TY - JOUR A1 - Tesmer, Maja A1 - Moller, P. A1 - Wieland, S. A1 - Jahnke, Christoph A1 - Voigt, Hans-Jürgen A1 - Pekdeger, Asaf T1 - Deep reaching fluid flow in the North East German Basin: origin and processes of groundwater salinisation N2 - Major element chemistry, rare-earth element distribution, and H and 0 isotopes are conjointly used to study the sources of salinisation and interaquifer flow of saline groundwater in the North East German Basin. Chemical analyses from hydrocarbon exploration campaigns showed evidence of the existence of two different groups of brines: halite and halite Ca-Cl brines. Residual brines and leachates are identified by Br-/Cl- ratios. Most of the brines are dissolution brines of Permian evaporites. New analyses show that the pattern of rare-earth elements and yttriurn (REY) are closely linked to H and O isotope distribution. Thermal brines from deep wells and artesian wells indicate isotopically evaporated brines, which chemically interacted with their aquifer environment. Isotopes and rare-earth element patterns prove that cross flow exists, especially in the post-Rupelian aquifer. However, even at depths exceeding 2,000 m, interaquifer flow takes place. The rare-earth element pattern and H and O isotopes identify locally ascending brines. A large-scale lateral groundwater flow has to be assumed because all pre-Rupelian aquifer systems to a depth of at least 500 m are isotopically characterised by Recent or Pleistocene recharge conditions. KW - hydrochemistry KW - rare-earth elements KW - stable isotopes KW - hydrostratigraphy KW - brines Y1 - 2007 ER -