Sprecher
Beschreibung
A vast peatland in the northwestern interior at a tributary of the Mooi River, Gerhardminnebronn Stream, in a Precambrian karstic landscape, reveals Holocene environmental change in a palaeoecologically underexplored region of South Africa. A core from a sinkhole within Mooi River Ecosystem for Scientific Trials and Investigations (METSI) was analysed for pollen, sedimentology, and geochemistry. Radiocarbon dates confirmed continuous sedimentation since the beginning of the Holocene. Sedimentology of core METSI is predominantly upward-fining clays, indicating higher basal depositional energy. Geochemistry (Si, Ca, Mg, Al) reflects regional Transvaal Supergroup geology including dolostones.
The Early Holocene (235–163 cm) shows minimal disturbance, transitioning from drier to wetter conditions (decreasing Asteraceae, increasing Phragmites-type and Typha pollen). Between 163–139 cm, open-land taxa such as Artemisia and Amaranthaceae increase. The Mid-Holocene (139–80 cm) shows moist conditions with wetland elements. From 80–18 cm, a sub-humid climate and increasing disturbances are evidenced by Glomus, Amaranthaceae, Pinus, and Myrtaceae (Eucalyptus) pollen—the latter exotic trees suggesting European settler introduction. The top shows increasing anthropogenic activity with Ambrosia, Pinus, Myrtaceae, Cerealia-type.
The METSI record correlates biostratigraphically with nearby core GMB, dated to 9,290±30 BP (150 cm) and 8,980±30 BP (116 cm). Due to its proximity to Gerhardminnebronn Stream, riverine exotics such as poplars (Populus sp.), maize (Zea mays) and oaks (Quercus sp.) are strongly represented. Results from both cores show environmental fluctuations and progressive anthropogenic disturbance from Early Holocene (San hunter-gatherers) through Late Holocene (early Iron Age farming communities, European settlers).