In the Galisteo drainage basin south of Santa Fe, a fold and several faults related to the Rio Grande rift deform late Eocene–Oligocene dikes, laccoliths, and the Espinaso Formation. The largest rift-related feature, a northerly plunging syncline, comprises the south end of the Santa Fe embayment of the Española Basin and the northern end of the Estancia Basin. The east limb of the syncline is cut by northerly trending, graben-forming, normal faults of the Agua Fria fault system in the Santa Fe embayment. East of the Tijeras-Cañoncito fault system, the east limb of the Estancia Basin is disrupted by down-to-the-west, normal faults of the Glorieta Mesa boundary fault and the Hub Mesa fault system. The fold is offset by down-to-the-northwest movement, and a small component of right slip, on the Tijeras-Cañoncito fault system, which separates the two basins. The above-mentioned rift-related fold and north-trending faults are superimposed across the southeastern margin of the San Luis uplift and the younger Galisteo Basin. Geologic maps and drill data reveal four, and possibly five, phases of Laramide deformation associated with recurrent movement along the Tijeras-Cañoncito fault system: (1) a possible Late Cretaceous, cryptic phase of strike slip associated with elevation of the highest portions of the Santa Fe Range uplift to the north-northeast; (2) the early Paleocene San Luis uplift that formed a southwest plunging, V-shaped anticlinal nose whose southeast limb is the Lamy monocline, which extends 25 km southwest from Precambrian basement at the margin of the Santa Fe Range at Cañoncito to the Cretaceous Menefee Formation; (3) following erosional beveling, the collapse of the southern shoulder of the San Luis uplift, forming a portion of the north-northeast–trending, latest Paleocene–Eocene Diamond Tail subbasin, the axial portion of which lies along the trend of the Tijeras-Cañoncito fault zone; (4) minor Eocene uplift which interrupted deposition in the basin; and (5) Eocene subsidence across the broader Galisteo subbasin and deposition of the Galisteo Formation and latest Eocene–Oligocene Espinaso Formation. Late Eocene–Oligocene intrusions in Los Cerrillos and the Ortiz Mountains deformed the Cretaceous and Tertiary host rocks. Across the Tijeras-Cañoncito fault system, the northwest-trending erosional edge of the Campanian Point Lookout Sandstone displays 400 m of pre–Diamond Tail Formation, right-lateral separation, and the Diamond Tail Formation shows no lateral offset between the overlapping San Lazarus and Los Angeles faults. Although the axis of the Galisteo Basin parallels the fault system, and the basin has been proposed to have formed in a releasing bend of a strike-slip fault along the Tijeras-Cañoncito fault system, any major Laramide strike-slip movement pre-dates the deposition of the Diamond Tail Formation and the formation of the Lamy monocline. The faulted core of the pre–Diamond Tail Lamy monocline, initially up ~800 m on the northwest, was reactivated during rift development and downdropped on the northwest by ~250 m of dip slip. An earlier period of movement (either early Laramide or older strike slip or down-to-the southeast Pennsylvanian movement) is suggested by contrasting thicknesses of Paleozoic formations across the fault zone.

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, δ 2 H, and δ 18 O), 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, NaSO 4 thermal waters from underlying bedrock. Both features likely contribute to chemical anomalies and thermal disturbances in the shallow Tesuque aquifer.