Earth's outgassing

[johnm33]

I think there's an upturn in Earths outgassing, so first I'll establish what I mean by outgassing.
This link is a good start and it starts with

There is considerable excitement in the natural (or geologic) hydrogen community and beyond: the hypothesis that natural hydrogen can be found in nature, today is undisputed, with seeps being confirmed all over the world. The distributions of seeps, however, may not reflect geological conditions, rather locations that have received more research attention.
Recently, the USGS indicated that there may be enough natural hydrogen below the ground to supply humanity’s need for liquid fuel for hundreds of years (USGS, 2022). Despite our advances in understanding of natural hydrogen, pivotal questions remain: Can commercial natural hydrogen fields be discovered? If so, what would they look like? Are they analogous to oil and gas fields? Will natural hydrogen revolutionise our low-carbon future?

Same source, a little older

Natural hydrogen is commonly known as native, geologic, white or golden hydrogen. The colour is not yet settled in the eyes of the marketers, although the results of an online poll during the conference suggested that attendees preferred the term ‘white hydrogen’.

The processes that create natural hydrogen are not fully understood. It is found in a large range of geological settings – in oceanic and continental crust, volcanic gases and hydrothermal systems (as discussed in talks by Isabelle Moretti, UPPA, France; Kayad Moussa, ODDEG, Djibouti; Eric Gaucher, University of Bern, Switzerland; Eric Deville, IFP School, France; Alain Prinzhofer; Viacheslav Zgonnik). The present known sources of natural hydrogen seem to be abiotic (that is, a non-living source). However, discussions highlighted that natural hydrogen can be considered as both biogenic or abiotic, because source interpretations can be subjective, and there is still much to learn about hydrogen and microorganisms.

This begins with an anecdotal account of an unexpected discovery.

IN THE SHADE of a mango tree, Mamadou Ngulo Konaré recounted the legendary event of his childhood. In 1987, well diggers had come to his village of Bourakébougou, Mali, to drill for water, but had given up on one dry borehole at a depth of 108 meters. “Meanwhile, wind was coming out of the hole,” Konaré told Denis Brière, a petrophysicist and vice president at Chapman Petroleum Engineering, in 2012. When one driller peered into the hole while smoking a cigarette, the wind exploded in his face.

“He didn’t die, but he was burned,” Konaré continued. “And now we had a huge fire. The color of the fire in daytime was like blue sparkling water and did not have black smoke pollution. The color of the fire at night was like shining gold, and all over the fields we could see each other in the light. … We were very afraid that our village would be destroyed.”

It took the crew weeks to snuff out the fire and cap the well. And there it sat, shunned by the villagers, until 2007. That was when Aliou Diallo, a wealthy Malian businessman, politician, and chair of Petroma, an oil and gas company, acquired the rights to prospect in the region surrounding Bourakébougou. “We have a saying that human beings are made of dirt, but the devil is made of fire,” Diallo says. “It was a cursed place. I said, ‘Well, cursed places, I like to turn them into places of blessing.’”
In 2012, he recruited Chapman Petroleum to determine what was coming out of the borehole. Sheltered from the 50°C heat in a mobile lab, Brière and his technicians discovered that the gas was 98% hydrogen. That was extraordinary: Hydrogen almost never turns up in oil operations, and it wasn’t thought to exist within the Earth much at all. “We had celebrations with large mangos that day,” Brière says.

