Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints

  title={Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints},
  author={Sanjoy M. Som and David C. Catling and Jelte P. Harnmeijer and Peter M. Polivka and Roger Buick},
According to the ‘Faint Young Sun’ paradox, during the late Archaean eon a Sun approximately 20% dimmer warmed the early Earth such that it had liquid water and a clement climate. Explanations for this phenomenon have invoked a denser atmosphere that provided warmth by nitrogen pressure broadening or enhanced greenhouse gas concentrations. Such solutions are allowed by geochemical studies and numerical investigations that place approximate concentration limits on Archaean atmospheric gases… Expand
Geoscience: Fossil raindrops and ancient air
An analysis of fossil imprints of ancient raindrops suggests that the density of the atmosphere 2.7 billion years ago was much the same as that today. This result casts fresh light on a long-standingExpand
Air density of the Permian atmosphere: Constraints from lithified raindrop imprints
Abstract In contrast to the composition of Earth's ancient atmosphere, the corresponding air density is almost unknown. A unique method to estimate the palaeo-atmospheric density is to use lithifiedExpand
Hydrogen-Nitrogen Greenhouse Warming in Earth's Early Atmosphere
It is shown that with an atmospheric composition consistent with the most recent constraints, the early Earth would have been significantly warmed by H2-N2 collision–induced absorption, key to warming the atmosphere of theEarly Earth. Expand
The Archean atmosphere
The Archean eon data imply that substantial loss of hydrogen oxidized the Earth, and detailed understanding of the coevolving solid Earth, biosphere, and atmosphere remains elusive, however. Expand
Examining the role of varying surface pressure in the climate of early Earth
Abstract. During the Archean Eon in 2.7 billion years ago, solar luminosity was about 75 % of the present-day level, but the surface temperature was suggested to similar to or even higher thanExpand
Atmospheric CO2 levels from 2.7 billion years ago inferred from micrometeorite oxidation
This model reproduces the observed oxidation state of micrometeorites at 2.7 Ga for an estimated atmospheric CO2 concentration of >70% by volume, which would help resolve how the Late Archean Earth remained warm when the young Sun was ~20% fainter. Expand
Ancient micrometeorites suggestive of an oxygen-rich Archaean upper atmosphere
The model of atmospheric micrometeorite oxidation suggests that Archaean upper-atmosphere oxygen concentrations may have been close to those of the present-day Earth, and that the ratio of oxygen to carbon monoxide was sufficiently high to prevent noticeable inhibition of oxidation by Carbon monoxide. Expand
6.4 – Geologic and Geochemical Constraints on Earth's Early Atmosphere
In this review, the authors examine the geologic and geochemical evidence for the evolution of the atmosphere in the first two billion years of Earth's history. The authors focus on evidence relevantExpand
The faint young Sun problem
For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the `faint young Sun problem'. For the early Earth, models ofExpand
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM
[1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previousExpand


Nitrogen-enhanced greenhouse warming on early Earth
Early in Earth’s history, the Sun provided less energy to the Earth than it does today. However, the Earth was not permanently glaciated, an apparent contradiction known as the faint young SunExpand
Atmospheric composition and climate on the early Earth
  • J. Kasting, M. Howard
  • Geology, Environmental Science
  • Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2006
It is argued, following others, that this interpretation of oxygen isotope data is incorrect—the same data can be explained via a change in isotopic composition of seawater with time, which implies that the early Earth was warm, not hot. Expand
A revised, hazy methane greenhouse for the Archean Earth.
Geological and biological evidence suggests that Earth was warm during most of its early history, despite the fainter young Sun. Upper bounds on the atmospheric CO2 concentration in the LateExpand
Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere.
  • J. Kasting
  • Geology, Medicine
  • Precambrian research
  • 1987
Climate models suggest that carbon dioxide concentrations during the Archean must have been at least 100-1000 times the present level to keep the Earth's surface temperature above freezing in the face of decreased solar luminosity, but periods of extensive glaciation during the early and late Proterozoic indicate that the climate at these times was relatively cool. Expand
Oxygen and hydrogen isotope evidence for a temperate climate 3.42 billion years ago
The results indicate that the Palaeoarchaean ocean was isotopically depleted relative to the modern ocean and far cooler than previously thought. Expand
Evidence from massive siderite beds for a CO2-rich atmosphere before approximately 1.8 billion years ago.
It is concluded that CO2 alone (without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth. Expand
Dating the rise of atmospheric oxygen
It is found that syngenetic pyrite is present in organic-rich shales of the 2.32-Gyr-old Rooihoogte and Timeball Hill formations, South Africa, indicating that atmospheric oxygen was present at significant levels during the deposition of these units. Expand
Evidence from massive siderite beds for a CO2-rich atmosphere before ~ 1.8 billion years ago
It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before ∼2.2 billion yearsExpand
The life, death and afterlife of a raindrop on Titan
  • R. Lorenz
  • Environmental Science, Geography
  • 1993
A model is presented which describes the descent rate and evaporation rate of methane raindrops on Titan. The model, using conventional aerodynamics, with raindrop distortion parameterized by theExpand
Organic haze, glaciations and multiple sulfur isotopes in the Mid-Archean Era
Abstract We use sulfur (S) isotope signatures within ancient sediments and a photochemical model of sulfur dioxide (SO 2 ) photolysis to interpret the evolution of the atmosphere over the first halfExpand