Clarifying the Context, Dating and Age Range of the Gondolin Hominins and Paranthropus in South Africa

Clarifying the Context, Dating and Age Range of the Gondolin Hominins and Paranthropus in South Africa

Journal of Human Evolution 65 (2013) 676e681 Contents lists available at ScienceDirect Journal of Human Evolution journal homepage: www.elsevier.com/locate/jhevol News and views Clarifying the context, dating and age range of the Gondolin hominins and Paranthropus in South Africa Andy I.R. Herries a,*, Justin W. Adams b a Australian Archaeomagnetism Laboratory, Department of Archaeology, Environment and Community Planning, Faculty of Humanities and Social Sciences, La Trobe University, Melbourne Campus, Bundoora, VIC 3086, Australia b Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Melbourne, VIC 3800, Australia article info Article history: caves and studies that show their accurate cross correlation (Lacruz Received 1 March 2013 et al., 2002; Herries et al., 2010, 2013), it is no longer necessary to Accepted 7 June 2013 rely on faunal estimations for the age of these deposits based on Available online 1 August 2013 correlations with the other end of the African continent, and with little data existing in between. Moreover, recent geochronological Keywords: studies on the South African caves have shown that many dates Geochronology Sterkfontein based on biochronological analysis with sites in East Africa are up to Palaeokarst half a million years too old (Herries et al., 2010; Herries and Shaw, Swartkrans 2011). This discordance may relate to South Africa functioning as Electron Spin Resonance both a continuous population refuge and geographic origin for several Pleistocene and extant lineages (see summary in Lorenzen et al., 2012; also Pickford, 2004). This expanding dataset on the complex, dynamic biogeography of African mammals precludes the assumption that the South and East African sites, separated by 3000e4000 km, had homologous first/last appearance dates of species/lineages. It also highlights the importance of using the Introduction current chronometric dating framework of South African localities to establish revised, ‘local’ biochronological data, particularly given In a recent article, Grine et al. (2012) provided a thorough the recycling in the literature of early biochronological dates that, themselves, were based in part on South African site dates that have analysis of the GD A-2 Paranthropus robustus M2, one of the two hominin specimens recovered from the Gondolin palaeocave in the been revised in recent years. Here we review the dated record of e< northeastern corner of the UNESCO Cradle of Humankind World Paranthropus in South Africa (2.0 1.0 Ma; Table 1), including that ew Heritage Site (‘Cradle’), South Africa (Menter et al., 1999). Although of Gondolin (1.95 1.78 Ma; Table 1) and review chronometric we appreciate the detailed approach of their research on the ages that Grine et al. (2012) dismiss as unreliable, so that such er- hominin specimen, we wish to clarify several incorrect citations of rors are not left to propagate their way through the published our work at the Gondolin site, including the probable origin of the literature. hominin specimens and age of the deposits. Moreover, Grine et al. (2012) suggest that Paranthropus occurs in South Africa between 1.9 Recovery and depositional context of the Gondolin hominins and 1.5 million years ago (Ma), an age range that does not reflect the ages produced by a number of dating studies on Paranthropus- As is the case at most South African palaeocaves, the Gondolin bearing sites and continues to argue for the reliability of bio- site was mined for lime deposits during the early twentieth cen- chronology based on correlations with East Africa over existing tury. The mining activity at Gondolin was particularly extensive and chronometric ages that exist for the sites. With recent advances in a obliterated the central portions of the cave system, leaving only number of dating methods that are applicable to the South African extensive ex situ dumpsites and partial in situ remnants of the original karstic deposits along the margins of the open cast mine (Menter et al., 1999; Herries et al., 2006a,b; Adams et al., 2007). One * Corresponding author. E-mail addresses: [email protected], [email protected] of these in situ remnant deposits, designated GD 2, preserves a (A.I.R. Herries). dense accumulation of fossils in a red siltstone matrix (Watson, 0047-2484/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jhevol.2013.06.007 A.I.R. Herries, J.W. Adams / Journal of Human Evolution 65 (2013) 676e681 677 Table 1 Age range for Paranthropus sites in South Africa. Site Unit Age Method Reference Swartkrans Member 1 Hanging Remnant 2.0e1.8 Ma UePb, ESR Pickering et al. (2011), Curnoe et