And last some indication of the possible duration of outgassing events. Abstract

Subsurface geological reservoirs of natural hydrogen gas (H2), a clean fuel and energy vector, are currently a target for energy resource exploration. Such reservoirs can be revealed by the presence of H2 within soil, analogous to hydrocarbon seepage in petroleum systems. Nevertheless, defining the level of soil H2 that can indicate a potentially economic resource is currently impossible, and identifying geological H2 within soil-gas is challenging because H2 concentrations and the isotopic composition (δ2H) may overlap with the in-situ biological signature. In spite of these limitations, analogies to conventional hydrocarbon systems suggest that the presence of surface advective gas flows can reveal (unlike diffusion) a subsoil source and even pressurised gas accumulations of H2. Here, a massive release of H2 is reported from a CH4–H2 rich seep in Turkey, known as Chimaera, an emblematic example of H2 advection. The site represents the first case where a closed-chamber flux method was applied for H2 seepage. H2 advection at the site was clearly indicated by numerous gas vents and flames, and by the heterogeneous spatial distribution of pervasive, invisible exhalation (miniseepage), inducing rapid H2 concentration build-up within the chamber. H2 emission (∼10 ± 3 kg day−1, with the highest H2 emission factor reported, thus far, of ∼5000 kg km−2 day−1) is continuous and long lasting (flames have been documented for millennia) and, using an analogy for hydrocarbon seeps, may stem from pressurised accumulations. The Chimaera case is illustrative of how detecting soil H2 advection may help unravel surface (biological) vs. subsoil (geological) gas origins in cases where, in the absence of significant gas seepage, soil H2 concentrations are within the range of biological production (100-103 ppmv, e.g., as for “fairy circles” observed in several countries). Interpretations must, however, be supported by additional geochemical data and evaluations of potential biological H2 production within the surface ecosystem.

Not that I think all outgassing is hydrogen seepage.

[johnm33]

A key takeaway from the second link above,
 

Natural hydrogen is often found in association with brines that also contain helium, carbon dioxide, nitrogen and methane. There are well-documented occurrences of hydrogen within copper mines in Ontario, Canada, and South African gold, platinum and chromite mines (Eric Deville), and in geothermal brines in Iceland (Isabelle Moretti & Kayad Moussa). One talk detailed the long-term monitoring of the Sao Francisco Basin, Brazil, where natural hydrogen seeps at volumes exceeding a few hundred kg per day per km2 (Maria Rosanne).

Some key processes for hydrogen production include: (a) deep hydration and radiolysis of water associated with the radioactive decay of uranium, thorium and potassium-bearing minerals; (b) oxidation of ferrous to ferric iron and mineral hydration, for example, during the serpentinisation of olivine (e.g. ophiolites); (c) decomposition in metamorphic areas; (d) very late organic matter maturation; and (e) primordial hydrogen originating from Earth’s core and mantle (as discussed in talks by Viacheslav Zgonnik; Chris Boreham; Isabelle Moretti; Eric Gaucher; Alain Prinzhofer).

my bold.
from the third

Zgonnik favors a third and more deep-seated source: He thinks primordial hydrogen, trapped soon after the planet’s birth in its iron core, is seeping to the surface through thousands of kilometers of rock. The evidence is spotty and Zgonnik acknowledges the theory is controversial. “It goes against many paradigms,” he says.

so I'm not the only one who thinks this.
You should at least skim this since they look at the reactions which can take place within the mantle, http://www.magniel.com/jse/B/vol0201B/vg040720.pdf which I strongly suspect are the cause of the phenomenon shown here
 A little more about the blobs, with a whole series of links of it's own. https://eos.org/features/the-unsolved-mystery-of-the-earth-blobs

Twice a day, Earth’s crust rises and falls with the tides. Although we’re more familiar with ocean tides, the solid Earth experiences the same forces as our oceans. As the Sun and the Moon pull on Earth, the entire planet flexes and stretches. In some places, the surface of Earth rises and falls by as much as 40 centimeters.

Scientists can track this movement using highly sensitive GPS measurements. A group of researchers led by Linguo Yuan at Academia Sinica in Taiwan analyzed measurements from GPS stations across the globe over 16 years and found that the Earth tide wasn’t what they expected: It seemed to be off-kilter just above where the blobs were located. The tides, they wrote in their 2013 paper, “provide significant information on the solid Earth’s deeper interior.”

