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Sources of Dissolved Carbonate in an Aquifer Free of Carbonate Minerals
Author(s) -
Pearson F. J.,
Friedman Irving
Publication year - 1970
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr006i006p01775
Subject(s) - carbonate , aquifer , carbonate minerals , groundwater recharge , geology , carbonate rock , precipitation , groundwater , atmosphere (unit) , dissolved organic carbon , mineralogy , environmental chemistry , geochemistry , hydrology (agriculture) , chemistry , calcite , oceanography , geotechnical engineering , physics , organic chemistry , meteorology , thermodynamics
Water from 14 wells in the Magothy aquifer, Long Island, New York, was sampled for chemical analysis and C 13 /C 12 ratio measurements of the dissolved carbonate. The Magothy is essentially free of carbonate minerals and contains water whose chemistry is controlled by the chemistry of the atmospheric precipitation that recharged the aquifer. Wells near the recharge area have δC 13 values of −25‰ and total carbonate contents corresponding to a P CO 2 of about 4×10 −3 atmosphere, showing that the carbonate here is derived from the soil zone. Downgradient, the total carbonate doubles, but the δC 13 values remain more negative than −18‰. The dissolved carbonate increase is due in part to carbonate mineral solution but results largely from oxidation of lignite in the aquifer by oxygen dissolved in the water.