Ocean-Floor Sediments Ocean-Floor Sediments (19.3)(19.3)

Sources of Deep Ocean-Basin Sources of Deep Ocean-Basin SedimentsSediments

• Refresher!!! What is a deep ocean-basin?

• Part of the ocean floor that is under deep water beyond the continental margin.

• Sediments usually finer

• Collected using core samples

• Samples show slow settlement and can be organic or inorganic

Core SamplesCore Samples

A scientist studying a core sample that was collected by drilling into sediment layers on the ocean floor.

Inorganic SedimentsInorganic Sediments

• Rocks carried from land by rivers

• Volcanic dust blown into ocean by wind

• Glaciers pick up sediment iceberg deposit in ocean

• Meteorites vaporize in atmosphere but creates dust that enters Earth’s atmosphere

Inorganic sediment deposited by a Inorganic sediment deposited by a river in Indonesiariver in Indonesia

Biogenic SedimentsBiogenic Sediments

• Majority of sediments on ocean floor are Biogenic

• Biogenic: sediments that are the remains of marine plants and animals.

• Most common compounds found in organic sediments are silica and calcium carbonate

Chemical DepositsChemical Deposits

• Chemical reactions in ocean produce solid materials that eventually settle to ocean floor as potato shaped lumps of minerals called nodules.

• Nodules commonly located on abyssal plains.

NodulesNodulesLumps of minerals that are made of oxides of manganese, iron, copper, or nickel that is found in scattered groups on the ocean floor.

Physical classification of sedimentsPhysical classification of sediments

• Two basic types

• (1) Muds: fine silt and clay sized particles of rocks. E.g. red clay

• (2) Ooze: soft, fine sediment. E.g. biogenic materials– Calcareous ooze-made of calcium carbonate– Siliceous ooze-made of silicon dioxide.