The European Atlas of Natural Radiation, recently published, contains a collection of maps of Europe showing the levels of natural sources of radiation. Among the lacunae of the Atlas are maps of U, Th and K concentrations in rocks due to lack of European-wide geochemical surveys of bedrock units. The objective of this paper is to investigate the usability of scattered geochemical data of rock samples for large-scale mapping of U, Th and K concentrations in geological units. For this purpose, geochemical data were compiled from literature sources to produce a geochemical database (LIT database) that includes 2817 entries of U, Th and K concentrations measured in rock samples of geological units outcropping in Portugal.

Given the methodical heterogeneity within LIT database, the influence of the geochemical analysis techniques was assessed through a three-way analysis of variance (ANOVA) using geological units, geochemical analysis techniques and loss on ignition (LOI) as categorical variables. The percentage of variation explained by geological factors was large (>35%), while the percentage of variation explained by the geochemical analysis techniques and LOI was generally lower than 5%. The geological factors were the main source of variability in the data, followed by the error component which can be assumed to represent the true spatial variability of geochemical concentrations. The pairwise comparison of the least square (LS) means computed through the ANOVA for each geochemical analysis technique indicates that LIT database can be considered consistent within itself, thus, reliable.

In order to validate the usability of literature data the terrestrial gamma dose rate (TGDR) calculated from LIT database (TGDR_calc) was compared to the TGDR displayed in the Radiometric Map of Portugal (TGDR_obs). The correlation between TGDR_calc and TGDR_obs was highly significant (p < 0.001) and the results of a paired sample t-test and Wilcoxon median tests indicate that the differences between the arithmetic means of TGDR_calc and TGDR_obs were not statistically significant (p = 0.126 and p = 0.14, respectively). Distributions of TGDR_calc and TGDR_obs were seemingly equal according to the Kolmogorov-Smirnov and Anderson-Darling tests. Although, systematic discrepancies between TGDR_calc and TGDR_obs were observed for sedimentary rocks, the compatibility of the RMP and LIT databases can be considered acceptable, which implies that the estimation of the contents of terrestrial radionuclides using literature data for large-scale mapping of U, Th and K contents in geological units is reasonable.

最近出版的《欧洲自然辐射图集》包含一组欧洲地图，显示了自然辐射源的水平。由于缺乏欧洲范围内对基岩单元的地球化学调查，Atlas的空缺中包括铀，Th和钾的浓度分布图。本文的目的是研究岩石样品的分散地球化学数据在地质单位中U，Th和K浓度的大规模制图的可用性。为此，从文献资料中收集了地球化学数据，以生成一个地球化学数据库（LIT数据库），其中包括在葡萄牙露头的地质单位岩石样品中测得的2817个U，Th和K浓度条目。

考虑到LIT数据库中方法上的异质性，使用地质单位，地球化学分析技术和灼烧损失（LOI）作为分类变量，通过方差三方分析（ANOVA）评估了地球化学分析技术的影响。地质因素解释的变化百分比很大（> 35％），而地球化学分析技术和LOI解释的变化百分比通常低于5％。地质因素是数据变化的主要来源，其次是误差分量，可以假定误差分量代表了地球化学浓度的真实空间变异性。

为了验证文献数据的可用性，将根据LIT数据库（TGDR _calc）计算出的地面伽马剂量率（TGDR）与显示在葡萄牙的辐射图（TGDR _obs）中的TGDR进行了比较。TGDR _calc和TGDR _obs之间的相关性非常显着（p <0.001），配对样本t检验和Wilcoxon中位数测试的结果表明TGDR _calc和TGDR _obs的算术平均值之间的差异无统计学意义（p =分别为0.126和p = 0.14）。TGDR _calc和TGDR _obs的分布根据Kolmogorov-Smirnov和Anderson-Darling检验，它们似乎相等。尽管在沉积岩中观察到了TGDR _calc和TGDR _obs之间的系统差异，但是RMP和LIT数据库的兼容性可以被认为是可以接受的，这意味着使用文献数据对U进行大规模制图可以估算陆地放射性核素的含量。 ，Th和钾的含量以地质单位为准。