Chemical Volcanology - Science topic

The use of lava pumice for horticulture is limited based on its serious deficiency in essential Calcium. In addition it is quite high in Potassium and Magnesium which make Calcium availability worse. I was mandated to use lava pumice in Hawaii ginger production systems but upon its poor performance made it use untenable. Another problem is these materials are too dense for container plantings. Not everything that is available has competitive usage qualities. The availability of minerals from pumic materials are also low.

It is possible that sulfur hexafluoride, SF₆, is present in volcanic emissions (see reference below). Among all sulfur fluorides, SF₆ ist by far the most stable. The compound is rather inert and also a very potent greenhouse gas.

I was interested to learn that Hydrogen Fluoride gas was measured using FTIR spectrometry from a boat as well as on the crater at Whakaari White Island, New Zealand. Reference: Love SP et al. 2000. Passive Infrared Spectroscopic Remote Sensing of Volcanic Gases: Ground-Based Studies at White Island and Ruapehu, New Zealand, and Popocatepetl, Mexico. in Remote Sensing of Active Volcanism. Volume 16. Wiley

Dr. van der Zwan,  I have found the papers on Web of Science you have spotted. Also a person from Hawaii also sent me some more papers. Thanks a lot for your advice and references.

This method allows to estimate the pressure (water pressure, first of all) under which the granitic magma crystallized. It would be better if your rock is equigranular because phenocrysts may shift bulk rock composition aside from the 'right' cotectic line.

Then, an important point is whether magma crystallized under water-saturated conditions because the 'dry' lithostatic pressure and water pressure have a different effect on melting / crystallization. If you are trying to estimate the depth of crystallization, the error is greater in the case of H2O-undersaturated magma.

Then, the addition of Ca has an effect opposite to that of water pressure. Leucogranites expectably reveal better results than granites, granodiorites etc. because they compositionally approach the experimental system Q-Ab-Or.

So, this is like one equation with several variables. For estimates of emplacement depth, additional methods are recommended.

A thorough description of the system Q-Ab-Or has been presented by Johannes and Holtz (1996).

Dear Juan-Francisco,

in 1966 I had the opportunity to stay a couple of hours on Surtsey south of Iceland. During that stay little Jolnir, in the sea, about 400 m away from Surtsey and its crater a bit open to the sea,  erupted phreatomagmatically and almost continuously. Basaltic clasts, up to several  cm in size, drifted on the sea  and some got stranded at the beach of Surtsey. I collected  some of them. They were so vesicular that per definition the represent pumice, but basaltic pumice. Later, back in Mainz University, I put some of these highly vesicular clasts in a large beaker filled with water and replaced regularly the amount water that  had evaporated. The reason was that I was interested how long it would take the pumiceous clasts to soak up sufficient water to subisde finally in the “sweet“water. It took three months. I had had used salt water of sea water salt content it would probably have taken even longer.    Thus my question I would have is how vesicular are your scoria clasts? If they had been pumiceous basaltic clasts they could have drifted on the sea surface for months and it would be very difficult to work out their origin.

With kind regards

Volker

I think the best way is to chip of the outer parts physically (with a hammer)- if that is difficult, i have in the past first broken the sample into small chips (1-2 cm) and then selcted for further processing only chips that were devoid of visible alteration.

Dear Paul, I think as already suggested by Martin Menzies, that the best should be to try to correlate as much as possible proximal and distal tephra. This can allow you at least to make a more confident attribution and dating of the possible source avoiding just one single data set and /or number date. Of coarse there are many possible sources but recently many papers on tephrostratigraphy have been published, especially in quaternary journals (eg.doi:10.1016/j.quascirev.2011.07.012; http://dx.doi.org/10.1016/j.quascirev.2012.09.009; http://dx.doi.org/10.1016/j.quascirev.2015.03.006; http://dx.doi.org/10.1016/j.quascirev.2014.04.002 and others) that could help to direct your effort. Data and literature related to very old volcanism are much less because often the proximal part is poorly known or unknown.  Have a good job.

Hi Szabolcs,

Attached is a photomicrograph in plane polarized light of a sample collected from Oamaru on the South Island.  These are from Surtseyan-style eruptions (so submarine explosive and different from what you're looking for) but you can see similarities in some of the vesicle morphology.  

