When I was an undergrad in 1990 we were taught that all six periods of the Scandinavian Bronze Age were 200 (or in one case 300) years long. The most recent radiocarbon work shows that they all had different lengths and were more likely 130-280 years long. And the periods with the most abundant metalwork finds, II and V, are the two shortest. So their previously known status as metal-rich eras looks even more pronounced now, and the intervening periods look even poorer.
Per. I. 1700-1500 cal BC (200 yrs)
Per. II. 1500-1330 (170 yrs)
Per. III. 1330-1100 (230 yrs)
Per. IV. 1100-950/20 (165 yrs)
Per. V. 950/20-800 (135 yrs)
Per. VI. 800-530/20 (275 yrs)
Each of these periods translates to a list of artefact and monument types that are commonly found together. Their relative ordering through time has been known since the 1880s. Current work looks at the absolute dates at which these typological laundry lists were current. It uses a new technology, radiocarbon dating of cremated bone, and new applications of Bayesian statistics, which allow us to constrain the uncertainty of the radiocarbon results using stratigraphical observations. The latter means that if we know that grave B was later than grave A because one sat on top of the other, then we can tell the software to disregard parts of the probability distributions that gainsay this observation.
Hornstrup, K.M et al. 2012. A New Absolute Danish Bronze Age Chronology As Based On Radiocarbon Dating Of Cremated Bone Samples From Burials. Acta Archaeologica 83. Copenhagen.
Count yourselves lucky. You've still got 6 periods. They did that Bayesian shizzle on our neolithic, and it all but vanished!
This goes to show how little I know. I thought that the most recent Scandinavian metal era began ca. 1971.
Haha! We were barely in the Rock Age back then.