MarkLogic 9 Product Documentation
cts:period

cts:period(
   $start as xs:dateTime,
   $end as xs:dateTime
) as cts:period

Creates a period value, for use as a parameter to cts:period-range-query or cts:period-compare-query.

Parameters
start	The dateTime value indicating start of the period.
end	The dateTime value indicating end of the period.

cts:period( xs:dateTime("1990-01-01T00:00:00Z"),
            xs:dateTime("2000-01-01T00:00:00Z"))

MarkLogic 9 Product Documentationcts:period