How old are Australia's pictographs? A review of rock art dating

Australia contains some of the world's richest and apparently longest traditions of rock pictographs. Dating this art, however, has been problematic, with few ‘direct’ and reliable dates of Pleistocene or early Holocene age having been obtained from visible, representational imagery. This paper critically reviews the evidence for the antiquity of pigment rock art in Australia by examining the various dating techniques employed. The accurate and reliable dating of rock art worldwide is crucial to understanding the evolution of modern human symbolism and whether cognitive modernism came about after, rather than with, the first signs of full biological modernism; understanding the pitfalls and devising proper methods are crucial prerequisites. Towards these ends, this paper reviews the results and techniques that have been employed to date the apparently earliest known pictographs in Australia.     

A Bayesian AMS C chronology of the Classic Maya Center of Uxbenká, Belize

Archaeologists require precise chronologies of cultural change to understand the nature and timing, and causes and effects, of ecological and social transformations. The Uxbenká Archaeological Project (UAP) has made chronology building a main goal, employing epigraphic data, artifact seriation, and high-precision AMS ¹⁴C dating. With more than 60 ¹⁴C dates with measurement errors below ±25 ¹⁴C yr, primarily on single charcoal specimens, Uxbenká may be the most intensively dated Classic Period site in the tropical Maya Lowlands. Here we take the next step, combining this rich chronometric dataset with associated stratigraphic information in OxCal's Bayesian framework to generate a high-resolution chronology of Uxbenká's early development and expansion in southern Belize. We show how archaeologists may take advantage of complex architectural stratigraphy to constrain broad calibrated ranges during the Classic Period, and to estimate dates for observed construction events that can not be directly dated (e.g., clearing/leveling plazas, laying plaster floors, renovating/rebuilding structural elements). Our analysis confirms the antiquity of the ceremonial Stela Plaza (Group A), where first construction is estimated between 60 cal BC and cal AD 220 and is associated with a Pre-Classic structure obscured by later construction and reorientation of the group to a N-S alignment ca. AD 150–310. The analysis also indicates initial leveling and construction at plaza Group B from cal AD 60–310 and Group D from cal AD 20–240, both earlier than previously assumed. Though Late Classic contexts are not as well represented by direct dates, architectural modifications are documented at all three plaza groups after AD 550, including the extensive plastering, laying paving stones, and construction of facades on existing structures. The resulting chronology revises our previous thinking on the mode of settlement and development of Classic Maya society at Uxbenká and indicates specific areas of investigation to elucidate events in the Late and Terminal Classic at the site, including political and social fragmentation and the abandonment of the urban core late in the Classic Period.     

Icelandic volcanic ash from the Late-glacial open-air archaeological site of Ahrenshöft LA 58 D, North Germany

Cryptotephra of Icelandic origin from the open-air archaeological site of Ahrenshöft LA 58 D (Kr. Nordfriesland, Schleswig-Holstein), northern Germany overlies a Late-glacial Havelte lithic assemblage, hitherto dated by ¹⁴C and biostratigraphy to the earliest part of the Late-glacial interstadial (GI-1e to GI-1c₃). Peaks in ash shards are observed in two profiles. Major and minor element geochemistry indicates volcanic ash originating in the Katla system. Precise correlation to previously described tephra is uncertain due to overlapping chemical characteristics. The Ahrenshöft ¹⁴C determinations, litho- and bio-stratigraphy encompass a broad age-span for the cryptotephra bearing sediments, from the end of the Allerød to the Preboreal. The most plausible volcanic eruption correlates are the Vedde Ash (∼Younger Dryas), already known from the European mainland, tephra AF555 (late Younger Dryas) and the Suduroy tephra (∼Preboreal/Boreal), hitherto recorded only in the North Atlantic region. These three ash horizons have been dated to, respectively, 12,171 ± 57 yr b2k in the NGRIP ice-core, c.11,500 cal BP, in Scotland and c.8000 cal BP, by radiocarbon from the Faroe Isles. Ongoing research on deposits from the type sites for the tephra layers may in the future differentiate these markers leading to better discrimination of the chemistries and a resolution of this question.     

