Recent Radiocarbon Dates Research Articles

Do counts of radiocarbon-dated archaeological sites reflect human population density? A preliminary empirical validation examining spatial variation across late Holocene California

AbstractResearchers increasingly rely on aggregations of radiocarbon dates from archaeological sites as proxies for past human populations. This approach has been critiqued on several grounds, including the assumptions that material is deposited, preserved, and sampled in proportion to past population size. However, various attempts to quantitatively assess the approach suggest there may be some validity in assuming date counts reflect relative population size. To add to this conversation, here we conduct a preliminary analysis coupling estimates of ethnographic population density with late Holocene radiocarbon dates across all counties in California. Results show that counts of late Holocene radiocarbon-dated archaeological sites increase significantly as a function of ethnographic population density. This trend is robust across varying sampling windows over the last 5000 BP. Though the majority of variation in dated-site counts remains unexplained by population density. Outliers reveal how departures from the central trend may be influenced by regional differences in research traditions, development-driven contract work, organic preservation, and landscape taphonomy. Overall, this exercise provides some support for the “dates-as-data” approach and offers insights into the conditions where the underlying assumptions may or may not hold.

Using the radiocarbon dates of Central Africa for studying long-term demographic trends of the last 50,000 years: potential and pitfalls

ABSTRACT This paper presents the first review of biases impacting Pleistocene and Holocene radiocarbon dates from Central Africa. Based on the pooling of the research expertise of the co-authors, twenty-four biases are listed, explained and documented and their impact on any radiocarbon date corpus demonstrated. To achieve this, a new corpus has been created of 1764 radiocarbon and TL assays from 601 archaeological sites published in the literature. Each date has been checked for its context. The irregular dynamics of research in space and time seriously impact the end result of previous analyses aiming to achieve a regional understanding of past demographic fluctuations. While peaks in the number of dates from the late Holocene seem to correspond to a positive demographic trend, it is suggested that the declines identified cannot be of any such use for the time being and that today’s picture does not presently support claims of a population “crash” at a regional or local level for any time period. The numbers are obscured by overall research deficits identifiable throughout the region. The maps of the dated sites presented offer good evidence of this and illustrate the vast expanses where no archaeological research has yet been carried out. The number of radiocarbon dates in Central Africa is more an indicator of the effort archaeologists have put into understanding a settlement than it is of ancient demographics. Successive waves of incoming people since c. 3500–3000 cal. BP, the two most important ones known since the 1990s, have created a cultural mosaic of coexisting technological groups. The last 40 years of research have revealed the inner complexity of these waves, some of which avoided parts of the region for centuries, thereby creating an irregular cultural mosaic of land use that is outlined by patterning in the radiocarbon dates.

STRONTIUM ISOTOPE STRATIGRAPHY REVEALS 100 KY-SCALE CONDENSATION, BEVELING, AND INTERNAL SHINGLING OF TRANSGRESSIVE SHELL BEDS IN THE MARYLAND MIOCENE

Abstract Condensed transgressive shell beds, rich in paleobiological information, are common in the Phanerozoic stratigraphic record, but their interpretation is complicated by the uncertain amount of time that each deposit represents. Miocene strata exposed in the Calvert Cliffs (Maryland, USA) are known for a series of regionally extensive, densely packed, meters-thick shell beds that serve as global exemplars of shallow-water condensation during marine transgression and onlap. Applying Sr isotope stratigraphy to calcitic scallops from the base and top of the oldest of these beds (Shattuck Zone 10), we demonstrate that its most densely fossiliferous part accumulated over the interval of 16.60–15.95 Ma, reflecting approximately 0.65 ±0.20 Myr of skeletal accumulation within the Miocene Climatic Optimum, with a likely 0.15 Myr-scale of time averaging per each firmground-bounded subunit. Both of these estimates are an order of magnitude longer than previous best estimates based on radiocarbon-dated Holocene analogs. Sr isotopes confirm subtle low-angle erosional beveling of the main body of Zone 10, truncating 0.3-Myr of record in updip sections, and demonstrate that a down-dip wedge of less shelly sand is an entirely younger (by ∼ 0.5 Myr) interleaved body. This condensation, beveling, and inter-shingling within Zone 10 quantified here sets a precedent for the magnitude of lateral and vertical temporal variability within condensed transgressive deposits, relevant to paleobiologic and other geohistorical analysis, and justifies the interpretation of comparably complex temporal fabrics based upon similar physical stratigraphic features found elsewhere in this and other very thin stratigraphic records.

