HCOV_0400, Oligocene Aquifer system thickness

Flanders is composed of an alternation of aquifers (sand, gravel, chalk, rock, etc.) and regionally occurring non-aquifers (e.g. clay). The sequence of these aquifers and aquitards has its own coding in Flanders: hydrogeological Coding of the Subsoil of Flanders (HCOV coding). The HCOV coding is composed of main hydrogeological units, sub-units and basic units. The main unit brings together a sequence of geological layers which have broadly the same hydrogeological characteristics and thus form a whole. HCOV_0400 (Oligocene Aquifer system) comprises the complete aquifer system between the final layers of the Boomse clay (Formation of Boom) and the Bartoon clai (Maldegem Formation). This is a sequence of aquifers, whether or not in contact with each other, separated by non-continuous clay layers of limited size. This main unit consists, inter alia, of the layers belonging to the Formations of Bilzen, Borgloon, Saint Huibrechts-Hern and Zelzate. The dataset ‘HCOV_0400, Oligocene Aquifer system thickness’ represents the thickness of this hydrogeological layer in a grid per grid cell.佛兰德斯地区由交替产出的含水层（aquifer，包括砂、砾石、白垩、岩石等介质）与区域性分布的非含水层（non-aquifer，例如黏土）构成。上述含水层与弱透水层（aquitard）的序列在佛兰德斯地区拥有专属编码体系：佛兰德斯地下水文地质编码（Hydrogeological Coding of the Subsoil of Flanders，简称HCOV编码）。该编码体系由主要水文地质单元、次级单元与基本单元三级组成。其中，主要水文地质单元汇集了一系列水文地质特征大体一致的地质层位，共同构成一个完整的水文地质整体。HCOV_0400（渐新世含水层系统）涵盖了博姆斯黏土（博姆组）最顶层与巴通黏土（马尔德赫姆组）之间的完整含水层系统。该系统由一系列彼此接触或相互分离的含水层构成，各含水层被规模有限的断续黏土层分隔开来。该主要水文地质单元除包含上述层位外，还涵盖比尔曾组、博尔洛恩组、圣伊韦尔茨-埃南组以及泽尔扎特组所属的地层。数据集"HCOV_0400, 渐新世含水层系统厚度"表征了该水文地质层在每个网格单元中的厚度。