U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Geologic Unit: Lak
Search archives
Map showing publication footprint
  • Usage in publication:
    • Lak member*
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
    • Siltstone
  • AAPG geologic province:
    • Powder River basin
Publication:

Imlay, R.W., 1947, Marine Jurassic of Black Hills area, South Dakota and Wyoming: American Association of Petroleum Geologists Bulletin, v. 31, no. 2, p. 227-273. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Named as a member of Sundance formation. Type section: on west side Stockade Beaver Creek about 5 mi northeast of Newcastle, WY in sec 18, T45N, R60W, in Powder River basin. Named after Lak Reservoir on L.A.K. Ranch. Reservoir is about 3 mi south of type section in the Powder River basin. 25 to 100 ft or more of mostly red, fine-grained sandstone and siltstone gradationally overlying Hulett sandstone member and underlying Redwater shale member (both new). At type consists of at least 80 ft of soft, maroon sandstone and siltstone, including 2 ft bed of greenish-gray siltstone 15 ft below top. Is of Late Jurassic (Callovian) age.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Lak member
  • Modifications:
    • Revised
Publication:

Peterson, J.A., 1954, Marine Upper Jurassic, eastern Wyoming: American Association of Petroleum Geologists Bulletin, v. 38, no. 4, p. 463-507. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Reallocated to member status in Rierdon formation herein assigned to Sundance group. Is of Late Jurassic (Callovian and Oxfordian) age.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Lak Member
  • Modifications:
    • Overview
Publication:

Rautman, C.A., 1975, Sedimentology of the "Lower Sundance" Formation (Upper Jurassic) Wyoming region: Wyoming Geological Association Earth Science Bulletin, v. 8, no. 4.


Summary:

Assigned to the "lower Sundance" Formation. May represent a paleoloess formed by reworking of silty sediments following withdrawal of the sea. Is of Late Jurassic age.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Lak Member*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Denver basin
    • Powder River basin
Publication:

Pipiringos, G.N., and O'Sullivan, R.B., 1976, Stratigraphic sections of some Triassic and Jurassic rocks from Douglas, Wyoming, to Boulder, Colorado: U.S. Geological Survey Oil and Gas Investigations Chart, OC-69, 1 sheet.


Summary:

Is one of seven members (Canyon Springs Sandstone, Stockade Beaver Shale, Hulett Sandstone, Lak, Pine Butte, Redwater Shale, and Windy Hill Sandstone (top) Members of Jurassic Sundance Formation north of Horse Creek, Laramie Co, WY in northern Denver basin north to Douglas, Converse Co, WY in Powder River basin. Measured sections shown graphically.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Search archives

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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 04 Apr 2024 04:02:26 PM MDT