Petrographic analysis of Cenozoic-Mesozoic-Permian well cuttings from two exploration wells in south-central New Mexico

The Grimm, Hunt, Brown and Am.Arctic Ltd.No. 1 Mobil well (TD 21,759 ft) and Sunland Park Unit No. 1 well (TD 18,232 ft) were drilled in southern Doña Ana County in 1972-73 and 1985, respectively.This study involved scanning cuttings from the two wells and petrographic analysis of 265 thin sections made from the cuttings.The study provides data essential for interpretation of stratigraphy and structure between fault-block ranges in south-central New Mexico.The Grimm well penetrated 1920 ft of basin-fill sediments; 3880 ft of andesitic and volcaniclastic rocks, probably correlative with the upper Eocene Palm Park and Rubio Peak Formations; 7000 ft of muddy volcanic arenites with minor conglomerates, correlative with lower Eocene-Paleocene Love Ranch and Eocene Lobo Formations; 2400 ft (including a 640 ft monzonite sill near the base) of fossiliferous shales, siltstones, sandstones, lime mudstones, and wackestones, believed correlative with the Lower Cretaceous U-Bar and Hell-to-Finish Formations.About 5360 ft of Permian-Pennsylvanian rocks and 1200 ft of Mississippian-Lower Ordovician rocks underlie the Cretaceous.The upper 200 ft of Permian rocks are shales, mudstones, sandstones, wackestones, and packstones, probably correlative with the Lower Permian Hueco Formation.The Sunland Park well penetrated 1530 ft of basin-fill sediments overlying Tertiary volcanic and volcaniclastic rocks.Distinctive characteristics of stratigraphic units in this well are mostly obscured by alteration and contact metamorphism adjacent to felsite intrusions encountered frequently between 1530 and 17,150 ft depths.Eighteen hundred ft of Cretaceous section, composed of fossiliferous shales, lime mudstones, wackestones, siltstones, and sandstones, was penetrated at 15,100 ft.Actual top of the Cretaceous is probably within the immediately overlying 4000 ft of muddy siltstones, sandstones, skarn, hornfels, and felsites.The Cretaceous section is underlain by 1332 ft of fossiliferous shales, silty-lime mudstones, wackestones, packstones, and minor siltstones and sandstones correlative with the Lower Permian Hueco Formation.Oligocene ash-flow tuffs and rhyolitic volcaniclastics, abundant north of the well sites, are not in the subsurface where these two wells were drilled.No evidence of earlier reported early Tertiary marine rocks or Jurassic rocks was found in either well during this study.

Cenozoic · Mesozoic · Permian · Petrography · Structural basin · Archaeology and Natural History · Geological Studies and Exploration · Geology · Paleontology

• Energy and Mineral Resources of New Mexico

  Fraser Goff, Cathy J Goff•Energy and Mineral Resources of…•2017

  Add to list