Let's take a look at how they are formed! How are coastal landforms formed?Ĭoastlines emerge or subside from the ocean through long-term primary processes such as climate change and plate tectonics. There are two main types of coastal landforms- erosional coastal landforms and depositional coastal landforms. For example, landscapes shaped by sea ice are found at high latitudes, and landscapes shaped by coral are found at low latitudes. Coastal landforms differ substantially according to latitude due to differences in climate. These typically involve some interaction between the marine environment and the terrestrial environment. When you next visit the coast, look out for these landforms and try to identify them! Coastal landforms - definitionĬoastal landforms are those landforms found along coasts that have been created by coastal processes of erosion, deposition, or both. The formation of the coastal landscape depends on many factors, including the type of rock these processes are acting on, how much energy is in the system, sea currents, waves, and tides. These processes result in either erosion or deposition, creating different types of coastal landforms. Where do they occur?Ĭoastal rock stacks are widespread in New Zealand wherever elevated topography abuts the coast, and absent only from long, sandy or shingly stretches like the central Bay of Plenty and South Canterbury Bight.Coastlines occur where the land meets the sea, and they are formed by marine and land-based processes.

Native plants, however, tend to dominate. Weed invasion can occur, however, promoted by instability of cliffs and seed transport by wind and birds. Most coastal rock stacks are protected by their inaccessibility to humans. Coastal rock stacks may support breeding sites for threatened seabirds, such as the light-mantled sooty albatross ( Phoebetria palpebrata ), Salvin’s albatross ( Thalassarche salvini ) and the Chatham albatross ( Thalassarche eremita ), and less threatened seabirds such as the common diving petrel ( Pelecanoides urinatrix ), grey-faced petrel ( Pterodroma macroptera ), red-billed gull ( Larus novaehollandiae ), white-fronted tern ( Sterna striata ), and the spotted shag ( Stictocarbo punctatus ). Threatened fauna include the Mokohinau skink ( Cyclodina mokohinau ) and a stag beetle ( Geodorcus ithaginis ).

A declining species is shore spurge ( Euphorbia glauca ). Nationally uncommon species include Buchanan’s orache ( Atriplex buchananii ), Cox’s fescue ( Festuca coxii ), Senecio carnosulus, Three Kings rangiora ( Brachyglottis arborescens ), coastal tussock ( Chionochloa bromoides ) and Macquarie Island saltgrass ( Puccinellia macquariensis ). Relict species include guano groundsel ( Senecio sterquilinus ). Threatened plants include the nationally vulnerable Cook’s scurvy grass ( Lepidium oleraceum ), coastal cress ( Lepidium flexicaule ), Lepidium naufragorum, Chatham Island forget-me-not ( Myosotidium hortensia ), mutton bird plant ( Leptinella featherstonii ) and Pimelea tomentosa. In big storms, however, waves may crest over the tops. Their summits are well above the high tide line and above the storm surge line (over 10m in height). Some are always surrounded by water, others are surrounded by sand at low tide. The bases of stacks occur below the high tide line.

Coastal rock stack, western Southland (Susan Wiser)Ī coastal rock stack is an isolated pinnacle of rock off the coast, generally with steep to vertical sides (Priestly 1990).

Sea stack landform