lecture 4 Flashcards
What are the four main types of sediment found on the ocean floor?
Terrigenous, Biogenous, Hydrogenous, Cosmogenous.
What is terrigenous sediment and how is it transported?
Sediment composed of pre-existing rocks that were weathered, eroded, and transported via water, wind, ice, and/or gravity. Transport methods include gravity (slumping), water (in suspension), ice (dropped from floating ice), and wind (in suspension).
What is biogenous sediment and how is it classified?
Sediment derived from the remains of organisms, including shells, bones, teeth, etc. It’s classified into macroscopic (visible to the naked eye) and microscopic (visible only under a microscope) biogenous sediment.
What is hydrogenous sediment?
Sediment derived from dissolved material in water that precipitates to form solids due to changes in conditions like temperature, pressure, and chemistry. It includes metal sulfides, manganese nodules, phosphates, carbonates, and evaporites.
What is cosmogenous sediment?
Sediment derived from extraterrestrial sources, including spherules (microscopic masses of silica, iron, nickel) and meteors (macroscopic metallic rocks from outer space)
What is the difference between weathering and erosion?
Weathering is the process by which rocks are broken down, while erosion is the process by which material is moved to a new location.
What is biogenic ooze?
Sediment with >30% skeletal remains and the rest clay-sized grains. It’s formed from the accumulation of microscopic organism tests (shells) on the ocean floor.
What distinguishes siliceous from calcareous ooze?
Siliceous ooze is made from organisms that have silica (SiO2) shells, like diatoms and radiolaria. Calcareous ooze is made from organisms with calcium carbonate (CaCO3) shells, like coccolithophores and foraminifera.
Which sediment is most commonly transported to the deep oceans by wind?
Most sediment in the deep oceans is terrigenous sediment transported there by wind.
What are the rates of deposition for different ocean sediments?
Lithogenous sediment: 1 m per 1000 years; Biogenous ooze: 1 cm per 1000 years; Abyssal clay: 1 mm per 1000 years; Manganese nodule: 0.001 mm per 1000 years.
