- Usage in publication:
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- Echooka member*
- Modifications:
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- Named
- Biostratigraphic dating
- Dominant lithology:
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- Sandstone
- Siltstone
- Shale
- Limestone
- AAPG geologic province:
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- Alaska Northern region
Summary:
Named [for Echooka River] as lower member (of 2) of Sadlerochit formation. Measured type section along Kemik Creek between 69 deg 22'N and 69 deg 23'N, Shaviovik and Sagavanirktok Rivers region, along north front of Brooks Range, northern AK. Varies in facies from one part of area to another. In northern Canning River area is typically sandy to conglomeratic and locally contains fossiliferous limestone. From Canning to Echooka River characteristically consists of massively bedded dense cherty siltstone that is dark-blue gray and locally limonite spotted. In Flood Creek area consists of blue-gray limy brown-weathering siltstone, gray limy shale, and blue-gray limestone. Thickness ranges from 300 to 600 ft. Unconformably overlies Lisburne group. Underlies Ivishak Member (new) (Sadlerochit formation). Seven measured sections, fossil list with locations, and geologic map of Shaviovik and Sagavanirktok Rivers region included in report. Age is Permian based on age of fossils.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Echooka Member*
- Modifications:
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- Areal extent
- AAPG geologic province:
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- Alaska Northern region
Summary:
Echooka Member of Sadlerochit Formation geographically extended eastward to Kongakut River-Joe Creek area as shown in correlation chart. Unconformably overlies Wahoo Limestone of Lisburne Group at most places but at Wahoo Lake contact appears gradational.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Echooka Member*
- Modifications:
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- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska Northern region
Summary:
Brachiopod assemblage from lower part of Echooka Member is equivalent to early Kazanian or earliest Late Permian age. Upper part of member contains assemblage of slightly younger Late Permian age. [Thus age of Echooka Member is Late Permian].
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Echooka Formation*
- Modifications:
-
- Revised
- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska Northern region
Summary:
Echooka Member of Sadlerochit Formation raised in rank to Echooka Formation of Sadlerochit Group. Divided into two newly-named members (ascending): Joe Creek and Ikiakpaurak Members. Type section of Echooka remains same. Age of Joe Creek Members ranges from Wolfcampian (early Sakmarian) to Guadalupian (early Kazanian). Age of Ikiakpaurak Member is early Late Permian (late Guadalupian Stage). [Thus age of Echooka Formation is Early and Late Permian].
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Echooka Formation
- Modifications:
-
- Revised
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska Northern region
Summary:
In subsurface Prudhoe Bay area Echooka Formation of Sadlerochit Group is probably equivalent to Ikiakpaurak Member of Echooka Formation of Sadlerochit Group of Detterman and others (1975). Unit is not divided into members. Age is mid-Permian based on microfloral assemblage.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).