Elko Formation

Last updated
Elko Formation
Stratigraphic range: Mid Eocene (Uintan)-Mid Miocene
~46.2–11.6  Ma
Type Formation
Sub-unitsElko Shale
Lithology
Primary Shale
Other Limestone
Location
Coordinates 40°48′N115°48′W / 40.8°N 115.8°W / 40.8; -115.8
Approximate paleocoordinates 41°30′N112°54′W / 41.5°N 112.9°W / 41.5; -112.9
Region Nevada
Country United States
Type section
Named for Elko County
Usa edcp relief location map.png
Orange pog.svg
Orange ff8040 pog.svg
Yellow pog.svg
Elko Formation (the United States)
Relief map of U.S., Nevada.png
Orange pog.svg
Orange ff8040 pog.svg
Yellow pog.svg
Elko Formation (Nevada)
Metasequoia occidentalis
Elko Formation Metasequoia occidentalis USNM P36883 img3.jpg
Metasequoia occidentalis
Elko Formation

The Elko Formation, also known as Elko Shale(s), is an oil shale geologic formation in Elko County, northern Nevada, United States. The deltaic and lacustrine shales and limestones preserve fossils dating back to the Middle Eocene of the Paleogene to Middle Miocene of the Neogene period. The frog genus Elkobatrachus and ant species Pseudocamponotus elkoanus were named after the formation.

Contents

Description

The formation ranges in age from the Middle Eocene (Uintan), with the underlying lower member dated at 46.1 ± 0.1 Ma and the upper member of the Eocene section dated at 38.9 ± 0.3 Ma. [1]

A younger section is dated to the Late Eocene to Early Oligocene (37.2 to 28.4 Ma) [2] and the Elko Shale member is dated to the Middle Miocene (16.0 to 11.6 Ma). [3]

Fossil content

The following fossils were reported from the formation: [1] [2] [3]

See also

References

Further reading