New radiometric dating of volcanic ash layers in Periadriatic foredeep basin system, Italy

2000 ◽  
Vol 155 (3-4) ◽  
pp. 327-340 ◽  
Author(s):  
G Bigazzi ◽  
F.P Bonadonna ◽  
E Centamore ◽  
G Leone ◽  
M Mozzi ◽  
...  
2001 ◽  
Vol 167 (1-2) ◽  
pp. 205-206
Author(s):  
G. Bigazzi ◽  
F.P. Bonadonna ◽  
E. Centamore ◽  
G. Leone ◽  
M. Mozzi ◽  
...  

2013 ◽  
Vol 59 (218) ◽  
pp. 1117-1128 ◽  
Author(s):  

AbstractThe IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around ∼74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.


Radiocarbon ◽  
1992 ◽  
Vol 34 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Richard Gillespie ◽  
A. P. Hammond ◽  
K. M. Goh ◽  
P. J. Tonkin ◽  
D. C. Lowe ◽  
...  

The radiocarbon dating of volcanic ash (tephra) deposits in New Zealand has been difficult on sites remote from the eruption, which contain either little carbon or degraded and contaminated charcoal. Although many studies of contamination removal from macroscopic charcoals from tephra sequences have been made, little attention has been paid to those containing no visible charcoal, because of the difficulty of obtaining sufficient carbon for radiometric dating. We report here experiments using accelerator mass spectrometry to establish a reliable method for dating a low-carbon aeolian and peat deposit containing a tephra horizon. Results so far demonstrate that improvements to existing chemical pretreatment methods are possible, and that dates obtained on oxidized fine-grained residues can approach the maximum age determined on good quality charred wood samples.


Recent discoveries in the Laetolil beds at Laetoli in northern Tanzania have revealed hominid tracks made by three individuals in a bed of cemented volcanic ash. The tracks extend for a distance of 27 m and indicate a fully upright, bipedal gait with weight distribution similar to that of modern man. A single trail proceeds alongside a dual trail in which the footsteps of the leading individual are almost exactly overprinted by the second set of tracks. Radiometric dating of an overlying tuff has yielded a figure of 3.6 Ma. Stone artefacts are unknown in the Laetolil beds, and a date of ca . 2 Ma for the earliest formalized tool-making is postulated on the evidence from Olduvai Gorge.


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