The Moyjil site, south-west Victoria, Australia: fire and environment in a 120,000-year coastal midden — nature or people?

Abstract

At Moyjil (Point Ritchie), a cliffed site at the mouth of the Hopkins River at Warrnambool, south-eastern Australia, an erosional disconformity of Last Interglacial age on both a rock stack and the adjacent headland represents a surface of possible human occupation. Shells of edible marine molluscs occur on the disconformity, together with a distinctive population of transported stones derived from a calcrete of MIS 7 age and bearing variable dark grey to near-black colouration suggestive of fire. Experimental fire produced similar thermal alteration of calcrete. A strong correlation exists between intensity and depth of dark staining on one hand and increased magnetic susceptibility on the other. Thermal luminescence analyses of blackened stones provide ages in the MIS 5e range, 100–130 ka, consistent with independent stratigraphic evidence and contemporaneous with the age of the surface on which they lie. The distribution of fire-darkened stones is inconsistent with wildfire effects. Two hearth-like features closely associated with the disconformity provide further indications of potential human agency. The data are consistent with the suggestion of human presence at Warrnambool during the Last Interglacial.

The Moyjil site, south-west Victoria, Australia: excavation of a Last Interglacial charcoal and and burnt stone feature — is it a hearth?

“…For example, the large stone from XU9c (Square L) revealed a dark-grey to black outer layer and grey core (Figure 15). Bowler et al (2018) attribute such colouration of stones at Moyjil to burning.…”

“…Significantly, S1 is surmounted by a fragment of naturally pink-coloured terra rossa sandstone (S2) that has cemented to S1 via subsequent deposition of carbonate (Figure 8). Bowler et al (2018) argue that S2 was placed upon the top of S1 through human agency, as movement by natural processes is less likely. S2 also has a small thermal spall on its east side cemented in place (Figures 11 and 12).…”

The Moyjil site, south-west Victoria, Australia: stratigraphic and geomorphic context

“…Dark staining of calcrete stones, which occur on Gsa and the marine abrasion surface of Block B, has raised the question of causation by fire (Bowler et al 2018). A detailed study to test the fire hypothesis examined the colour change from pale calcrete to dark grey/black stones (Bowler et al 2018). The colour change can be replicated in small, hearth-sized wood fires.…”

“…Correlations between the size of stones and their colour, and between their colour and magnetic susceptibility, support the conclusion that fire controlled the variation in the three attributes. In addition, the ages determined by thermoluminescence analysis of small black stones from Gsa on the headland reflect thermal resetting near the time of their deposition as part of unit Q2 rather than the age of their source, unit R. Spatial clustering of the darkened stones in some cases may be reminiscent of hearths of human agency (see Bowler et al 2018 andMcNiven et al 2018 for discussion).…”

“…In this, the second in a series of papers concerned with the possibly archaeological materials at Moyjil, we present the geological context of the features, in particular, descriptions and interpretations of the geomorphology and stratigraphy of the site. Other papers in the series provide an overview of the project (Sherwood 2018), examine the site's geochronology (Sherwood et al 2018a), shell taphonomy (Sherwood et al 2018b) and evidence for fire (Bowler et al 2018), and present an archaeological investigation of a hearth-like feature (McNiven et al 2018).…”