What happens during silicate weathering?
Oelkers, Géochimie et Biogéochimie Experimentale (France), “silicate weathering (chemical weathering) is thought to control climate by consuming atmospheric carbon dioxide (CO2)” over a geological time scale. The CO2 is eventually stored as carbonates in the ocean.
What effect does weathering of silicate rocks have on the carbon cycle?
For example, if CO2 builds up in the atmosphere, the greenhouse effect will serve to increase the surface temperature, which will in turn increase the rate of rainfall and silicate weathering, which will remove carbon from the atmosphere.
How are silicates weathered?
In chemical weathering minerals are changed into new minerals and mineral byproducts. Some minerals like halite and calcite may dissolve completely. Others, especially silicate minerals, are altered by a chemical process called hydrolysis. Hydrolysis is the reaction of minerals in weakly acidic waters.
What affects silicate weathering?
The connection between silicate weathering, the global carbon cycle and climate change is extremely complex, and many factors can affect weathering rates, including climatic (mainly temperature and runoff), tectonic (exposed lithology, elevation and physical erosion rates) and biological influences (e.g., Velbel, 1992.
Is silicate weathering negative feedback?
Further, the mechanism by which silicate weathering acts as a negative feedback—through the reaction of carbonic acid with silicate rocks—is broadly applicable to the entirety of Earth history.
Why is the carbonate-silicate cycle a negative feedback on climate?
The stabilizing negative feedback in the carbonate-silicate cycle is produced by the dependence of the silicate weathering rate on temperature. When surface temperatures drop, the weathering rate slows down, and CO2 accumulates in the planet’s atmosphere.
How does chemical weathering of silicate rocks provide a climate feedback over long timescales?
This theory holds that silicate weathering responds to climate: when atmospheric pCO2 and surface temperatures rise, chemical weathering accelerates, consuming more atmospheric CO2 and cooling global climate; when pCO2 falls, weathering fluxes decrease, permitting buildup of CO2 and consequent warming.
What is the difference between carbonate weathering and silicate weathering?
Whereas silicate weathering removes carbon dioxide (CO2) from the atmosphere, weathering of accessory carbonate and sulfide minerals is a geologically relevant source of CO2.
Does silicate weathering increase or decrease CO2?
between atmospheric CO2 level and surface temperature. The rate of silicate weathering slows as the climate cools, causing CO2 to increase and warming the surface through the greenhouse effect.
How does the weathering of silicate rocks on Earth’s surface contribute to removing CO2 from the atmosphere?
When carbonic acid comes in contact with certain silicate minerals, it triggers a chemical process known as the Urey reaction. This reaction pulls gaseous carbon dioxide from the atmosphere and combines it with water and calcium or magnesium silicates, producing two bicarbonate ions.
What is the relationship between silicate weathering and atmospheric CO2 levels?
The rate of silicate weathering slows as the climate cools, causing CO2 to increase and warming the surface through the greenhouse effect.
What is the carbon dioxide weathering feedback?
Weathering Feedback If you remove carbon dioxide from the atmosphere, you weaken the greenhouse effect and this leads to cooling of the Earth. Like many chemical reactions, this chemical weathering occurs more rapidly in hotter climates, which are associated with higher levels of carbon dioxide.
Is chemical weathering a positive or negative feedback?
negative feedback
The chemical weathering works as a negative feedback that moderates long-term climate change. This negative feedback mechanism links CO2 level in the atmosphere to the temperature and precipitation of the atmosphere.
Is weathering positive or negative feedback?
The chemical weathering works as a negative feedback that moderates long-term climate change. This negative feedback mechanism links CO2 level in the atmosphere to the temperature and precipitation of the atmosphere.
What type of feedback is chemical weathering?
Is chemical weathering a negative feedback loop?
Is weathering a positive feedback mechanism?
Is silicate weathering a negative feedback mechanism?
Further, the mechanism by which silicate weathering acts as a negative feedback—through the reaction of carbonic acid with silicate rocks—is broadly applicable to the entirety of Earth history.
What is the chemical pathway of silicate weathering of calcium silicate?
This reaction structure is representative of general silicate weathering of calcium silicate minerals. The chemical pathway is as follows: River runoff carries these products to the ocean, where marine calcifying organisms use Ca 2+ and HCO 3− to build their shells and skeletons, a process called carbonate precipitation :
What is the slower response time scale of silicate weathering?
Instead, the slower response time scale can be understood in terms of the different prescribed functional response of silicate weathering, which in Sundquist [ 1991] is where Fws is the rate of silicate weathering; Fwsi the initial rate of silicate weathering, and the ratio of atmospheric CO 2 to its initial value.
Does silicate weathering balance volcanic degassing?
Silicate weathering balances elevated degassing after approximately 6 million years using the weak feedback, compared to only approximately 500,000 years using the strong feedback. Fig. 4. The response of p CO 2 to a permanent change in volcanic degassing rate using two different weathering curves in LOSCAR.