Geologic units in Chaves county, New Mexico

San Andres Formation (Guadalupian and Leonardian) at surface, covers 32 % of this area

Limestone and dolomite with minor shale. Guadalupian in south, in part Leonardian to north.

Eolian and piedmont deposits (Holocene to middle Pleistocene) at surface, covers 23 % of this area

Interlayered eolian sands and piedmont-slope deposits along the eastern flank of the Pecos River valley, primarily between Roswell and Carlsbad. Typically capped by thin eolian deposits.

Piedmont alluvial deposits (Holocene to lower Pleistocene) at surface, covers 18 % of this area

Includes deposits of higher gradient tributaries bordering major stream valleys, alluvial veneers of the piedmont slope, and alluvial fans. May locally include uppermost Pliocene deposits.

Artesia Group (Guadalupian) at surface, covers 11 % of this area

Shelf facies forming broad south-southeast trending outcrop from Glorieta to Artesia area; includes Tansill, Yates, Seven Rivers, Queen and Grayburg Formations (Guadalupian). May locally include Moenkopi Formation (Triassic) at top.

Alluvium (Holocene to upper Pleistocene) at surface, covers 5 % of this area

Alluvium

Ogallala Formation (Lower Pliocene to middle Miocene) at surface, covers 3 % of this area

Alluvial and eolian deposits, and petrocalcic soils of the southern High Plains. Locally includes Qoa.

Older alluvial deposits of upland plains and piedmont areas, and calcic soils and eolian cover sediments of High Plains region (Middle to lower Pleistocene) at surface, covers 3 % of this area

Includes scattered lacustrine, playa, and alluvial deposits of the Tahoka, Double Tanks, Tule, Blanco, Blackwater Draw, and Gatuna Formations, the latter of which may be Pliocene at base; outcrops, however, are basically of Quaternary deposits.

Eolian deposits (Holocene to middle Pleistocene) at surface, covers 2 % of this area

Eolian deposits.

Upper Chinle Group, Garita Creek through Redonda Formations, undivided (Upper Triassic) at surface, covers 1 % of this area

Upper Chinle Group, Garita Creek through Redonda Formations, undivided

Santa Rosa Formation (Carnian) at surface, covers 0.7 % of this area

Includes Moenkopi Formation (Middle Triassic) at base in most areas.

Yeso Formation (Leonardian) at surface, covers < 0.1 % of this area

Sandstones, siltstones, anhydrite, gypsum, halite, and dolomite.

Lacustrine and playa-lake deposits (Holocene) at surface, covers < 0.1 % of this area

Includes associated alluvial and eolian deposits of major lake basins.

Salado Formation (Upper Permian) at surface, covers < 0.1 % of this area

Evaporite sequence, dominantly halite.

Rustler Formation (Upper Permian) at surface, covers < 0.1 % of this area

Siltstone, gypsum, sandstone, and dolomite.