Hydrogeologic-Framework Controls on Groundwater Flow and Chemistry in the Binational Mesilla Basin-Paso del Norte Region John W. Hawley, Ph.D. [email protected] Emeritus Senior Environmental Geologist, N.M. Bureau of Geology & Mineral Resources; and Visiting Senior Hydrogeologist, N.M. Water Resources Research Institute (WRRI), NMSU Maps, Block Diagrams, and Cross Sections Compiled by Baird H. Swanson, Swanson Geoscience LLC *See next slide Conclusions and inferences presented are those of the presenter and are based primarily on his hydrogeologic research in the Mesilla Basin region dating back to 1962. Much of this work has been administered by the NM Water Resources Research Institute, and has continued since 2007 as part of ongoing interdisciplinary and multi- institutional Transboundary Aquifer Assessment Project Index map for locations of Rio Grande rift (RG-rift) basins and highlands of the binational Mesilla Basin Study Area Major landscape features include basin-floor areas inundated by pluvial Lakes Palomas (Bolsón de Los Muertos- El Barreal) and Otero (west-central Tularosa Basin) at their Late Quaternary deep stages; and Los Médanos de Samalayuca dunes (2017 Google earth® image-base). Left: NM WRRI TCR- 363 Study Area, with Mesilla GW Basin outlined in green; and locations of Hydrogeologic Cross-Section A-A′ to S-S′ s shown with blue and red lines. USGS DEM base with UTM-NAD83 SI- system and latitude- longitude (degree- min-sec) location coordinates. Right: 392 Well Control Points Groundwater Mesilla GW Basin Area, with thick (GW) Basins, saturated Santa Fe Inter-Basin Gp. Basin Fill (blues). Uplifts, and Rio Grande Valley linking GW- Floor (dark blue) Underflow Southern Jornada (light green), Cedar- “Corridors” of Corralitos (green), the Mesilla Tularosa (brown), Basin Hueco (gray brown), El Parabién (pink), and Regional Malpais-Los Muertos Study Area (violet). Inter-basin GW-flow Corridors (light blue), and Bedrock Uplifts (tan) Index Map for aquifer-management units in Mexico that also shows major hydrographic and GW-flow system boundaries south of 32° N latitude. Southern Mesilla GW Basin (green) and El Parabien GW Basin (lgt. brown). Red dash-dot line shows Acuifero Conejos-Médanos “delineación oficial” (boundary of Zona Hidrogeológica de Conejos Médanos in yellow)(INEGI 2012). Late Quaternary Lake Palomas at 1,210 m amsl high stand (lgt. blue). Mesilla Basin hydrographic boundary-blue line. Dashed blue line marks approximate boundary of NE- directed GW flow to Paso del Norte. Section of the Stiff- Diagram Map of the Transboundary Mesilla-El Parabien Basin and Acuifero Conejos-Médanos Area. Texas Water Development Board compilation; from Sierra Hibbs, Creel, and de Los six others (1997) Muertos Proposed and existing M&I Groundwater Production Sites in USA and Mexico: New Ciudad Juárez (JMASCJ) Wellfield outlined with red oval (42“-1.07 m pipeline: red line) Mex USA Mesilla GW Santa Basin Teresa (green) I-Park El Parabién Foxconn GW Basin (beige) Sources: USGS Water 1,210 m amsl Science High Stage of Centers, Paleo-Lake and NM Palomas (blue) WRRI Rift-Basin Hydrogeologic Framework Complexity “Seismic reflection, gravity, and drilling data have delineated the many large, deep basins that form the upper crustal expression of the [Rio Grande] rift. Initially, the primary emphasis was on gravity studies. However, the petroleum industry has released a considerable amount of seismic reflection data for research purposes . In general, the basins are asymmetrical and more complex structurally than their surface expression would suggest.” G. Randy Keller (2004) p. 450 Gravity Map (4 mgal-CI), with interpreted extent of main RG-rift basins in the border region, from Jiménez and Keller 2000 (Fig. 7). Red line: geologic section and gravity profile in next slide. Pemex Moyotes No.1- blue circle Computer model of gravity profile A- (right), and geologic section (left), with Cenozoic RG-rift and Laramide basin in open-circle pattern, from Jiménez and Keller 2000 (Fig. 6). Red line: gravity profile. Pemex Moyotes No.1- blue circle Schematic representation of Study Area pre-Santa Fe Group bedrock topography, and its primary stratigraphic and structural components. Mesilla Groundwater Basin boundary in green. Compilation scale 1:100,000, 100-ft (~30-m) contour interval. Google earth® image-based graphic by Swanson Geoscience LLC. 13 Mesilla Basin Trans- Boundary Sector X-Section Base: MSL; 5x Vertical Exaggeration Pliocene and Early Pleistocene regional- geomorphic setting of distributive fluvial systems (DFSs) that terminated in the Hueco Bolson and Bolsón de los Muertos and deposited the Upper Santa Fe Group aquifer system: Rios Grande, Mimbres, Casas Grandes, Santa Maria, and Carmen. 2018 Google Earth® image base US-Mexico Border Block Diagram: SW corner- Central Mesilla 107°W, 25,000 ft (7.6 km) Groundwater bmsl base, and no VE. As Basin much as 2,500 ft (760 m) of Santa Fe Gp basin-fill For cross-section (yellow) overlies a thick details, see slides 13 sequence of bedrock units: and 14 Tlvs/Tls-Lower Tertiary volcanic and sedimentary rocks (gray/light brown), K/Pz-Cretaceous and Paleozoic sedimentary rocks (pale green/blue), and XY-Proterozoic igneous and metamorphic rocks (tan). Blue arrows: Inferred Paleo-Lake Palomas-EPdN underflow A. Structure-contour map of base of Santa Fe Group Basin-Fill in the Lower Mesilla Valley-Paso del Norte area, with SE-trending black line showing location of hydrogeologic section (B). From NM-WRRI TCR-332 A B. Hydrogeologic section of Lower Mesilla Valley and El Paso del Norte Area showing Santa Fe Gp. aquifer-system pinch out over bedrock units (white). Rio Grande Alluvium (yellow) B QUESTIONS.