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Chalk is so common in Cretaceous marine beds that the Cretaceous Period was named for these deposits. The name Cretaceous was derived from Latin creta, meaning chalk. [10] Some deposits of chalk were formed after the Cretaceous. [11] The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.
The ability of waves to cause erosion of the cliff face depends on many factors. The hardness (or inversely, the erodibility ) of sea-facing rocks is controlled by the rock strength and the presence of fissures , fractures , and beds of non-cohesive materials such as silt and fine sand .
If waves carve notches at a narrow point on both sides of a promontory on the rocky cliffed coast, a natural arch may be formed. [4] When the arch collapses as the coastline recedes further a stack is left behind on the wave-cut platform. The best-known example in Germany is the Lange Anna on Heligoland, while, in England, a prominent example ...
The chalk of Old Harry Rocks used to be part of a long stretch of chalk between Purbeck and the Isle of Wight, but remained as a headland after large parts of this seam were eroded away. As the headland suffered hydraulic action (a process in which air and water are forced into small cracks by the force of the sea, resulting in enlarging cracks ...
The secondary principle to the creation of seaward sediment fining is known as the hypothesis of asymmetrical thresholds under waves; this describes the interaction between the oscillatory flow of waves and tides flowing over the wave ripple bedforms in an asymmetric pattern. [4] "The relatively strong onshore stroke of the waveforms an eddy or ...
Although ocean waves caused severe damage during Superstorm Sandy in 2012, back bay flooding also caused extensive damage in that storm. In numerous places, it was the primary source of property ...
Big ocean waves caused by a phenomenon known as “spring tide” crashed into coastal parts of South Africa over the weekend, leaving two people dead and injuring several, authorities said Monday.
Hundreds of feet of younger sediment cover the White River group in southwest South Dakota. Miocene sandstones, which often form cliffs, often overlay the White River Formation. A period of erosion occurred in South Dakota during the Pliocene. Particularly in western South Dakota, the mobilization of coarse sediments formed the Ogallala aquifer ...