Bar B Formation

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Thickness339 ft (103 m)
Bar B Formation
Stratigraphic range: middle Pennsylvanian–late Pennsylvanian
TypeFormation
UnderliesBursum Formation
OverliesNakaye Formation
Thickness339 ft (103 m)
Lithology
PrimaryLimestone, shale
Location
Coordinates33°01′07″N 107°14′20″W / 33.0185°N 107.2390°W / 33.0185; -107.2390
RegionNew Mexico
CountryUnited States
Type section
Named forBarbee Draw (drainage)
Named byV.C. Kelley and Caswell Silver
Year defined1952
Bar B Formation is located in the United States
Bar B Formation
Bar B Formation (the United States)
Bar B Formation is located in New Mexico
Bar B Formation
Bar B Formation (New Mexico)

The Bar B Formation is a geologic formation found the Caballo Mountains of New Mexico. It preserves fossils showing it was deposited in the middle to late Pennsylvanian.[1][2]

The Bar B formation is mostly cyclic[2] beds of shale and limestone, with shale making up about 80% of the formation and limestone the other 20%. Chert is present in some of the limestone. The upper 50 feet (15 m) include reddish-brown siltstone, limestone conglomerate, and calcareous siltstone. The total thickness is about 339 ft (103 m).[3] The formation rests on the Nakaye Formation and is unconformably overlain by the Bursum Formation.[2]

The formation likely correlates with the Panther Seep Formation in the San Andres Mountains.[1][2]

Fossils

The formation contains abundant bryozoan fossils.[3]

History of investigation

See also

References

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