The Kimmeridge Clay occupies a considerable area of the seafloor and Portland Harbour lies over these easily eroded material.
It connects a "Portland" of limestone (in that case Miocene to Pleistocene limestone) to the mainland.Return to the Chesil Beach Centre car park and sum up problems that might arise in the future, including the return of an 1824-type hurricane and storm surge, depletion of pebble resources, possible future weakening of the beach and whether it will break through, effects.In the marshes of its margins are marine molluscs, particularly Cerastoderma but also with Conus which is common in the sea here.Mountain belts are formed when tectonic forces squish marine sedimentary deposits to the edges of the continents.Baden-Powell stated (1930) that the Raised Beach marks the earliest known date at which pebbles from the Dawlish breccia, from the Budleigh Salterton pebble beds, and perhaps from the Tertiary gravels were assembled in one deposit in the Portland district.The outer most layer is called the crust and it sits on top of the mantle.At Fawley, near Southampton, sea-level rise in the last 6000 years has been about.1 trucchi slot nettuno cm per annum ( Hodson and West, 1972 ).
This is unlikely to be a coincidence.
This shows the relationship of the beach to the Fleet Lagoon.
Wave Action Top left: The Chesil Beach in very calm conditions (18th October, 1998).Many deposits of loess were formed in the past when winds blew over glacial deposits during the pleistocene.The geology of the seafloor around Portland was investigated by Donovan and Stride (1961) by an acoustic survey supported by coring, the observations of divers and sample collection.Morris stated that "Successive storm waves had broken chunks off the low silty cliff in the foreground, all that stood between the ravenous sea and the cottages at the top end of Brandy Row".St Ninian's tombolo on the Shetland Islands The tombolo connecting Portland Bill to the mainland in Dorset.North of the extended Portlandian escarpment the Fleet river deposited gravels, remains of which are seen at Fleet Common, at Langton Herring, and near Wyke Regis.Rock mass is also added to the continents through a variety of intrusive and extrusive igneous processes.These are primarily to protect Chiswell against flooding by wave action.Not only do the actions of geomorphological processes shape the landscape, landscape also determines which processes occur and at what rates they occur.Start at at Portland Bill car park.The bank looms over some of the housing and there is, of course, an interesting history of events in this area.