Rehabilitation of National Route R61 (Section 8, Majola Tea to Tombo) Between Mthatha and Port St Johns, Eastern Cape
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PALAEONTOLOGICAL HERITAGE STUDY: COMBINED DESKTOP AND FIELD-BASED ASSESSMENT Rehabilitation of National Route R61 (Section 8, Majola Tea to Tombo) between Mthatha and Port St Johns, Eastern Cape John E. Almond PhD (Cantab.) Natura Viva cc, PO Box 12410 Mill Street, Cape Town 8010, RSA [email protected] June 2013 1. SUMMARY The South African National Roads Agency SOC Limited (SANRAL) is proposing to rehabilitate Section 8 of the National Route R61 (Majola Tea km 51 to Tombo km 66) between Mthatha and Port St Johns, Eastern Cape. The proposed work would involve the rehabilitation of the existing road without having to widen the road reserve. Road material is to be sourced from two new borrow pits and one hardrock quarry. This Phase 1 palaeontological heritage assessment for the road project has been commissioned by SRK Consulting, Port Elizabeth, in accordance with the requirements of the National Heritage Resources Act (Act 25 of 1999). Section 8 of the R61 traverses dark basinal mudrocks of the Ecca Group (Karoo Supergroup) of Early to Middle Permian age that are extensively intruded by dolerites of the Early Jurassic Karoo Dolerite Suite. Bedrock exposure of the Ecca sediments, which are not assigned to a specific formation in this part of the Main Karoo Basin, is generally poor and biased towards road cuttings through more resistant-weathering impure sandstone packages as well as baked sediments adjacent to dolerite intrusions. Potentially fossiliferous mudrock successions are also well represented, however. No vertebrate, invertebrate or plant body fossils were observed within the Ecca Group sediments within the study area which appear to be at most very sparsely fossiliferous here. The only palaeontological remains recorded within the Ecca bedrocks along Section 8 of the R61 were small-scale invertebrate burrows, some of which are branching and probably referable to the common ichnogenus Chondrites. These trace fossils are common and of fairly low heritage significance, so no special conservation measures are proposed here. Late Caenozoic gravelly, silty and sandy colluvial and soil deposits observed within R61 road cuttings en route are generally of low palaeontological sensitivity and no fossil or subfossil material was recorded therein during the present field assessment. Both of the borrow pit sites (BP7, BP9) as well as the proposed new hardrock quarry and its access road are largely underlain by major Karoo dolerite intrusions (sills) and are of no palaeontological heritage significance. The dolerite in most cases is deeply weathered to yield resistant, rounded corestones embedded in friable sabunga. Adjacent sedimentary country rocks of the Ecca and Lower Beaufort Groups have been baked to quartzites and hornfels, compromising their fossil heritage potential. No fossils were observed within these thermally metamorphosed country rocks. It is concluded that the proposed rehabilitation of Section 8 of the R61 between Mthatha and Port St Johns - including the proposed new borrow pits and hardrock quarry as well as access road and 1 John E. Almond (2013) Natura Viva cc modifications to stormwater structures plus other infrastructural developments - is of LOW palaeontological heritage significance. Pending the discovery of substantial new fossils during before or during development, no further specialist palaeontological studies or mitigation in this respect are considered necessary for this road project. Should substantial fossil remains be exposed during construction, however, such as vertebrate bones and teeth, plant-rich fossil lenses or dense fossil burrow assemblages, the Environmental Control Officer should safeguard these, preferably in situ, and alert ECPHRA (i.e. The Eastern Cape Provincial Heritage Resources Authority. Contact details: Mr Sello Mokhanya, 74 Alexander Road, King Williams Town 5600; [email protected]) as soon as possible so that appropriate action (e.g. recording, sampling or collection) can be taken by a professional palaeontologist. The palaeontologist concerned with mitigation work will need a valid collection permit from SAHRA. All work should conform to international best practice for palaeontological fieldwork and the study (e.g. data recording fossil collection and curation, final report) should adhere to the minimum standards for Phase 2 palaeontological studies recently published by SAHRA (2013). These recommendations should be incorporated into the Environmental Management Plan for the road project. 