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Geochemical evolution of waters within the north coast limestone aquifers of Puerto Rico; a conceptualization based on a flow path in the Barceloneta area

Water-Resources Investigations Report 86-4080

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,

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Abstract

Water samples along a groundwater flow path in the Barceloneta area, Puerto Rico, were collected from wells screened in the Montebello Limestone Member of the Cibao Formation (artesian aquifer) and in the overlying Aguada and Aymamon Limestones (water table aquifer). The groundwater chemistry changes as water migrates from recharge areas to downgradient zones in the aquifers. Dissolved magnesium, dissolved sulfate, pH, and carbon-13 isotope generally increase down-gradient. Total inorganic carbon and calcium decrease within the freshwater parts of the aquifer. Mass transfer calculations show that the likely reaction model is carbon dioxide incorporation as water infiltrates through the soil zone, followed by calcite dissolution as water recharges the aquifer. As water moves downgradient within the artesian aquifer, carbon dioxide may degas as a result of calcite precipitation while gypsum and dolomite are dissolved. Within the water table aquifer, continuous recharge of waters rich in carbonic acid maintains the dissolution of the carbonate minerals. Near the coast the mixing of fresh groundwater with saltwater is the primary process affecting water chemistry within the water table aquifer. (Author 's abstract)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geochemical evolution of waters within the north coast limestone aquifers of Puerto Rico; a conceptualization based on a flow path in the Barceloneta area
Series title:
Water-Resources Investigations Report
Series number:
86-4080
Edition:
-
Year Published:
1987
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
iv, 28 p. :ill., maps ;28 cm.