Oracle Glossary:MINVALUE

This parameter can be used in this situations  as minimum value specified in a sequence declaration:
CREATE SEQUENCE …
MINVALUE .. value …
…. can be used in flashback version query:
This keywords instruct Oracle to retrieve all available data
versions
The age of the data available is determined by the undo_retention
parameter
SELECT … fields …
FROM   … table …
VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE
WHERE  … conditions …