Evidence for dilution of deep, confined ground water by vertical recharge of isotopically heavy Pleistocene water

Journal Article · Wed May 01 04:00:00 EDT 1991 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1991)019<0433:EFDODC>2.3.CO;2· OSTI ID:5541798

Siegel, D I ^[1]

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1. Syracuse Univ. NY (USA)

New analyses of the isotopic composition of water, {sup 14}C-dating of dissolved inorganic carbon, and order-of-magnitude Darcy calculations suggest that a dilute body of water, trending north-south in the Cambrian-Ordovician aquifer of Iowa, was emplaced as vertical recharge of Pleistocene-age water from the base of the Des Moines lobe of late Wisconsin time. The recharge occurred through more than 300 m of overlaying Silurian to Mississippian age rocks. The {delta}{sup 18}O values range from {minus}10{per thousand} to {minus}9{per thousand} for the dilute water body and are consistent with a mixture of Des Moines lobe meltwater and precipitation found today in the north-central US. These results suggest that (1) the climate at the end of the last glaciation was mild and (2) a ground-water stable isotope signature similar to that of modern precipitation in an aquifers recharge area is not a priori evidence for relatively recent recharge.

• OSTI ID: 5541798
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 19:5; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
AQUIFERS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CAMBRIAN PERIOD
CARBON 14
CARBON ISOTOPES
CARBONIFEROUS PERIOD
CENOZOIC ERA
CLIMATES
DEVELOPED COUNTRIES
EVEN-EVEN NUCLEI
FEDERAL REGION VII
GEOLOGIC AGES
GEOLOGIC HISTORY
GLACIERS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROLOGY
IOWA
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MATTER
MIXING
NORTH AMERICA
NUCLEI
ORDOVICIAN PERIOD
ORGANIC MATTER
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PALEOZOIC ERA
PLEISTOCENE EPOCH
QUATERNARY PERIOD
RADIOISOTOPES
RECHARGE
SILURIAN PERIOD
STABLE ISOTOPES
USA
WATER
YEARS LIVING RADIOISOTOPES