Geologic formation in west Texas, US
The Hueco Formation is a geologic formation in west Texas and southern New Mexico.[1][2][3] It preserves fossils dating back to the early Permian period.[4][5]
Description
The formation is composed most of massive gray fossiliferous limestone with some shale and sandstone, with a thickness in excess of 5,000 feet (1,500 m). It overlies the Panther Seep Formation[6] with a slight disconformity, and its base is typically a thick biostromal limestone bed.[7] The formation unconformably underlies the Wilkie Ranch Formation.[8] It intertongues with the Abo Formation in the southern San Andres Mountains.[5]
In the Robledo Mountains, the Hueco is promoted to group rank and divided into (in ascending stratigraphic order) the Shalem Colony, Community Pit, Robledo Mountains, and Apache Dam Formations.[9] In the Hueco Mountains, the uppermost formation is the Alacran Mountain Formation.[10]
The Hueco Formation is contemporary with the Abo Formation and represents continued marine sediment deposition south of the prograding Abo deltas.[7]
History of investigation
The formation was first defined by G.B. Richardson in 1904, but mistakenly thought to be Pennsylvanian in age.[1] Nelson dated the formation as earliest Permian in the Franklin Mountains in 1940.[4] Spencer G. Lucas et al. promoted the formation to group rank in 1998.[9]
