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W.R. Lowell

Publications and source records attributed to W.R. Lowell.

4 recordsLinked to original sources
USGS1953

Beaverhead formation, a Laramide deposit in Beaverhead County, Montana

The name Beaverhead formation is proposed for a thick sequence of conglomerate, sandstone, siltstone, and limestone that crops out over an area of at least 400 square miles in Beaverhead County, Montana, extends southward across the Montana-Idaho boundary, and may extend eastward into Madison County. These rocks are clearly sedimentary by-products of the Laramide orogeny and probably range from late Cretaceous to early Eocene. The Beaverhead formations consists predominantly of conglomerate. In part of the area, an upper and a lower conglomerate member are separated by a middle member of limestone. Where the limestone member is inconspicuous or absent, the upper and lower conglomerate members cannot be differentiated. The most nearly complete and best-exposed known section of the Beaverhead formation, designated the type section, is near the mouth of McKnight Canyon, 6 miles west of Dell, Montana. Here the formation can be divided into four mappable units; elsewhere no more than three units can be recognized. In the McKnight Canyon section, the top and bottom members are dominantly conglomerate, composed of pebbles, cobbles, and subordinate boulders set in a sandy matrix cemented by calcite; breccia beds occur locally. This coarse debris was derived from rocks of Precambrian, Paleozoic, and Mesozoic age and consists largely of limestone and quartzite. The intermediate member consists of two mappable units: a lower thick, massive limestone, locally concretionary, and an upper sequence of interbedded siltstone, sandstone, arkose, limestone, and subordinate conglomerate. At McKnight Canyon, where the base and the top of the formation have been faulted and eroded, the exposed thickness of the section is approximately 9700 feet. The Beaverhead formation rests unconformably on rocks as young as the Colorado group and as old as early Paleozoic, and it probably rests unconformably upon rocks as young as the Montana group and as old as Precambrian. It is unconformably overlain by vertebrate-bearing fluviatile or lacustrine tuffaceous beds of Eocene and Oligocene age. The coarse debris that composes the formation was eroded from nearby mountains that were uplifted in Late Cretaceous, Paleocene, and early Eocene time, and was deposited in basins adjacent to these mountains. The resulting rocks, a product of Laramide orogeny, were later folded and displaced by overthrusting and block faulting. In places, these rocks are overlain by thrust sheets of Paleozoic rocks. © 1953, The Geological Society of America, Inc.

Montana↗
USGS1952

Stratigraphic sections of the Phosphoria in Montana, 1947-48

The U. S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Montana and other western states. These data will not be fully synthesized and analyzed for several years, but segments of the data, accompanied by little or no interpretation, will be published as preliminary reports as they are assembled. This report, which contains abstracts of many of the sections measured in southwestern Montana (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952). Many people have taken part in this investigation. The program of which this work is a part was organized by V. E. McKelvey. J. G. Evans, J. E. Joyce, J. A. Kelleher, R. L. Konizeski, J. A. Mann, R. L. Parker, J. E Smedley, L. A. Thomas, and W. H. Wilson participated in the description of strata and collection of samples referred to in this report. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. All the P 2 O 5 , F, V 2 O 5 , and acid-insoluble analyses were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. The Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were about equally distributed between the Bureau of Mines and the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbit by chemists I. Barlow, A. Caemmerer, J. Greene, N. Guttag, and E. H. Humphrey. The spectrographic analyses were made by D. M. Mortimer, of the Bureau Mines in Albany, and the oil-shale analyses were made by the Bureau of Mines Petroleum and Oil-Shale Experiment Station at Laramie, Wyo. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske. Organization of the tabular data has been largely by Anita Cozzetto.

Montana↗