Distribution of rare earth elements in crystalline bedrock groundwaters: Oslo and Bergen regions, Norway

One hundred and fifty Norwegian bedrock groundwater samples, from Bergen an d from Vestfold (Oslofjord), have been analysed by ICP-MS techniques at two laboratories for a large suite of trace elements including rare earth elem ents (REEs) and Y. The bedrock lithologies include granites (dominated by t he Permian Drammen Granite) and Permian latites/rhomb porphyries from Oslof jord, and Caledonian/Precambrian granitic and gneissic lithologies in the B ergen area. The REEs show good correlation with each other, with the except ion of Eu. REEs generally show a weak negative correlation with pH. REE con centrations are highest in waters in acidic lithologies and generally decre ase with increasing atomic weight. Yttrium, La, Ce and Nd are the most abun dant REEs in the waters, with median concentrations exceeding 0.1 mu g/l. O n crustal (PAAS)-normalised plots,distinct geochemical signatures are obser ved for the different lithologies. Most groundwaters exhibit negative Eu an omalies on such plots, except for latitic waters from the Oslo area which s how a positive Eu anomaly. Aquifer host-rock-normalised plots for groundwat ers from Vestfold indicate minor enrichment in heavier REEs and depletion i n Ce during water-rock interaction. (C) 1998 Elsevier Science Ltd. All righ ts reserved.