The correlation between radon exposure and the increased probability of lung cancer is widely recognized. In Portugal, several efforts have been made to estimate the radon potential in granitic rocks, however, existing knowledge on sedimentary rocks is limited. For this reason, extensive representative sampling was conducted in the well-known Lower and Middle Jurassic of the Lusitanian Basin (Central Portugal) to evaluate the radon potential of latter type of rocks. This paper compares the variability of ²²⁶Ra and ²²²Rn activity, emanation coefficient, and radon production rate in several lithologies deposited on paleoenvironments ranging from distal continental to deep marine. To reach this goal, 190 samples were collected in 16 well-studied outcrop sections. ²²⁶Ra and ²²²Rn activity varies between 2.8-119.6 and 0.1–19.6 Bq/kg, respectively. Higher values are linked to sandstones, fine-grained siliciclastics, marls and black shales. The emanation coefficient is lower in lithologies presenting a low siliciclastic/carbonate ratio, namely in dolostones, dolomitic limestones, limestones and marly limestones, with median values ranging between 6.5 and 9.7%. The distribution of radon production rate in the different lithological groups varies between 1.7 and 241.1 Bq.m⁻³.h⁻¹, increasing in samples of continental source (sandstones and fine-grained siliciclastics) and proximal marine with major continental influence (dolostones), as well as from marls and black shales associated to deeper marine environments.

The variability of the radon potential in sedimentary rocks varies according to lithology but, since the typical organization of these rocks in layers, the dip of these ones in each structural block also contribute to increase the variability.

ra暴露与肺癌发生率增加之间的相关性已得到广泛认可。在葡萄牙，已经做出了一些努力来估计花岗石中the的潜力，但是，有关沉积岩的现有知识有限。因此，在著名的卢西塔尼亚盆地（中葡萄牙）的中侏罗统进行了广泛的代表性采样，以评估后一种岩石的the势。本文比较了沉积在从远陆到深海的古环境中的几种岩性中²²⁶ Ra和²²² Rn活度，发散系数和ra产生率的变异性。为了实现这一目标，在16个经过充分研究的露头部分中收集了190个样品。²²⁶Ra和²²² Rn活性分别在2.8-119.6和0.1-19.6 Bq / kg之间变化。较高的价值与砂岩，细粒硅质碎屑岩，泥灰岩和黑色页岩有关。在具有低硅质碎屑/碳酸盐比的岩性中，即在白云岩，白云质石灰岩，石灰岩和马里石灰岩中，发散系数较低，中值介于6.5和9.7％之间。在不同岩性组中的分布速率在1.7至241.1 Bq.m ^-3 .h ^-1之间变化，在陆源（砂岩和细粒硅质碎屑岩）和近海受主要大陆影响的样品（白云岩）中增加以及来自深海环境的泥灰岩和黑色页岩。

沉积岩中the势的变化随岩性而变化，但是由于这些岩石的典型组织是分层的，因此这些岩石在每个结构块中的倾角也有助于增加变化性。