Glacial recharge and paleohydrologic flow systems in the Illinois basin: Evidence from chemistry of Ordovician carbonate (Galena) formation waters

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Geological Society of America, Bulletin; (United States)

DOI:https://doi.org/10.1130/0016-7606(1994)106<1430:GRAPFS>2.3.CO;2· OSTI ID:6640529

Stueber, A M ^[1]; Walter, L M ^[2]

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1. Southern Illinois Univ., Edwardsville, IL (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)

The Illinois basin provides an opportune setting for elucidating the roles of remnant evaporite brines and meteoric waters in the evolution of formation waters in an intracratonic sedimentary basin. Formation waters from carbonate reservoirs in the Upper Ordovician Galena Group have been analyzed geochemically to study the origin of their salinity, their chemical and isotopic evolution, and their relationship to paleohydrologic flow systems. Chloride/bromide ratios and Cl/Br-Na/Br relations indicate that initial brine salinity resulted from subaerial evaporation of seawater rather than from halite dissolution. Subsequent subsurface dilution of the brines by meteoric waters is disclosed by [delta]D-[delta][sup 18]O covariance; however, the remnant evaporite brine has not been completely expelled from these Ordovician strata. Galena formation waters have [sup 87]Sr/[sup 86]Sr ratios that range from 0.708 17 (a value nearly equal to that of coeval seawater) to 0.710 43. This is the greatest range of Sr isotopic ratios found in waters from any stratigraphic unit in the basin. Two fluid mixing events are revealed in plots of [sup 87]Sr/[sup 86]Sr vs. 1/Sr. 41 refs., 11 figs., 1 tab.

• OSTI ID: 6640529
• Journal Information: Geological Society of America, Bulletin; (United States), Journal Name: Geological Society of America, Bulletin; (United States) Vol. 106:11; ISSN 0016-7606; ISSN BUGMAF
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical &amp; Physicochemical Properties
58 GEOSCIENCES
580000* -- Geosciences
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BRINES
BROMIDES
BROMINE COMPOUNDS
CARBONATE ROCKS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
COMPILED DATA
DATA
ELECTRON CAPTURE RADIOISOTOPES
EVAPORITES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
GLACIERS
GROUND WATER
HALIDE MINERALS
HALIDES
HALITE
HALOGEN COMPOUNDS
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
HYDROLOGY
ILLINOIS BASIN
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
METEORIC WATER
MINERALS
NUCLEI
NUMERICAL DATA
ORDOVICIAN PERIOD
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PALEOZOIC ERA
RADIOISOTOPES
ROCKS
SALINITY
SEAWATER
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STABLE ISOTOPES
STRATIGRAPHY
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
WATER