Quentin Bourgeois

Ancient DNA studies revealed that, in Europe from 6500 to 4000 bce, descendants of western Anatolian farmers mixed with local hunter-gatherers resulting in 70–100% ancestry turnover¹, then steppe ancestry spread with the Corded Ware complex 3000–2500 bce². Here we document an exception in the wetland, riverine and coastal areas of the Netherlands, Belgium and western Germany, using genome-wide data from 112 people 8500–1700 bce. A distinctive population with high (approximately 50%) hunter-gatherer ancestry persisted 3,000 years later than in most European regions, reflecting incorporation of female individuals of Early European Farmer ancestry into local communities. In the western Netherlands, the arrival of the Corded Ware complex was also exceptional: lowland individuals from settlements adopting Corded Ware pottery had hardly any steppe ancestry, despite a Y-chromosome characteristic of people associated with the early Corded Ware complex. These distinctive patterns may reflect the specific ecology that they inhabited, which was not amenable to full adoption of the early Neolithic type of farming introduced with Linearbandkeramik³, and resulted in distinct communities where transfer of ideas was accompanied by little gene flow. This changed with the formation of Lower Rhine–Meuse Bell Beaker users by fusion of local people (13–18%) and Corded Ware associated migrants of both sexes. Their subsequent expansion then had a disruptive impact across a much wider part of northwestern Europe, especially in Great Britain where they were the main source of a 90–100% replacement of local Neolithic ancestry.

Understanding how the dispersal of cultural innovations intersects with the spread of genes remains a central challenge in prehistoric archaeology. Here, we examine how the third millennium BCE Corded Ware (CW) and Bell Beaker (BB) burial traditions disseminated across Europe and their relation to the influx of steppe ancestry. To investigate these spatiotemporal dynamics during one of Europe’s most transformative periods, we compiled a dataset of radiocarbon dates from 967 burials, applying kernel density estimation alongside optimal linear estimation. We show that the adoption of CW and BB funerary rites is not synchronized with, and often contradicts, the spread of steppe ancestry. Furthermore, we show that these burial traditions spread rapidly and polyfocally among dispersed communities before a brief yet continent-wide consolidation phase around 2600 BCE for CW and 2400 BCE for BB, suggesting broad, simultaneous societal changes among preliterate societies.

Summary: The first phase of the ancient DNA revolution painted a broad-brush picture of European Holocene prehistory, whereby 6500-4000 BCE, farmers descending from western Anatolians mixed with local hunter-gatherers resulting in 70-100% ancestry turnover, then 3000-2500 BCE people associated with the Corded Ware complex spread steppe ancestry into north-central Europe. We document an exception to this pattern in the wider Rhine-Meuse area in communities in the wetlands, riverine areas, and coastal areas of the western and central Netherlands, Belgium and western Germany, where we assembled genome-wide data for 109 people 8500-1700 BCE. Here, a distinctive population with high hunter-gatherer ancestry (∼50%) persisted up to three thousand years later than in continental European regions, reflecting limited incorporation of females of Early European Farmer ancestry into local communities. In the western Netherlands, the arrival of the Corded Ware complex was also exceptional: lowland individuals from settlements adopting Corded Ware pottery had hardly any steppe ancestry, despite a characteristic early Corded Ware Y-chromosome. The limited influx may reflect the unique ecology of the region’s river-dominated landscapes, which were not amenable to wholesale adoption of the early Neolithic type of farming introduced by Linearbandkeramik, making it possible for previously established groups to thrive, and creating a persistent but permeable boundary that allowed transfer of ideas and low-level gene flow. This changed with the formation-through-mixture of Bell Beaker using populations ∼2500 BCE by fusion of local Rhine-Meuse people (9-17%) and Corded Ware associated migrants of both sexes. Their expansion from the Rhine-Meuse region then had a disruptive impact across a much wider part of northwest Europe, including Britain where its arrival was the main source of a 90-100% replacement of local Neolithic peoples.

