The geochemical classification of soils is crucial for the scientific development and utilization of land, particularly in the investigation of selenium-rich soils, which plays a guiding role in the cultivation layout of local selenium-rich agricultural products. This study involves the collection and analysis of over 6000 samples of soil, water quality, and crops from the entire area of Licheng District in Jinan City, Shandong Province. By analyzing the data in conjunction with the geochemical classification standards for soil nutrient levels, soil environmental geochemical levels, and comprehensive soil quality geochemical levels, we delineated a distribution area of selenium-rich soils covering 192.26 km² in Licheng District, providing a bibliographic basis for the scientific planning of agriculture and forestry in the region.

The Early Cretaceous intermediate intrusive rocks have important significance in understanding the crust–mantle interaction, iron mineralization, and tectonic evolution in the western Shandong Peninsula. In this study, we present new zircon U–Pb ages, and Hf isotope, whole-rock geochemistry, Sr–Nd isotopes, and the mineral chemistry of the diorite-porphyrite in the southern Xintai area, mid-western Shandong Peninsula. The diorite-porphyrite formed at ca. 125 Ma. They have intermediate SiO₂ (59.57–62.29 wt.%) and MgO (2.78–3.58 wt.%) contents, high Mg# values (53–56), high Sr (589–939 ppm) and low Y (9.2–10.8 ppm) contents, and high Sr/Y ratios (54–94), showing adakitic affinity. The diorite-porphyrite exhibits lower zircon ε_Hf(t) values (−30.1 to 7.5) and whole-rock ε_Nd(t) values (−3.5 to −6.0), with (⁸⁷Sr/⁸⁶Sr)_i ratios of 0.70514–0.70567. We suggest that the diorite-porphyrite was derived from the partial melting of the local delamination of lower continental crust and then by the interaction with the enriched lithospheric mantle. The genesis of diorite-porphyrite may be related to the rollback process of the Paleo-Pacific slab in the Early Cretaceous. This geodynamic process induced the melting of the enriched lithospheric mantle, subducted oceanic crust, and local delamination of lower continental crust, which produced different types of adakitic magmatism in the western Shandong Peninsula.