Pottery from Tell Khaiber: A Craft Tradition of the First Sealand Dynasty By Daniel Calderbank (Archaeology of Ancient Iraq 1). Ludlow: Moonrise Press 2021. Pp. xii + 282. £ 35. ISBN 978-1-910169-02-5 (cloth).

<i>Pottery from Tell Khaiber: A Craft Tradition of the First Sealand Dynasty</i> By Daniel Calderbank (Archaeology of Ancient Iraq 1). Ludlow: Moonrise Press 2021. Pp. xii + 282. £ 35. ISBN 978-1-910169-02-5 (cloth).

New Evidence of Grinding Activities in Patagonian Steppe during the Late Holocene (ca. 2000 Years BP): the Laguna Azul Site (Somuncurá Plateau, Río Negro Province, Argentina)

ABSTRACT is paper aims to present the first record of micro vegetable remains in grinding-stone tools found in hunter-gatherer contexts located in Laguna Azul (Somuncurá plateau, Argentina). These grinding-stone tools resulted from excavations of two hunting blinds (known as “parapets”) related to late Holocene radiocarbon dates of 1756 ± 28 years BP (D-007084; δ 13C = 20.2‰) and 1906 ± 26 years BP (D-007085; δ 13C = −19.8‰). The combination of micro-wear and starch grains studies allows us to discuss the autochthonous and allochthonous vegetation processing activities. From these remains, four types of vegetation with nutritive potential were identified: Chenopodaceas, Amaranthaceas, Prosopis sp. and Araucaria sp. The grinding stone tools’ microscopic analysis gave evidence of the specific processing motions employed. This evidence-based data enables us to discuss the relationship between the hunter-gatherers and their environment during the late Holocene and also to establish new assumptions about circuits of mobility and communication.

Late Holocene cryptotephra and a provisional 15 000-year Bayesian age model for Cascade Lake, Alaska

Abstract. Multiple chronometers can be employed for dating Holocene palaeoenvironmental records, each with its own inherent strengths and weaknesses. Radiocarbon dating is one of the most widely used techniques for producing chronologies, but its application at high-latitude sites can sometimes be problematic. Here, cryptotephra were identified in a core from Cascade Lake, Arctic Alaska, and used to identify and resolve an age bias in Late Holocene radiocarbon dates from the top 1.42 m of the sediment sequence. Identifiable geochemical populations of cryptotephra are shown to be present in detectable concentrations in sediment from the north flank of the Brooks Range for the first time. Major-element glass geochemical correlations are demonstrated between ultra-distal cryptotephra and reference samples from the Late Holocene caldera-forming eruption of Opala, Kamchatka, as well as three eruptions in North America: the White River Ash (northern lobe), Ruppert tephra and the Late Holocene caldera-forming eruption of Aniakchak. The correlated ages of these cryptotephra provide evidence for an old-carbon effect and support preliminary palaeomagnetic secular variation (PSV) correlated ages reported for Cascade Lake. Chronological data from Cascade Lake were then combined using a Bayesian approach to generate an age–depth model that extends back through the Late Holocene and provisionally to 15 000 cal yr BP.

Holocene Aridity-Induced Interruptions of Human Activity along a Fluvial Channel in Egypt’s Northern Delta

Geoarchaeological information presented here pertains to a subsidiary Nile channel that once flowed west of the main Sebennitic distributary and discharged its water and sediments at Egypt’s then north-central deltaic coast. Periodical paleoclimatic episodes during the later Middle and Upper Holocene included decreased rainfall and increased aridity that reduced the Nile’s flow levels and thus likely disrupted nautical transport and anthropogenic activity along this channel. Such changes in this deltaic sector, positioned adjacent to the Levantine Basin in the Eastern Mediterranean, can be attributed to climatic shifts triggered as far as the North Atlantic to the west, and African highland source areas of the Egyptian Nile to the south. Of special interest in a study core recovered along the channel are several sediment sequences without anthropogenic material that are interbedded between strata comprising numerous potsherds. The former are interpreted here as markers of increased regional aridity and reduced Nile flow which could have periodically disrupted the regional distribution of goods and nautical activities. Such times occurred ~5000 years B.P., ~4200–4000 years B.P., ~3200–2800 years B.P., ~2300–2200 years B.P., and more recently. Periods comparable to these are also identified by altered proportions of pollen, isotopic and compositional components in different radiocarbon-dated Holocene cores recovered elsewhere in the Nile delta, the Levantine region to the east and north of Egypt, and in the Faiyum depression south of the delta.

