scientific test. Olive trees do not develop annual tree-rings. Furthermore, no proof could be produced that this branch was alive during the eruption. The olive leaves found in an underlying horizon had no connection to the branch and could have been preserved in dry ground like this for ages before the eruption occurred. The remains of the branch were not found in a tight-fitting context but in a much larger cavity and it seems that the outer part of the branch, including the bark edge (waney edge)—contrary to the assertions of Friedrich et al. (2006)—are missing. The other issue in this scientific discussion is that dating the Thera eruption by 14C is much more problematic than is acknowledged by scientists, since it clashes distinctly with historical and archaeological dating.


Antiquity ◽  
2014 ◽  
Vol 88 (339) ◽  
pp. 267-267 ◽  

The date of the volcanic eruption of Santorini that caused extensive damage to Minoan Crete has been controversial since the 1980s. Some have placed the event in the late seventeenth century BC. Others have made the case for a younger date of around 1500 BC. A recent contribution to that controversy has been the dating of an olive tree branch preserved within the volcanic ash fall on Santorini. In this debate feature Paolo Cherubini and colleagues argue that the olive tree dating (which supports the older chronology) is unreliable on a number of grounds. There follows a response from the authors of that dating, and comments from other specialists, with a closing reply from Cherubini and his team.


2021 ◽  
pp. 1-8
Author(s):  
Grégoire Guillet ◽  
Susanne Preunkert ◽  
Ludovic Ravanel ◽  
Maurine Montagnat ◽  
Ronny Friedrich

Abstract The current paper studies the dynamics and age of the Triangle du Tacul (TDT) ice apron, a massive ice volume lying on a steep high-mountain rock wall in the French side of the Mont-Blanc massif at an altitude close to 3640 m a.s.l. Three 60 cm long ice cores were drilled to bedrock (i.e. the rock wall) in 2018 and 2019 at the TDT ice apron. Texture (microstructure and lattice-preferred orientation, LPO) analyses were performed on one core. The two remaining cores were used for radiocarbon dating of the particulate organic carbon fraction (three samples in total). Microstructure and LPO do not substantially vary with along the axis of the ice core. Throughout the core, irregularly shaped grains, associated with strain-induced grain boundary migration and strong single maximum LPO, were observed. Measurements indicate that at the TDT ice deforms under a low strain-rate simple shear regime, with a shear plane parallel to the surface slope of the ice apron. Dynamic recrystallization stands out as the major mechanism for grain growth. Micro-radiocarbon dating indicates that the TDT ice becomes older with depth perpendicular to the ice surface. We observed ice ages older than 600 year BP and at the base of the lowest 30 cm older than 3000 years.


Antiquity ◽  
2010 ◽  
Vol 84 (323) ◽  
pp. 202-215 ◽  
Author(s):  
M.G.L. Baillie

Good archaeology relies on ever more precise dates – obtainable, notably, from ice-cores and dendrochronology. These each provide year-by-year sequences, but they must be anchored at some point to real historical time, by a documented volcanic eruption, for example. But what if the dating methods don't agree? Here the author throws down the gauntlet to the ice-core researchers – their assigned dates are several years too old, probably due to the spurious addition of ‘uncertain’ layers. Leave these out and the two methods correlate exactly…


Author(s):  
Ioannis T. Georgiou

Geometry consistent spatio-temporal measurements of the experimental acceleration of olive tree branches were analyzed with advanced POD tools in an effort to gain knowledge on the mechanics-dynamics of this bio-mechanical structure. To pave the way for understanding the dynamics of this system, both the typical olive tree as a whole and its typical branch are approached as interacting soft-stiff continuum mechanical systems. The POD analysis reveals that the impact response is a nonlinear vibration with very fast dissipation. The POD modal amplitudes are nonlinear vibrations of continuous, broadband frequency spectrum. Initially they exhibit regular phases of nonlinear slow dissipation-and-amplification followed by irregular, fast dissipation-and-amplification phases. Sequentially applied impacts at the branch soft area results in a complete detachment of the fruit. The POD analysis reveals that this occurs because the response is highly localized in the soft area where the impact is applied and thus it transfers its momentum to the fruits. The work is supplemented with analysis of field measurements of the acceleration dynamics of orchard olive tree branches excited by harvesting devices generating combing clouds of impulsive forces aimed at detaching the olive fruit by momentum transfer.


Radiocarbon ◽  
2020 ◽  
Vol 62 (4) ◽  
pp. 953-961 ◽  
Author(s):  
Ronny Friedrich ◽  
Bernd Kromer ◽  
Lukas Wacker ◽  
Jesper Olsen ◽  
Sabine Remmele ◽  
...  

ABSTRACTAnnually resolved tree-ring samples of the time period 1625–1510 BCE were analyzed from the German oak tree-ring chronology. Blocks of the same tree rings were previously used to generate IntCal calibration data. The new dataset shows an offset to the calibration data IntCal13 of 24 years and resembles annual data for the same time period derived from tree-ring records in other growth locations. A subset of samples of the period 1625–1585 BCE was additionally measured in three other laboratories (ETH, AAR, AA) for quality control.