[johnm33]

This looks at the core mantle boundary, link
My take differs here inasmuch as I'm guessing that the core [x2] was once saturated in H+ and that this has been 'leaking' into the silicon and oxygen based minerals for eons. Being so small the whole mineral base was permeated with H+ and some event precipitated a reaction whence various solvents were formed almost instantly, directly into a supercritical state setting off a cascade of reactions, H4Si, CH4 and H2O spring immediately to mind, and these solvents both released metals from their oxidised state and dissolved those metals into high temp SiO2/H2O solutions which precipitated the further breakout of H+ from the metals and H2 from the H4Si, and the whole shebang headed towards the surface, reacting further as it did.
The heat generated further melted the outer cores lower melt temperature metals and these being liquid form the core of the ulvz.
Silane/H4Si

[kassy]

I think there's an upturn in Earths outgassing

Much of these articles have been posted in the hydrogen thread. You hear more about it because it is a hot topic.

The data do not support an upturn.

[be cause]

that sounds like people outgassing !

[johnm33]

The data do not support an upturn.

What data are you talking about?
There certainly seems to be variability in the short and long term, but since these are geological processes it's going to be difficult to establish any causal relationship. When I'm ready I was going to 'cherrypick' Toba as a start date and look for variability in the interim.
So these two papers address, to some degree and in some manner, short term fluctuations. 
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/99EO00202
https://www.nature.com/articles/npre.2008.1764.1.pdf
The second introduces and examines another criteria which I haven't got around to yet, but where I differ from their view is that I see the 'magma' not as semi molten lava-like rock but as a collection of semi liquid or gel-like 'distillates' which remain in their solvent. As various chemicals are expelled from distillates reactions with other  bodies occur and the resultant pressure waves temporarily liquify the mix the various bodies can rise and fall according to their densities and the forces acting upon them. I think some of the less dense distillates have been exuded as 'muds' and can explain otherwise difficult 'deposits' dolomite springs to mind.

As shown in Fig.1, there is striking correlation between El Niño (represented by JMA
Index) and frequency of earthquake and slowdown of earth rotation. With the exception
of El Niño 1982-1983, El Niño all happened with higher frequency of earthquakes in
region A and relative slowdown in earth's rotation speed. The frequency of earthquake in
1990s was remarkably higher than in 1980s. During the same period, there was also a
relative slowdown of earth rotation. As a result, the frequency of El Niño in 1990s was
higher than 1980s

[SteveMDFP]

...
So these two papers address, to some degree and in some manner, short term fluctuations. 
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/99EO00202
https://www.nature.com/articles/npre.2008.1764.1.pdf
The second introduces and examines another criteria which I haven't got around to yet, but where I differ from their view is that I see the 'magma' not as semi molten lava-like rock but as a collection of semi liquid or gel-like 'distillates' which remain in their solvent. As various chemicals are expelled from distillates reactions with other  bodies occur and the resultant pressure waves temporarily liquify the mix the various bodies can rise and fall according to their densities and the forces acting upon them. I think some of the less dense distillates have been exuded as 'muds' and can explain otherwise difficult 'deposits' dolomite springs to mind.....

I'd been unaware of the "dolomite problem" in geology.  Interesting problem:
‘Dolomite Problem’: 200-year-old geology mystery resolved
https://news.umich.edu/200-year-old-geology-mystery-resolved/

A number of economically important minerals arise from interaction between rock and liquid water, it seems dolomite is one of them.

With the earth's magma having been slowly mixing for the past several billion years, it seems that any chemical reactions that could take place has long ago reached equilibrium.  However, it is well understood that at these vast pressures, very large amounts of gasses are dissolved within the rock.  This, in fact, is why volcanic eruptions are commonly explosive. 
However, I'm deeply skeptical that geologic processes could underly the ENSO phenomenon.

[johnm33]

snip
 With the earth's magma having been slowly mixing for the past several billion years, it seems that any chemical reactions that could take place has long ago reached equilibrium.
snip
However, I'm deeply skeptical that geologic processes could underly the ENSO phenomenon.

