BLOCKY CALCITE CEMENT FROM THE SUWANNEE TERRANE - EVIDENCE FOR MIXINGOF MIDDLE TO HIGH-LATITUDE METEORIC AND SEA-WATER

Blocky calcite cement from the Suwannee Terrane, an exotic terrane jux taposed against Gondwanaland during the Ordovician and now located in Georgia, Florida, and Alabama, has delta(13)C = -7.8 to 16.5 parts per thousand PDB and delta(18)O = -6.8 to -11.6 parts per thousand PDB. T his cement is interpreted to have formed during sulfate reduction, whi ch is supported by the coeval presence of pyrite and non-ferroan calci te cement. Isotopic values define part of a mixing line between calcit e cements precipitated from marine, organic carbon-dominated and meteo ric, inorganic-carbon dominated fluids.