U-series dating of soda straw stalactites from excavated deposits: method development and application to Blanche Cave, Naracoorte, South Australia

This study aimed to further test the method, reported by St Pierre et al. (2009), to develop robust chronologies of deposits in limestone caves through U/Th (Uranium/Thorium or U-Series) dating of soda straw stalactites. The chronology of fossil bearing deposits at Blanche Cave was further constrained with thermal ionisation mass spectrometry (TIMS) U/Th dating of 17 additional soda straw stalactite samples, and results were compared to recalibrated ¹⁴C ages of charcoal. The results support the assertion that soda straw stalactites can provide ages close to the time of sediment deposition and may be used as reliable chronological markers, particularly for periods reaching or beyond the radiocarbon dating limit. The application of an enhanced cleaning technique facilitated the reduction of detrital Th in samples, significantly increasing age accuracy and precision. Additionally U/Th age accuracy and precision was increased through the application of site-specific measured U/Th ratios to correct for the detrital ²³⁰Th component in samples.     

Crenostrea sp. cf. C. cannoni (Marwick, 1928) (Bivalvia: Ostreoidea) and associated fauna from east of Heard Island,Kerguelen Plateau: age and palaeoenvironmental value

Quilty, P.G., Clark, N. & Hibberd, T., 21.01.2015. Crenostrea sp. cf. C. cannoni (Marwick, 1928) (Bivalvia: Ostreacea) and associated fauna from east of Heard Island, Kerguelen Plateau: age and palaeoenvironmental value. Alcheringa 39, xxx–xxx. ISSN 0311-5518

A well-preserved single left valve of a large oyster embedded in coarse volcaniclastic sediment and identified as Crenostrea sp. cf. C. cannoni (Marwick, 1928) was dredged from east of Heard Island, central southern Indian Ocean. It is accompanied by a fragment of the pectinid bivalve Austrochlamys sp. indet. and foraminifera. Austrochlamys sp. indet. and other bivalve fragments were analysed for ⁸⁷Sr/⁸⁶Sr, δ¹⁸O and δ¹³C, the results yielding an age of 17.5 Ma (later early Miocene) and a water temperature of ca 10°C. Foraminifera and sediment characteristics indicate that accumulation occurred in mid-continental shelf depths, at a location where nutrient supply was good.

Patrick G. Quilty [p.quilty@utas.edu.au], School of Earth Sciences (Private Bag 79) and Institute for Marine and Antarctic Studies (IMAS: Private Bag 129), University of Tasmania, Hobart, Tasmania 7001, Australia. Nicola Clark [nc118@leicester.ac.uk], Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK. Ty Hibberd [ty.hibberd@aad.gov.au], Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia.     

前剂量热释光测定年代方法

分析了三种测量方法──多次激活、加剂量法和钉子技术的优缺点,并对细粒石英前剂量方法进行了专门研究。结果表明,细粒五英前剂量方法测量简便,减少了来自多次激活、试验剂量和归一引起的误差,最小可测年龄能达到几十年。     

Carnivores and their prey in the Wezmeh Cave (Kermanshah,Iran): a Late Pleistocene refuge in the Zagros

Wezmeh Cave is located on the northeastern edge of the Islamabad plain, a high intermontane valley in the western‐central Zagros. In 1999 a disturbed but large faunal assemblage was recovered from this site. The abundant and extremely diverse faunal spectra present at Wezmeh Cave has highlighted the importance of this assemblage. Carnivore remains constitute the bulk of the assemblage; red fox (Vulpes vulpes) has the highest number of identified specimens followed by spotted hyena (Crocuta crocuta), brown bear (Ursus arctos), wolf (Canis lupus), felids (lion, leopard, lynx/caracal and wildcat), mustelids (badger, polecat, marten) and viverrids (mongoose). Artiodactyls (bovid, cervid, suid), equids, rhinoceros (Dicerorhinus sp.) and small animals (Cape hare, porcupine, tortoise, snake, birds) are also present. According to U‐series dating, the site was occupied from around 70 ka BP through to sub‐recent periods by carnivores. Amongst this rich assemblage, a human fossil tooth was also found and dated by non‐invasive spectrometry gamma dating to 20–25 ka BP. A preliminary zooarchaeological and taphonomic study shows that Wezmeh Cave was used by multiple carnivore species, a unique phenomenon in the Zagros Mountains in particular and southwest Asia in general. Copyright © 2008 John Wiley & Sons, Ltd.     

