Geologic units in Guadalupe county, New Mexico

Piedmont alluvial deposits (Holocene to lower Pleistocene) at surface, covers 21 % 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.

Upper Chinle Group, Garita Creek through Redonda Formations, undivided (Upper Triassic) at surface, covers 17 % of this area

Upper Chinle Group, Garita Creek through Redonda Formations, undivided

Santa Rosa Formation (Carnian) at surface, covers 16 % of this area

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

Alluvium (Holocene to upper Pleistocene) at surface, covers 15 % of this area

Alluvium

Artesia Group (Guadalupian) at surface, covers 8 % 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.

San Andres Formation (Guadalupian and Leonardian) at surface, covers 7 % of this area

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

Ogallala Formation (Lower Pliocene to middle Miocene) at surface, covers 5 % of this area

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

Garita Creek Formation (Carnian) at surface, covers 5 % of this area

Garita Creek Formation

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 4 % 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.

Trujillo Formation (Norian) at surface, covers 0.5 % of this area

Trujillo Formation

Glorieta Sandstone (Leonardian) at surface, covers 0.3 % of this area

Texturally and mineralogically mature, high-silica quartz sandstone.

San Rafael Group (Middle Jurassic) at surface, covers 0.3 % of this area

Consists of Entrada Sandstone, Todilto and Summerville Formations, Bluff Sandstone, and locally Zuni Sandstone (or only Acoma Tongue of Zuni).

Morrison Formation (Upper Jurassic) at surface, covers 0.2 % of this area

Upper Jurassic nonmarine rocks.

Upper and lower Cretaceous rocks of east-central and northeast New Mexico (Cenomanian and Albian) at surface, covers 0.1 % of this area

Consists of Dakota Group, which includes Romeroville Sandstone (Cenomanian), Pajarito Shale, and Mesa Rica Sandstone (Albian); the underlying Tucumcari Shale (Albian) in Tucumcari area and Glencairn Formation (Albian) in Union County.

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

Includes associated alluvial and eolian deposits of major lake basins.

Entrada Sandstone (Middle Jurassic) at surface, covers < 0.1 % of this area

Entrada Sandstone