Early historical forest clearance caused major degradation of water quality at Lake Væng, Denmark

Although humans have impacted their environment over millennia, details of these impacts, especially on aquatic systems, is still surprisingly scarce despite potential disturbance by early land use. This study examined a high-resolution radiocarbon-dated Holocene record from the Danish Lake Væng, using geochemical and biological proxies, and related the observed impacts to other lake records with catchment disturbance. The results indicate a lengthy and varying history of aquatic eutrophication linked to human activity. Modest impacts on the lake coincided with the first signs of landscape disturbance during the Neolithic (c. 4500 cal. yrs BP). Observed impacts intensified in the Late Bronze and Pre-Roman Iron Age. Viking Age/Medieval deforestation and erosional inputs to the lake associated with new ploughing technology (1200 cal. yrs BP), however, led to a major reorganisation of the aquatic ecosystem . Filamentous bloom-forming cyanobacteria, common today in heavily culturally impacted lakes, reached a historical maxima. The lake ecosystem subsequently recovered somewhat but remains eutrophic to date. The erosion record from Lake Væng shows a striking similarity with other Danish lake records, especially the notable increase in Medieval Period catchment inputs, which are observed in other European lacustrine records. Numerous European lowland lakes may have shifted into a degraded ecological state millennia ago, but degradation intensified during the onset of the Medieval Period. Hence, assuming pre-industrial conditions as relatively pristine reference baselines for more recent cultural eutrophication could be flawed in landscapes intensively used by humans for millennia.

Insular networks: An exploration of material distribution, insularity and island identity on the edge of Europe in the Shetland Neolithic

Shortly after arriving in the Shetland archipelago early in the 4th millennium BC, communities began to quarry and make stone tools from riebeckite felsite, quarried from the Northmavine region of North Mainland. The effort expended traveling to the quarry sites, extracting, making and crafting tools was considerable indicating the importance of felsite to Neolithic communities. Results from the North Roe Felsite Project are presented in this paper. The quarrying and distribution of felsite in Shetland can tell us much about insularity, choice, and island identities on a wider scale. The geospatial distribution of 416 felsite tools from across the archipelago was explored. Felsite is used to make tools for utilitarian and ceremonial purposes and, with two exceptions compromising 0.33% of the total dataset, no tools can be securely provenanced outside of Shetland. At a time of increasing communications elsewhere in the Neolithic world, communities in Shetland appear to become focused on the archipelago. This insularity is also evident in contemporary material culture including pottery and funerary structures which do not follow mainland or Orcadian styles, strongly suggesting an island-focused society during this period. Recent radiocarbon dates suggest that these dynamics were established in the Early Neolithic, before 3500 BC. Felsite, therefore, allows us to explore the otherwise elusive early prehistory of the islands. The distribution network of tools from the quarry complex around the archipelago strongly indicates a preference for maritime travel and transportation, even where terrestrial routes are available. The patterns also suggest settlement and activity across Shetland with important foci at previously understudied locations across North and West Mainland. The study has considerable implications for understanding movement, choice, and identity in past island societies and their relationship to material culture.

New chronostratigraphic records of the early-to-middle Holocene in the north-central region of Chile indicate Andean foothills housed hunter-gatherers during pulses of extreme aridity

The scarcity of middle Holocene radiocarbon dates in different regions of the Andes has been interpreted as an indicator of discontinuity in human occupations in response to adverse environmental conditions due to marked aridity. In the subtropical Andes of north-central Chile and adjacent areas, this paucity has been detected in radiocarbon ages between 8000 and 6000 cal BP. A systematic programme of cave excavations with detailed chronologies in the Combarbalá area in the Andean western foothills at 31°S allows questioning the role these spaces and ecosystems played for hunter-gatherers throughout the Holocene. The elusive record of dateable material has been addressed by excavating deposits under rock-shelters which tend to trap sedimentary material. This dataset has been compared with the available climate records and shows a collation between the onset of various site chronologies during the early-to-middle Holocene and periods of extreme aridity. The organization of mobility and the role of Andean foothills for hunter-gatherer settlements is reviewed. Resource availability in the area, namely fresh water supply, good-quality toolstones, faunal resources, and shelters, attracted mobile populations to these environments as indicated by our records as well as others in the broader region.

