Cairns for All Purposes

While tar kilns and charcoal piles might not appear that often in the archaeological database of the Finnish Heritage Agency, there is a type of heritage that seems almost overly common within Satakunta - that is cairns. It was also cairns that I first got to visit when arriving to the region and they have been a common part of my weekly visitation schedule ever since. Cairns are fairly easy to spot for anyone moving in the nature, but a lot harder to determine without prior knowledge.

The first cairn I visited in Satakunta - Rihtmäenperkko II in Rauma.

Cairns are typically described as human-made piles of stones, that have been built for a variety of purposes and this variety makes them a bit harder to further determine. While the archaeologists mostly focus on cairns that were used for burials, humans have also piled rocks for example as landmarks, oven-bases and ritual sites, but also just to simply remove rocks from a field. Besides, some rock-formations are naturally born rather than results of human activities. It's also important to note that the types of burial cairns varies around Finland a bit, so I now concentrate on the Bronze Age cairns that are typical to the coastline of Satakunta.

As mentioned before, determining the nature of a cairn can sometimes be tricky, but there are certain clues to look for. In Satakunta, burial cairns are typically built on the highest point of a hill, although they can also appear a bit lower on the hillside as well. Unlike natural formations, the rocks have been piled within a clearly defined area and, unlike other rock piles, the rocks chosen for a burial cairn are similar in shape and size, with possibly one bigger center-stone among the others.

A good way of determining the possible era for a discovered site, is by looking into the post-glacial rebound. To explain it shortly, after the weight of the ice sheets was lifted following the last glacial period, the ground level has been slowly rising each year. Thus, cairns that were typically built relatively close to the seashore during the Bronze Age appear now far inland. By checking how many meters above the current sea level the cairn is, we can easily compare the information to the sea-level of different periods and find out whether the elevation is typical to Bronze Age cairns or if the cairn was actually under water during the period. While the post-glacial rebound rate varies around Finland, the information of its local speed can often be found in books about local history.

The information is useful also when looking for new sites, as we can easily make models of how a researched area once looked like and determine the likely places for cairns or other remains from a certain period.

Rough model of the sea-level at the end of the Bronze Age with known cairns marked with stars.

When visiting a site, all aforementioned observations and calculations are marked down and then used to deduct the likely period and purpose for the site. As especially burial cairns are fairly actively researched among archaeologists, it's likely that one day soon the deductions are put into a test through an excavation. However, as there are thousands of burial cairns in Finland, it might take a while before a certain cairn is opened up for research.

In case you've discovered a cairn that isn't recorded into the archaeological database, follow these introductions to report it to the Finnish Heritage Agency.