You'll see that that's their suggestion not neccesarily mine, mine being [to Kassy's point] that there are definitely fluctuations in the outbreak of fluids along ocean ridges. I again differ from the mainstream view here, inasmuch as I think that the scalding hot richly saline waters are from a considerable depth and not recycled oceanic waters. I suspect some of the extremophiles that inhabit the different types of hydrothermal vents may also be present at those same depths. Dolomite is not the only 'rock' I suspect as a 'distillate' there are any number of deposits of 'refined' materials that fit, plus many ancient cave cities were carved out of soft rock which then slowly hardened once exposed to air. Tura limestone also behaved like this. I'm skeptical too that the chemical reactions have reached equilibrium as there is definitely enough chemical energy is some of the hydrogen rich 'solvents' to create Lava within the depth of the crust, at least as best as I can tell.

[johnm33]

The 'refined' mineral deposits such as bentonite kaolin etc. are probably the result of phase changes and transition states of water. Supercritical water as it drops below 'critical' thresholds is going to drop some of its solutes and what remains may be more liquid and tend to rise into and cracks caused by tidal flexing, however small they may be. Similarly when water meets an hydrophilic mineral it can form an exclusion zone EZ a few molecules deep where all solutes are expelled along with some H² as the water forms an OH structure which under the pressure extant is forced through the mineral. [This would suggest that the sunken areas of hydrogen seeps should be both wetter than and have a slightly richer oxygen content in the soil] Releasing oxygen and refoming into H2O once the transit is complete.

This water is not in a form familiar to us — it is not liquid, ice or vapor. This fourth form is water trapped inside the molecular structure of the minerals in the mantle rock. The weight of 250 miles of solid rock creates such high pressure, along with temperatures above 2,000 degrees Fahrenheit, that a water molecule splits to form a hydroxyl radical (OH), which can be bound into a mineral's crystal structure.

from
This next paper discusses, at length, some of the possibilities of the potential for dissolving elements of Earths mantle or CMB?

Conclusions

The extremely high concentrations of gold in fluid inclusions of chloride brines and CO2-rich fluids were determined. The concentrations are much greater than previously thought possible as a consequence of gold being in the form of nanoparticles. The presence of gold nanoparticles in fluid inclusions was confirmed by optical and spectroscopic analysis. Based on these results we might assume that there are reservoirs of fluids containing gold nanoparticles in the Earth’s lithosphere that can be a source of Au-bearing mineralizing fluids for the formation of gold deposits. Therefore, the data obtained significantly broadens our understanding of the boundary parameters of the deep processes of transport and accumulation of gold by hydrothermal fluids. Further study of these newly discovered fluids will expand of our understanding of the gold behavior in deep fluid systems and mechanism of its accumulation in the Earth’s crust.

Just how much water is down there? It's probably worth considering other bodies. https://www.popularmechanics.com/space/a14555/water-worlds-in-our-solar-system/
5 oceans ? 50?
Somewhere along the way it occured to me that if we have so much H² outgassing, and we're losing almost 100,000 tons to space every year how likely really is it that this was gathered together in an accretion period when gravity was so much less of an attraction?

[kassy]

It is the most abundant element in the universe so that probably helps. And when was the time when gravity was so much less of an attraction and why did it happen?

[johnm33]

https://en.wikipedia.org/wiki/Accretion_(astrophysics)

Abstract
Pebbles of millimeter sizes are abundant in protoplanetary discs around young stars. Chondrules inside primitive meteorites—formed by melting of dust aggregate pebbles or in impacts between planetesimals—have similar sizes. The role of pebble accretion for terrestrial planet formation is nevertheless unclear. Here, we present a model where inward-drifting pebbles feed the growth of terrestrial planets. The masses and orbits of Venus, Earth, Theia (which later collided with Earth to form the Moon), and Mars are all consistent with pebble accretion onto protoplanets that formed around Mars’ orbit and migrated to their final positions while growing. The isotopic compositions of Earth and Mars are matched qualitatively by accretion of two generations of pebbles, carrying distinct isotopic signatures. Last, we show that the water and carbon budget of Earth can be delivered by pebbles from the early generation before the gas envelope became hot enough to vaporize volatiles.

from
Or try
The theory is that the solar system was drawn together from a 'cloud' of dust and gas and somehow ended up in it's current arrangement travelling through 'space' towards Vega orthogonal to it's rotational plane at about 220km.per.sec. My point being htf would that lead to the capture of so much hydrogen that we no longer have the gravitational muscle to hang on to? Just stretches the elastic in my credulity past breaking.

