A pyroclastic flow deposit on Venus

Ghail, R. C.; Wilson, Lionel

doi:10.1144/sp401.1

Cited by 26 publications

(22 citation statements)

References 44 publications

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“…Our model shows that a mass flux of 4 $ 3 Â 10 8 kg s À 1 is required to sustain an explosive volcanic event at the altitude of Scathach Fluctus. Ghail and Wilson (2013) estimate the volume of Scathach Fluctus to be 225-875 km 3 , and the density to be close to 2000 kg m À 3 , consistent with a welded ignimbrite (Lepetit et al, 2009). Assuming a dense rock equivalent density of 2800 kg m À 3 , this implies $ 30% void space.…”

Section: Deposit Emplacement Emissions and Limits Of Detectabilitymentioning

confidence: 76%

“…A full description of the deposit is provided in Ghail and Wilson (2013). Assuming this eruption occurred at 1200 K, from a vent at a similar elevation to the deposit itself and of radius 25 m, in order for it to behave explosively, the model shows there must have been an H 2 O content of over 4.5% (which erupts at a volume fraction of 0.749, between Fig.…”

Section: Scathach Fluctusmentioning

confidence: 99%

“…It has proved difficult to determine the nature of these less common volcanic deposits seen in the radar imagery of Venus and confirmation of an explosive origin has so far mostly proved to be controversial (Campbell and Rogers, 1994;Grosfils et al, 2011;Keddie and Head, 1995;McGill, 2000). One recent exception is a proposed pyroclastic deposit known as Scathach Fluctus, identified by Ghail and Wilson (2013). This pyroclastic interpretation was arrived at via a combination of radar characteristics, flow morphology, and flow interaction with other geomorphological features.…”

Section: Introductionmentioning

confidence: 99%

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Explosive volcanic activity on Venus: The roles of volatile contribution, degassing, and external environment

Airey

Mather

Pyle

et al. 2015

Planetary and Space Science

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We investigate the conditions that will promote explosive volcanic activity on Venus. Conduit processes were simulated using a steady-state, isothermal, homogeneous flow model in tandem with a degassing model. The response of exit pressure, exit velocity, and degree of volatile exsolution was explored over a range of volatile concentrations (H2O and CO2), magma temperatures, vent altitudes, and conduit geometries relevant to the Venusian environment. We find that the addition of CO2 to an H2O-driven eruption increases the final pressure, velocity, and volume fraction gas. Increasing vent elevation leads to a greater degree of magma fragmentation, due to the decrease in the final pressure at the vent, resulting in a greater likelihood of explosive activity. Increasing the magmatic temperature generates higher final pressures, greater velocities, and lower final volume fraction gas values with a correspondingly lower chance of explosive volcanism. Cross-sectionally smaller, and/or deeper, conduits were more conducive to explosive activity. Model runs show that for an explosive eruption to occur at Scathach Fluctus, at Venus’ mean planetary radius (MPR), 4.5% H2O or 3% H2O with 3% CO2 (from a 25 m radius conduit) would be required to initiate fragmentation; at Ma’at Mons (~9 km above MPR) only ~2% H2O is required. A buoyant plume model was used to investigate plume behaviour. It was found that it was not possible to achieve a buoyant column from a 25 m radius conduit at Scathach Fluctus, but a buoyant column reaching up to ~20 km above the vent could be generated at Ma’at Mons with an H2O concentration of 4.7% (at 1300 K) or a mixed volatile concentration of 3% H2O with 3% CO2 (at 1200 K). We also estimate the flux of volcanic gases to the lower atmosphere of Venus, should explosive volcanism occur. Model results suggest explosive activity at Scathach Fluctus would result in an H2O flux of ~107 kg s−1. Were Scathach Fluctus emplaced in a single event, our model suggests that it may have been emplaced in a period of ~15 days, supplying 1–2×104 Mt H2O to the atmosphere locally. An eruption of this scale might increase local atmospheric H2O abundance by several ppm over an area large enough to be detectable by near-infrared nightside sounding using the 1.18 µm spectral window such as that carried out by the Venus Express/VIRTIS spectrometer. Further interrogation of the VIRTIS dataset is recommended to search for ongoing volcanism on Venus