Volunteers are a key part of the archaeological labour force and, with the growth of digital datasets, these citizen scientists represent a vast pool of interpretive potential; yet, concerns remain about the quality and reliability of crowd-sourced data. This article evaluates the classification of prehistoric barrows on lidar images of the central Netherlands by thousands of volunteers on the Heritage Quest project. In analysing inter-user agreement and assessing results against fieldwork at 380 locations, the authors show that the probability of an accurate barrow identification is related to volunteer consensus in image classifications. Even messy data can lead to the discovery of many previously undetected prehistoric burial mounds.

This paper presents WODAN2.0, a workflow using Deep Learning for the automated detection of multiple archaeological object classes in LiDAR data from the Netherlands. WODAN2.0 is developed to rapidly and systematically map archaeology in large and complex datasets. To investigate its practical value, a large, random test dataset—next to a small, non-random dataset—was developed, which better represents the real-world situation of scarce archaeological objects in different types of complex terrain. To reduce the number of false positives caused by specific regions in the research area, a novel approach has been developed and implemented called Location-Based Ranking. Experiments show that WODAN2.0 has a performance of circa 70% for barrows and Celtic fields on the small, non-random testing dataset, while the performance on the large, random testing dataset is lower: circa 50% for barrows, circa 46% for Celtic fields, and circa 18% for charcoal kilns. The results show that the introduction of Location-Based Ranking and bagging leads to an improvement in performance varying between 17% and 35%. However, WODAN2.0 does not reach or exceed general human performance, when compared to the results of a citizen science project conducted in the same research area.

Although the history of automated archaeological object detection in remotely sensed data is short, progress and emerging trends are evident. Among them, the shift from rule-based approaches towards machine learning methods is, at the moment, the cause for high expectations, even though basic problems, such as the lack of suitable archaeological training data are only beginning to be addressed. In a case study in the central Netherlands, we are currently developing novel methods for multi-class archaeological object detection in LiDAR data based on convolutional neural networks (CNNs). This research is embedded in a long-term investigation of the prehistoric landscape of our study region. We here present an innovative integrated workflow that combines machine learning approaches to automated object detection in remotely sensed data with a two-tier citizen science project that allows us to generate and validate detections of hitherto unknown archaeological objects, thereby contributing to the creation of reliable, labeled archaeological training datasets. We motivate our methodological choices in the light of current trends in archaeological prospection, remote sensing, machine learning, and citizen science, and present the first results of the implementation of the workflow in our research area.

The emergence of Corded Ware Groups throughout Europe in the 3^rd millennium BC is one of the most defining events in European history. From the Wolga to the Rhine communities start to speak Indo-European languages and bury their dead in an extremely similar fashion. Recent ancient DNA-analyses identify a massive migration from the Eurasian steppe as the prime cause for this event. However, there is a fundamental difference between expressing a Corded Ware identity—the sharing of world views and ideas—and having a specific DNA-profile. Therefore, we argue that investigating the exchange of cultural information on burial rites between these communities serves as a crucial complement to the exchange of biological information. By adopting a practice perspective to 1161 Corded Ware burials throughout north-western Europe, combined with similarity indexes and network representations, we demonstrate a high degree of information sharing on the burial ritual between different regions. Moreover, we show that male burials are much more international in character than female burials and as such can be considered as the vector along which cultural information and Corded Ware identity was transmitted. This finding highlights an underlying complex societal organization of Corded Ware burial rites in which gender roles had a significant impact on the composition and transmission of cultural information. Our findings corroborate recent studies that suggest the Corded Ware was a male focused society.

The thousands of Bronze Age burial mounds of northwestern Europe often have complex histories, with multiple construction phases and secondary burials added to these mounds. It can be difficult to understand the dynamic nature of these events and the ebb and flow of activities in these monumental funerary landscapes. This article presents chronological models of five Bronze Age barrows from two sites. A total of 41 radiocarbon-dated cremation burials were fitted into several chronological sequences. The results from the chronological models at both sites suggest that the creation of a burial mound was just one event within a much longer funerary history. For both sites, there are indications that the deceased were buried in flat graves decades and sometimes more than a century prior to any monument construction. Once in place, the barrows were then used as a repository for the dead for decades afterwards. At the same time, a comparison of the models suggests that funerary events at both sites were punctuated. At one site, several barrows were in use simultaneously, at the other, barrows seem to be each other’s successor. The models provide evidence for both protracted histories as well as punctuated events.DOI: 10.2458/azu_rc.57.17925