Quaternary International最新文献

In the last decade Bayesian analysis of radiocarbon dates has become commonplace for archaeologists grappling with regional chronologies. Here we present Bayesian analysis for radiocarbon dates from Moche cultural contexts from the north coast of Peru with the aim to understand the duration of the phenomenon and to compile all known dates in a single location for future analysis and use. The analysis demonstrates that the long-standing Moche ceramic sequence does not provide a perfect proxy for tracking the timing of all social interactions. However, our results show general agreement with traditional relative Moche chronologies. Finally, our study shows that Moche was a shorter cultural phenomenon than has been previously argued, with the current data indicating that it began between the late 4th and early 6th centuries CE and lasted until the 9th century CE.

The Late Intermediate Period (LIP, cal AD 1000–1450) in the central Andes is defined as a hiatus after the collapse of Tiwanaku and Wari, expansive state polities of the Middle Horizon (cal AD 600–1000), and before the domination of the Inca empire in the Late Horizon (cal AD 1450–1532). The LIP is often characterized as a unit, but major developments took place within this long period, including diasporic migrations and the new colonization of some regions, demographic change, intensified conflict, large-scale adverse climate episodes, and changes associated with the onset of Inca expansion. Here we make a preliminary attempt to clarify the chronology of these developments. A database of published and new radiocarbon dates is compiled for the south-central highlands and coastal valleys in order to model overall and subregional demographic trends using an updated “dates-as-data” cumulative kernel density estimate (CKDE) approach, and to examine specific LIP phenomena in two subregions. Our results indicate major demographic change including 1) substantial population growth beginning in the 13th century, 2) a marked 14th-century population surge in most, but not all, subregions included here, 3) evidence of population decline in several subregions during the same intervals when neighboring populations are expanding. Population growth was associated with intensified violence and increased physiological stress in the upper Nasca drainage. In the altiplano of Peru and Bolivia, population growth accompanied the rise of defensive hillforts and monumental cemeteries. Our date models also indicate a more complicated terminal LIP in the altiplano, with the height of classically “LIP” societies overlapping with early evidence for imperial Inca presence. This paper highlights the ways that more refined chronology can make advances in our understanding of a turbulent post-collapse era in the Andes.

In 2013 archaeological radiocarbon databases covering 13,000–7000 ¹⁴C BP for nine countries in South America, including Peru, were published in a special issue of Quaternary International. The past decade has seen new field research and radiocarbon ages contributed to the Peruvian archaeological record, two updates to the southern hemisphere calibration curve, and research papers drawing from South American radiocarbon databases to explore region- and continent-scale patterns of human-environment interaction, settlement dynamics, and paleodemography.

This paper provides an update to the Peruvian archaeological radiocarbon database for the Late Pleistocene to early Middle Holocene. The new database (version 2) includes 493 radiocarbon dates spanning 20,000 to 7000 ¹⁴C BP. No radiocarbon dates >13,000 ¹⁴C BP meet basic archaeological criteria. First, I review the structure of Peru's early archaeological radiocarbon record and highlight several research and landscape taphonomic biases. Second, I examine distributions of archaeological sites through time, beginning with basic site and date frequencies and progressing to Bayesian analysis of aggregated radiocarbon dates. Third, applying established criteria for well-dated archaeological events, I identify some unresolved problems in early Peruvian radiocarbon chronologies, with the goal of outlining priorities for future archaeological and chronometric research.

The middle Holocene saw major changes in political and socioeconomic organization in Peru. Still, not all Peruvian groups transitioned to food production or engaged in mound or monument construction, yet we know relatively little about those who maintained a mobile lifestyle centered on foraging. Using GIS and statistical analyses to interrogate a database of radiocarbon dates, we assess the Peruvian record of forager distributions through the middle Holocene. We identify patterns consistent with biases stemming from disproportionate research attention, regional and intrasite sampling methodologies, and taphonomy that may be hampering our study of middle Holocene foragers. Further confounding our understanding of foragers during this period are reports of middle Holocene radiocarbon gaps attributed to population decline across South America in response to climate-induced scarcity of freshwater and other resources. We show, however, that this might also be an artifact of sampling in some cases and argue for both increased archaeological attention to middle Holocene foragers and greater awareness of perceptual biases that might influence research design and, therefore, research attention and outcomes.

The South Coast of Peru, the location where Peru's widely used period/horizon relative ceramic chronology was established and where archaeological samples were obtained for the earliest radiocarbon studies, has figured prominently in the development of chronologies in the Central Andes. We examine the current state of chronology in the region with a compilation of 770 published and unpublished radiocarbon dates from >60 sites in the Nasca and Ica drainages and on the Paracas Peninsula, spanning a period of approximately 8000 years, to evaluate the relative ceramic chronologies and explore the timing and duration of major cultural changes. Kernel Density Estimate (KDE) summaries of Bayesian phase models demonstrate the following aspects of regional cultural dynamics: the earliest settlements began in the Preceramic ca. 6000 BCE and are found on the coast; the Paracas culture was established ca. 900 BCE and cultural development was first focused in the north and then spread south; a reverse direction of cultural influence is found during the Nasca culture when innovation began in the south and spread north; an early mixture of Late Nasca/local Loro culture is found in Nasca (510–720 CE) followed by the spread of Loro elsewhere and the establishment of intrusive highland Wari colonies that peaked in the mid-9th century CE; and the Late Intermediate Period was variable throughout the region in terms of timing and duration, reflecting a turbulent period. The results of the study reveal strong temporal overlap in the ceramic styles indicating they are not purely sequential and consequently are inadequate as chronological markers on a regional level. The research highlights the potential of radiocarbon evidence to reveal sub-regional temporal heterogeneity and to help us better understand the dynamics of cultural change.

