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Farm Aar and Farm Plateau, southern Namibia
Farm Aar is a private farm, and a Namibian National Heritage Site, covering ~210 km.sq. in southern Namibia, near the town of Aus. It lies amongst low arid hills in a sparsely populated region. Farm Plateau is situated adjacent to Farm Aar.
Stratigraphy, age and palaeoenvironmental interpretation
Fossils lie within the shallow-marine sandstones of the Kliphoek Member of the Dabis Formation, Kuibis Subgroup, Nama Group (Elliott et al. 2011). No radiometric date has been obtained from the Farm itself, owing to a lack of datable volcanic ash layers, but dating of ash beds higher in the same stratigraphic sequence from Farms Swartkloofberg and Witputs, also in southern Namibia, dates the Kuibis Subgroup to >545 Ma (Grotzinger et al. 1995). Direct dating of correlative fossiliferous members assigned to the Kuibis Subgroup in the northern sub-basin of the Nama Basin (at Farm Hauchabfontein) dates them at ~549 Ma (Grotzinger et al. 1995), making the Namibian Ediacaran organisms some of the youngest known from anywhere on Earth. Namibian Ediacara-type fossils are most commonly found in shallow marine storm-sand and mass flow deposits, often preserved in three dimensions (Fedonkin et al. 2007 and references therein).
Significance of the site
Farm Plateau is very close to the site of the earliest discoveries of Ediacaran fossils in Africa (with specimens first collected in 1908 by Schneiderhöhn and Range; see Gürich 1930; Germs 1972), though fossils there are not particularly abundant today. Farm Aar is undergoing current study, and the site possesses biomineralizing taxa (e.g. Cloudina), representing some of the first macro-organisms to produce calcified skeletons in the geological record.
Recent research has focused on elucidating the detailed morphology and life habit of key Ediacaran taxa such as Rangea (Vickers-Rich et al., 2013) and Ernietta (Ivantsov et al., 2015), while also exploring the biomineralizing taxa Cloudina and Namacalathus (e.g. Wood et al., 2015), which together formed some of the first carbonate reef systems (Penny et al., 2014). Detailed redox geochemistry has also recently been undertaken in Namibia, suggesting that there may be a direct link between oxygen concentrations in the water column, and the nature of the biotic assemblage preserved on a particular bed (Fred's latest paper REF).
Small museums have been set up on both Farms, with the owners of Farm Aar also running a small tourist operation. Farm Aar is well known in archaeological circles for its Stone Age tools and rock engravings (e.g., Wendt 1977/78).
Key references
Pflug 1966, 1972; Germs 1972; Grotzinger et al. 1995; Grazhdankin and Seilacher 2002; Fedonkin et al. 2007, 2012; Cohen et al. 2009; Elliott et al. 2011.
Farm Aar is a private farm, and a Namibian National Heritage Site, covering ~210 km.sq. in southern Namibia, near the town of Aus. It lies amongst low arid hills in a sparsely populated region. Farm Plateau is situated adjacent to Farm Aar.
Stratigraphy, age and palaeoenvironmental interpretation
Fossils lie within the shallow-marine sandstones of the Kliphoek Member of the Dabis Formation, Kuibis Subgroup, Nama Group (Elliott et al. 2011). No radiometric date has been obtained from the Farm itself, owing to a lack of datable volcanic ash layers, but dating of ash beds higher in the same stratigraphic sequence from Farms Swartkloofberg and Witputs, also in southern Namibia, dates the Kuibis Subgroup to >545 Ma (Grotzinger et al. 1995). Direct dating of correlative fossiliferous members assigned to the Kuibis Subgroup in the northern sub-basin of the Nama Basin (at Farm Hauchabfontein) dates them at ~549 Ma (Grotzinger et al. 1995), making the Namibian Ediacaran organisms some of the youngest known from anywhere on Earth. Namibian Ediacara-type fossils are most commonly found in shallow marine storm-sand and mass flow deposits, often preserved in three dimensions (Fedonkin et al. 2007 and references therein).
Significance of the site
Farm Plateau is very close to the site of the earliest discoveries of Ediacaran fossils in Africa (with specimens first collected in 1908 by Schneiderhöhn and Range; see Gürich 1930; Germs 1972), though fossils there are not particularly abundant today. Farm Aar is undergoing current study, and the site possesses biomineralizing taxa (e.g. Cloudina), representing some of the first macro-organisms to produce calcified skeletons in the geological record.
Recent research has focused on elucidating the detailed morphology and life habit of key Ediacaran taxa such as Rangea (Vickers-Rich et al., 2013) and Ernietta (Ivantsov et al., 2015), while also exploring the biomineralizing taxa Cloudina and Namacalathus (e.g. Wood et al., 2015), which together formed some of the first carbonate reef systems (Penny et al., 2014). Detailed redox geochemistry has also recently been undertaken in Namibia, suggesting that there may be a direct link between oxygen concentrations in the water column, and the nature of the biotic assemblage preserved on a particular bed (Fred's latest paper REF).
Small museums have been set up on both Farms, with the owners of Farm Aar also running a small tourist operation. Farm Aar is well known in archaeological circles for its Stone Age tools and rock engravings (e.g., Wendt 1977/78).
Key references
Pflug 1966, 1972; Germs 1972; Grotzinger et al. 1995; Grazhdankin and Seilacher 2002; Fedonkin et al. 2007, 2012; Cohen et al. 2009; Elliott et al. 2011.