Cheers,

Lyndsay

Hello Mark,

Thank you for the response.

First I'd like to correct a gigantic typo I've made.

Blue jets, sprites and elves are observed in  the ionosphere (I typed magnetosphere, instead of ionosphere; "magnetosphere" is meaningless in the context here).

Second, thunderstorms above which such phenomena have been observed, from space, correspond to what volcanologists refer to as VEI 3 éruptions (in terms of intensity-scale).

If I am not mistaken, such eruptions are not rare in the sense that 60 such eruptions are detected and tracked using satellite (and radar imagery) each year. Most of these are also detected and tracked using remote sensing and other monitoring techniques from the ground.

They are quite a matter for attention as they are the most common hazardous eruptions occuring each year on the planet.

They pose a diversity of hazards.

First they are the most common volcanic hazard to international air traffic. They have already incurred huge economic impacts to the international air traffic industry and to society at large (more than 300 ashcloud - airplane encounters since 1980 or so; tens of severely damaging encounters)

Second, the fallout of material (ash, pumice etc..) can accumulate on the roofs of buildings and roof collapse can occur (eg. the major Harbour town of Rabaul, PNG, was completely flattened during the 19 Sept 1994 eruption).

As eruptions trigger their own thunderstorms and as eruptions often occur within the subtropics, rainfall and increased runoff on impervious ash leads to devastating mudflows. Fine ash is also a health hazard to people and animals and ash and aérosols from volcanoes can also deveastate crops and natural ecosystems...

Third, they are often associated with pyroclastic density currents, equally devastating potentially.

VEI3 eruptions typically generate volcanic clouds rising 10 to 20 km above sea-level.

So in terms of thermal energy flux, they are expected to match thunderstorms.

In sum, if elves, sprites and blue jets are observed above normal thunderstorms, they should also be observed above VEI3 eruption clouds.

Such volcanic eruption clouds are not at all rare.

Observing such phenomena would enable to relate them to eruption cloud parameters (electrification, mass loading of water and ice particles, mass loading of ash and aerosols ?) and the comparison between these phenomena arising from normal thunderstorms and from volcanic eruption clouds could be a novel way to advance the understanding of elves, sprites and blue jets.

Truly I can see no reason why they would not have been detected or studied above volcanic eruption clouds, not to mention that first detection of those sprites etc. would assure a milestone Nature or Science paper to the discoverers (publication opportunities generally).

Finally, when the volcanology and atmospheric sciences have worked together, great advances in understanding have resulted.

In the end, the question remains. I hope someone might have the answer ?

And if not, as you say, I share the view that this would make an exciting cross-disciplinary research proposal.

Perhaps if this work has not been carried out, an insightful question would also be why not ?

All the best,

Gerald

I also vote for clinopyroxene. The larger laths show the expected interference colors for augite; the smaller grains have lower interference colors, consistent with thicknesses less than 30 microns. The relief and inclined extinction are also consistent with cpx.  -- Jane

Other papers that you can also use and regarding mediterranean active volcanic system are:

Smith et al., 2011, doi:10.1016/j.quascirev.2011.07.012

Tomlison et al., 2015, http://dx.doi.org/10.1016/j.quascirev.2014.10.028

Regards

Even for a mantle cumulate, they seem to be very Cr-poor. Perhaps you should have a look at the GeoRoc website (http://georoc.mpch-mainz.gwdg.de/georoc/), where you can find a precompiled file with spinel analyses to see whether you find a match.

A common practice in isotope work on altered rocks is to leach your samples (after crushing, picking etc) with HCl (warm, maybe half hour at a time). Pipette the HCl out and keep it in a separate beaker. Add new HCl to the sample and repeat. Then you process the leached sample (residue of original sample), and the acid washes as separate samples, and measure them for their isotopes (column separations, mass spectrometry). If the alteration was mostly H2O-fluid based, Nd probably will have remained unaffected, but Sr and Pb may well have been affected. The idea is that the secondary minerals (from alteration) will break down in the HCl and provide you with some idea of the composition of the alteration material, while the repeated washes will leave you with a residue that is effectively all primary minerals. The isotopes of the washed and the residue should kind of settle in on a isotopic composition (the last wash should be about the same as the residue). If not you didn't do enough leaching yet. Once you figure out how much leaching (how many rinses) you need for 1 sample, you have an idea of how many rinses the other samples will need.

