Sediment Notes What can sediments tell us about our beach?

Color Color can help you identify what mineral the sediment is made of. This can help you determine its source.

Waianapanapa State Park - Maui, Hawaii

Ponte Vedra Beach, Florida (tiny red coral organisms)

Puu Mahana - Big Island of Hawaii (Olivine-rich rocks)

Puu Mahana - Big Island of Hawaii Caladesi Beach – Clearwater, Florida (Quartz-rich rocks)

Pfeiffer Beach, Big Sur, California (garnet-rich rocks)

Rockaway Beach, Pacifica, California (bluish-gray limestone mixing with volcanic greenstone)

Santorini, Greece ( Iron-rich rocks from red lava cliffs)

Shape Rivers smooth out the surface of a sediment grain as it travels to the ocean. In general, the rounder the sediment is, the farther it has traveled from its source. The hardness of the mineral can also affect the roundness of a particle.

Is the source close or far? Quartz grains, which are very hard, are pretty rounded, which means it probably traveled a long way.

Is the source close or far? These grains are very angular, so they have only traveled a very short distance from the source.

Is the source close or far? Notice some grains are not very rounded… While some grains are very rounded. The minerals are different & get weathered at different rates.

Size Small sediments =low energy beach (small to no waves) Large sediments =high energy beach (big, strong waves)

Aleutian Islands

Biggest Boulders High wave energy Cobbles Pebbles Sand Silt Low wave energy Smallest Clay

4 TYPES OF SEDIMENTS Terrigenous - from continents Biogenous – plant or animal origin Hydrogenous - precipitated from water Cosmogenous - from outer space

TERRIGENOUS SEDIMENTS Most common type of sediment Composed of weathered rock material from land *Most common composition: QUARTZ CLAY MINERALS

TERRIGENOUS SED. CONT. *On continental margins: - Carried to the ocean by rivers - Coarse sediment is nearest to the shore - Finer sediment is found offshore *In ocean basins: - Carried by turbidity currents & found near continents - Very fine sediment could be blown far from land by wind.

BIOGENOUS SEDIMENTS *From benthic organisms: -coral reef debris & shell fragments *From zooplankton - Calcium carbonate composition: Foraminifera & Coccolithophores - Silicate composition: Radiolaria & Diatoms Click me to see me make sand!

HYDROGENOUS SEDIMENTS *Manganese nodules (deep ocean basin) from: - hydrothermal vent water

*Evaporites: Restricted circulation + high evaporation= precipitation of salts

COSMOGENOUS SEDIMENTS Always <1% of a sediment Rain down uniformly from space, but most abundant in deep ocean sediments because not "diluted" by other kinds of sediments *Meteorite fragments & dust *Rare earth elements