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Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Geological Period: Cretaceous, Jurassic, Triassic · Rock Type: Greensand, Limestone, Mudstone
Landscape processes: Coastal, Volcanic / Igneous
Description
Minnis Mass movement, Jurassic stratigraphy/palaeontology The Minnis area is ofnational importance because of the diverse range of fossils found here, ranging in age from the Lower Jurassic to Upper Cretaceous, a Wnescale of over 100 million years. The fossils are revealed through an active mud flow that transports liquefied muds and disaggregated blocks of strata from the slope to the level of the coast road. This material is periodically cleared to the seaward side of the road, where active marine erosion is a significant factor in exposing the fossils. The mudflow itself is a good, and perhaps best known, example of this type of mass movement feature in Northern Ireland. The area of the mudflow is composite, consisting of an amphitheatre like bowl slide, backed by low cliffs of the Ulster White Limestone Formation at its western end and a flow slide on the east. The underlying geology of the area has led to conditions promoting mudflow. The stable cliff forming rocks of the Antrim Lava Group and Ulster White Limestone Formation are underlain by unstable rocks of the Waterloo Mudstone and Hibernian Greensand Formations. The Waterloo Mudstone is capable of absorbing a large amount of water and when it becomes saturated, it liquefies and flows down the slope. The mud descends via a series of chutes from a sharp ridge crest to the east of the bowl down to road level. Evidence suggests the actual slope is on the Triassic Mercia Mudstone Group. The flows are composed of rock and mud mainly from the overlying Jurassic age Waterloo Mudstone and the Cretaceous age Hibernian Greensand Formations. Blocks of Antrim Lava Group and the Ulster White Limestone Formation can also be transported. Substantial amounts of mud can be generated, so much so that the main road has to be closed. A diverse range of fossil fauna have been recovered from the site. From the Lower Jurassic, Ammonites Psiloceras sp planorbis and sampsoni, Caloceras sp multicostatum, intermedium and johnstoni, Schlotheima sp angulata, extrandosa and complanata, plus fragments of Waehneroceras sp, a Nautiloid Cenoceras striatus, Belemnites Schwegleria or Nannobelus, Bivalves cf. Ceratomya, Isognomon cf isognomoides, Modiolus laevis, Plagiostoma sp gigantea and rigidum, Liostrea hisingeri, Mactromya cardioides, Cardinia listeri, Gastropods, Arthropods Pseudoglyphea sp, Coleia sp, Glyphea cf. tomesi, Echinoids Eodiadema bechei and Miocardis lobatum, Ophiuroid Palaeocoma escheri, Crinoid Isocrinus psilonoti, Corals Heterastrea murchisoni and Montlivaltia haimei, Vertebrates Ichthyosaur and Plesiosaur and occasional fossilised driftwood have all been found. The Upper Cretaceous sediments at Minnis have been much less extensively sampled than the Lower Jurassic. This is partly down to the difficulty in extracting fossils from the Ulster White Limestone and also the absence or inconspicuous nature of more obvious specimens such ammonites or vertebrates. However, Sponges cf. Acrochordonia sp, Etheridgia mirabilis, Hallirhoa sp, Mirabilis sp, Wollenmania sp, Entonia sp, Jerea sp and Rhizopoterium sp, Belemnites Belemnitella mucronata, Echinoids Echinocorys sp, Serpulid worms Rotularia sp, and fish teeth Hybodontids, Synechodontiformes, Heterodontiformes, Orectolobiformes, Lamniformes, Carachariniformes, Batoidea and Holosteans have been found or extracted. The high degree of disturbance means that detailed study of the sediments is not possible. However, the fossils found in the various lithologies of the Lower Jurassic allow general interpretation of the environment of deposition and preservation. Corals indicate that clear water with low sedimentation rates were common. The Crinoid, Ophiuroid and miocardid remains were likely preserved oy rapid sediment input. The well preserved articulated vertebrate remains in association with pyritised Caloceras specimens suggest an oxygen depleted sea floor during the Hettangian stage. Fragmentary Echinoid rich material represents periods of low deposition. The evidence suggests the limestone with abundant shell debris and intact psiloceratids at angles to the bedding are storm lag deposits. https://www.daera-ni.gov.uk/publications/minnis-assi