Little has been known about the Norfolk Ridge; however, it generally lies about 1,000–1,200 m (3,300–3,900 ft) below sea level and consists of Late Cretaceous continental crust.

[9] The geology has only been well characterised near Grande Terre, Norfolk Island and near Northland but there is now sufficient evidence from oceanographic studies to revise the former view that the tectonics were just those of the two ends of the ridge.

This was previously not understood from the geological studies near Grande Terre and Northland which fitted best an induced subduction initiation model.

There is no evidence of the allochthons that are found in New Caledonia and Northland, except for one limited nappe area on the ridge's eastern flank.

[11] The limited rocks dredged include undated andesitic to trachyandesitic lava, a 26.3 ± 0.1 Ma shoshonite, 23 – 16 Ma or probable Pliocene limestone, Cretaceous black shales, late Eocene mudstone and middle to late Eocene sedimentary breccias.