Geochemistry of Holocene sediments from Chilika Lagoon, India: inferences on the sources of organic matter and variability of the Indian summer monsoon

We present bulk organic carbon isotopic composition (δ13C), total organic carbon (TOC) content, and total organic carbon to total nitrogen (C/N) ratio along with major and trace element geochemistry of an AMS radiocarbon-dated Holocene sediment core collected from Chilika Lagoon, India. The data are used to understand changes in the organic matter (OM) sources and the strength of the Indian summer monsoon (ISM). Our results indicate that during early to middle Holocene (10.4–4.9 ka), terrestrial (23–65%) and macrophyte (24–32%) sources were significant contributors to the sediment OM; marine component contributed ≤23%. An abrupt shift in the OM sources was observed at ~4.0 ka, marked by a significant decrease in OM contributions from the terrestrial (5%) and macrophyte (14%) end-members, and an increase in the marine end-member source (70%) into the lagoon. The period from ~4.0 to 2.1 ka recorded the lowest and highest contribution from the terrestrial (5–11%) and marine (50–70%) sources, respectively. This was followed by a gradual increase in the terrestrial and decrease in the marine contribution to 21% and 25% till the present, respectively. During this period, phytoplankton became the major source (31–40%) of OM to the lagoon. This period also experienced increasing anthropogenic activities in the catchment. In this study, proxy records show a strong ISM during early Holocene (10.4–9.0 ka), which was followed by a gradual weakening until 4.9 ka. At ~4.0 ka, an abrupt and pronounced weakening of ISM occurred that was followed by an amelioration of ISM precipitation towards 1.1 ka. Later, the ISM gradually weakened to the present-day condition. Overall, Chilika Lagoon core records exhibit that changes in the Northern Hemisphere summer insolation regulate the long-term trend of ISM during the Holocene.

New AMS 14C dates track the arrival and spread of broomcorn millet cultivation and agricultural change in prehistoric Europe

Broomcorn millet (Panicum miliaceum L.) is not one of the founder crops domesticated in Southwest Asia in the early Holocene, but was domesticated in northeast China by 6000 bc. In Europe, millet was reported in Early Neolithic contexts formed by 6000 bc, but recent radiocarbon dating of a dozen 'early' grains cast doubt on these claims. Archaeobotanical evidence reveals that millet was common in Europe from the 2nd millennium bc, when major societal and economic transformations took place in the Bronze Age. We conducted an extensive programme of AMS-dating of charred broomcorn millet grains from 75 prehistoric sites in Europe. Our Bayesian model reveals that millet cultivation began in Europe at the earliest during the sixteenth century bc, and spread rapidly during the fifteenth/fourteenth centuries bc. Broomcorn millet succeeds in exceptionally wide range of growing conditions and completes its lifecycle in less than three summer months. Offering an additional harvest and thus surplus food/fodder, it likely was a transformative innovation in European prehistoric agriculture previously based mainly on (winter) cropping of wheat and barley. We provide a new, high-resolution chronological framework for this key agricultural development that likely contributed to far-reaching changes in lifestyle in late 2nd millennium bc Europe.

Re-evaluating archaeomagnetic dates of the vitrified hillforts of Scotland

A re-analysis of archaeomagnetic data from seven vitrified hillforts in Scotland, sampled in the 1980s, shows excellent agreement with recent radiocarbon dates. In the past thirty years our knowledge of the secular variation of the geomagnetic field has greatly improved, especially in the 1st millennium BC, allowing earlier archaeomagnetic data to be reconsidered. We evaluate the likelihood of the data with respect to a state-of-the-art field geomagnetic model and find close coherence between the observed directions and the model for the closing centuries of the first millennium BC. A new Bayesian method of calibration gives the most likely number of separate events required to produce a series of magnetic directions. We then show that the burning of three of the four oblong forts most likely took place around the same time, and our estimate for the date of this is indistinguishable from recent radiocarbon dates from another fort of similar type.

