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     all the data currently contained in four distinct databases managed by the Mineral Resources Program (MRP) (NURE, RASS, Archival PLUTO, Temporary PLUTO) plus all additional data generated by Geologic Division projects in the future.

     A nationally consistent geochemical database provides baseline information on the natural abundance and spatial variation of chemical elements to which changes caused by agricultural and irrigation practices, waste disposal, urbanization, industrial pollution, mineral exploration and mining activities, environmental remediation and restoration activities, and other land-use practices can be compared. Human-induced chemical changes to the environment are superimposed on a variable natural geochemical background where trace-element abundances can range over several orders of magnitude within short distances. These variations are inadequately documented and their existence is often overlooked in the setting of public policy. Important aspects of change cannot be measured, or their consequences anticipated, unless the present composition of the earth's surface materials is known. The establishment of the National Geochemical Database is critical to obtai ning this knowledge.

  美国矿物资源历史统计数据(1900 -)

Summary by 李晓霞 on 2002-10-26

Last updated by 李晓霞 on 2002-10-26

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