[johnm33]

If there are a variety of chemical processes and reactions taking place at depth then it would follow that these would be represented on the surface to some extent. If you look through the quakes on here , you'll need to follow through to the area the the info and local mapping pages where you can select 3d to see how popular 10km depth is for some earthquake phenomenon. It suggests some kind of phase transition but I can't find any papers on that yet, need to know the correct terms I suppose.
Maybe there's some clue in this where at least it's implied that a reaction may have occured at 10km. Then looking at an analysis of the mud the plate structure of the particles is compatable with them having been contained as part of an hydroxyl lattice before some exothermic reaction/transition occured. For this to work for me the exuded mud would have to be more or less homogenous to indicate a prior complex saturated solution which it seems to be.
Davidovits's geopolymer institute https://www.geopolymer.org/ has some interesting things to say.

[John_the_Younger]

My vague recollection from a 1970's graduate school class is supported by a Wikipedia search - mantle earthquakes are rare and ...

he Mohorovičić discontinuity – usually called the Moho discontinuity, Moho boundary, or just Moho – is the boundary between the crust and the mantle of Earth. It is defined by the distinct change in velocity of seismic waves as they pass through changing densities of rock.[2]

The Moho lies almost entirely within the lithosphere (the hard outer layer of the Earth, including the crust).[3] Only beneath mid-ocean ridges does it define the lithosphere–asthenosphere boundary (the depth at which the mantle becomes significantly ductile). The Mohorovičić discontinuity is 5 to 10 kilometres (3–6 mi) below the ocean floor, and 20 to 90 kilometres (10–60 mi) beneath typical continental crusts, with an average of 35 kilometres (22 mi).

I'm fascinated by discoveries of Earth processes unknown or little understood when I was a student.  (But scientists knew a little bit back then.) [This is a teaser - more when I do a book report on Parkinson.]

[Renerpho]

I'm fascinated by discoveries of Earth processes unknown or little understood when I was a student.  (But scientists knew a little bit back then.)

The half-life of knowledge in geology (the amount of time that has to elapse before half of the knowledge is superseded or shown to be untrue) has been estimated to be about eight years.^[source]

[johnm33]

"MOHO" When I first began looking at 'quakes I thought the 'popular' 10km depth must be a transition zone and when I checked to see if it coincided with the moho I was kind of surprised that it was below it, it remains a puzzle. Even more puzzling, at least to me, are the transition zones at 660km and 410km, but I'm probably thinking in the wrong terms, that is phase transitions in hydrogen based solvents there have to be other processes in play too.
The image is a 3d from the above linked site, I've turned it to best illustrate both the 10km 'zone' and a second zone at 30km this shows the geographic distribution.

[kassy]

The theory is that the solar system was drawn together from a 'cloud' of dust and gas and somehow ended up in it's current arrangement travelling through 'space' towards Vega orthogonal to it's rotational plane at about 220km.per.sec. My point being htf would that lead to the capture of so much hydrogen that we no longer have the gravitational muscle to hang on to? Just stretches the elastic in my credulity past breaking.

Why would it not? It´s light and reacts with loads of elements. When slabs subduct some water can move out of certain rock types which is a similar process. They get slowly cooked of under high pressure.

Hydrogen is also very light so it is relatively hard to hang on too. Mars might not have an atmosphere now because it lost most of it early on. 

[johnm33]

Looks like a pressure wave will be passing beneath this caldera in the next few days so a small increase in outgassing may occur locally. Then that wave passes out to the mid Atlantic ridge and turns north so Iceland and Gakel too may see some activity increase in seven to ten days.