Cloghfin Port ASSI

The site is of importance due to the range of Mesozoic (Triassic and Cretaceous) strata exposed, providing one of the most complete sequences in the Larne-Lough Neagh Basin and demonstrates the facies and palaeogeographic variations between this and adjacent areas.

The rocks at the site range in age from the mid Triassic (approximately 220 Ma) to the late Cretaceous (approximately 80 Ma) and contain abundant invertebrate fossils.

The site is of national importance due to the range of Mesozoic strata exposed, providing one of the most complete sequences in the Larne-Lough Neagh Basin and demonstrates the facies and palaeogeographic variations between this and adjacent areas. Its importance is enhanced by recent studies on the Upper Triassic rocks here, part of ongoing research into rocks of this age in the Islandmagee – Larne area.

Cloghfin Port is the type locality for the Cloghfin Sponge Bed Member which is rich in the phosphatised remains of hexactinellid sponges, giving the Member its name. The presence of glauconitised chalk pebbles indicates that an erosive surface separates the Cloghfin Sponge Beds from the next member of the sequence, the Galboly Chalk Member. The sequence continues through the Cloghastucan, Creggan, Boheeshane, Larry Bane, Ballintoy and Glenarm Chalk Members which collectively enhance this remarkable series through the Mesozoic. The sequence is truncated by Palaeogene (approximately 58 million years old) erosion.

Recent research on the Upper Triassic (formerly Rhaetic) rocks have shown that they may provide important new insights into the worldwide T-J boundary extinction event through the assessment of the terrestrially derived arthropod cuticle material found here. The rocks also appear to host porpitid hydrozoans which, if confirmed, would be the only known examples of Triassic porpitids, and would also be a very rare example of ediacaran-type preservation within the Phanerozoic. To date these rocks have yielded the richest vertebrate and ichnofossil faunas of this age seen in Northern Ireland while the series contributes significantly to the proposal of Waterloo ASSI as a candidate Global Stratotype Section and Point (GSSP) for the base of the Jurassic System.