Deep-rooted piercement structures in deep sedimentary basins — Manifestations of supercritical water generation at depth?

Hovland, Martin; Fichler, Christine; Rueslåtten, Håkon; Johnsen, Hans Konrad

doi:10.1016/j.gexplo.2005.11.056

Cited by 22 publications

(19 citation statements)

References 9 publications

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“…In a suite of recent papers, Hovland and various teams of co-workers (e.g. Hovland et al, 2005Hovland et al, , 2006a have used molecular theory, their own and past experiments, and reservoir modeling to introduce the important new concept that, in some conditions, supercritical brines may deposit ''geological scale'' salt deposits.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal salt—but how much?

Talbot

2008

Marine and Petroleum Geology

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Section: Introductionmentioning

confidence: 99%

Hydrothermal salt—but how much?

Talbot

2008

Marine and Petroleum Geology

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“…Some experimental studies of supercritical brines have been reported in the literature; e.g., Tester et al [8], who examined the phase behavior of synthetic brines below and above their CP. The researchers observed the process through a sapphire window in the pressure chamber, and when the brines were passing into the supercritical region at a temperature of 407˚C and 298 bar pressure (the CP of seawater), they could see a "cloud" formed by the onset of "shock crystallization" of NaCl and Na 2 SO 4 [8,13,14]. The sudden phase transition occurred as the solubility of the salts declined to nearzero over a temperature range of only a few degrees C. The resulting solids were found to consist of amorphous microscopic particles of sizes between 10 and 100 µm.…”

Section: Supercritical Brinesmentioning

confidence: 99%

“…It is therefore important to find out more on the nature of the driving mechanisms. The idea that mud volcanoes may represent surface manifestation of phase separation of water at depth was first discussed some years ago [13], see Figure 3. Since then, new data has appeared in the geologic literature, which tends to support that idea.…”

Section: Mud Volcanoesmentioning

confidence: 99%

Buried Hydrothermal Systems: The Potential Role of Supercritical Water,“ScriW”, in Various Geological Processes and Occurrences in the Sub-Surface

Hovland¹,

Rueslåtten²,

Johnsen³

2014

AJAC

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It is well known that seawater that migrates deep into the Earth's crust will pass into its supercritical domain at temperatures above 407˚C and pressures above 298 bars. In the oceanic crust, these pressures are attained at depths of 3 km below sea surface, and sufficiently high temperatures are found near intruding magmas, which have temperatures in the range of 800˚C to 1200˚C. The physico-chemical behaviour of seawater changes dramatically when passing into the supercritical domain. A supercritical water vapour (ScriW) is formed with a density of 0.3 g/cc and a strongly reduced dipolar character. This change in polarity is causing the ScriW to lose its solubility of the common sea salts (chlorides and sulphates) and a spontaneous precipitation of sea salts takes place in the pore system. However, this is only one of many cases where the very special properties of ScriW affect its surroundings. The objective of this paper is to increase awareness of the many geological processes that are initiated and governed by ScriW. This includes interactions between ScriW and its geological surroundings to initiate and drive processes that are of major importance to the dynamics and livelihood of our planet. ScriW is the driver of volcanism associated with subduction zones, as ScriW deriving from the subduction slab is interacting with the mantle rocks and reducing their melting point. ScriW is also initiating serpentinization processes where olivines in the mantle rocks (e.g. peridotite) are transformed to serpentine minerals upon the uptake of OH-groups from hydrolysed water. The simultaneous oxidation of Fe 2+ dissolved from iron-bearing pyroxenes and olivines leads to the formation of magnetite and hydrogen, and consequently, to a very reducing environment. ScriW may also be the potential starter and driver of the poorly understood mud and asphalt volcanism; both submarine and terrestrial. Furthermore, the lack of polarity of the water molecules in ScriW gives the ScriW vapour the potential to dissolve organic matter and petroleum. The same applies to supercritical brines confined in subduction slabs. If these supercritical water vapours migrate upwards to reach the critical point, the supercritical vapour is condensed into steam and dissolved petroleum is partitioned from the water phase to become a separate fluid phase. This opens up the possibility of transporting petroleum long distances when mixed with ScriW. Therefore, we may, popularly, say that ScriW drives a gigantic underground refinery system and also a salt factory. It is suggested that the result of these processes is that ScriW is rejuvenating the world's ocean waters, as all of the ocean water circulates into the porous oceanic crust and out again in cycles of less than a million years. In summary, we suggest that ScriW participates in and is partly responsible for: 1) Ocean water rejuvenation and formation; 2) Fundamental geological processes, such as volcanism, earthquakes, and metamorphism (including serpentinization); 3) Solid salt producti...

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“…These were, however, pure 'physical' experiments and the geological significance of their results was not addressed before very recently (Hovland et al, 2005(Hovland et al, , 2006a. Because supercritical water oxidation is currently a rapidly expanding 'green science', further laboratory experiments on salt precipitation and scale control are common.…”

Section: Introductionmentioning

confidence: 99%

“…This means that supercritical water essentially acts as a non-polar fluid with solvation properties resembling those of low-polarity organic fluids. For this reason, supercritical water (within a certain temperature and pressure range) is able to dissolve organic liquids but unable to dissolve common sea salts (Tester et al, 1993;Hodes et al, 2004), results which have also been modelled by molecular modelling (Hovland et al, 2006a).…”

Section: Introductionmentioning

confidence: 99%