U-Th dating, taphonomy, and taxonomy of shell middens at Klasies River main site indicate stable and systematic coastal exploitation by MIS 5c-d

Abstract

The archaeological record, particularly of shellfish, from the Klasies River main site (KRM) is important in understanding the fluctuating nature of coastal occupational patterns and changing coastal ecologies. In this paper, we provide new uranium–thorium (U-Th) dates for one of the earlier phases of coastal exploitation at KRM, and the microstratigraphic analyses generate novel information about the taphonomy of shell-bearing deposits from the Later Stone Age (LSA) to the MSA I period that, in turn, provide a broader context for middening at the site. A wide range of syndepositional taphonomic processes related to human activities and post-depositional effects include burning, fragmentation and compaction, chemical alteration, and cementation. Despite such issues influencing recovery, shellfish data are informative and are presented from three layers of the Witness Baulk: Shell Midden One (SMONE), Black Occupational Soils (BOS), and Silty Black Soils (SBLS). These coarse shell midden deposits exhibit visible decalcification coupled with cementation with secondary carbonate formation in association with conditions of high moisture and soft sedimentation deformation of the underlying sediments of SBLS. This stratigraphy section is chronologically anchored for the first time using U-Th dating of speleothems associated with a hiatus after the deposition of BOS. The three ages, 110,060 ± 1,100, 109,800 ± 970, and 106,000 ± 2,100 years, place the BOS layer as the base of the SASL sub-member at over 110 ka, making the underlying middens from the LBS member even older. The zooarchaeological analyses of the three layers indicate coastal ecological changes from more sheltered conditions prior to the hiatus, with the exploitation of alikreukel and brown mussels predominating. Before 110 ka, in BOS and SBLS, more exposed coastal conditions occurred, and the diversity of exploited shellfish increased. SMONE and BOS are associated with MSA II/Mossel Bay lower lithic technology and SBLS with MSA I technology, indicating asynchronous coastal ecological and technological changes. The MIS 5c-d evidence for early coastal occupation at KRM provides details on the period during which coastal occupation became stable and systematic on the South African coast and puts the KRM amongst the handful of sites with shell-bearing deposits, occurring prior to 110 ka in South Africa.

Human occupational intensity and palaeoecology at Klasies River from MIS 5–3: Preliminary taphonomic analyses of faunal remains from the Deacon and Wurz excavations

“…More recent data from Brenner et al (2022) show that, while Perna perna still dominate (%MNI= 39), alikreukel (Turbo sarmaticus) become almost equally common in the MSA II Lower (%MNI=29). Wurz et al (2022) also indicate that opercula and the sizes of alikreukel are noticeably smaller in the MSA II Lower layers. Taken together, this could suggests a change in coastal ecology or foraging strategies in this phase.…”

“…This could mean that large carnivores were using the site as a den at this time; however, acid-etched bone is not common in this phase (Table 7). Micro-morphological analyses also show that occupational hiatuses occurred in this phase (Wurz et al, 2022), which may be apparent as periods of carnivore activity. It is likely then that, during these hiatuses in the MSA II, carnivores may have ravaged the remains of large herbivores.…”

“…Although slightly cooler than the MSA I, SSTs may not have varied significantly throughout MSA II (Loftus et al, 2017). Using Thackeray's (1988) data, Loftus et al (2017 argue that the relative stability of SST during MIS 5 at KRM suggests that these layers were generally deposited during interstadial periods (but see Brenner et al, 2022;Wurz et al, 2022). This may be associated with a short-lived sea-level stillstand at c.108 ka that is possibly linked to extensive dune deposition at c. 110 ka (Cawthra et al, 2018).…”

“…High shellfish densities and the occurrence of fish and bird remains also suggest an expanded diet breadth for Klasies people then (Von den Driesch, 2004;Van Niekerk, 2011;Reynard et al, in prep.). Wurz et al (2022) reports smaller sizes of Turbo sarmaticus opercula from the MSA II Lower layers which is often used as evidence for more intensive shellfish harvesting as large species become more depleted (Steele and Klein, 2009). Furthermore, micro-morphological data show intensive shell middening in the MSA II (Wurz, et al, 2022) indicating more intensified site-use activities at this time.…”

“…Wurz et al (2022) reports smaller sizes of Turbo sarmaticus opercula from the MSA II Lower layers which is often used as evidence for more intensive shellfish harvesting as large species become more depleted (Steele and Klein, 2009). Furthermore, micro-morphological data show intensive shell middening in the MSA II (Wurz, et al, 2022) indicating more intensified site-use activities at this time. Overall, the taphonomic and faunal data show more evidence of intensified resource extraction in the MSA II Lower than in other layers.…”