New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater

Shallow groundwater geochemistry in the Española Basin, Rio Grande rift, New Mexico: Evidence for structural control of a deep thermal source
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Published:April 01, 2013
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CiteCitation
P.S. Johnson, D.J. Koning, F.K. Partey, 2013. "Shallow groundwater geochemistry in the Española Basin, Rio Grande rift, New Mexico: Evidence for structural control of a deep thermal source", New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater, Mark R. Hudson, V.J.S. (Tien) Grauch
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We have developed a conceptual model for the Tesuque aquifer system in the southeastern Española Basin near Santa Fe, New Mexico, based on measurements of chemical, isotopic, and thermal properties of groundwater from 120 wells. This study concentrates on a single groundwater-flow unit (GFU) of the Tesuque aquifer associated with the Santa Fe River drainage, where groundwater flows east to west across north-trending rift structures. We examine links between groundwater flow, temperature, water chemistry, and major fault structures. Hydrologic and hydrochemical processes are assessed through spatial mapping of temperature and chemical composition (Ca:Na ratios, F, As, B, Li, δ2H, and δ18O), Piper and bivariate plots, Spearman rank-order correlations, and flow-line modeling of mineral saturation (PHREEQC software). Results help delineate recharge and discharge areas and demonstrate spatial correspondence of major rift structures with changes in chemical and thermal data. Thermal wells with anomalous discharge temperatures and regional thermal gradients exceeding 40 °C/km align with structural boundaries of the Cañada Ancha graben and Caja del Rio horst. Mg-Li geothermometry characterizes temperatures associated with deep circulating groundwater. Important features of the conceptual model are (1) a forced convection system in the Tesuque aquifer associated with the Caja del Rio horst drives upward flow and discharge of warm, Na-rich groundwater in the western half of the Cañada Ancha graben; and (2) major horst-graben structures concentrate upward flow of deep, NaSO4 thermal waters from underlying bedrock. Both features likely contribute to chemical anomalies and thermal disturbances in the shallow Tesuque aquifer.
- aquifers
- basins
- chemical composition
- chromatography
- correlation
- D/H
- deep aquifers
- discharge
- Espanola Basin
- faults
- flow lines
- geologic thermometry
- ground water
- heat sources
- hydrochemistry
- hydrogen
- hydrology
- hydrothermal alteration
- ICP mass spectra
- ion chromatography
- ions
- isotope ratios
- isotopes
- mass spectra
- metasomatism
- models
- New Mexico
- North America
- O-18/O-16
- optical spectra
- oxygen
- recharge
- rift zones
- Rio Grande Rift
- Rocky Mountains
- Sangre de Cristo Mountains
- Santa Fe County New Mexico
- Santa Fe New Mexico
- saturation
- spectra
- stable isotopes
- structural controls
- temperature
- thermal history
- thermal properties
- trace elements
- U. S. Rocky Mountains
- United States
- Tesuque Aquifer
- Agua Fria Fault