PALAEONTOLOGICAL SPECIALIST STUDY: DESKTOP ASSESSMENT Expansion of River Bend Citrus Farm near Addo, Sundays River Valley Municipality, Eastern Cape John E. Almond PhD (Cantab.) Natura Viva cc, PO Box 12410 Mill Street, Cape Town 8010, RSA [email protected] August 2012 1. SUMMARY The study area on the River Bend Citrus Farm (Remainder of Farm 82 Wolve Kop, Portion 1 of Farm 77 Wellshaven and Portion 3 of Farm 77 Honeyvale) some 10 km north of Addo, Sundays River Valley Municipality, is largely underlain by non-marine, fluvial to estuarine sediments of Early Cretaceous age that are assigned to the Kirkwood Formation (Uitenhage Group). This succession has yielded important fossil biotas of Mesozoic land plants (ferns, cycads, conifers etc) and non- marine molluscs as well as sparse but numerous specimens of fossil bones, including large and small dinosaurs, from several localities along the northern margin of the Algoa Basin. There is also evidence for occasional marine incursions here in Early Cretaceous times from fossil marine molluscs. However, the Kirkwood Formation bedrocks are mantled by alluvial sediments of the Coerney River in the southern part of the study area. Elsewhere they appear to lie beneath a thick (2m or more) superficial cover of soils, alluvium and colluvium of low palaeontological sensitivity. The proposed extension of the cultivated area on the River Bend Citrus Farm is therefore not considered significant in terms of palaeontological heritage conservation. It is concluded that no further palaeontological heritage studies or specialist mitigation are required for this agricultural project, pending the discovery or exposure of any substantial fossil remains (e.g. vertebrate bones and teeth, large blocks of petrified wood, fossil plant-rich horizons, buried laminated shales) during the construction phase. The ECO responsible for these developments should be alerted to the possibility of important fossil remains being found either on the surface or exposed by fresh excavations during construction. Should fossil remains be discovered during construction, these should be safeguarded (preferably in situ) and the ECO should alert the Eastern Cape Provincial Heritage Resources Authority (ECPHRA. Contact details: Mr Sello Mokhanya, 74 Alexander Road, King Williams Town 5600; Email: [email protected]) so that appropriate mitigation (e.g. recording, sampling or collection) can be taken by a professional palaeontologist. The specialist involved would require a collection permit from SAHRA (Contact details: Mrs Colette Scheermeyer, P.O. Box 4637, Cape Town 8000; Tel: 021 462 4502; Email: [email protected]). Fossil material must be curated in an approved repository (e.g. museum or university collection) and all fieldwork and reports should meet the minimum standards for palaeontological impact studies developed by SAHRA. John E. Almond (2012) 1 Natura Viva cc 2. INTRODUCTION & BRIEF The company San Miguel Fruits SA (Pty) Ltd is proposing to expand by 300 or more hectares the area under cultivation on the River Bend Citrus Farm situated near Addo, Sundays River Valley Municipality, Eastern Cape. Three properties that form part of the existing farm are involved, approximately 1058 hectares in combined extent : Remainder of Farm 82 Wolve Kop, Portion 1 of Farm 77 Wellshaven and Portion 3 of Farm 77 Honeyvale (Fig. 1). The study area, located on the western side of the R335 tar road between Addo and Suurberg, c. 10 km north of Addo and 22 km ESE of Kirkwood, lies on gently sloping ground either side of the Coerney River (a tributary of the Sundays River) at elevations of around 90 to 150m amsl and just south of the Suurberge Range. The Addo Elephant National Park lies just to the east (AENP in Fig. 1). The proposed agricultural expansion will include the following components: clearing of indigenous vegetation; landscaping and levelling the site for citrus orchards; installation of water reticulation and irrigation infrastructure; construction of a balancing dam; establishment of unpaved access roads; establishment of windbreaks. The size and configuration of the area to be cleared will be determined in consultation with project specialists during the environmental impact assessment process. The company Public Process Consultants (Contact details: Sandy Wren, Public Process Consultants, PO Box 27688, Greenacres, 6057; Phone 041 - 374 8426; Fax 041 - 373 2002; Cell 082 4909 828; Email [email protected]) has been appointed by San Miguel Fruits SA (Pty) Ltd as the independent Environmental Assessment Practitioner (EAP) to undertake the Scoping and Environmental Impact Assessment for the project. In accordance with the National Heritage Resources Act, 1999, a palaeontological heritage assessment