isotopic ratios
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2022 ◽  
Author(s):  
Kelly D. Thomson ◽  
et al.

Excel spreadsheets containing sample locations and full detrital zircon U-Pb isotopic ratios and age results. Text file containing detailed description of detrital zircon U-Pb results and three supplemental figures.


2022 ◽  
Author(s):  
Kelly D. Thomson ◽  
et al.

Excel spreadsheets containing sample locations and full detrital zircon U-Pb isotopic ratios and age results. Text file containing detailed description of detrital zircon U-Pb results and three supplemental figures.


Author(s):  
Brenden Riddle ◽  
Jimmy Fox ◽  
David Tyler Mahoney ◽  
William Ford ◽  
Yi-Tin Wang ◽  
...  

2022 ◽  
Vol 233 (1) ◽  
Author(s):  
Hana Johanis ◽  
Václav Tejnecký ◽  
Ondřej Drábek ◽  
Luboš Borůvka ◽  
Martin Mihaljevič

Author(s):  
Kata Molnár ◽  
Pierre Lahitte ◽  
Stéphane Dibacto ◽  
Zsolt Benkó ◽  
Samuele Agostini ◽  
...  

AbstractLate Miocene to Pleistocene volcanism within the Vardar zone (North Macedonia) covers a large area, has a wide range in composition, and is largely connected to the tectonic evolution of the South Balkan extensional system, the northern part of the Aegean extensional regime. The onset of the scattered potassic to ultrapotassic volcanism south from the Scutari-Peć transverse zone occurred at ca. 8.0 Ma based on this study. Here, we focused on three volcanic centers located on deep structures or thrust faults along the western part of the Vardar zone, for which there is none to very little geochronological and geochemical data available. Pakoševo and Debrište localities are represented as small remnants of lava flows cropping out at the southern edge of Skopje basin and at the western edge of Tikveš basin, respectively. Šumovit Greben center is considered as part of the Kožuf-Voras volcanic system, and it is located on its westernmost side, at the southern edge of Mariovo basin, which is largely composed of volcaniclastic sediments. We present new eruption ages applying the unspiked Cassignol-Gillot K–Ar technique on groundmass, as well as petrological and geochemical data, supplemented with Sr and Nd isotopes to complement and better understand the Neogene-Pleistocene volcanism in the region. Eruption ages on these rocks interlayered between sedimentary formations allow to better constrain the evolution of those sedimentary basins. Rocks from the three volcanic centers belong to the high-K calc-alkaline–shoshonitic series based on their elevated K content. The oldest center amongst these three localities, as well as other Late Miocene centers within the region, is the trachyandesitic Debrište, which formed at ca. 8.0 Ma, and exhibits the highest Nd and lowest Sr isotopic ratios (0.512441–0.512535 and 0.706759–0.706753, respectively). The basaltic trachyandesite Pakoševo center formed at ca. 3.8 Ma and its Nd and Sr isotopic ratios (0.512260 and 0.709593, respectively) bear the strongest signature of crustal contamination. The rhyolitic Šumovit Greben center is a composite volcanic structure formed at ca. 3.0–2.7 Ma. Its youngest eruption unit has a slightly higher Nd and lower Sr isotopic ratios (0.512382 and 0.709208, respectively) representing a magma with a lesser extent of crustal assimilation than the other samples from this center. The overall trend through time in the Sr and Nd isotopic ratios of the Late Miocene to Pleistocene mafic volcanic centers in the region implies an increasing rate of metasomatism of the lithospheric mantle.


Author(s):  
Grzegorz Żabiński

The jubilee of Professor Andrzej Nadolski and Professor Marian Głosek is an excellent opportunity for discussing some most recent methods of technological analyses in archaeology and their applications in arms and armour studies. New opportunities are offered by Computed Tomography (CT) and by Neutron Imaging (NI). The latter is insensitive to material density; therefore details that are not detectable by X-ray or CT can be seen in NI images. A considerable progress has also been made in the field of radiocarbon dating. Yet another field are analyses of the chemical composition of smelting slag and slag inclusions in ferrous artefacts. Such analyses can be used for identification of smelting processes, as well as for provenance studies. These take a number of variables into consideration (major and trace elements, as well as isotopic ratios). What seems to be especially promising in provenance studies are isotopes of osmium (Os).


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1400
Author(s):  
Lluís Casas ◽  
Roberta Di Febo ◽  
Mauro Brilli ◽  
Francesca Giustini ◽  
Marco Gozzi ◽  
...  

The Forma Urbis Romae (F.U.) was a 3rd-century-AD monumental map of ancient Rome consisting of 151 rectangular marble slabs. Several efforts have been made to reconstruct it from its current incomplete and fragmentary condition. In this paper, we explore the potential of an archaeometric approach to serve this purpose. Almost a hundred F.U. fragments have been characterized, particularly focusing on cathodoluminescence (CL) microscopy and stable isotopes (δ18O and δ13C). Different statistical methods have been used to quantify the similarity between samples. The central assumption is that samples from a given slab share similar CL colors and isotopic ratios. The assumption has been verified for samples from single fragments and then it has been used to check ten debated reconstruction hypotheses. The measured isotopic ratios confirm the Proconnesian nature of the F.U. marble, except for a fragment. Beyond provenance, the results cast doubts on four out of the ten checked reconstruction hypotheses and support the other six. The reconstruction of the F.U. remains a fascinating challenge, and both isotopic and CL analyses have demonstrated their potential to tackle it. Further research could extend the presented methodology to a higher number of samples. The innovative use of CL to reconstruct a fragmented artwork could be applied to other projects.


2021 ◽  
Vol 576 ◽  
pp. 117215
Author(s):  
M.A. Finch ◽  
R.F. Weinberg ◽  
V.R. Barrote ◽  
P.A. Cawood
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