Beaches are loose deposits of sand, gravel or shells that cover the shoreline in many places.
They make up two-thirds of the world’s ice-free coastlines.
Beaches serve as buffer zones or shock absorbers that protect the coastline, sea cliffs or dunes from direct wave attack.
It is an extremely dynamic environment where sand, water and air are always in motion.
Beaches also provide important coastal recreational areas for a many people.
Fine-grained sand beaches tend to be quite flat.
Formation
Sandy beaches are soft shores that are formed by deposition of particles that have been carried by water currents from other areas.
The transported material is in part derived from the erosion of shores, but the major part is derived from the land and transported by rivers to the sea.
The two main types of beach material are quartz (silica) sands of terrestrial origin and carbonate sands of marine origin.
The carbonate sand is weathered from mollusc shells and skeletons of other animals.
Other material includes heavy minerals, basalt (volcanic origin) and feldspar.
The Wentworth Scale
Chester Keeler Wentworth was born in Aspen, Colorado, on May 7, 1891, one of five children of Frank Louis Wentworth and Anna Maria Keeler Wentworth. Chester graduated from the University of Chicago with an A.B. degree in geology in June 1918. Chester took his M.S. degree in 1921, and his Ph.D. in 1923, both at the University of Iowa. It was during his time as a student at Iowa that Chester’s unusual combination of aptitudes led to the achievement for which he is most widely known - the Wentworth scale for the classification of clastic sedimentary rocks.
Chester K. Wentworth, Fellow of The Geological Society of America since 1923, died in Hilo, Hawaii, on January 6, 1969, after several years of illness.
The original scale was devised in 1898 by the American sedimentary petrologist J.A. Udden was adapted (1922) by C.K. Wentworth, who expanded the definitions of the various grades to conform with actual usage by researchers; most sedimentologists have adopted the Udden scale with the Wentworth modifications.
Grain Size
Grain size scale, in sedimentology, division of a continuous range of particle sizes into a series of discrete groups. Several such scales have been devised for the purpose of standardizing terms and providing a basis for statistical analysis. On most scales, the finest particles are designated clay, followed by silt, sand, granules, gravel, pebbles, cobbles, and boulders. The size limits for each grade vary from scale to scale.
The Earthcache
To log this earthcache send us the answers of the following questions by email:
1.Looking at the rocky beach, using the Wentworth Scale in the listing classify the sediment according to grain size (average size of stones).
2. Examine the sediment composition at the rocky beach and tell me whether the sediment if mono (only one type of material) or multimineralic (more than one type of material)?
3. Take a photo with the GPS showing the location or surrounding landscape.
After sending the answers by email you can log it, if there is any problem we will contact you. If you do not send us the answers, your log will be deleted.