Evolution of the Earth: Plate Tectonics Through Time

Sleep, Norman H.

doi:10.1016/b978-0-444-53802-4.00158-5

Cited by 8 publications

(4 citation statements)

References 202 publications

(303 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The choice of Cartesian two‐dimensional modeling space is common in studies focusing on Precambrian lithospheric processes (e.g., Gerya, 2014) and in scaling analyses (e.g., Sleep, 2015); however, when applying the outcomes to the Earth, the planar 2D model space yields hotter geotherms. This setup greatly underestimates the internal heat required to achieve specific mantle temperatures, when compared to spherical geometries (O’Farrell et al., 2013; O’Farrell & Lowman, 2010).…”

Section: Discussionmentioning

confidence: 99%

Craton Formation in Early Earth Mantle Convection Regimes

et al. 2022

View full text Add to dashboard Cite

Observations from Archaean cratons provide relevant constraints on our understanding of the processes that shaped the early Earth. Tectonic evidence of craton-making processes are generally interpreted via opposing models involving vertical or horizontal tectonics. Vertical tectonics involves the relative vertical displacement of crustal fragments, in a context where lateral motion at the plate scale is negligible (Van Kranendonk et al., 2007), whereas horizontal tectonics can be reconciled with an environment with increased lateral large-scale mobility, which may comprise juxtaposition of lithospheric blocks (

show abstract

Section: Discussionmentioning

confidence: 99%

Craton Formation in Early Earth Mantle Convection Regimes

et al. 2022

View full text Add to dashboard Cite

show abstract

“…where pe is the ejecta production rate and rsub is the ejecta loss rate caused by resurfacing of the Earth and loss to the mantle due to subduction or the geological process that preceded subduction (Sleep, 2015). The coefficient, ce , represents the cation content in a ejecta particle, which is 5 mol/kg (Zahnle & Sleep, 2002).…”

Section: Ejecta Weatheringmentioning

confidence: 99%

“…The ejecta weathering depends on the amount and size distribution of the ejecta particles (e.g., Charnay et al, ; Sleep & Zahnle, ). The amount of the ejecta,

m e j

, can be calculated as follows:

\frac{d m e j}{d t} = p e j - \frac{1}{c e j} F e j - r s u b,

where

p e j

is the ejecta production rate and

r s u b

is the ejecta loss rate caused by resurfacing of the Earth and loss to the mantle due to subduction or the geological process that preceded subduction (Sleep, ). The coefficient,

c e j

, represents the cation content in a ejecta particle, which is 5 mol/kg (Zahnle & Sleep, ).…”

Section: Modelmentioning

confidence: 99%

Probable Cold and Alkaline Surface Environment of the Hadean Earth Caused by Impact Ejecta Weathering

Kadoya

Krissansen‐Totton

Catling

2020

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Constraining the surface environment of the early Earth is essential for understanding the origin and evolution of life. The release of cations from silicate weathering depends on climatic temperature and pCO 2 , and such cations sequester CO 2 into carbonate minerals in or on the seafloor, providing a stabilizing feedback on climate. Previous studies have suggested that this carbonate-silicate cycle can keep the early Earth's surface temperature moderate by increasing pCO 2 to compensate for the faint young Sun. However, the Hadean Earth experienced a high meteorite impactor flux, which produced ejecta that is easily weathered by carbonic acid. In this study, we estimated the histories of surface temperature and ocean pH during the Hadean and early Archean using a new model that includes the weathering of impact ejecta, empirically justified seafloor weathering, and ocean carbonate chemistry. We find that relatively low pCO 2 and surface temperatures are probable during the Hadean, for example, at 4.3 Ga, log 10 (pCO 2 ) (in bar) is −2.21 +3.01 −2.54 [2 ] and temperature is 259.2 +84.1 −14.4 [2 ] K. Such a low pCO 2 would result in a circumneutral to basic pH of seawater, for example, 7.90 +1.21 −1.69 [2 ] at 4.3 Ga.A probably cold and alkaline marine environment is associated with a high impact flux. Hence, if there was an interval of an enhanced impact flux, that is, Late Heavy Bombardment, similar conditions may have existed in the early Archean. Therefore, if the origin of life occurred in the Hadean, life likely emerged in a cold global environment and probably spread into an alkaline ocean. Plain Language SummaryThe Earth's environment during the Hadean eon, 4.5 to 4 billion years ago, is obscured by a lack of geological evidence. However, life likely arose then, so improving our knowledge of the early environment is essential for understanding the origin and evolution of life. Here, we build a geological carbon cycle model that simulates the early surface environment and generates probability distributions for the level of atmospheric carbon dioxide (CO 2 ), average surface temperature, and ocean pH over time. During the Hadean, CO 2 dissolved in water is consumed by reacting with material ejected from meteorite impacts, so CO 2 levels tend to be low and the greenhouse effect weak. The consequences are low surface temperature and alkaline seawater. The probability that the surface temperature was lower than the freezing point of water and that seawater pH exceeded 7 is 70% at 4.3 billion years ago. Thus, if life began in the Hadean, it likely emerged in a cold global environment, and early life may have spread into an alkaline ocean. Key Points:• We estimate the range of pCO 2 , surface temperature, and ocean pH in the Hadean and Archean • A cold, Hadean surface environment and circumneutral to basic ocean pH is likely because of impact ejecta weathering • The origin of life may have occurred in a cold environment, and early life may have spread into a cold alkaline ocean Supporting Information:• Supporti...

show abstract

“…In the future, exploring other tectonic regimes (e.g. stagnant lid) may be of interest to exoplanet studies and potential investigations of Earth's future evolution (Sleep 2015).…”

Section: Earth's Deep-water Cyclementioning

confidence: 99%

Effect of Surface-Mantle Water Exchange Parameterizations on Exoplanet Ocean Depths

Komacek

Abbot

2016

ApJ

View full text Add to dashboard Cite

Terrestrial exoplanets in the canonical habitable zone may have a variety of initial water fractions due to random volatile delivery by planetesimals. If the total planetary water complement is high, the entire surface may be covered in water, forming a "waterworld." On a planet with active tectonics, competing mechanisms act to regulate the abundance of water on the surface by determining the partitioning of water between interior and surface. Here we explore how the incorporation of different mechanisms for the degassing and regassing of water changes the volatile evolution of a planet. For all of the models considered, volatile cycling reaches an approximate steady state after~2 Gyr. Using these steadystates, we find that if volatile cycling is either solely dependent on temperature or seafloor pressure, exoplanets require a high abundance (0.3% of total mass) of water to have fully inundated surfaces. However, if degassing is more dependent on seafloor pressure and regassing mainly dependent on mantle temperature, the degassing rate is relatively large at late times and a steadystate between degassing and regassing is reached with a substantial surface water fraction. If this hybrid model is physical, super-Earths with a total water fraction similar to that of the Earth can become waterworlds. As a result, further understanding of the processes that drive volatile cycling on terrestrial planets is needed to determine the water fraction at which they are likely to become waterworlds.

show abstract

Evolution of the Earth: Plate Tectonics Through Time

Cited by 8 publications

References 202 publications

Craton Formation in Early Earth Mantle Convection Regimes

Craton Formation in Early Earth Mantle Convection Regimes

Probable Cold and Alkaline Surface Environment of the Hadean Earth Caused by Impact Ejecta Weathering

Effect of Surface-Mantle Water Exchange Parameterizations on Exoplanet Ocean Depths

Contact Info

Product

Resources

About