An Integrated Paleomagnetic, Multimethod- Paleointensity, and Radiometric Study on Cretaceous and Paleogene Lavas From the Lesser Caucasus: Geomagnetic and Tectonic Implications

Sixteen rhyolitic and dacitic Cretaceous and Paleocene-Eocene lavas from the Lesser Caucasus have been subjected to paleomagnetic and multimethod paleointensity experiments to analyze the variations of the Earth's magnetic field. Paleointensity experiments were performed with two methods. Thellier-type experiments with the IZZI method on 65 specimens (nine flows) yielded 15 successful determinations and experiments with the multispecimen method on 14 samples (seven flows) yielded two successful determinations. The joint analysis of the results obtained with both methods produced a mean FuK = (19.9 ± 3.7) µT for upper Cretaceous and FPg = (20.7 ± 3.3) µT for Paleogene sites. Low virtual axial dipole moments for the Cretaceous (3.4 × 1022 Am2) and Paleogene (3.5 × 1022 Am2) samples support the idea of a lower average dipole moment during periods of stable polarity of the Earth magnetic field. Mean flow paleomagnetic directions did not match expected upper Cretaceous to Paleogene directions calculated from the European Apparent Polar Wander Path. While inclination results roughly agreed with expected values, a group of sites showed nearly North-South paleodeclinations (D = 1.1° ± 14.2°), and another group displayed eastward deviated paleodeclinations (D = 72.9° ± 26.6°). These results suggest the occurrence of nearly vertical-axis rotations, probably as a result of continental collision since Oligocene. In addition to paleomagnetic and palaeointensity analyses, new K-Ar absolute age determinations have been performed on three of the studied sites, yielding Late Cretaceous ages (78.7 ± 1.7, 79.7 ± 1.6, and 83.4 ± 1.8 Ma (2σ)).Project PID2019-105796GB-100/AEI/10.13039/501100011033 (Agencia Estatal de Investigación, Spain). M. Calvo-Rathert acknowledges funding from the Fulbright Commission and the Spanish Ministry of Science, Innovation, and Universities for a research stay at Hawaii University at Manoa. A. Goguitchaichvili acknowledges financial support from UNAM-PAPIIT no. IN101920. N. García-Redondo acknowledges financial support from Junta de Castilla y León and the European Research Development Fund (ERDF). EHB acknowledges financial support for laboratory maintenance and measurements to SOEST-HIGP and National Science Foundation grants. These is SOEST 11143 and HIGP 2420 contribution

New archeointensity results from Teotihuacan (Central Mexico).

1 p.International audienceWe carried out systematic rock-magnetic and archeointensity invetigations on 84 pottery fragments (about 549 samples) of Teotihuacan ceramics. Three localities are sampled: Xalla, Teopancazco and Cueva de las Varillas. The principal aim of this study is to try to establish first archeointensity reference curve for Mesoamerica from 300 a.C. and 1500 d.C. The samples selected are related to about 50 C14 and AMS radiometric data available. Thus there are almost ideal conditions to know absolute geomagnetic intensity variation trough time. Rock-magnetic investigation included susceptibility vs temperature and hystresis measurements. In addition some X-Ray and microscopy studies were performed on selected specimens. The samples are characterized by stable remanent magnetization observed upon both thermal and alternating field demagnetizations. Both Ti-poor and Ti-rich titanomagnetites are responsible for the magnetization. 61 out 84 fragments yielded acceptable archeointensity results yielding an extremely high success rate. The cooling rate and anisotropy correction were applied to all samples. The mean intensities found range from 72.8 to 15.9 microT acceptable archeointensity results yielding an extremely high success rate. The cooling rate and anisotropy correction were applied to all samples. The mean intensities found range from 72.8 to 15.9 microT showing very low within fragment dispersion

Archaeomagnetic dating of Copper Age furnaces at Croce di Papa village and relations on Vesuvius and Phlegraean Fields volcanic activity

Metallurgic furnaces, discovered in the archaeological site of Croce di Papa, Nola, at 15 km NE from the Vesuvius summit, were dated here by using archaeomagnetic technique. They are positioned between the deposits of the Vesuvius eruption of Pomici di Avellino and of the Phlegraean eruption of Agnano-Monte Spina. A revision of available age data and associated uncertainties for these two eruptions was carried out in order to provide constraints on the Croce di Papa furnaces age determination. The adopted archaeomagnetic technique provides an accurate age of 3136–3027 BCE corresponding to 5085 to 4976 a BP that represents the upper age limit of the Agnano-Monte Spina eruption. This study provides evidences for the existence of human settlements in the Campanian Plain in the first century of the forth millennium BC and allow to assess the limited impact of the Agnano-Monte Spina eruption on climate and human settlement

Radon Concentration in Water on the Several Regions of Georgia

Quantitative assessment of radon distribution in Georgia has been carried out. According to field data, assessment background value of Radon in water from the surface, shallow and deep layer

Indoor Radon Concentrations in Selected Buildings of Georgia

Within the project “Radon mapping and radon risk assessment in Georgia”, funded by the Shota Rustaveli National Science Foundation of Georgia in 2019‒2022 (SRNSFG FN-19-22022), systematic radon (222Rn, Rn) surveys in indoor air, soil gas, and waters were carried out in Georgia. The indoor radon study included 702 locations in 11 administrative regions of Georgia. Altogether, 1338 rooms in 107 schools, 540 kindergartens, 6 city halls, and 57 homes were examined for radon all year round by exposing solid-state nuclear track detectors RSFV from Radosys Ltd. Rn concentrations ranged from 2 to 1226 Bq m3, with an annual arithmetic mean value of 84 Bq m3 for all the regions. The annual effective doses ranged from 0.2 to 3.8 mSv with an arithmetic mean value of 1.2 mSv a1