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A variety of felsic and mafic granulites and ultramafic rocks occur as xenoliths within a 12.7 Ma ultrapotassic dyke intruding Xigaze flysch immediately to the north of the Yarlung-Tsangpo suture zone in southern Tibet. Garnet-clinopyroxene-plagioclase-quartz thermobarometry on mafic granulite xenoliths gives temperatures of 1130-1330[degrees]C and pressures between 22 and 26 kbar indicating equilibration in the high-pressure and ultrahigh-temperature granulite field and defining a geotherm of c. 16[degrees]C [km.sup.-1]. Ultramafic xenoliths consist mainly of hornblende and biotite, probably of restitic crustal rather than mantle origin, and attained peak metamorphic conditions of 920-1130[degrees]C and 17-24 kbar, whereas felsic granulites equilibrated at 870-900[degrees]C at an inferred pressure of 17 kbar. In situ U-(Th)-Pb laser ablation inductively coupled plasma mass spectrometry dating of zircons shows that protoliths may include Proterozoic basement rocks, Late Cretaceous calc-alkaline tonalites of the Gangdese batholith root and/or remnants of a Neo-Tethyan oceanic arc. Certain zircons from a felsic granulite and an ultramafic xenolith have mean [sup.206]Pb/[sup.238]U ages of 16.8 [+ or -] 0.9 Ma and 15.6 [+ or -] 0.6 Ma, respectively, and monazites from a micaceous xenolith yielded a mean [sup.208]Pb/[sup.232]Th age of 14.4 [+ or -] 0.4 Ma. These results show that the southern Tibet basement reached a thickness of c. 80 km by 17-14 Ma at the latest and has remained unchanged until the present day. Supplementary material: Mineral analyses used for pressure temperature estimations and results of [sup.40]Ar/ [sup.30]Ar laser single-grain fusion experiments are available at http://www.geolsoc.org.uk/SUP18325.

The late Caledonian Galway Batholith is cut by two major faults which divide it into three separate areas: the western, central and eastern blocks. The upthrown and more deeply eroded central block is bounded by these faults, in the west by the north-northeast trending Shannawona Fault and in the east by the north-northwest trending Barna Fault. We present new granite field relations from part of the central block (Inveran sector) which are fundamental in establishing the order and style of emplacement for the granites of the central block and the batholith as a whole. Unequivocal field evidence from the Inveran sector indicates upward movement of early central block granites which then became the solid roof rocks to subsequent intrusions. In the case of the Knock Granite these earlier intrusions were block stoped. We use this field evidence to review the geology of the central block in a 200 [km.sup.2] area that incorporates the previously mapped Costelloe and Spiddal areas. Sharp intrusive contacts are a predominant feature of this sector of the central block and are in marked contrast to the gradational contacts recorded elsewhere in the batholith. Whereas juxtaposition of plutons in the western block occurred as the granites were partly crystallized, the central block reveals earlier, deeper level granites that were consolidated by the time they were intruded by late-stage higher level granites.

In this study, a novel methodology was investigated to improve the spatial resolution and predictive power of geogenic radon maps. The data inputs comprise indoor radon measurements and seven geogenic factors including geological data (i.e. bedrock and Quaternary geology, aquifer type and soil permeability) and airborne geophysical parameters (i.e. magnetic field strength, gamma-ray radiation and electromagnetic resistivity). The methodology was tested in Castleisland southwest Ireland, a radon-prone area identified based on the results of previous indoor radon surveys. The developed model was capable of justifying almost 75 % of the variation in geogenic radon potential. It was found that the attributes with the greatest statistical significance were equivalent uranium content (EqU) and soil permeability. A new radon potential map was produced at a higher spatial resolution compared with the original map, which did not include geophysical parameter data. In the final step, the activity of radon in soil gas was measured at 87 sites, and the correlation between the observed soil gas radon and geophysical properties was evaluated. The results indicate that any model using only geophysical data cannot accurately predict soil radon activity and that geological information should be integrated to achieve a successful prediction model. Furthermore, we found that EqU is a better indicator for predicting indoor radon potential than the measured soil radon concentrations., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

A detailed investigation of geogenic radon potential (GRP) was carried out near Graiguenamanagh town (County Kilkenny, Ireland) by performing a spatial regression analysis on radon-related variables to evaluate the exposure of people to natural radiation (i.e., radon, thoron and gamma radiation). The study area includes an offshoot of the Caledonian Leinster Granite, which is locally intruded into Ordovician metasediments. To model radon release potential at different points, an ordinary least squared (OLS) regression model was developed in which soil gas radon (SGR) concentrations were considered as the response value. Proxy variables such as radionuclide concentrations obtained from airborne radiometric surveys, soil gas permeability, distance from major faults and a digital terrain model were used as the input predictors. ArcGIS and QGIS software together with XLSTAT statistical software were used to visualise, analyse and validate the data and models. The proposed GRP models were validated through diagnostic tests. Empirical Bayesian kriging (EBK) was used to produce the map of the spatial distribution of predicted GRP values and to estimate the prediction uncertainty. The methodology described here can be extended for larger areas and the models could be utilised to estimate the GRPs of other areas where radon-related proxy values are available.

