Travertine precipitation in the Paleoproterozoic Kuetsjärvi 1 Sedimentary Formation, Pechenga Greenstone Belt, NE 2 Fennoscandian Shield 3 4 Salminen, P.E. a* , Brasier, A.T. b , Karhu, J.A a , Melezhik, V.A. c,d 5 a Department of Geosciences and Geography, P.O. Box 64 (Gustaf Hällsrömin katu 2a), 00014 University of 6 Helsinki, Finland 7 b Department of Geology and Petroleum Geology, Meston Building, University of Aberdeen, Scotland. AB24 8 3UE 9 c Geological Survey of Norway, Leiv Eriksson vei 39, N-4791 Trondheim, Norway 10 11 *Corresponding author, Tel. +358 02941 50834, fax: +358 02941 50826, E-mail: 12 paula.salminen@alumni.helsinki.fi 13 Abstract 14 15 Precambrian travertines, tufas and speleothems either formed rarely or they have not been identified in previous 16 studies. In the absence of high pCO 2 soils in Paleoproterozoic, karst solution and speleothem formation occurred 17 by processes distinct from those commonly found in present-day low temperature karst environments. However, 18 the high pCO 2 atmosphere could itself have encouraged karst formation. The Paleoproterozoic Kuetsjärvi 19 Sedimentary Formation of the Pechenga Greenstone Belt, NW Russia, includes abundant terrestrial carbonate 20 precipitates. These precipitates were sampled from a drillcore representing a complete section of the ca. 120-m- 21 thick formation and were investigated for C and O isotopes, acid-soluble elemental contents and petrography. 22 The newly obtained results were used to constrain the origins of the precipitates and to illuminate different 23 terrestrial carbonate types. The investigated drillcore includes abundant small-scale cavities and veins, which are 24 commonly filled with dolomite and quartz. Dolomite crusts are found both in the cavities and on 25 1