1 Pol ish Geo log i cal In sti tute -Na tional Re search In sti tute, Rakowiecka 4, 00-975 Warszawa, Po land Oszczepalski, S., Chmielewski, A., Mikulski, S.Z., 2016. Con trols on the dis tri bu tion of rare earth el e ments in the Kupferschiefer se ries of SW Po land. Geo log i cal Quar terly, 60 (4): 811-826, doi: 10.7306/gq.1325 This study deals with the spa tial dis tri bu tion and the PAAS-nor mal ized pat terns of rare earth el e ments (REE) stud ied by ICP-MS in the Kupferschiefer se ries of SW Po land. The most char ac ter is tic fea ture is a pro gres sive en rich ment in REE content (in clud ing Y and Sc) out ward from the rocks with py ritic and Pb-Zn min er al isa tion, across the rocks with cop per min er alisa tion, to wards the ox i dized (Rote Fäule) ar eas. The same trend can also be ob served with re spect to LREE, MREE and HREE. Whereas REE dis tri bu tion di a grams for shales with py rite and Pb-Zn min er al isa tion are al most flat, di a grams for shales with he ma tite and cop per min er al isa tion are con vex-up ward and the stron gest con vex ity is at trib uted to the tran si tion from hematitic al ter ation to cop per-rich rocks. REE dis tri bu tion di a grams nor mal ized to PAAS show strong MREE en richment rel a tive to LREE and HREE, which is typ i cally the high est in the he ma tite zone, lower in shale with cop per min er al isation, and the low est in shales with Pb-Zn and py rite min er al isa tion. The sys tem atic in crease in the con cen tra tion of REE to wards the Rote Fäule, and the strong en rich ment in MREE in the tran si tion zone are in dic a tive of vari able in ten sity of leaching and for ma tion of the REE en rich ments (in clud ing MREE) by MREE>HREE>LREE flu ids, as ev i denced by the MREE-enriched sig na tures. Over print ing of sec ond ary en rich ments over the orig i nal REE pat tern due to re dis tri bu tion along the path ways of ex pand ing flu ids are pos tu lated to ac count for the ap par ent dif fer ences in the dis tri bu tion and con cen tra tion of REE (in clud ing the MREE-en riched trend) be tween the ox i dized rocks, cop per-bear ing rocks, and re duced lithologies bar ren in cop per.