Expanding the utility of Uranium-series dating of speleothems for archaeological and palaeontological applications

Uranium-series (U-series) dating of speleothems is frequently used for palaeoclimate studies but its archaeological and palaeontological applications are limited to stratigraphically significant speleothem formations, such as flowstones, to provide maximum and minimum temporal points. This study targeted soda straw stalactites for U-series dating. In contrast to other speleothem formations, soda straw stalactites are fragile, have typically short life spans (usually only years but rarely up to a few hundred years) and are frequently incorporated into cave deposits. Results of thermal ionisation mass spectrometry (TIMS) U-series dating of soda straw stalactites from palaeontological excavations at Blanche Cave, South Australia, show that small, dense, clean straws tend to yield ages closest to the time of stratigraphic deposition. A correlation between soda straw U-series ages and radiocarbon ages of charcoal from the site is shown. Multiple soda straw age determinations for a single stratigraphic unit are required in order to verify age concordance. In conjunction with other dating methods, U-series dating of soda straw stalactites may help to significantly constrain the age of stratigraphic units and associated archaeological and palaeontological deposits in order to provide more robust chronologies. Here we advocate the collection of soda straw stalactites at future excavations of limestone cave sites.     

Geoarchaeological tsunami deposits at Palaikastro (Crete) and the Late Minoan IA eruption of Santorini

The explosive eruption at Santorini in the Aegean Sea during the second millennium BCE was the largest Holocene volcanic upheaval in the Eastern Mediterranean region. The eruption was disastrous for the Minoan settlements at Santorini, but the effect on human society in the neighbouring islands and regions is still clouded in uncertainty. Tsunami generation was suggested, but comparatively little evidence was found. The lack of firm tsunami traces is particularly puzzling in Crete with its coastal settlements of the Late Minoan IA period, during which the Santorini eruption occurred. Here, we report the discovery of extensive geoarchaeological tsunami deposits at Palaikastro in north-eastern Crete. These deposits are characterized by a mixture of geological materials, including volcanic Santorini ash, and archaeological settlement debris. Various tsunami signatures were identified: (1) erosional contact with the underlying strata, (2) volcanic ash intraclasts in the lower part of the deposit, (3) reworked building stone material in the lower part of the deposit, (4) individual marine shells, (5) marine micro-fauna, (6) imbrication of rounded beach pebbles, settlement debris, ceramic sherds and even bones, (7) multi-modal chaotic composition. Late Minoan human settlement activities at Palaikastro provided architectural and stratigraphic frameworks in space and time that recorded and preserved tsunami evidence as geoarchaeological deposits. Such stratigraphic resolution and preservation may not occur in the natural landscape. Volcanic ash transported by wind from Santorini south-east to Crete preceded the tsunami. Geological, archaeological and radiocarbon dating criteria all converge, indicating that the tsunami deposits are coeval with the Minoan Santorini eruption. Field evidence suggests that tsunami waves at Palaikastro were at least 9 m high. Inverse tsunami modeling was attempted, based on these newly discovered tsunamigenic deposits. The initial wave in the generation region at Santorini that best fits the stratigraphic data is a wave with +35 to −15 m initial amplitude and a crest length of about 15 km.     

Differentiating between anthropogenic calcite in plaster,ash and natural calcite using infrared spectroscopy: implications in archaeology

Infrared spectroscopy provides information not only on the type of calcium carbonate polymorph, but also on the extent of atomic order. In calcite, three major infrared absorption peaks are identified: ν₃, ν₂, and ν₄. It was shown that the ratio between ν₂ and ν₄ bands reflects the order of the calcite crystal structure. In this paper we analyse this ratio in geologically formed calcites, archaeological plasters, modern plasters and experimentally prepared plasters. For the geological calcite, the values of the ν₂/ν₄ ratio are around 3, whereas for the experimentally prepared plasters, the values are around 6.5. The ν₂/ν₄ ratio for archaeological plasters varies from 3 to 6. This shows that a high ratio is indicative of disorder in the crystal, and implies that the calcite was formed from calcium oxide at high temperatures. It also implies that this disorder can be preserved for at least 14,000 years. The ν₂/ν₄ ratio of calcite from archaeological sites can thus be used to differentiate between anthropogenic calcite, such as in plaster, mortar and wood ash, from geogenic calcite, such as in limestone. The ratio may also be used to identify plaster or ash that still retains its original crystals and therefore carbon-14 content.