A late Quaternary vertebrate deposit in Kudjal Yolgah Cave, south‐western Australia: refining regional late Pleistocene extinctions

Abstract

We describe the stratigraphy and chronology of Kudjal Yolgah Cave in south‐western Australia, a late Quaternary deposit pre‐ and post‐dating regional human arrival and preserving fossils of extinct and extant fauna. Single‐grain optically stimulated luminescence (OSL) dating shows that seven superposed units were deposited over the past 80 ka. Remains of 16 mammal species have been found at the site, all of them represented in Unit 7, for which seven OSL ages indicate accumulation between 80 and 41 ka. Single‐grain OSL equivalent dose distribution patterns show no evidence of reworking of older or younger sediments into Unit 7, but late Holocene charcoal has been washed into the top of it from adjacent Unit 2, deposited 1.2 ka ago. Six species that failed to survive the Pleistocene are recorded in Unit 7, but only the south‐western wombat Vombatus hacketti is recorded in younger units. Two species, the large extinct kangaroos Protemnodon sp. cf. P. roechus and Procoptodon browneorum, are represented by articulated specimens near the top of Unit 7, immediately adjacent to an OSL sediment sample dated to 41 ± 2 ka. These are the youngest reliably dated records of these genera from mainland Australia, and among the youngest megafaunal remains from the continent. All species currently known from the middle Pleistocene of the south‐west persisted into the late Pleistocene, which removes a key pillar supporting the argument against a driving role for human impacts in the extinctions.

Last Interglacial Iberian Neandertals as fisher-hunter-gatherers

“…The majority of accepted grains display rapidly decaying OSL curves (reaching background levels within 0.5 s), which are characteristic of quartz signals dominated by the most readily bleached (so-called 'fast') OSL component (compare with the OSL decay curve shape for a fast-dominated Risø calibration quartz grain; Hansen et al) (80). The single-grain OSL dose-response curves are generally well-represented by either a single saturating exponential function or a saturating exponential plus linear function, as has been widely reported for quartz grains with fast-dominated OSL signals (e.g., ( (117)(118)(119)(125)(126)(127), which can be common in cave environments (e.g., (128)(129)(130). Postdepositional mixing or bioturbation is not thought to have contributed significantly to the heterogeneous De datasets observed in Area C and the SEx trench given the preservation of clear stratigraphic layering at these sample localities.…”

Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration

“…5). Five species of macropodine, including a species each of Macropus, Notamacropus, Osphranter and Protemnodon, as well as a species of small-sized sthenurine, define a kangaroo fauna that bears little resemblance to the 'typical' Upper Pleistocene sthenurine-dominated kangaroo faunas of southern Australia 6,30 . Also, macropodines that are commonly documented from Pleistocene open sites in the bordering MDB catchment to the south of the FRB; such as Macropus giganteus titan, Macropus ferragus, Notamacropus agilis siva and Protemnodon anak 31 , are notably absent from the SWC macropodid fauna.…”

“…Megafauna fossils from Tasmania were directly dated using radiocarbon 103 and were A*-rated 11 . Sediment containing megafauna fossils from southwest Western Australia were dated using associated speleothem (U-series) and sediments (OSL) and were A-rated 30,104 . Egg shell from the LEB has been dated using radiocarbon, OSL and amino acid racemisation, including remains previously identified as the extinct giant flightless bird Genyornis and the extant Emu Dromaius 105 .…”

Climate‐driven ecological stability as a globally shared cause of Late Quaternary megafaunal extinctions: the Plaids and Stripes Hypothesis

“…Even at lower latitudes in the western USA where people were more abundant than in the Arctic, archaeological evidence connecting megafaunal extinctions to hunting remains problematic (Grayson, ; Grayson & Meltzer, ; Meltzer, ). Archaeological evidence for overkill by humans is similarly ambiguous in Australia (Wroe et al, ; Jankowski et al, ). That said, it is unclear what convincing archaeological evidence for human overkill of megafauna would actually look like (Grayson, ), and whether archaeology is even capable of providing evidence for less direct, but nonetheless lethal impacts of humans (Burney et al, ): impacts like changes to fire regimes and disruption of food webs.…”