2015 ◽  
Vol 127 ◽  
pp. 124-134 ◽  
Author(s):  
E.S. Abdel-Halim ◽  
Humaid H. Alanazi ◽  
Salem S. Al-Deyab

2006 ◽  
Vol 6 (4) ◽  
pp. 5905-5931 ◽  
Author(s):  
T. M. Jenk ◽  
S. Szidat ◽  
M. Schwikowski ◽  
H. W. Gäggeler ◽  
S. Brütsch ◽  
...  

Abstract. Long-term concentration records of carbonaceous particles (CP) are of increasing interest in climate research due to their not yet completely understood effects on climate. Nevertheless, only poor data on their concentrations and sources in the past is available. We present a first long-term record of organic carbon (OC) and elemental carbon (EC) concentrations - the two main fractions of CP – along with the corresponding fraction of modern carbon (fM) derived from radiocarbon (14C) analysis. The combination of concentration measurements with 14C analysis of CP allows a distinction and quantification of natural, biogenic and anthropogenic fossil sources in the past. CP were extracted from an ice archive, with resulting carbon quantities in the microgram range. Analysis of 14C by accelerator mass spectrometry (AMS) was therefore highly demanding. We analysed 33 samples of 0.4 to 1 kg ice from a 150.5 m long ice core retrieved at Fiescherhorn glacier in December 2002 (46°33'3.2" N, 08°04'0.4'' E; 3900 m a.s.l.). Samples were taken from below the firn/ice transition down to bedrock, covering the time period 1650–1940 and thus the transition from the pre-industrial to the industrial era. Before 1800, OC was of pure biogenic origin with a mean concentration of 21±2 μg kg−1}. In 1940, OC concentration was more than a factor of 3 higher than this biogenic background, almost half of it originating from anthropogenic sources, i.e. from combustion of fossil fuels. The biogenic EC concentration was nearly constant over the examined time period with 6±1 μg kg−1. In 1940, the additional anthropogenic input of atmospheric EC was about 50 μg kg−1.


2012 ◽  
Vol 8 (6) ◽  
pp. 5867-5891 ◽  
Author(s):  
I. Mariani ◽  
A. Eichler ◽  
S. Brönnimann ◽  
R. Auchmann ◽  
T. M. Jenk ◽  
...  

Abstract. Water stable isotope ratios and net snow accumulation in ice cores are usually interpreted as temperature and precipitation proxies. However, only in a few cases a direct calibration with instrumental data has been attempted. In this study we took advantage of the dense network of observations in the European Alpine region to rigorously test the relationship of the proxy data from two highly-resolved ice cores with local temperature and precipitation, respectively, on an annual basis. We focused on the time period 1961–2001 with the highest amount and quality of meteorological data and the minimal uncertainty in ice core dating (±1 yr). The two ice cores come from Fiescherhorn glacier (Northern Alps, 3900 m a.s.l.) and Grenzgletscher (Southern Alps, 4200 m a.s.l.). Due to the orographic barrier, the two flanks of the Alpine chain are affected by distinct patterns of precipitation. Therefore, the different location of the two ice cores offers the unique opportunity to test whether the precipitation proxy reflects this very local condition. We obtained a significant spatial correlation between annual δ18O and regional temperature at Fiescherhorn. Due to the pronounced intraseasonal to interannual variability of precipitation at Grenzgletscher, significant results were only found when weighting the temperature with precipitation. For this site, disentangling the temperature from the precipitation signal was thus not possible. Significant spatial correlations between net accumulation and precipitation were found for both sites but required the record from the Fiescherhorn glacier to be shifted by −1 yr (within the dating uncertainty). The study underlines that even for well-resolved ice core records, interpretation of proxies on an annual or even sub-annual basis remains critical. This is due to both, dating issues and the fact that the signal preservation intrinsically depends on precipitation.


2006 ◽  
Vol 2 (6) ◽  
pp. 1051-1073 ◽  
Author(s):  
O. Solomina ◽  
G. Wiles ◽  
T. Shiraiwa ◽  
R. D’Arrigo

Abstract. Tree rings, ice cores and glacial geologic histories for the past several centuries offer an opportunity to characterize climate variability and to identify the key climate parameters forcing glacier expansions. A newly developed larch ring-width chronology is presented for Kamchatka that is sensitive to past summer temperature variability. This record provides the basis to compare with other proxy records of inferred temperature and precipitation change from ice core and glacier records, and to characterize climate for the region over the past 400 years. Individual low growth years in the larch record are associated with several known and proposed volcanic events that have been observed in other proxy records from the Northern Hemisphere. Comparison of the tree-rings with an ice core record of melt feature index for Kamchatka's Ushkovsky volcano confirms a 1–3 year dating accuracy for this ice core series over the late 18th to 20th centuries. Decadal variations of low summer temperatures (tree-ring record) and high annual precipitation (ice core record) are broadly consistent with intervals of positive mass balance measured and estimated at several glaciers, and with moraine building, provides a basis to interpret geologic glacier records.


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