At www.sciencedaily.com/releases/2016/08/160809095145.htm …. the discovery of a circular earthwork enclosure in southern Spain, dating to the Bell Beaker period (2600-2200BC) is interesting as we don't know yet that it has anything to do with the Beaker Folk. Excavations unearthed bones, sherds, jewelry etc. It is unclear if the sherds of pottery come from bell beakers or the C14 dates have provided the link. The site consists of concentric circular trenches cut into segments at regular distances. In the centre was a deep round hole 19m wide. The hole was filled with various things such as burnt clay bricks and the word 'ritual' is mentioned. The site appears to have been used for a short period only.
This enclosure seems to fit in with the general pattern of the Bell Beaker period, burnt material 'enclosed' as if to separate it from the surrounding human world. Seahenge fits into this pattern – an upturned tree that had perhaps been struck by lightning. It is expensive to have lots of charcoal and black sludge dated in a laboratory and this would not happen on your average archaeological dig. It is not a matter that the technology is available but comes down to cost and motivation.
At www.sciencedaily.com/releases/2016/08/160809122721.htm … here the archaeology is in Michigan and the Great Lakes area and concerns pre-European monuments, many of which have been ploughed over (as they have in Europe). Some innovative computer modelling claims to have created life like images of lost monuments – but once again, the topic involves circular earthworks and mounds. The enclosures were located near rivers as these were the main arteries of discourse in a canoe paddling culture. Unlike the Spanish example the circular enclosures are fairly recent – as recent as 1000-1600AD. Is this derived from datable finds retrieved from them and if so, might they have been in use over a long time, re-used in the way that Iron Age and Saxon period people re-used barrows in Britain?
At www.sciencedaily.com/releases/2016/07/160721072831.htm … is a story about re-use of barrows in Britain. In this instance, a Bronze Age barrow. These were round barrows as opposed to the long barrows of Neolithic people so we may assume a preference for circular mounds was still a focus of activity in the pre-Roman and post-Roman periods (and the latter date is not too far from the 1000AD of the earlier link).