Sedimentary and geochemical characteristics of two small permafrost-dominated Arctic river deltas in northern Alaska

Arctic river deltas are highly dynamic environments in the northern circumpolar permafrost region that are affected by fluvial, coastal, and permafrost-thaw processes. They are characterized by thick sediment deposits containing large but poorly constrained amounts of frozen organic carbon and nitrogen. This study presents new data on soil organic carbon and nitrogen storage as well as accumulation rates from the Ikpikpuk and Fish Creek river deltas, two small, permafrost-dominated Arctic river deltas on the Arctic Coastal Plain of northern Alaska. A soil organic carbon storage of 42.4 ± 1.6 and 37.9 ± 3.5 kg C m− 2 and soil nitrogen storage of 2.1 ± 0.1 and 2.0 ± 0.2 kg N m− 2 was found for the first 2 m of soil for the Ikpikpuk and Fish Creek river delta, respectively. While the upper meter of soil contains 3.57 Tg C, substantial amounts of carbon (3.09 Tg C or 46%) are also stored within the second meter of soil (100–200 cm) in the two deltas. An increasing and inhomogeneous distribution of C with depth is indicative of the dominance of deltaic depositional rather than soil forming processes for soil organic carbon storage. Largely, mid- to late Holocene radiocarbon dates in our cores suggest different carbon accumulation rates for the two deltas for the last 2000 years. Rates up to 28 g C m− 2 year− 1 for the Ikpikpuk river delta are about twice as high as for the Fish Creek river delta. With this study, we highlight the importance of including these highly dynamic permafrost environments in future permafrost carbon estimations.

Extinction pattern of Alpine cave bears - new data and climatological interpretation

ABSTRACTCave bears have disappeared from the Alps from different altitudes at different times. The temporal progression of the HDEL (Height Dependent Extinction Line) – a compilation of the geologically most recent radiocarbon dates per altitude level – is not consistent with the general cooling of the temperatures from about 45 ka BP. The cave bear sites of the Northern Alps with the most recent radiocarbon ages are not situated in the lowlands but in caves in altitudes of 1,500 m to 1,700 m above sea level (a.s.l.).Cave bears fed almost exclusively on herbs and leaves. It was assumed that with the general cooling in the OIS 3 since about 45 ka BP also the migration of the alpine elements into the lowlands took place. It could be recognized that the populations in the lower situated cave bear site became earlier extinct than the cave bear population in the higher altitudes.With new radiocarbon dates, done at the Curt-Engelhorn-Center Archaeometry at the Reiss-Engelhorn-Museen in Mannheim (Germany), the HDEL can be determined much more precisely and the causes of gradual extinction are also better understood.

A Holocene “Frozen Accident”: Sediments of Extreme Paleofloods and Fires in the Bedrock-Confined Upper Huis River, Western Cape, South Africa

Wildfires and flooding events are common and are forceful intrinsic controls over landscape evolution, biodiversity, and preserved sediment architecture in dryland environments. Charcoal-bearing Holocene flood sediments of the upper Huis River provide a rare perspective on the powerful and episodic sedimentary processes in a bedrock-confined fluvial setting in the tectonically stable SW Cape Fold Belt in South Africa. The sediments described in this paper are associated with high-magnitude, debris-flow-dominated paleofloods, and their charcoal content is linked to a series of radiocarbon-dated Holocene paleofires that occurred from ∼ 2165 ± 37 BP to ∼ 653 ± 35 BP. The five sedimentary facies associations are documented as products of: a) noncohesive pseudoplastic debris flows; b) transitional, high-matrix-strength debris flows with heterogeneous fluid content and flow behavior; c) low-cohesion debris flows; d) hyperconcentrated flows; and e) fluvial channel flow in the upper Huis River. The last is interpreted mainly from massive, subrounded to subangular boulder bars, which provide key evidence for the dramatic scouring of the upper Huis valley. The paleofloods, which not only filled the valley with debris-flow sediments up to 12 m thick, but also subsequently flushed it out nearly to the bedrock, had estimated extreme discharges of few thousands of m3/s. In summary, the upper Huis River sediments are exceptional because they preserve the geological record of recurring fires, and at least three extreme paleofloods (i.e., massive sedimentation events) over a period of ∼ 1500 years in an area typified by the fire-prone and fire-dependent Fynbos Biome. Furthermore, this study provides insights into what the gaps in the commonly fragmented bedrock-confined alluvial stratigraphic record would be like, should there be “more record than gap.”

