The Observatories Nabaos and the Gellap Ost Research Station cover plains and washes with shale outcrops of the Karoo Sequence (Ecca Group, Prince Albert Formation). The soil parent materials are shale (partly shattered and with thin calcareous layers) and colluvial materials (sand to loam). The main soil units are Leptosols, Cambisols and Regosols. The rocky outcrops and slopes are dominated by shallow Leptosols and epileptic Regosols whereas the plains and washes are characterized by weakly developed Regosols. Partly stronger developed Cambisols occur on parts with a loamy parent material (Paleosoils). The soils are characterised by slightly acidic to neutral pH values and a relatively low electrical conductivity of < 0.2 mS cm-1.

Box-Whisker-overview of selected soil properties in three depths (cm) on the observatory
(RS = rooting space / m³)

Map with location of soil units
on the observatory