concurrent range zone (overlap zone) A body of strata which is characterized by the overlapping stratigraphic range of two or more taxa, selected as diagnostic, and after which the zone is named. Concurrent range zones are very widely used in the time correlation of strata.

2. See OPPEL ZONE. Compare ASSEMBLAGE ZONE; and PARTIAL RANGE ZONE.

concurrent range zone(overlap zone) A body of strata which is characterized by the overlapping stratigraphic range of two or more taxa, selected as diagnostic, and after which the zone is named. Concurrent range zones are very widely used in the time correlation of strata. See also Oppel zone. Compare assemblage zone.