Minerals sedimentation on plain seashore beaches ?

[Externet]

Heavier, denser materials subject to thousands of years of pounding, grinding and swept by surf... Are they supposed to sink under the lighther silicate sands on a plain beach ?

 

What minerals are typically supposed to lie under the beach sands, down to bedrock or down to whatever stops them from sinking further ?

[Acme]

Heavier, denser materials subject to thousands of years of pounding, grinding and swept by surf... Are they supposed to sink under the lighther silicate sands on a plain beach ?

 

What minerals are typically supposed to lie under the beach sands, down to bedrock or down to whatever stops them from sinking further ?

It is not a simple matter of density or weight. Large dense stones can actually rise through sediments as smaller particles work under them. The only sure way to know what lies beneath is to dig/drill down and find out.

Sedimentation

...The physics of the most common sedimentation process, the settling of solid particles from fluids, has long been known. The settling velocity equation formulated in 1851 by G.G. Stokes is the classic starting point for any discussion of the sedimentation process. Stokes showed that the terminal settling velocity of spheres in a fluid was inversely proportional to the fluids viscosity and directly proportional to the density difference of fluid and solid, the radius of the spheres involved, and the force of gravity. Stokes equation is valid, however, only for very small spheres (under 0.04 millimetre [0.0015 inch] in diameter) and hence various modifications of Stokes law have been proposed for nonspherical particles and particles of larger size.

 

No settling velocity equation, however valid, provides a sufficient explanation of even the basic physical properties of natural sediments. The grain size of the clastic elements and their sorting, shape, roundness, fabric, and packing are the results of complex processes related not only to the density and viscosity of the fluid medium but also to the translational velocity of the depositing fluid, the turbulence resulting from this motion, and the roughness of the beds over which it moves. These processes also are related to various mechanical properties of the solid materials propelled, to the duration of sediment transport, and to other little-understood factors. ...

[studiot]

Fine particles move sideways, more along the beach.

 

Heavier particles move more up the beach.

 

http://www.bbc.co.uk/education/clips/zhp4d2p

Edited December 24, 2014 by studiot