1 PALAEONTOLOGICAL HERITAGE: COMBINED DESKTOP & FIELD-BASED BASIC ASSESSMENT Grid connection for the proposed Impofu North, Impofu West & Impofu East Wind Farms near Humansdorp, Eastern Cape John E. Almond PhD (Cantab.) Natura Viva cc, PO Box 12410 Mill Street, Cape Town 8010, RSA
[email protected] August 2019 EXECUTIVE SUMMARY The present report provides a palaeontological heritage Basic Assessment of the proposed Impofu grid connection. This includes (a) the approximately 120 km-long, 2 km-wide 132 kV grid connection corridor between the proposed Impofu North, Impofu West and Impofu East Wind Farms and the national grid in the Nelson Mandela Bay Municipality (NMBM) near Port Elizabeth, Eastern Cape. Potential impacts of the proposed new Impofu collector switching station, wind farm switching stations and short 132 kV transmission lines linking them to the collector switching station as well as of substation extension areas are also considered. The report is based on a combined desktop and field-based study of the preferred grid connection corridor, incorporating a 2 km wide zone, with a special focus on areas underlain by potentially fossiliferous bedrocks. The grid connection study area is underlain by several formations of potentially fossiliferous sediments of the Gamtoos Group, Cape Supergroup, Uitenhage Group and Algoa Group (Sections 6 & 7, Table 1). However, on the southern coastal platform most of the fossils originally preserved in these bedrocks appear to have been destroyed by tectonic deformation and deep chemical weathering. The overlying Late Caenozoic superficial sediments such as alluvium, soils and ferricretes, are likewise of low palaeontological sensitivity. Relict patches of Plio-Pleistocene aeolianites (wind-blown sands) of the Nanaga Formation (Algoa Group) present in the subsurface on the interior coastal platform contain Early Stone Age artefacts but any associated fossils such as mammalian remains, or terrestrial gastropods have probably been destroyed by weathering here.