The expansion and impact of the Wari polity across the Andes has been heavily debated by scholars over the past two decades. We use radiocarbon dates, Bayesian statistics, and contextual data from several Andean regions to review the chronology for Wari expansion, political reorganization, and impact on local settlements. We recognize that Wari political and economic influence will vary in space and time and present a model that addresses how influential moments (expansion, reorganization, collapse) in Wari's trajectory may or may not have had broader impacts across the landscapes of its peer polities. Our model, while not completely comprehensive, draws on both Wari's presence in the north highlands and in the south, where scholars have argued for distinct trajectories and character of Wari influence. It also examines data from local communities in these same regions contemporary with identified Wari settlements, but perhaps without outward indicators of Wari hegemony, to evaluate broader patterns in Middle Horizon settlement through the latter half of the first millennium CE.

Recent articles provide a captivating set of radiocarbon dates from Machu Picchu and environs, with important ramifications for the site and the Inca Empire more broadly. Here, we present Bayesian models of these dates that incorporate life history details of each dated individual, including age at death, age of tissue formation for dated samples, family relationships, and associated grave goods. We calibrate dates with a bespoke calibration curve mixture specific to Machu Picchu. These model boundaries suggest the site was first occupied ∼ AD 1435 (1410–1455, 95%) and abandoned ∼ AD 1495 (1480–1515, 95%). This is consistent with dates from the region and builds on the consensus that ethnohistoric dates are unreliable. Anchoring Inca history to this radiocarbon chronology allows us to explore the ethnohistoric sources in a new light. We can more plausibly trace the life history of the ruler Pachacutec, including his founding of the Machu Picchu royal estate. Regionally, this approach leads us to reassess the conquest of the earliest and largest Inca conquest, the southern quarter. This area was subject to waves of intense interaction for nearly two centuries by multiple royal houses, possibly starting under Yahuar Huacac, Pachacutec's grandfather, events that were almost completely scrubbed from Inca praise narratives.

Using the Central Andean Chavín Phenomenon as a case study, this paper explores the middle ground between top-down (big data) and bottom-up (Bayesian modeling) approaches to archaeological radiocarbon data. Compiling radiocarbon dates associated with the Chavín Phenomenon addresses questions of chronology, demonstrating that the relevant phases at interacting sites are relatively brief and broadly contemporary. In addition, the definition of a discrete span of time associated with the Chavín Phenomenon makes it possible to explore the context for that period of heightened interaction. Juxtaposing that timespan with a compilation of Central Andean radiocarbon dates identifies contemporary non-participatory sites, enabling characterization of the sociopolitical milieu within which the Chavín Phenomenon emerged, flourished, and faded. The identification of that corpus of sites also highlights the importance of a shift in focus from identification of interaction to characterization of interaction. Bottom-up approaches to radiocarbon chronology will be a key element of that effort, while high-level summary of radiocarbon assemblages can identify where additional dating and Bayesian modeling can have the greatest interpretive impact.

A multi-proxy study of biotic and abiotic components was conducted on surface sediment samples from six lakes/wetlands located along the western transitional boundary of the contemporary Indian Summer Monsoon (ISM) in the Indian Subcontinent. The primary goal is to assess the suitability of various proxies as representatives of modern vegetation, environmental and climatic conditions. The collected data indicate significant variations in the composition and density of pollen in response to climate-induced and anthropogenic ecological changes throughout the northwest India transect. The palynological studies from eastern Rajasthan shows high forest elements in comparison to western Haryana and western Uttar Pradesh. In addition, the palynological data was juxtaposed with other biotic proxies such as diatom and isotopic studies, along with geochemical proxies and paleomagnetic data of the surface lake sediments. The presence of marker pollen taxa including Cerealia type Poaceae, Chenopodiaceae, and Brassicaceae, allows for distinct recognition of anthropogenic activities throughout the whole transect. The diversity and distribution of diatoms also support the palynological data in response to climate-induced and anthropogenic ecological changes. Furthermore, grain size, geochemistry (TOC/TN ratio with stable carbon isotope), and magnetic susceptibility data offer crucial insights about the sediment's depositional settings and general mineralogical composition. Stable carbon isotope data shows C₃ dominance in relatively humid areas and C₄ dominance in semi-arid areas, suggesting climate-driven control over sediment organic matter composition. Canonical correspondence analysis (CCA) indicates that biotic variables (pollen, diatom, stable isotopic composition) are significantly controlled by modern precipitation and temperature. Redundancy analysis reveals a significant influence of current average temperature and precipitation on major element oxide variations in surface lake sediments. Therefore, we propose using palynological, stable carbon isotope, diatom data, along with grain size, environmental magnetism, and geochemistry, to establish a multiproxy modern analogue for quantitative palaeoclimatic reconstructions. As a result, this study provides the first modern analogues from a climate-sensitive region that separates the area under ISM influence from an area with meager precipitation in western India.