Richard Fullagar

Optical and radiocarbon dating at Jinmium rock shelter in northern Australia

The Jinmium rock shelter is located in the Kimberley region of northern Australia. Claims for ancient rock art and an early human presence at this site were based on thermoluminescence ages of 50–75 thousand years (kyr) for quartz sands associated with buried circular engravings (pecked cupules) and on thermoluminescence ages of 116–176 kyr for the underlying artefact-bearing deposits. Here we report substantially younger optical ages for quartz sand, and ages based on measurements of radioactive carbon in charcoal fragments, from the occupation deposit. Using conventional (multiple-grain) optical dating methods, we estimate that the base of the deposit is 22 kyr. However, dating of individual grains shows that some have been buried more recently. The single-grain optical ages indicate that the Jinmium deposit is younger than 10 kyr. This result is in agreement with the late-Holocene ages obtained for the upper two-thirds of the deposit from radiocarbon measurements. We suggest that some grains have older optical ages because they receivedinsufficient exposure to sunlight before burial. The presence of such grains in a sample will cause age overestimates using multiple-grain methods, whether using thermoluminescence or optical dating.

Human Adaptation and Plant Use in Highland New Guinea 49,000 to 44,000 Years Ago

New Guineas Ancient Colonies Isolated by water, Australia and New Guinea were some of the last major parts of the world colonized by modern humans. Summerhayes et al. (p. 78; see the Perspective by Gosden) describe an archaeological site in the highlands of New Guinea that sheds light on this migration. The record extends back to nearly 50,000 years ago and thus represents one of the earliest known records. Nuts and yams were widely consumed, and the variety of stone tools discovered implies that the early humans may have cleared forest patches to promote the growth of useful plants. Archaeological sites in the New Guinea Highlands trace the arrival of modern humans to nearly 50,000 years ago. After their emergence by 200,000 years before the present in Africa, modern humans colonized the globe, reaching Australia and New Guinea by 40,000 to 50,000 years ago. Understanding how humans lived and adapted to the range of environments in these areas has been difficult because well-preserved settlements are scarce. Data from the New Guinea Highlands (at an elevation of ~2000 meters) demonstrate the exploitation of the endemic nut Pandanus and yams in archaeological sites dated to 49,000 to 36,000 years ago, which are among the oldest human sites in this region. The sites also contain stone tools thought to be used to remove trees, which suggests that the early inhabitants cleared forest patches to promote the growth of useful plants.

The Early to Middle Stone Age transition and the emergence of modern human behaviour at site 8-B-11, Sai Island, Sudan

Site 8-B-11 at Sai Island in northern Sudan is a stratified site containing late Middle and early Upper Pleistocene occupation levels in excellent conditions of preservation. In Middle Pleistocene times, the banks of a small gully were repeatedly occupied by human groups leaving Acheulean and Sangoan material cultures in an interstratified pattern. Optical age determinations on aeolian intercalations within the gully sediments range between 220 and 150 ka. This sequence is truncated by Nile floodplain silts in which three occupation levels with Lupemban-related Nubian Complex assemblages (Van Peer, 1998) are stratified. The long archaeological sequence at 8-B-11 is a rare African case to document the Early to Middle Stone Age transition by means of primary context situations in direct stratigraphic super-position (Clark, 2001; Tryon & McBrearty, 2002). In contrast to the Acheulean, the early MSA Sangoan levels show sophisticated behaviours involving considerable technological and symbolic investment. Quartzite cobbles were used in the grinding of vegetal materials. Yellow and red ochre were exploited and ground to pigments using shaped mortars and selected chert nodules. We conclude that 8-B-11 is a key site with regard to the initial emergence of modern human behaviour outside subsaharan Africa (McBrearty Brooks, 2000).

Megafaunal extinction in the late Quaternary and the global overkill hypothesis

The global blitzkrieg hypothesis explains differential rates of megafaunal extinction between the worlds landmasses in the late Quaternary based on a proposed leap in predation efficiency enjoyed by colonising societies. It is characterised by appealing simplicity. Selective over hunting, facilitated by naiveté to human predation, produced rapid mass extinctions of large animals wherever subsistence societies colonised new landmasses. Taken at face value the circumstantial case for blitzkrieg is compelling and despite a paucity of direct evidence it has gained considerable support. Our review of the model suggests that it overlooks much contradictory data and rests on simplistic interpretations of complex biogeographicat and anthropological phenomena. These interpretations and assumptions do not account for major differences between the biotas, ecologies and human cultures of the landmasses involved. The assertion that responses of remote island species to human predation provide realistic models for those of continental taxa is poorly founded, exaggerating the likely predation efficiency of humans colonising continents. An absence of terrestrial predators over evolutionarily significant periods, together with restricted ranges and small populations, renders island faunas uniquely vulnerable to invaders. The argument, that climate cannot explain these phenomena because previous Glacial Maxima did not cause comparable extinctions, presupposes that their local effects were at least as severe as those of the Last Glacial Maximum. This has yet to be demonstrated and at most it would indirectly support a role for anthropogenic influence, not overkill per se. Overlooked or underplayed are the influences of translocated and other invading species. Similarly, differences in the origins, technologies and traditions of colonising human societies are rarely considered. These factors strongly impact on the predation efficiency, density and range of human populations, critically affecting the outcomes of predator-prey modeling. When a fuller constellation of influences and constraints is considered it is reasonable to posit that rapid mass extinction through selective human predation may largely describe megafaunal extinctions on remote islands, but the argument is not convincing for continents. This is especially so regarding Australia. Because even the largest Australian species were prey to endemic carnivores, their responses to human predation would not have been comparable to those of oceanic island species. No kill-sites or specialized big-game hunting/butchering tools are known and, on the basis of ethnographic and archaeological data, it is probable that predation efficiency, population density and range of the first Australians were insufficient to effect rapid mass extinction. Chronologies of human arrival and the disappearance of megafauna remain poor, but the most recent estimates for human-megafaunal coexistence in Australia range from 10,000 to 43,000 years. Although human predation may have been a contributing factor in megafaunal extinctions, rapid overkill is unlikely to describe the actual mechanism in most instances. The role of human predation and its significance relative to competing factors, human and otherwise, varied considerably between landmasses, as did the speeds with which extinctions occurred. Blitzkrieg and other mono-factorial models are heuristically valuable devices, but a growing body of evidence suggests that extinction can rarely, if ever, be attributed to a single cause.