Hello Mingdao,

You could compare your cpx data to published analyses that may be slightly more recent than 1962, for instance by using the GeoRoc (http://georoc.mpch-mainz.gwdg.de/georoc/ ) website. However, if I remember correctly (I don't have the paper handy here), Ewart (Ewart, A., 1976. A petrological study of the younger Tongan andesites and dacites, and the olivine tholeiites of Niua Fo'ou Island, S.W. Pacific. Contrib. Mineral. Petrol. 58, 1-21; I hope this is the correct reference) demonstrated that quench crystallisation of pyroxene could increase their Al content to higher values than expected from equilibrium crystallisation. Perhaps something similar is at work here.

Marlina

As a tiny addition to the previous answers: because of the mafic nature of the silicate melt needed to produce Pele's hairs, they are far more commonly found in association with intraplate volcanoes than arc volcanoes. But I did see them on Ambryn Volcano in Vanuatu (formerly New Hebrides), which is an unusually mafic arc volcano.

There are several possibilities why tuffs are zeolitized or not:

 - Difference in fluid chemistry that reacts with tuffs to form zeolites.

 - Differences in fluid accessibility (e.g. water/rock ratio, permeability, etc.)

 - Welded tuffs vs non welded tuffs.

 - Cooling history after deposition.

The colour that the picture shows is far from red but anyway it could be interesting to check the comparison between the chemistry of the water before the change and the actual gas contents (SO2 for example). In some cases the water of volcanic crater lakes changed from blu or green to red, in proximity (before or after) of phreatic eruptions. https://www.researchgate.net/publication/266477967_A_way_to_hydrothermal_paroxysm_Colli_Albani_Volcano_Italy

Dear Mr. Ge Songsheng,

I feel fine with the gradual unraveling of the details and it is good to see that you try and constrain the origin of this rock. The basic of all that is, that we have to follow up a clear pathway: (1) Geology (in the field and study) including , in places, geophysics, (2) Mineralogy, (3) Chemistry (4)-if necessary more advanced and more highly-sophisticated methods. And then discussion and interpretation. Otherwise we end up into speculation and the outcome is a matter of conjecture. This is not to complain about your doing; it is my simple attempt to get much of what we are faced with in RG Q&A back on track. Please apologize for that philosophical side leap. I can´t get out of my suit that I had on for 40 years.

I wish all the best

Harald G. Dill

Recalculation of your analysa to formula (Fe",Zn,Mg)(Fe"',Al,Cr,Ti)2O4 and ploting them to triangular diagrams Mg-Fe"-Zn and Al-Fe"'-Cr would help you to determine exact mineral name of your phases. I suppose that your crystals are zoned and there are represented at least two different minerals. This is typical situation for spinelides, which normally are very complex.

On photos given below you can to zsee zonation in crystals of zincochromite connected with their enrichment by Zn from core to rims.

Dear Maria: We have a global network named NOVAC. Please visit our website: www.novac-project.eu

Hi Adrian

Besides numerous outcrops of intrusive carbonatites, there are some occurrences of extrusive carbonatites in Cape Verde archipelago. Carbonatitic tephra is konown in the islands of Santiago and Brava. The first publication referring to extrusive carbonatites in oceanic islands was published in Nature in 1981 (Silva et al. 1981. An oceanic carbonatite volcano on Santiago, Cape Verde Islands. Nature 294, 644–645). The latest publications (2010) are from recent (Late Pleistocene/Holocene) extrusive carbonatitic events in Brava (see Mourão et al. 2010. Journal of African Earth Sciences 56, 59–74. and Madeira et al. 2010. Journal of Volcanology and Geothermal Research 196, 219–235). We recognized a minimum of 5 recent small carbonatitic eruptions in Brava Island producing ash and lapilli fall and a block and ash flow. The presence of carbonatite lava flows is uncertain.

You may also want to look at the geochemistry of these products in Mourão et al. 2012. Contrib Mineral Petrol 163: 995–1009 and Mourão et al 2012. Chemical Geology 334, 44–61.

