Detrital zircon geochronology of Paleoproterozoic metasedimentary rocks from Jämsä, Central Finland

Abstract

In this short communication, we present new detrital single grain zircon U-Pb data for six metasedimentary rock samples from Jämsä, Central Finland. Four samples are from the southern parts of the Central Finland granitoid complex and two from metasedimentary rocks mixed with the volcanic belts bordering it to the south. Based on the obtained results, the detrital zircon populations of all the samples are similar, i.e. they are bimodal with peaks at 2.05–1.95 Ga and 2.90–2.70 Ga. The maximum depositional ages of the individual samples are interpreted as 1.93–1.90 Ga. Thus, the zircon populations are similar to both the Pirkanmaa migmatite belt, which borders the granitoid complex to the south, and the lowermost members of the volcano-sedimentary Tampere group to the west from our study area. The results further strengthen the similarities between the volcano-sedimentary successions in Tampere and Jämsä areas. Similarities between the detrital zircon populations within, and south of the Central Finland granitoid complex need to be taken into account in further refinements of regional tectonic models.

Keywords

• finland
• paleoproterozoic
• svecofennian
• central finland granitoid complex
• zircon
• u-pb
• metasedimentary rocks
• deposition age