Late Holocene aridification recorded in the stable carbon and nitrogen isotope composition of soils from Nainital, Lesser Himalaya

This study incorporates micromorphology, geochemistry, and stable carbon and nitrogen isotope compositions of soil organic matter (δ13C and δ15N) in a radiocarbon-dated Holocene Alfisol section from Nainital, northwest Himalaya, India to understand pedogenic and vegetation response to changing Indian Summer Monsoon (ISM). Soil micromorphology suggests this soil to be an Alfisol that formed in semiarid to humid conditions. Extensive illuviation with thick clay pedofeatures found in the Bt-horizon suggests wet conditions and intense monsoon during early to middle Holocene (9.0–∼4.6 ka). The δ13C varies from −14.2‰ to −22.6‰ and reflects abrupt changes in the proportions of C3 and C4 plants in the ecosystem during late Holocene. An average δ13C of −21.6 ± 1.0‰ during early to middle Holocene (9.0–4.6 ka) indicates that the vegetation was dominated by C3 plants growth under hot humid and strong monsoonal conditions. On the other hand, δ13C (−16.7 ± 2.1‰) during late Holocene (∼4−1 ka) suggests distinct vegetation shift towards increasing C4 plants abundance related to aridification (weak ISM) at ∼4 ka. The pattern of δ15N variability in the soil is similar to that observed for the δ13C variability in the profile. The δ15N varies from +4.4% to +8.3%, with significantly more positive values during late Holocene (weaker monsoon) compared to early to middle Holocene (stronger monsoon), consistent with the relationship between δ15N and mean annual precipitation observed on a global scale. Our study demonstrates a strong and rapid adjustment of vegetation in response to ISM variability during Holocene.

Radiocarbon Dates Reveal Serpent Mound Is More than Two Thousand Years Old

Recent radiocarbon dating (Herrmann et al. 2014) found that Serpent Mound was likely built during the Early Woodland period—around 320 BC. Herrmann et al. (2014) also suggested that the effigy was ...

Preliminary Investigation of Sri Lankan Copper-alloy Statues

The historical framework for the discussion is the chronology of Sri Lankan culture, which, based on the most recent archaeological evidence and radiocarbon dates, has been defined by three major periods: Early Historic (500 BC-300 AD), Middle Historic (300 AD-1200 AD) and Late Historic (1200 AD-1815 AD). A classification for the evolution of bronze sculpture with reference to the established historical chronology for Sri Lanka has been proposed by Reedy (2007) who sets out the following four major developmental periods of Late Anuradhapura (ca.432–993 AD), Polonnaruva (late 10th to early 13th century), Divided Kingdoms (13th to late 16th century), and Kandyan (17th to 19th century). This technical study investigated thirty sculptures including 25 tin bronzes in The Metropolitan Museum of Art and five from the Archaeological Department of Sri Lanka, representing all four major historic periods. The methods used to analyse the manufacture, composition, and condition of the statues were examination under magnification and Ultraviolet light, X-ray radiography, elemental analysis using X-ray fluorescence spectroscopy, and metallography. The results of the study included the finding that all the statues in the sample were cast using the lost-wax technique. Size does not seem to have had a bearing on whether statues were cast solid or hollow. Many of the small seated figures in the sample were solid cast, while a few were hollow cast. In addition the radiographs indicate that a variety of armatures of different thickness, size, and shape were present inside the hollow figures, irrespective of the size of the statues. Generally, metal of low porosity and few casting defects are observed in most of the radiographs, indicating that the castings are generally of good quality. Traces of five gates (or vents) observed on the backs of a group of five Lokapala figures examined, indicated that they were cast face-down in a horizontal position. Ten figures, particularly those from the later periods, show traces of gilding or intact gold layers. In all but one case, gold was found in association with mercury, confirming that they were amalgam gilded. Metallurgical studies were carried out on four figures in the sample: a Buddha, a Bodhisattva and two Hindu deities. A sample from a tang that was cast onto the goddess figure in antiquity proved to be quenched high-tin bronze, as evident from its microstructure; a tin content of 24.8 w/o was confirmed using X-ray energy dispersive spectroscopy in a scanning electron microscope. The four statues were from different historical periods and showed different microstructures, reflecting dissimilarities in composition, thermal history, and state of preservation.

Insights into the Earliest Formative Period of Coastal Ecuador: New Evidence and Radiocarbon Dates from the Real Alto Site

AbstractOne of the most intriguing questions of South American archaeology is the time, place, and origin of the earliest pottery. Since the late 1950s, the earliest pottery has been attributed to the materials of the Early Formative Valdivia culture (5600–3500 BP), coastal Ecuador. Excavations at the Real Alto site conducted in the 1970s and 1980s allowed the rejection of the spectacular “Jomon–Valdivia” hypothesis and established a local origin of the phenomenon. Recent radiocarbon dates from a joint Russian–Japanese–Ecuadorian project at Real Alto open a new page in our knowledge of the transition from pre-ceramic Las Vegas to ceramic Valdivia cultures.