You must also be assigned the Unified Archive Administration rights profile. The root role has all of these rights.
For more information, see Assigning Limited Rights to Zone Administrators.
source-host$ archiveadm create -r -z zonename archive-name
For example, using the zone name my-zone and the archive path /net/server/my-zone-archive.uar:
host1$ archiveadm create -r -z my-zone /net/server/my-zone-archive.uar