is required as part of a Heritage Impact Assessment for this project since important fossil material (e.g. Cretaceous dinosaurs) has previously been recorded from the Kirkwood – Addo area of the Eastern Cape study area. The various categories of heritage resources recognised as part of the National Estate in Section 3 of the Heritage Resources Act include, among others: geological sites of scientific or cultural importance; palaeontological sites; palaeontological objects and material, meteorites and rare geological specimens. In view of the very limited exposure of Creatceous bedrocks within the study area, a preliminary desktop assessment of the fossil heritage resources in the study region was commissioned by Public Process Consultants. John E. Almond (2012) 2 Natura Viva cc Fig. 1. Location of the study site (orange areas) on the River Bend Citrus Farm located c. 10 km north of Addo, Sundays River Valley Municipality, Eastern Cape (Image abstracted from Basic Information Document prepared by Public Process Consultants, Greenacres, February 2011). 2.1. Approach used for this specialist palaeontological study This palaeontological report provides an assessment of the recorded or inferred palaeontological heritage within the study area near Addo, with recommendations for specialist palaeontological mitigation where this is considered necessary. The report is based on (1) a review of the relevant scientific literature, including previous palaeontological impact assessments for the Eastern Cape region (e.g. Almond 2010), and (2) published geological maps and accompanying sheet explanations. In preparing a palaeontological desktop study the potentially fossiliferous rock units (groups, formations etc) represented within the study area are determined from geological maps. The known fossil heritage within each rock unit is inventoried from the published scientific literature, previous palaeontological impact studies in the same region, and the author’s field experience (Consultation with professional colleagues as well as examination of institutional fossil collections may play a role here, or later following scoping during the compilation of the final report). This data is then used to assess the palaeontological sensitivity of each rock unit to development (Provisional tabulations of palaeontological sensitivity of all formations in the Western, Eastern and Northern Cape have already been compiled by J. Almond and colleagues; e.g. Almond et al. 2008). The likely impact of the proposed development on local fossil heritage is then determined on the basis of (1) the palaeontological sensitivity of the rock units concerned and (2) the nature and scale of the development itself, most notably the extent of fresh bedrock excavation envisaged. When rock units of moderate to high palaeontological sensitivity are present within the John E. Almond (2012) 3 Natura Viva cc development footprint, a field-based assessment by a professional palaeontologist is usually warranted. On the basis of the desktop and any recommended follow-up field assessment studies, the likely impact of the proposed development on local fossil heritage and any need for specialist mitigation are then determined. Adverse palaeontological impacts normally occur during the construction rather than the operational or decommissioning phase. Mitigation by a professional palaeontologist – normally involving the recording and sampling of fossil material and associated geological information (e.g. sedimentological data) – is usually most effective during the construction phase when fresh fossiliferous bedrock has been exposed by excavations, although pre-construction recording of surface-exposed material may sometimes be more appropriate. To carry out mitigation, the palaeontologist involved will need to apply for a palaeontological collection permit from the relevant heritage management authority (i.e. SAHRA, Cape Town). It should be emphasized that, providing appropriate mitigation is carried out, the majority of developments involving bedrock excavation can make a positive contribution to our understanding of local palaeontological heritage. 2.2. Assumptions & limitations The accuracy and reliability of palaeontological specialist studies as components of heritage impact assessments are generally limited by the following constraints: 1. Inadequate database for fossil heritage for much of the RSA, given the large size of the country and the small number of professional palaeontologists carrying out fieldwork here. Most development study areas have never been surveyed by a palaeontologist. 2. Variable accuracy of geological maps which underpin these desktop studies. For large areas of terrain these maps are largely based on aerial photographs