Building a tephrostratigraphic framework for the Paleolithic of Central Anatolia, Turkey

Here we report the recognition of the Minoan tephra layer in the Acigöl Basin (western Turkey), which represents the most eastward occurrence of this tephra on land and the first in continental deposits out of lacustrine sediments in mainland Turkey. The correlation is supported by glass and mineral geochemistry, which includes solution and laser‐ablation ICP‐MS data for trace and rare earth elements. Thickness and grain size data allow the extension of already described occurrences to an area of about 359 000 km2, from the eastern Mediterranean to Black Sea throughout central–western Turkey. Coupling dispersal area and grain‐size data suggests the joint influence of high and low atmosphere dynamics in dispersal of fine ash during volcanic eruptions. The thickness and lateral continuity of the Minoan tephra in the Acigöl Basin testifies to the widespread impact on the Late Bronze Age environment of mainland Turkey of this important ash deposit. Copyright © 2013 John Wiley & Sons, Ltd.

Section: Discussion and Concluding Remarksmentioning

confidence: 53%

Recognition of the Minoan tephra in the Acigöl Basin, western Turkey: implications for inter‐archive correlations and fine ash dispersal

Sulpizio

Alçiçek

Zanchetta

et al. 2013

“…In relation to other LDA efforts for geochemical classification of tephra‐derived glass, our final model performed comparably in terms of accuracy on reference data: our study = 95.1%; Tryon et al . () = 95–97%; Stokes and Lowe () = 97.5%; Charman and Grattan () = 90.3%.…”

Section: Resultsmentioning

confidence: 95%

Machine learning classifiers for attributing tephra to source volcanoes: an evaluation of methods for Alaska tephras

Bolton

Jensen

Wallace

et al. 2019

Glass composition-based correlations of volcanic ash (tephra) traditionally rely on extensive manual plotting. Many previous statistical methods for testing correlations are limited by using geochemical means, masking diagnostic variability. We suggest that machine learning classifiers can expedite correlation, quickly narrowing the list of likely candidates using well-trained models. Eruptives from Alaska's Aleutian Arc-Alaska Peninsula and Wrangell volcanic field were used as a test environment for 11 supervised classification algorithms, trained on nearly 2000 electron probe microanalysis measurements of glass major oxides, representing 10 volcanic sources. Artificial neural networks and random forests were consistently among the top-performing learners (accuracy and kappa > 0.96). Their combination as an average ensemble effectively improves their performance. Using this combined model on tephras from Eklutna Lake, south-central Alaska, showed that predictions match traditional methods and can speed correlation. Although classifiers are useful tools, they should aid expert analysis, not replace it. The Eklutna Lake tephras are mostly from Redoubt Volcano. Besides tephras from known Holocene-active sources, Holocene tephra geochemically consistent with Pleistocene Emmons Lake Volcanic Center (Dawson tephra), but from a yet unknown source, is evident. These tephras are mostly anchored by a highly resolved varved chronology and represent new important regional stratigraphic markers.

“…Various eruptions and deposits of the Acigöl Complex were examined as potential sources (i.e. Young Dome, Korudag, Bogazköy, lower Acigöl Tuff, upper Acigöl Tuff, Kaleci, Tepeköy, Guneydag, Kuzay and Karniyarik) that range in age from 200 to 20 ka (Druitt et al, 1995;Tryon et al, 2009Tryon et al, , 2011Siebel et al, 2011). Compositions of some of the younger eruptions (i.e.…”

Section: Acigöl Complex Anatoliamentioning

confidence: 99%

Discovery of cryptotephra at Middle–Upper Paleolithic sites Arma Veirana and Riparo Bombrini, Italy: a new link for broader geographic correlations

Hirniak

Smith

Johnsen

et al. 2019

Chemical characterization of cryptotephra is critical for temporally linking archaeological sites. Here, we describe cryptotephra investigations of two Middle-Upper Paleolithic sites from north-west Italy, Arma Veirana and Riparo Bombrini. Cryptotephra are present as small (<100 µm) rhyolitic glass shards at both sites, with geochemical signatures rare for volcanoes in the Mediterranean region. Two chemically distinct shard populations are present at Arma Veirana (P1 and P2). P1 is a high silica rhyolite (>75 wt.%) with low FeO (<1 wt.%) and a K 2 O/ Na 2 O > 1 and P2 is also a high silica rhyolite (>75 wt.%) but with higher FeO (2.33-2.65 wt.%). Shards at Riparo Bombrini (P3) are of the same composition as P1 shards at Arma Veirana, providing a distinct link between deposits at both sites. Geochemical characteristics suggest three possible sources for P1 and P3: eruptions from Lipari Island (56-37.7 ka) in Italy, the Acigöl volcanic field (200-20 ka) in Turkey and the Miocene Kirka-Phrigian caldera (18 Ma) in Turkey. Eruptions from Lipari Island are the most likely source for P1,3 cryptotephra. This study highlights how cryptotephra can benefit archaeology, by providing a direct link between Arma Veirana and Riparo Bombrini as well as other deposits throughout the Mediterranean.