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Section: Deposit Emplacement Emissions and Limits Of Detectabilitymentioning

confidence: 76%

Section: Scathach Fluctusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Explosive volcanic activity on Venus: The roles of volatile contribution, degassing, and external environment

Airey

Mather

Pyle

et al. 2015

Planetary and Space Science

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“…Head & Wilson 1986). However, geomorphological evidence exists for an extensive pyroclastic flow deposit near Diana Chasma, which, if found to be a common form of volcanic deposit on Venus, would have implications for the mantle volatile content and the volcanic origin of atmospheric SO 2 on the planet (Ghail & Wilson 2013).…”

Section: Volcanismmentioning

confidence: 99%

“…A pyroclastic flow deposit on Venus Ghail & Wilson (2013) The asymmetry of lunar near-and farside maria is still under investigation. Here, Morota et al (2014) study the relationship between mare distribution and crustal thickness on the Moon using remotely sensed geological and geophysical data.…”

Section: R C Ghail and L Wilsonmentioning

confidence: 99%

Volcanism and tectonism across the inner solar system: an overview

Platz

Byrne

Massironi

et al. 2014

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Volcanism and tectonism are the dominant endogenic means by which planetary surfaces change. This book, in general, and this overview, in particular, aim to encompass the broad range in character of volcanism, tectonism, faulting and associated interactions observed on planetary bodies across the inner solar system -a region that includes Mercury, Venus, Earth, the Moon, Mars and asteroids. The diversity and breadth of landforms produced by volcanic and tectonic processes are enormous, and vary across the inventory of inner solar system bodies. As a result, the selection of prevailing landforms and their underlying formational processes that are described and highlighted in this review are but a primer to the expansive field of planetary volcanism and tectonism. In addition to this extended introductory contribution, this Special Publication features 21 dedicated research articles about volcanic and tectonic processes manifest across the inner solar system. Those articles are summarized at the end of this review.

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The distribution of volcanism in the Beta‐Atla‐Themis region of Venus: Its relationship to rifting and implications for global tectonic regimes

et al. 2017

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A new analysis of the spatial relationships between volcanic features and rifts on Venus provides new constraints on models of planetary evolution. We developed a new database of volcanic features for the Beta‐Atla‐Themis (BAT) region and used nearest neighbor measurements to determine relationships between different types of volcanic features and the rifts. Nearest neighbor analysis shows that all the dome‐type and corona‐type subpopulations tend to cluster. Rift associations were inferred from the deviation of a feature's population distribution (as a function of distance from rift) from that of a random population. Dome‐type features in general have no discernible relationship with rifts. Most corona‐type features have a strong association with rifts, with intermediate and large volcanoes also tending to occur close to or on rifts. Shield fields, on the other hand, tend to occur away from rifts. Our new evidence supports classifications of rifts on Venus into different types, possibly by age, with a shift from globally dispersed (more uniform) volcanism toward the more rift‐focused distribution, which suggests a shift in tectonic regime. Our observations are consistent with recent models proposing the evolution of Venus from a stagnant lid regime to a subcrustal spreading regime. We also present evidence for a failed rift on Venus and note that this process may be analogous, albeit on a larger scale, to a proposed model for the evolution of the East African rift system.

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A pyroclastic flow deposit on Venus

Cited by 26 publications

References 44 publications

Explosive volcanic activity on Venus: The roles of volatile contribution, degassing, and external environment

Explosive volcanic activity on Venus: The roles of volatile contribution, degassing, and external environment

Volcanism and tectonism across the inner solar system: an overview

The distribution of volcanism in the Beta‐Atla‐Themis region of Venus: Its relationship to rifting and implications for global tectonic regimes

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