Subsurface research often makes use of information from locations where subsurface investigations occurred or that had temporary outcrops. In time, data and knowledge of these locations increases, though compilation of the former information, and uniquely identifying these in subsequent publications is seldom done. Data quality control and documentation are therefore required, including tracing the data sources to their unique reference in governmental databases. In this paper, a five-step approach is described on how all relevant data can be uniquely combined into a reference dataset for the Neogene of Flanders. The dataset is made available in the online web portal for soil and subsoil in Flanders. The individual data points, as well as the reference dataset, can be consulted and are re-usable in an accessible format by scientists, professionals and citizens with an interest in the subsurface, and even so by machines. The reference dataset approach can be elaborated for other subsurface data collections and is proposed to evolve to a standard practice for open subsurface data in Flanders. It increases the visibility and the quality of the data and the research. Inclusion of a reference dataset URL in research or other portals further contributes to data and knowledge integration. Such an open data approach is pivotal for (governmental) data management institutes providing geological services that facilitate a more sustainable use and management of the subsurface.

Table 2, Table 3 and Table 4 as the resulting dataset from 'De Nil, K., De Ceukelaire, M. & Van Damme, M., 2020. A reference dataset for the Neogene lithostratigraphy in Flanders, Belgium. Geologica Belgica, 23/3-4. https://doi.org/10.20341/gb.2020.021' Table 2. The general and different (sub)reference datasets resulting from the individual Neogene 2020 papers, with their DOV URL. Table 3. List of the individual boreholes and (temporary) outcrops of the Neogene reference set, with reference to the different individual papers of this collection, sorted by location as mentioned in the papers. *Complete ‘https://www.dov.vlaanderen.be/data/boring/’ with this unique code. **Complete http://collections.naturalsciences.be/ssh-geology-archives/arch/ with this unique code. Table 4. List of the individual CPT’s with reference to the different individual papers of this collection, sorted by DOV name.