Preliminary report on the stratigraphy and structure of some selected localities in the Eastern Brooks Range, Alaska, 1952

Geology of the Lake Peters area, northeastern Brooks Range, Alaska

“…Norris, Price, and Mountjoy ( 1963) mapped the continuation of these rocks east of the International Boundary as N eruokpuk Formation and tentatively assigned them a Precambrian or Cambrian ( ~) age. Brosge, Dutro, Mangus, and Reiser (1960;, p. 2182-2185 formally defined the Neruokpuk Formation and tentatively divided it into four informal members. Two of these members, the quartzite-schist member and overlying phyllitechert member, are in the Lake Peters area.…”

“…7). Brosge, Dutro, Mangus, and Reiser ( 1962, p. 2183-2184 and Sable ( 1965, p. 35 undulatory quartz, especially strongly undulose composite quartz grains, is viewed by some workers (Folk, 1961) as evidence of an original metamorphic terrane, although agreement on this is by no means universal (Blatt and Christie, 1963). (Pettijohn 1957, p. 669-670).…”

“…Rocks mapped as the phyllite-chert member of Brosge, Dutro, Mangus, 3Jild Reiser ( 1960Reiser ( , 1962 were not mapped as a separate unit in the Lake Peters area by the writer. Most of that member in the Lake Peters ~re-a is included in the N eruokpuk Formation undivided; part of it is included in the.calcareous sandstone member.…”

“…2 Previous authors have suggested the formation may be Precambrian (Norris and others, 1963;Payne and others, 1951) or pre-Carboniferous (Leffingwell, 1919). Brosge, Dutro, Mangus, andReiser (1962, p. 2184) tentatively correlated their phyllitechert member of the N eruokpuk Formation with similar rocks in the southern Brooks Range that contain Late Devonian fossils. They correlated n. limestone member in the N eruokpuk Formation with the Skajit Limestone in the southern Brooks Range; the Skajit contains Middle ( ~) and Late Devonian fossils.…”

“…The oldest quartzite-schist member "may represent different stratigraphic intervals at different localities" (Brosge and others, 1962(Brosge and others, , ·P· 2184(Brosge and others, -2185, but these authors considered it to be Devonian or pre-Devonian ( ~) in age. Since no fossils were found in the mapped area, the writer follows Brosge, Dutro, Mangus, and Reiser ( 1962) in assigning theN eruokpuk Formation a Devonian or older age. However, the writer feels it noteworthy to mention that the hiatus, represented by the unconformity at the base of the Kekiktuk Conglomerate, implies folding, uplift, and erosion of at least 6,000 feet of N eruokpuk rocks prior to Kekiktuk deposition.…”