Low-temperature water-rock interactions in bedrock aquifers of southern Rhode Island: Results of laboratory simulations

Conference · Mon Mar 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5710237

Veeger, A I; Moulton, K L ^[1]

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1. Univ. of Rhode Island, Kingston, RI (United States). Dept. of Geology

The nature of low-temperature chemical reactions occurring in bedrock aquifers of southern Rhode Island was investigated in the laboratory using flow-through columns. Crushed samples of Narragansett Pier Granite (NPG), Scituate Granite Gneiss (SGG), Hope Valley Alaskite Gneiss (HVAG) and Ten Rod Granite Gneiss (TRGG) were placed in flow-through columns. Water was circulated through the columns at a 3 ml/min and maintained at 25 C and at equilibrium with atmospheric carbon dioxide. Samples were collected from the columns at increasing time intervals and were analyzed for pH, conductivity, major cations and anions, and silica. The leachate compositions show that distinctive chemical differences can be expected in ground water that flows through each of these different rock types. Chemical modeling of the leachate solutions shows that reactions involving plagioclase feldspar (albiteoligoclase), reactive accessory minerals such as sphene, and, to a lesser degree, potassium feldspar and biotite, dominate the solution chemistry, with amorphous oxides and aluminosilicates formed as products of the weathering reactions. Small concentrations of reactive minerals may profoundly affect the composition of the leachate. Batch experiments using mineral separates revealed that the calcium in the NPG leachate was almost entirely attributable to sphene which comprises less than 1% of the rock.

• OSTI ID: 5710237
• Report Number(s): CONF-9303211-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
GROUND WATER
ROCK-FLUID INTERACTIONS
WATER CHEMISTRY
RHODE ISLAND
AQUIFERS
BENCH-SCALE EXPERIMENTS
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
GNEISSES
GRANITES
HYDROLOGY
LEACHATES
MINERALOGY
CHEMISTRY
DATA
DEVELOPED COUNTRIES
DISPERSIONS
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
INFORMATION
KINETICS
METAMORPHIC ROCKS
MIXTURES
NORTH AMERICA
NUMERICAL DATA
OXYGEN COMPOUNDS
PLUTONIC ROCKS
REACTION KINETICS
ROCKS
SOLUTIONS
USA
WATER
540310* - Environment
Aquatic- Basic Studies- (1990-)
580000 - Geosciences