Tag Archive for: experiments

This month the Dutch government installed a 15 cent deposit on tin cans to encourage people to recycle their cans. Recycling is however not a recent invention, it has been around since early prehistory. During the Vlaardingen Culture phase (3400-2500 BC) flint axes were often recycled to make other tools such as scrapers and flint borers. To better understand the recycling of these axes we conducted several experiments with reconstructed flint axes. The experiments were now published in the journal Lithic Technology.

Flake core from Vlaardingen Arij Koplaan (trench 17), made from a recycled flint axe. The flakes struck from these kind of cores were used to make a wide variety of tools including borers, scrapers and strike-a-lights.

Based on our experiments we concluded that importance of recycled flint axes in this period was so far underestimated. We now estimate that on some sites up to 40% of all the flint originally came from broken/reused flint axes.

The article was published open access and it can be downloaded via this link.
Also read our previous blog about the setup of the experiments.

The research project Putting Life into Late Neolithic Houses is a rather comprehensive research project that aims to understand various aspects of Neolithic life in the Rhine/Meuse delta of the Netherlands. Because of the interdisciplinary nature of the project, people with different skills and knowledge are required. Apart from academics, the project needs people skilled in crafts. Our team member Diederik Pomstra is such a craftsperson.

Knowing Diederik’s background, one would not expect him to be an experimental archaeologist. He studied Dutch and International Law in Utrecht, and trained as a jurist, he started his professional career at Amnesty International where he facilitated the work of the doctors who documented the effects of torture, and at VluchtelingenWerk Nederland where he gave legal advice to refugee lawyers. Although this challenging work to defend human rights and being confronted with the devastating consequences of war did affect him, he never consciously exchanged his job for a career in experimental archaeology.

Becoming a self-employed stone age craftsperson was not a watershed moment. The interest for prehistoric technology was already present early on. “Life just brought me there,” Diederik recalls when elaborating on his trajectory from being a jurist to an archaeologist. However, a moment that did boost his profession as an experimental archaeologist, or at the very least steered him towards becoming a full-time archaeologist was a chance encounter with Annelou van Gijn during a Mesolithic living project in Horsterwold (Flevoland) in 2005. Since then, Diederik contributes to research projects of scientists from various universities as a toolmaker and performer of experiments (fig. 1).

Figure 1: Diederik Pomstra explaining how to grain a hide, 11 July 2021.

Being a nature-lover all his life, experimental archaeology certainly increased that devotion to nature, although he would say that nature led him towards experimental archaeology rather than vice versa. Gaining extensive experience in prehistoric crafts certainly made him more aware of nature as a source for tools and materials. Now, he keeps a close eye on what the seasons offer in order to plan the harvesting of the materials and shape them into tools subsequently, a transformation process that fascinates him time and again. While he was already familiar with most materials he works with, antler is something he learned to appreciate along the way. In that sense, his profession broadened his horizon. Yet, even after all those years of professional experience, he is still driven by an insatiable creative hunger for trying out new materials. For example, making a lime bark canoe, as an equivalent of the Native American birch bark canoe, is on top of his bucket list. “It is so logical,” says Diederik referring to the bark and its properties to make a boat. And seeing the ‘logic’ of natural sources to make tools is exactly why we need a craftsperson in our research team.

Launching the dugout on September the 16th

On 16 September, the dugout – or boat made from a hollowed log – was launched at Natsec, a canoe club near the Vlaardingen cultuurhuis (figure 1). The making of the dugout, which is part of the research project Putting Life into Late Neolithic houses, started in June 2021 and lasted through July 2022. Starting from an oak tree, it took the volunteers of Masamuda 30.433 minutes, or 507 hours, or more than 21 entire days to finish the dugout. During those 507 working hours, the volunteers performed no less than 516 experiments with various tools and had to register every experiment on paper (figure 2).

Figure 1: Launching the dugout on 16 September 2022.


Figure 2: Erwin, Ellen and Leo filling in the paperwork on 26 June 2021.

The volunteers, of which the majority had no previous experience in making a dugout, worked exclusively with a Neolithic toolkit. Such a prehistoric toolkit consists of axes and adzes, wedges made of antler, chisels of antler or bone, and flint scrapers. In addition to the dugout, they also made paddles from ash tree.

The Putting Life team wishes to thank the volunteers for their effort, endeavor and dedication in making the dugout.

On the 22nd of October 2022 we hosted a hide-working workshop for the volunteers of Masamuda. The workshop was aimed to gain insight into hide-working traces on Vlaardingen Culture (VLC) scrapers. On the VLC site of Hekelingen III several scrapers were found with hide working traces which potentially could be linked to the scraping of fatty hides with the use of additives (Van Gijn 1990). To test this hypothesis, we scraped two sealskins with flint scrapers using additives. One hide was scraped with sand while the other was scraped with dried clay. The sealskins were donated to the project by Zeehondencentrum Pieterburen, a seal rescue center. These skins belonged to weaners, common seals (Phoca vitulina), who died of pneumonia, the skins were removed during the autopsy. We chose to use sealskins because these are notoriously fat and because seal bones were found both in Hekelingen III and in Vlaardingen (Brinkkemper et al. 2010).

Removing the blubber

Unlike most mammals, seals have a thick layer of blubber (fat) below their skin. The first step in the hide-working process therefore consisted of removing the layer of blubber (see figure 1). We did this using unmodified flint flakes. The sharp edges of the flakes proved to be effective tools for this task. It took the volunteers approximately two and a half hours to remove the thick layer of fat.

Figure 1. Removing the layer of blubber with flint flakes.

Framing the skins

Once the layer of fat was removed small incisions were made in the skins to facilitate stretching them in a frame. The skins were stretched in a wooden frame and laid down in the grass for further processing (see figure 2).

Figure 2. Framing the seal skins in a wooden frame.

Scraping with additives

Now the entire skins were covered in additives which were added to absorb the fat (see figure 3). One skin was covered in sand while the other was covered in ground dry clay. After this, the hides were scraped with flint scrapers which were hafted in a wooden haft (see figure 4 and 5). The hides were scraped for approximately fifty minutes. It could be noted during the process that the scrapers already acquired a macroscopically visible gloss, this was especially true for the scrapers used to scrape the hide with sand. This is not entirely surprising as it is known that flint can be polished using sand in combination with leather. The additives indeed absorbed fat from the hides and it therefore seemed that this was indeed an effective method for removing excessive fat from these skins. The use-wear traces on the scrapers still need to be studied, but the fact that they acquired macroscopically visible traces in the form of a macroscopically visible gloss and clear rounding of the edges indicates that they must attained have well developed wear traces.


To be continued…

After this the hides will have to be scraped again in order to remove the remaining fat. They will have to be dried, stretched and rubbed to create a kind of fat cured leather. In this case the fat inside the skin will serve to cure and preserve the skins. All the tools used in the experiments will be analyzed microscopically and the wear traces on these tools will be compared to archaeological scrapers of which the wear traces have been tentatively interpreted as being the result of scraping hides with additives. Hopefully, this will provide more insights into the hide-working processes in the Neolithic.


Brinkkemper, O., E. Drenth and J.T. Zeiler, 2010. De voedseleconomie van de Vlaardingen cultuur in Nederland. Een algemeen overzicht, Westerheem Special 2010: Vlaardingen-cultuur, 26-51.

Van Gijn, A.L., 1990. The wear and tear of flint. Principles of functional analysis applied to Dutch Neolithic assemblages, Leiden  Faculty of Archaeology.