al. (2001): this paper. Swartkrans Member 1 Lower Bank Sometime between 2.3 and 1.6 Ma UePb Pickering et al. (2011), (likely contemporary with Hanging Remnant) Gondolin GD 1 w1.78 Ma Palaeomag. Fauna Herries et al. (2006a,b), Adams et al. (2007) Gondolin GD 2 1.95e1.78 Ma (w1.8 Ma) Palaeomag. Fauna Herries et al. (2006a,b), Adams et al. (2007) Gondolin GD A 1.95ew1.78 Ma Correlation/fauna Herries et al. (2006a,b), Adams et al. (2007) Kromdraai B Member 3 1.8e1.6 Ma Palaeomag. Fauna Thackeray et al. (2002), Herries et al. (2009) Sterkfontein Member 5b 1.4e1.1 Ma Palaeomag. UePb, ESR Curnoe (1999), Pickering and Kramers (2010), Herries and Shaw (2011) Swartkrans Member 2 1.7e1.1 Ma UePb Balter et al. (2008) Cooper’s D Upper Facies A and C <1.4 Ma UePb de Ruiter et al. (2009) Cooper’s D Lower Facies A and C 1.6e1.4 Ma UePb de Ruiter et al. (2009) Drimolen All 2.0e<1.4 Ma Faunal estimate Keyser et al., 2000. This paper. Swartkrans Member 3 1.3e0.6 Ma UePb, ESR Blackwell (1994), Balter et al. (2008) 1993; Menter et al., 1999). The GD 2 deposits were excavated in the equating the in situ GD 1 deposits with the ex situ GD A dumpsite, late 1970s and yielded a rich faunal assemblage that was later only Grine et al. (2012) establishes GD 1 as the sole in situ source de- partially described (Watson, 1993). Subsequent analysis of the posits for the ex situ Gondolin hominins, GD A blocks and processed entire GD 2 assemblage (Adams and Conroy, 2005; Adams, 2006, fossils; a position that has not been advocated in any prior publi- 2010) failed to identify any primate remains among the 95,549 cations on the Gondolin hominins or fossil deposits (e.g., Menter specimens recovered from the GD 2 sample. The only other in situ et al., 1999; Adams and Conroy, 2005; Herries et al., 2006a,b; fossil-bearing deposits thus far identified at Gondolin, designated Adams, 2006, 2010; Adams et al., 2007). In sum, we wish to rein- GD 1, occur along the western rim of the excavated cave system and force that: 1) the Dumpsite A ex situ calcified sediments have never consist of a complex mix of grey breccia, conglomerates and other been described as being either largely or exclusively derived from finer-grained clastic sediments that have become partially decal- deposits near the GD 1 datum point; 2) only the grey ‘Conglomerate cified through erosional dissolution (Adams et al., 2007). Excava- Unit’ ex situ blocks from Trench A are similar to those in the GD 1 in tion of these deposits and analysis of the 4843 specimens recovered situ deposits; 3) both of the ex situ Gondolin hominin teeth were fossil assemblage also failed to identify any primate specimens and processed from ‘Finer Clastic Unit’ blocks that have a red siltstone the hominin remains are an oddity in this respect (Adams, 2006). matrix dissimilar to that of the GD 1 deposits (but resembling that At present, the only primate (including hominin) bearing de- near the northern [GD 2] and southern [GD 3] datum points); and posit at Gondolin is ‘Dumpsite A’, a massive ex situ pile of calcified 4) neither of the Gondolin hominin specimens have been defini- sediments near the southwestern edge of the mined cave system tively associated with excavated in situ deposits at the site (GD 1, (Menter et al., 1999; Adams, 2006). Excavation in 1997 into the top GD 2). of the dumpsite through two adjacent 1 m2 units to a depth of approximately 2 m (Trench A) yielded both the GD A-2 P. robustus M2, as well as a partial, indeterminate hominin lower molar (GD A- Dating of the Gondolin site deposits 1) (Menter et al., 1999). In their description of the recovery of the two hominin specimens, Menter et al. (1999) noted the occurrence It has seemingly become the opinion that the South African of at least two types of calcified sediment blocks within Dump A: a palaeocave sites are too complex to understand and thus date grey, clastic ‘breccia’ (Conglomerate Unit sensu Menter et al., 1999) accurately. This is a view perpetuated by studies of, and arguments and a fine, red siltstone with sporadic clasts (Finer Clastic Unit over, the dating and geology of complex multi-generational sites sensu Menter et al., 1999). Both hominin teeth were recovered from where multiple phases of karstification, infilling and erosion occur, small blocks attributed to this Finer Clastic Unit and no attempt was such as Sterkfontein (Partridge, 2000; Clarke, 2007; Pickering and made to specifically associate the ex situ blocks with the limited GD Kramers, 2010). Moreover, mis-citation and continued misrepre- 1 or GD 2 in situ remnants (Menter et al., 1999). Given the distur- sentation of dating methods in papers that are not fundamentally bance of the original palaeocave system through mining and about dating, as is the case in Grine et al.

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