Definition of unconformable in US English:



  • (of rock strata in contact) marking a discontinuity in the geological record, and typically not having the same direction of stratification.

    • ‘At this locality, the upper layers of the Mishan Formation are truncated below the unconformable contact at the base of the overlying Agha Jari Formation.’
    • ‘However, of greatest interest is the unconformable contact between the Wiens Formation and Neptune Group.’
    • ‘This angular relationship has been interpreted as evidence for an unconformable contact.’
    • ‘In this transect, the contact between the Carboniferous strata and the volcanic sequence appears to be an unconformable sedimentary contact.’
    • ‘Along much of its exposed length, the unconformable contact was intensely sheared during subsequent ductile deformation.’