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Plume

About: Plume is a research topic. Over the lifetime, 10333 publications have been published within this topic receiving 275216 citations.


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Journal ArticleDOI
23 Jul 2009-Nature
TL;DR: McKinnon et al. as mentioned in this paper reported that ammonia is present in the plume, along with various organic compounds, deuterium and, very probably, Ar-40, which provides strong evidence for the existence of at least some liquid water, given that temperatures in excess of 180 K have been measured near the fractures from which the jets emanate.
Abstract: Jets of water ice from surface fractures near the south pole of Saturn's icy moon Enceladus produce a plume of gas and particles. The source of the jets may be a liquid water region under the ice shell-as suggested most recently by the discovery of salts in E-ring particles derived from the plume-or warm ice that is heated, causing dissociation of clathrate hydrates. Here we report that ammonia is present in the plume, along with various organic compounds, deuterium and, very probably, Ar-40. The presence of ammonia provides strong evidence for the existence of at least some liquid water, given that temperatures in excess of 180 K have been measured near the fractures from which the jets emanate. We conclude, from the overall composition of the material, that the plume derives from both a liquid reservoir (or from ice that in recent geological time has been in contact with such a reservoir) as well as from degassing, volatile-charged ice. As part of a general comprehensive review of the midsize saturnian satellites at the conclusion of the prime Cassini mission, PI McKinnon and co-I Barr contributed to three review chapters.

495 citations

Journal ArticleDOI
15 Sep 2011-Nature
TL;DR: This paper presented petrological evidence for a large amount of dense recycled oceanic crust in the head of the plume and developed a thermomechanical model that predicts no pre-magmatic uplift and requires no lithospheric extension.
Abstract: Large igneous provinces (LIPs) are known for their rapid production of enormous volumes of magma (up to several million cubic kilometres in less than a million years), for marked thinning of the lithosphere, often ending with a continental break-up, and for their links to global environmental catastrophes. Despite the importance of LIPs, controversy surrounds even the basic idea that they form through melting in the heads of thermal mantle plumes. The Permo-Triassic Siberian Traps--the type example and the largest continental LIP--is located on thick cratonic lithosphere and was synchronous with the largest known mass-extinction event. However, there is no evidence of pre-magmatic uplift or of a large lithospheric stretching, as predicted above a plume head. Moreover, estimates of magmatic CO(2) degassing from the Siberian Traps are considered insufficient to trigger climatic crises, leading to the hypothesis that the release of thermogenic gases from the sediment pile caused the mass extinction. Here we present petrological evidence for a large amount (15 wt%) of dense recycled oceanic crust in the head of the plume and develop a thermomechanical model that predicts no pre-magmatic uplift and requires no lithospheric extension. The model implies extensive plume melting and heterogeneous erosion of the thick cratonic lithosphere over the course of a few hundred thousand years. The model suggests that massive degassing of CO(2) and HCl, mostly from the recycled crust in the plume head, could alone trigger a mass extinction and predicts it happening before the main volcanic phase, in agreement with stratigraphic and geochronological data for the Siberian Traps and other LIPs.

483 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the effects of interlayer communication through low-permeability seals. But they focused on the effects on shallow aquifers and evaluated the possible implications for shallow groundwater resources, rather than the CO2 plume itself, and concluded that large-scale pressure changes appear to be of more concern to groundwater resources than changes in water quality caused by the migration of displaced saline water.

480 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of ambient gas on the expansion dynamics of the plume generated by laser ablation of an aluminum target has been investigated using frequency doubled radiation from a Q-switched Nd:YAG laser.
Abstract: The effect of ambient gas on the expansion dynamics of the plasma generated by laser ablation of an aluminum target has been investigated using frequency doubled radiation from a Q-switched Nd:YAG laser. The diagnostic tools include fast photography of overall visible plume emission using a 2 ns gated intensified charged coupled device and space and time resolved emission spectroscopy using a 50 cm monochromator/spectrograph and photomultiplier tube. The expansion behavior of the plasma was studied with ambient air pressure ranging from 10−6 to 100 Torr. Free expansion, plume splitting and sharpening, hydrodynamic instability, and stagnation of the plume were observed at different pressure levels. Space and time resolved emission spectroscopic studies showed a twin peak distribution for Al and Al+ species at farther distances illustrating plume splitting at pressures higher than 100 mTorr. Combining imaging together with time resolved emission diagnostics, a triple structure of the plume was observed. The expansion of the plume front was compared with various expansion models and found to be generally in good agreement.

475 citations

Journal ArticleDOI
25 Jun 2009-Nature
TL;DR: The identification of a population of E-ring grains that are rich in sodium salts, which can arise only if the plumes originate from liquid water, and the abundance of various salt components in these particles exhibit a compelling similarity to the predicted composition of a subsurface Enceladus ocean in contact with its rock core.
Abstract: Images from the Cassini spacecraft showed erupting plumes of water vapour and ice particles on Saturn's moon Enceladus, prompting speculation a subsurface ocean might be acting as a source of liquid water. Two groups this week report evidence relevant to the search for this subsurface ocean. The results, at first sight contradictory, leave the ocean a possibility, though still a hypothetical one. Postberg et al. used the Cassini Cosmic Dust Analyser to determine the chemical composition of ice grains in Saturn's E-ring, which consists largely of material from Enceladus. They find a population of E-ring grains rich in sodium salts, which should be possible only if the plumes originate from liquid water. Schneider et al. used Earth-based spectroscopic telescopes to search for sodium emission in the gas plumes erupting from Enceladus and found none. This is inconsistent with a direct supply from a salty ocean and suggests alternative eruption sources such as a deep ocean, a freshwater reservoir or ice. Or if there is a salty reservoir of water, some process not yet determined must be preventing the sodium from escaping into space. Saturn's moon Enceladus emits plumes of water vapour and ice particles from fractures near its south pole, raising the possibility of a subsurface ocean. Minor organic or siliceous components, identified in many ice grains, could be evidence of interaction between Enceladus' rocky core and liquid water; however it has been unclear whether the water is still present today or if it has frozen. Now, the identification of a population of E-ring grains that are rich in sodium salts suggests that the plumes originate from liquid water. Saturn's moon Enceladus emits plumes of water vapour and ice particles from fractures near its south pole1,2,3,4,5, suggesting the possibility of a subsurface ocean5,6,7. These plume particles are the dominant source of Saturn’s E ring7,8. A previous in situ analysis9 of these particles concluded that the minor organic or siliceous components, identified in many ice grains, could be evidence for interaction between Enceladus’ rocky core and liquid water9,10. It was not clear, however, whether the liquid is still present today or whether it has frozen. Here we report the identification of a population of E-ring grains that are rich in sodium salts (∼0.5–2% by mass), which can arise only if the plumes originate from liquid water. The abundance of various salt components in these particles, as well as the inferred basic pH, exhibit a compelling similarity to the predicted composition of a subsurface Enceladus ocean in contact with its rock core11. The plume vapour is expected to be free of atomic sodium. Thus, the absence of sodium from optical spectra12 is in good agreement with our results. In the E ring the upper limit for spectroscopy12 is insufficiently sensitive to detect the concentrations we found.

473 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023834
20221,400
2021326
2020311
2019268
2018326