2. OUTLINE OF PROPOSED DEVELOPMENT The South African National Roads Agency SOC Limited (SANRAL) is proposing to rehabilitate Section 8 of the Route R61 between Mthatha and Port St Johns, Eastern Cape, to provide a 25 year design life and to bring it up to National Roads Standards. Section 8 extends from Majola Tea in the west (km 51) to Tombo in the east (km 66) (Fig. 1). The existing road is a single carriageway and stretches along rolling mountainous terrain. It has an average surfaced width of 10.5 m and 1 m gravel shoulders on either side. The proposed work would involve the rehabilitation of the existing road (without having to widen the road reserve). Widening of the road will mainly be limited to the shoulder and six intersections. The widening of shoulders will be accomplished using gabions at shoulder breakpoint. Pavement rework will involve the stabilisation of existing in-situ base and adding a new base layer of 150 mm followed by Cape seal. Sidewalks will also be established at designated points. Damaged concrete and rusted Armco pipe culverts will be replaced either by excavation or by pipe jacking. Road material is to be sourced from two new borrow pits and one hard rock quarry (Fig. 1). The present combined desktop and field-based palaeontological heritage assessment has been commissioned by SRK Consulting (South Africa) (Pty) Ltd (Contact details: Ground Floor, Bay Suites, 1a Humewood Rd, Humerail, Port Elizabeth, 6001. P O Box 21842, Port Elizabeth, 6000. Tel: +27-(0)41-509-4800. Fax: +27-(0)41-509-4850) as part of the Basic Assessment of the proposed road development, in accordance with the requirements of the National Heritage Resources Act (Act 25 of 1999). This study will also contribute to environmental management plans for the borrow pits and hard rock quarry developments. 2 John E. Almond (2013) Natura Viva cc Pit 7 Quarry Pit 9 Fig. 1. Extract from 1: 250 000 topographical map 3128 Mthatha (Courtesy of the Chief Directorate: National Geo-spatial Information, Mowbray) showing the location of the R61 Section 8 between Majola Tea and Tombo, Eastern Cape (emphasized in orange), as well as of the proposed new hardrock quarry (blue rectangle) and two borrow pits (blue triangles). Scale bar = c. 10 km. 3 John E. Almond (2013) Natura Viva cc 2.1. Legislative context – the National Heritage Resources Act (1999) The extent of the proposed development (over 5000 m2 or linear development of over 300m) falls within the requirements for a Heritage Impact Assessment (HIA) as required by Section 38 (Heritage Resources Management) of the South African National Heritage Resources Act (Act No. 25 of 1999). The various categories of heritage resources recognised as part of the National Estate in Section 3 of the National Heritage Resources Act include, among others: geological sites of scientific or cultural importance palaeontological sites palaeontological objects and material, meteorites and rare geological specimens According to Section 35 of the National Heritage Resources Act, dealing with archaeology, palaeontology and meteorites: (1) The protection of archaeological and palaeontological sites and material and meteorites is the responsibility of a provincial heritage resources authority. (2) All archaeological objects, palaeontological material and meteorites are the property of the State. (3) Any person who discovers archaeological or palaeontological objects or material or a meteorite in the course of development or agricultural activity must immediately report the find to the responsible heritage resources authority, or to the nearest local authority offices or museum, which must immediately notify such heritage resources authority. (4) No person may, without a permit issued by the responsible heritage resources authority— (a) destroy, damage, excavate, alter, deface or otherwise disturb any archaeological or palaeontological site or any meteorite; (b) destroy, damage, excavate, remove from its original position, collect or own any archaeological or palaeontological material or object or any meteorite; (c) trade in, sell for private gain, export or attempt to export from the Republic any category of archaeological or palaeontological material or object, or any meteorite; or (d) bring onto or use at an archaeological or palaeontological site any excavation equipment or any equipment which assist in the detection or recovery of metals or archaeological and palaeontological material or objects, or use such equipment for the recovery of meteorites. (5) When the responsible heritage resources authority has reasonable cause to believe that any activity or development which will destroy, damage or alter any archaeological or palaeontological site is under way, and where no application for a permit has been submitted and no heritage resources management procedure in terms of section 38 has been followed, it may— (a) serve on the owner or occupier of the site or on the person undertaking such development an order for the development to cease immediately for such