Early human occupation of northern Australia: archaeology and thermoluminescence dating of Jinmium rock-shelter, Northern Territory

The nature and date of the human colonization of Australia remains a key issue in prehistory at the world scale, for a sufficiently early presence there indicates either Homo sapiens sapiens arriving precociously in a place remote from a supposed African origin, or a greater competence in sea-crossing than has been expected of archaic humans. Stratigraphic integrity, the new science of luminescent dating and the recognition of worked stone and of rock-engraving are immediate issues in this report from far northwestern Australia.

Early stone technology on Flores and its implications for Homo floresiensis

In the Soa Basin of central Flores, eastern Indonesia, stratified archaeological sites, including Mata Menge, Boa Lesa and Kobatuwa (Fig. 1), contain stone artefacts associated with the fossilized remains of Stegodon florensis, Komodo dragon, rat and various other taxa. These sites have been dated to 840–700 kyr bp (thousand years before present). The authenticity of the Soa Basin artefacts and their provenance have been demonstrated by previous work, but to quell lingering doubts, here we describe the context, attributes and production modes of 507 artefacts excavated at Mata Menge. We also note specific similarities, and apparent technological continuity, between the Mata Menge stone artefacts and those excavated from Late Pleistocene levels at Liang Bua cave, 50 km to the west. The latter artefacts, dated to between 95–74 and 12 kyr ago, are associated with the remains of a dwarfed descendent of S. florensis, Komodo dragon, rat and a small-bodied hominin species, Homo floresiensis, which had a brain size of about 400 cubic centimetres. The Mata Menge evidence negates claims that stone artefacts associated with H. floresiensis are so complex that they must have been made by modern humans (Homo sapiens).

Human occupation of northern Australia by 65,000 years ago

The time of arrival of people in Australia is an unresolved question. It is relevant to debates about when modern humans first dispersed out of Africa and when their descendants incorporated genetic material from Neanderthals, Denisovans and possibly other hominins. Humans have also been implicated in the extinction of Australia’s megafauna. Here we report the results of new excavations conducted at Madjedbebe, a rock shelter in northern Australia. Artefacts in primary depositional context are concentrated in three dense bands, with the stratigraphic integrity of the deposit demonstrated by artefact refits and by optical dating and other analyses of the sediments. Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.

Pleistocene seed-grinding implements from the Australian arid zone

Grinding-stones as a technology are seen as a key element in the artefactual transformations of the latest Pleistocene – both for themselves and the foods which were ground on them. In Australia, as in other regions, their age and status is also material to what (if any) kind of a broad-spectrum revolution in foraging accompanied them.

The role of silica in Polish formation

Abstract The proportion of amorphous silica is a major determinant of polish development on stone tools used to process plants. Amorphous silica occurs in significant amounts both in plants and in certain types of stone used to make lithic artefacts. Four stages of polish formation are derived from the glass polishing theory because they are useful for identifying mechanisms of how silica acts as a polishing agent. Amorphous silica is found to be an important polishing agent, even for wood with a very low silica content. Polishing agents may also contribute to polishes arising from stone tool contact with bone, skin, meat and shell. Implications are considered for flint, obsidian, quartz and other stone tool materials with use-polish. It is concluded that use-polish may be a less precise indicator of Australian contact materials than has been reported for other areas.

The archaeology, chronology and stratigraphy of Madjedbebe (Malakunanja II): A site in northern Australia with early occupation.

Published ages of >50 ka for occupation at Madjedbebe (Malakunanja II) in Australias north have kept the site prominent in discussions about the colonisation of Sahul. The site also contains one of the largest stone artefact assemblages in Sahul for this early period. However, the stone artefacts and other important archaeological components of the site have never been described in detail, leading to persistent doubts about its stratigraphic integrity. We report on our analysis of the stone artefacts and faunal and other materials recovered during the 1989 excavations, as well as the stratigraphy and depositional history recorded by the original excavators. We demonstrate that the technology and raw materials of the early assemblage are distinctive from those in the overlying layers. Silcrete and quartzite artefacts are common in the early assemblage, which also includes edge-ground axe fragments and ground haematite. The lower flaked stone assemblage is distinctive, comprising a mix of long convergent flakes, some radial flakes with faceted platforms, and many small thin silcrete flakes that we interpret as thinning flakes. Residue and use-wear analysis indicate occasional grinding of haematite and woodworking, as well as frequent abrading of platform edges on thinning flakes. We conclude that previous claims of extensive displacement of artefacts and post-depositional disturbance may have been overstated. The stone artefacts and stratigraphic details support previous claims for human occupation 50-60 ka and show that human occupation during this time differed from later periods. We discuss the implications of these new data for understanding the first human colonisation of Sahul.