Stratigraphic sections of the Phosphoria formation in Montana, 1948

Abstract

This report concerns work done partly on behalf of the U. S. Bureau of Reclamation and partly on behalf of the U. 8. Atomic Energy Commission, and is published with the permission of the Commission.

Mineral resources in Permian rocks of southwest Montana

“…28B) were obtained primarily from the maps of Kennedy (1949;written commun., 1952) and Honkala (1953). The author has also studied much of the geology of the phosphate area in detail.…”

“…In the absence of outcrops, therefore, Honkala ( 1953) assumed that phosphorite and perhaps Inost of the ~{eade .Peak Member are absent from that area. This absence may reflect another area of uplift, perhaps broader but not as high.…”

“…Permian strata, described later in more detail, are nearly 200 feet thick. Honkala ( 1953) indicated that about 3,500 feet of ~1esozoic strata overlies the Permian. The basal 470 feet of Mesozoic strata is Dinwoody Formation and is overlain by 800 feet of Woodside Formation; both units are Triassic.…”

“…S. Geological Survey (Kennedy, 1949, andwritten commun., 1952;Honkala, 1953;Cressman and Swanson, 1964, lots 1251-1255, 1342-1343 Phosphate has been mined there fairly recently. Permian strata in this area crop out at the crest of the range and in some of the valleys that drain the area.…”

“…B. Hall (written commun., 1957), Honkala (1949b), Honkala (1953), Karlstrom (1948), Kennedy (1949 andwritten commun., 1952), Klemme (1949), Klepper (1950), Klepper and others (1957), M. R. Klepper (unpub. map compilation of region about Boulder Batholith), Love and others (1955), Lowell (1949), , McMannis (1955), Mann (1950), G. T. Moore (1956), Myers (1952), Peale (1896), E. S. Perry (unpub.…”