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Geology topics

A. Thomas Ovenshine

Publications and source records attributed to A. Thomas Ovenshine.

5 recordsLinked to original sources
USGS1979

Assessing Metallic Resources in Alaska

In the last two decades federal and state governments have become in creasingly preoccupied with classi fying public lands according to the uses that may be made of them. One outcome of the classifying can be a change in the land's legal status from one in which any use is tolerated to one in which only selected activities are allowed. Since such a change af fects the economic and recreational opportunities of individuals and in stitutions, a variety of interest groups have developed to follow and influ ence the classifying process. Perhaps nowhere has the process been more closely scrutinized or more hotly de bated than in Alaska, where land-use decisions for much of the state's 375 million acres are being made.

Alaska↗
USGS1974

Alaska

No abstract available.

Alaska↗
USGS1970

Observations of iceberg rafting in Glacier Bay, Alaska, and the identification of ancient ice-rafted deposits

Observations of icebergs in a modern glacial marine environment indicate that ancient rocks that received iceberg-rafted material should contain: (1) local concentrations of stones that originated when icebergs overturned, and (2) small pellets of till that were originally sediment filling the spaces between clear ice crystals. The till pellets are especially significant in identifying an ancient glacial setting because they originate through a process unique to glaciers—the flow-and recrystallization-induced segregation of originally disseminated fine sediment. Thus when freed by melting and deposited by iceberg rafting, the pellets would reliably indicate the presence of glacial ice in an ancient environment. In the Gowganda Formation, a Precambrian glacial deposit, strata that contain outsized, presumably iceberg-rafted stones also contain abundant small flattened clasts of unsorted graywacke interpreted as the lithified counterparts of the till pellets observed on modern icebergs.

Alaska↗
USGS1970

Analyses of rock and stream-sediment samples from the Craig C-6 Quadrangle, Alaska

Analytical data for 26 rock and 8 stream-sediment samples from the Craig C-6, 1:63,360-scale quadrangle are presented in this report, together with a statistical treatment of the data. The samples were collected in 1969 as part of the Heavy Metals Program of the U.S. Geological Survey. The most comprehensive discussion of the geology of the study area is a report by A. F. Buddington and Theodore Chapin (1929). Known metalliferous lodes of the area are described and additional references to specific areas are given by Berg and Cobb (1967). Additional data is given in reports by Condon (1961), Smith (1914), and Wright and Wright (1908). Supplemental publications are being prepared on the general geology and mineral occurrences of the study area.

Alaska↗