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Map showing publication footprint
  • Usage in publication:
    • Fortune Lakes slate*
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Slate
    • Iron-formation
  • AAPG geologic province:
    • Lake Superior region
Publication:

James, H.L., 1958, Stratigraphy of pre-Keweenawan rocks in parts of northern Michigan, IN Shorter contributions to general geology, 1957: U.S. Geological Survey Professional Paper, 314-C, p. C27-C44. [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/pp/pp314C]


Summary:

Pg. 30 (table 1), 39. Fortune Lakes slate, uppermost formation of Paint River group (new) of Animikie series. Main areas of exposure are between Crystal Falls and Fortune Lakes, and between Alpha and Brule River, Iron County, Northern Peninsula, northwestern Michigan (Lake Superior region). Consists mostly of slate and minor graywacke, with characteristic thin beds (10 feet or less) of coarse, massive graywacke about 300 feet above base. Sideritic slate is present in some areas between Crystal Falls and Alpha; one exposure near Fortune Lakes oxidized chert-siderite rock (iron-formation) is present. Aggregate thickness probably at least 4,000 feet, based on structural inferences. Overlies Stambaugh formation (new) of Paint River group. Age is middle Precambrian (Animikie Series). Report includes stratigraphic sequence chart.
Type locality not designated. Named from Fortune Lakes, Iron Co., Northern Peninsula, northwestern MI (Lake Superior region).

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 1403).


Map showing publication footprint
  • Usage in publication:
    • Fortune Lakes Slate*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Lake Superior region
Publication:

Cannon, W.F., and Gair, J.E., 1970, A revision of stratigraphic nomenclature for middle Precambrian rocks in northern Michigan, IN Note and Discussion: Geological Society of America Bulletin, v. 81, no. 9, p. 2843-2846.


Summary:

Pg. 2845 (fig. 2, stratigraphic chart compiled from Leith and others, 1935; James, 1958; Gair and Thaden, 1968). Fortune Lakes Slate of Paint River Group of Marquette Range Supergroup (new; replaces †Animikie series of James, 1958, south of Lake Superior, in Michigan and Wisconsin). Present in Iron River-Crystal Falls district, northwestern Michigan. Overlies Stambaugh Formation of Paint River Group. Age is middle Precambrian.

Source: Publication.


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 ([ ]).

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