Permian paleogeography of west-central Pangea: Reconstruction using sabkha-type gypsum-bearing deposits of Parnaíba Basin, Northern Brazil

Abrantes, Francisco R.; Nogueira, Afonso César Rodrigues; Soares, Joelson Lima

doi:10.1016/j.sedgeo.2016.06.004

Cited by 40 publications

(12 citation statements)

References 21 publications

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“…Thus, more evenly distributed land areas would provide more land–ocean interfaces compared with the other extreme, the Permian time period, which is known for Pangaea, the presence of a huge supercontinent and large inland deserts (Glennie, 1987 ; Abrantes et al , 2016 ). This is a scenario of an extremely unequal land–water distribution in the natural history of our planet, which was the worst case for habitability on Earth.…”

Section: What Makes a Planet Superhabitable?mentioning

confidence: 99%

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World

2020

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The fact that Earth is teeming with life makes it appear odd to ask whether there could be other planets in our galaxy that may be even more suitable for life. Neglecting this possible class of ''superhabitable'' planets, however, could be considered anthropocentric and geocentric biases. Most important from the perspective of an observer searching for extrasolar life is that such a search might be executed most effectively with a focus on superhabitable planets instead of Earth-like planets. We argue that there could be regions of astrophysical parameter space of star-planet systems that could allow for planets to be even better for life than our Earth. We aim to identify those parameters and their optimal ranges, some of which are astrophysically motivated, whereas others are based on the varying habitability of the natural history of our planet. Some of these conditions are far from being observationally testable on planets outside the solar system. Still, we can distill a short list of 24 top contenders among the >4000 exoplanets known today that could be candidates for a superhabitable planet. In fact, we argue that, with regard to the search for extrasolar life, potentially superhabitable planets may deserve higher priority for follow-up observations than most Earth-like planets.

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Section: What Makes a Planet Superhabitable?mentioning

confidence: 99%

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World

2020

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“…On the surface of the mudflats, precipitation from the evaporation of saline groundwaters forms efflorescent evaporites, either as powdery undulating surfaces or as hard crystalline crusts (Smoot & Lowenstein, 1991;Warren, 2016). Subaerial exposure and desiccation of gypsum in the vadose zone results in fractures and the reworking of fragments by water inflow (Kendall & Harwood, 1996;Abrantes et al, 2016).…”

Section: Ephemeral Saline Lake-saline Pan/mudflatmentioning

confidence: 99%

Sedimentology and isotope geochemistry of transitional evaporitic environments within arid continental settings: From erg to saline lakes

et al. 2020

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Arid continental basins typically contain a spectrum of coeval environments that coexist and interact from proximal to distal. Within the distal portion, aeolian ergs often border playa, or perennial, desert lakes, fed by fluvial incursions or elevated groundwaters. Evaporites are common features in these dryland, siliciclastic dominant settings. However, sedimentary controls upon evaporite deposition are not widely understood, especially within transitional zones between coeval clastic environments that are dominantly controlled by larger scale allocyclic processes, such as climate. The sulphur (δ 34 S) and oxygen (δ 18 O, Δ 17 O) isotope systematics of evaporites can reveal cryptic aspects of sedimentary cycling and sulphate sources in dryland settings. However, due to the lack of sedimentological understanding of evaporitic systems, isotopic data can be easily misinterpreted. This work presents detailed sedimentological and petrographic observations, coupled with δ 34 S, δ 18 O and Δ 17 O data, for the early Permian Cedar Mesa Sandstone Formation (western USA). Depositional models for mixed evaporitic/clastic sedimentation, which occurs either in erg-marginal or lacustrine-marginal settings, are presented to detail the sedimentary interactions present in terms of climate variations that control them. Sedimentological and petrographical analysis of the evaporites within the Cedar Mesa Sandstone Formation reveal a continental depositional environment and two end member depositional models have been developed: erg-margin and lake-margin. The δ 34 S values of gypsum deposits within the Cedar Mesa Sandstone Formation are consistent with late Carboniferous to early Permian marine settings. However, a marine interpretation is inconsistent with sedimentological and petrographic evidence. Consequently, δ 34 S, δ 18 O and Δ 17 O values are probably recycled and do not reflect ocean-atmosphere values at the time of evaporite precipitation. They are most likely derived from the weathering of older marine evaporites in the hinterland. Thus, the results demonstrate the need for a combination of both sedimentological and geochemical analysis of evaporitic systems to better understand their depositional setting and conditions.

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“…9D and E), interlayered with microbial laminae. These nodules generally have a microcrystalline structure (secondary) suggesting conversion from anhydrite, and are characterized by irregular margins and a displacive growth pattern, indicating a formation process within the capillarygroundwater zone of an upper sabkha setting, possibly experiencing subaerial exposure (Warren, 2006(Warren, , 2016Abrantes et al, 2016). The remnants of selenitic structures observed within this facies, indicate that the nodules formed through progressive displacive growth of gypsum crystals around a nucleus (generally represented by the selenites) until the original shapes changed into a mainly nodular morphology.…”

Section: Depositional Modelmentioning

confidence: 99%

The onset of the Messinian Salinity Crisis in the central Mediterranean recorded by pre‐salt carbonate/evaporite deposition

et al. 2020

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The Calcare di Base is a carbonate/evaporitic unit formed before the deposition of the massive halite bodies in the main depozones of the Mediterranean region, and has been at the centre of a fiery debate between different 'schools of thought' about its genesis, environmental conditions and timing of deposition. It crops out extensively in Southern Italy, across Neogene basins located on the Tyrrhenian and Ionian margins of northern Calabria, where it was studied through a detailed facies and stratigraphic analysis that revealed the presence of a continental/shallow-marine to slope system, active during the onset of the Messinian Salinity Crisis. During the Calcare di Base deposition, an arid climate regime with intermittent humid phases occurred with a precession forced cyclicity, facing an overall generally cold climatic period. During arid periods, stressed environmental conditions permitted the establishment of widespread microbial-mediated carbonate production, frequently associated with evaporitic (gypsum-dominated) deposition, along a sabkha-type environment with extensive salinas and hypersaline coastal lagoons grading seaward into a carbonate/evaporite shallow-marine shelf. This is testified to by microbial boundstones and dissolution breccias commonly associated with nodular gypsum and arenites affected by desiccation, typically forming metre-scale shallowing-upward peritidal cycles. Seaward, gravity flow deposits are interpreted as re-sedimented shelf limestones, defining a slope apron. Mixed carbonate/evaporite megabreccias and disorganized floatbreccias were deposited along the upper slope, whereas soft deformation with slides, slumps and channelized turbidites further developed along the lower slope to basin. During the humid climate episodes, that affected the platform system with a precession-forced cyclicity, the carbonate production was reduced together with the evaporitic deposition, leading to the widespread deposition of marlstones and fine to coarse siliciclastic deposits.

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Permian paleogeography of west-central Pangea: Reconstruction using sabkha-type gypsum-bearing deposits of Parnaíba Basin, Northern Brazil

Cited by 40 publications

References 21 publications

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World

Sedimentology and isotope geochemistry of transitional evaporitic environments within arid continental settings: From erg to saline lakes

The onset of the Messinian Salinity Crisis in the central Mediterranean recorded by pre‐salt carbonate/evaporite deposition

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