Comparison of γ-ray spectrometry and ICP-MS methods for measuring radioactive heat-producing elements of rocks: a case study on borehole samples from the Sichuan Basin, China

We compared the consistency of γ-ray spectrometry and inductively coupled plasma mass spectrometry by analyzing measurement results of the radioactive heat-producing elements U, Th, and K from borehole samples. This analysis was based on 49 samples obtained from mudstone, siltstone, and carbonate rock, and 11 of the 15 control groups showed great consistency. The radioactive heat production (RHP) of carbonate rocks was relatively low (0.23–0.63 µW m−3) and was mainly contributed by U. Mudstone and siltstone have higher RHPs, which was 1.73 ± 0.46 and 2.04 ± 0.49 µW m−3, respectively

Conductive heat flow pattern of the central-northern Apennines, Italy

We analyzed thermal data from deep oil exploration and geothermal boreholes in the 1000-7000 m depth range to unravel thermal regime beneath the central-northern Apennines chain and the surrounding sedimentary basins. We particularly selected deepest bottom hole temperatures, all recorded within the permeable carbonate Paleogene-Mesozoic formations, which represent the most widespread tectono-stratigraphic unit of the study area. The available temperatures were corrected for the drilling disturbance and the thermal conductivity was estimated from detailed litho-stratigraphic information and by taking into account the pressure and temperature effect. The thermal resistance approach, including also the radiogenic heat production, was used to infer the terrestrial heat flow and to highlight possible advective perturbation due to groundwater circulation. Only two boreholes close to recharge areas argue for deep groundwater flow in the permeable carbonate unit, whereas most of the obtained heat-flow data may reflect the deep, undisturbed, conductive thermal regime

Geothermal flow and water-load seafloor depth of the Eastern Mediterranean Sea

We used bathymetry, sediment thickness and terrestrial heat-flow data to investigate the nature of the Eastern Mediterranean Sea lithosphere. We processed bathymetric data by removing the subsidence caused by sediment deposition to obtain the water-loaded seafloor depth. Terrestrial heat flow measurements were corrected for sedimentation and climatic changes to infer the purely conductive steady-state geothermal flow. Water-load seafloor depths and thermal data were then compared to reference models of continental lithosphere stretching and ocean plate cooling. The results argue that the Levantine Basin is floored by a continental stretched crust that thinned by a factor of 1.6-2.7, whereas the Herodotus Basin crust is of oceanic type. The water-loaded seafloor depths in all the Eastern Mediterranean are consistent with geological ages of > 250 Ma. The mantle heat flow in the Herodotus Basin (33 mW m-2) is consistent with that of the oceanic Ionian lithosphere, whereas in the Levantine Basin (26 mW m-2) is comparable to that of the Sinai continental microplate

A new FSA approach for in situ γ\gamma-ray spectroscopy

An increasing demand of environmental radioactivity monitoring comes both from the scientific community and from the society. This requires accurate, reliable and fast response preferably from portable radiation detectors. Thanks to recent improvements in the technology, $\gamma$-spectroscopy with sodium iodide scintillators has been proved to be an excellent tool for in-situ measurements for the identification and quantitative determination of $\gamma$-ray emitting radioisotopes, reducing time and costs. Both for geological and civil purposes not only $^{40}$K, $^{238}$U, and $^{232}$Th have to be measured, but there is also a growing interest to determine the abundances of anthropic elements, like $^{137}$Cs and $^{131}$I, which are used to monitor the effect of nuclear accidents or other human activities. The Full Spectrum Analysis (FSA) approach has been chosen to analyze the $\gamma$-spectra. The Non Negative Least Square (NNLS) and the energy calibration adjustment have been implemented in this method for the first time in order to correct the intrinsic problem related with the $\chi ^2$ minimization which could lead to artifacts and non physical results in the analysis. A new calibration procedure has been developed for the FSA method by using in situ $\gamma$-spectra instead of calibration pad spectra. Finally, the new method has been validated by acquiring $\gamma$-spectra with a 10.16 cm x 10.16 cm sodium iodide detector in 80 different sites in the Ombrone basin, in Tuscany. The results from the FSA method have been compared with the laboratory measurements by using HPGe detectors on soil samples collected in the different sites, showing a satisfactory agreement between them. In particular, the $^{137}$Cs isotopes has been implemented in the analysis since it has been found not negligible during the in-situ measurements.Comment: accepted by Science of Total Environment: 8 pages, 10 figures, 3 table

Thermal regime and tectonic pattern of the central-northern Apennines

Pojam stres se upotrebljava kako bi se opisao osjećaj straha, nezadovoljstva, nemira i nelagode. To je složen proces između određene osobe i njenog života. Stres koji studenti doživljavaju na fakultetu je jedan vrlo značajan čimbenik koji može nepovoljno utjecati na svakodnevno funkcioniranje studenata i kvalitetu studiranja. Cilj istraživanja je utvrditi razinu stresa studenata prve i treće godine stručnog studija te usporediti razinu stresa između studenata prve i treće godine studija. Hipoteza istraživanja zasniva se na pretpostavci da je razina stresa kod studenata prve godine stručnog studija veća od studenata treće godine stručnog studija. Ispitanici su studenti prve i treće godine stručnog studija sestrinstva na Visokoj tehničkoj školi u Bjelovaru. U istraživanju je korišten socio – demografski upitnik koji je konstruiran za potrebe ovog istraživanja, a koji obuhvaća podatke o spolu i dobi. Podaci su obrađeni deskriptivnim statističkim metodama

Thermal log analysis for recognition of ground surface temperature change and water movements

International audienceA joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in near-by boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a horizontally layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using an inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved to be negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960?1990. The absence of the Little Ice Age in the middle ages seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes. This discrepancy can be attributed to local environmental conditions