Globally, indoor radon exposure is the leading cause of lung cancer in non-smokers and second most common cause after tobacco smoking. Soil-gas radon is the main contributor to indoor radon, but its spatial distribution is highly variable, which poses certain challenges for mapping and predicting radon anomalies. Measurement of indoor radon typically takes place over long periods of time (e.g. 3 months) and is seasonally adjusted to an annual average concentration. In this article we investigate the suitability of using soil-gas radon and soil-permeability measurements for rapid radon risk assessments at local scale. The area of Castleisland, Co. Kerry was chosen as a case study due to availability of indoor radon data and the presence of significant radon anomalies. In total, 135 soil-gas and permeability measurements were collected and complemented with 180 indoor radon measurements for an identical 6 km 2 area. Both soil-gas and indoor radon concentrations ranged from very low (<10 kBqm -3 , 0.1 Bqm -3 ) to anomalously high (>1433 kBqm -3 , 65,000 Bqm -3 ) values. Our method classifies almost 50% of the area as a high radon potential area, and allows assessment of geogenic controls on radon distribution by including other geological variables. Cumulatively, the percentage of indoor radon variance explained by soil-gas radon concentration, bedrock geology, subsoil permeability and Quaternary geology is 34% (16%, 10%, 4% and 4% respectively). Soil-gas and indoor radon anomalies are associated with black shales, whereas the presence of karst and geological faults are other contributing factors. Sampling of radon soil-gas and soil permeability, used in conjunction with other geogenic data, can therefore facilitate rapid designation of radon priority areas. Such an approach demonstrates the usefulness of high-resolution geogenic maps in predicting indoor radon risk categories when compared to the application of indoor radon measurements alone. This method is particularly useful to assess radon potential in areas where indoor radon measurements are sparse or lacking, with particular application to rural areas, land rezoned for residential use, or for sites prior to building construction., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Radon ( 222 Rn) and thoron ( 220 Rn) account for almost two-thirds of the annual average radiation dose received by the Irish population. A detailed study of natural radioactivity levels and radon and thoron exhalation rates was carried out in a legislatively designated "high radon" area, as based on existing indoor radon measurements. Indoor radon concentrations, airborne radiometric data and stream sediment geochemistry were collated, and a set of soil samples were taken from the study area. The exhalation rates of radon (E 222 Rn ) and thoron (E 220 Rn ) for collected samples were determined in the laboratory. The resultant data were classified based on geological and soil type parameters. Geological boundaries were found to be robust classifiers for radon exhalation rates and radon-related variables, whilst soil type classification better differentiates thoron exhalation rates and correlated variables. Linear models were developed to predict the radon and thoron exhalation rates of the study area. Distribution maps of radon and thoron exhalation rates (range: E 222 Rn [0.15-1.84] and E 220 Rn [475-3029] Bq m -2 h -1 ) and annual effective dose (with a mean value of 0.84 mSv y -1 ) are presented. For some parts of the study area, the calculated annual effective dose exceeds the recommended level of 1 mSv y -1 , illustrating a significant radiation risk. Airborne radiometric data were found to be a powerful and fast tool for the prediction of geogenic radon and thoron risk. This robust method can be used for other areas where airborne radiometric data are available.

To date there is no gold standard for sampling microplastics. Zooplankton sampling methods, such as plankton and Neuston nets, are commonly used to estimate the concentrations of microplastics in seawater, but their ability to detect microplastics is limited by their mesh size. We compared different net-based sampling methods with different mesh sizes including bongo nets (>500 μm), manta nets (>300 μm) and plankton nets (>200 μm and >400 μm) to 1 litre bottle grabbed, filtered (0.45 μm) samples. Concentrations of microplastics estimated using net-based methods were ~3 orders of magnitude less than those estimated by 1 litre grab samples. Some parts of the world with low human populations, such as Ascension Island and the Falkland Islands, lack baseline data on microplastics. Using the bottle grab sampling method we found that microplastic litter was present at these remote locations and was comparable to levels of contamination in more populated coastal regions, such as the United Kingdom., (Copyright © 2018 Elsevier Ltd. All rights reserved.)