I hope this helped.

Best regards

José Madeira

Dear Robin,

There are several papers reviewing and discussing the significance of melt inclusions starting back in 1858 with the Sorby’s paper. However, I would like to suggest you starting with Roedder (1979) that is a very clear introduction to melt inclusion. You can find and download this publication at the Bodnar’s Lab of VT webpage (http://www.geochem.geos.vt.edu/fluids/) click on Edwin Roedder memorial virtual library on the right. The Russian literature on significance of melt inclusions is wide and important, but hard to find (see Sobolev, A.V., and Kostyuk, V.P. (1976) Magmatic crystallization based on study of melt inclusions. Fluid inclusion research, 9, 182-253.). Other good contributions to start understanding the melt inclusion technique are:

Lowenstern, J.B. (1995) Applications of silicate-melt inclusions to the study of magmatic volatiles. Short Course Handbook, 23, 71-99.

Audétat, A., and Lowenstern, J.B. (2014) 13.6 - Melt Inclusions. In H.D. Holland, and K.K. Turekian, Eds. Treatise on Geochemistry (Second Edition), p. 143-173. Elsevier, Oxford.

Frezzotti, M.-L. (2001) Silicate-melt inclusions in magmatic rocks: applications to petrology. Lithos, 55(1–4), 273-299.

Métrich, N., and Wallace, P.J. (2008) Volatile abundances in basaltic magmas and their degassing paths tracked by melt inclusions. In K.D. Putirka, and F.J. Tepley, III, Eds. MInerals, Inclusions and Volcanic Processes, 69, p. 363-402. The Mineralogical Society of America.

Kent, A.J.R. (2008) Melt inclusions in basaltic and related volcanic rocks. In K.D. Putirka, and F.J. Tepley, III, Eds. MInerals, Inclusions and Volcanic Processes, 69, p. 273-331. The Mineralogical Society of America.

Schiano, P. (2003) Primitive mantle magmas recorded as silicate melt inclusions in igneous minerals. Earth-Science Reviews, 63(1-2), 121-144.

Sobolev, A.V. (1996) Melt inclusions in minerals as a source of principal petrological information. Petrology, 4(3), 209-220.

Bodnar, R.J., and Student, J.J. (2006) Melt inclusions in plutonic rocks: Petrography and microthermometry. Melt Inclusions in Plutonic Rocks, 36(Short Course ), 1-25.

De Vivo, B., and Bodnar, R.J. (2003) Melt inclusions in volcanic systems. Elsevier Sciences, Amsterdam.

And others…

Regarding what you can do with the volume of melt inclusion (MI), the proposed calculation by Armienti is very interesting and smart.

Based on your X-ray tomography technique, you can obtain one of the most important petrographic information regarding MI. That is the ratio between the total volume of MI and the volume of the bubble. If this ratio is constant in most of the MI from olivines of one single volcanic sample, then you can assess that all the bubbles of the MI studied have originated as “shrinkage” bubbles (see Roedder 1979 for better explanation). If the ratio is highly variable, it is likely possible that the melt was saturated during olivine crystallization and that you have heterogeneously trapped melt plus fluid.

I strongly believe that is difficult to find a void bubble in a MI unless the trapped melt was volatile-poor, and melts from Etna are known to be volatile-rich (Metrich and Wallace and references therein). Rather, the shrinkage bubble has undetectable amount of gas or vapor reacted with glass at the interface (Roedder, 1979). Al though is not easy task to understand the evolution of MI after trapping (Steele-MacInnis et al., 2011 and reference therein), as a shrinkage bubble forms the internal pressure of the MI should decrease and melt of the MI should exsolve volatiles in the bubble. There is a lot of debate on modification of MI after trapping.

Also, I recommend you to understand the meaning of the temperature of homogenization that is needed in Armienti’s calculation. There are things you need to be aware about this parameter, and I would suggest reading these two papers:

“Danyushevsky, L.V., McNeill, A.W., and Sobolev, A.V. (2002) Experimental and petrological studies of melt inclusions in phenocrysts from mantle-derived magmas: an overview of techniques, advantages and complications. Chemical Geology, 183(1-4), 5-24.

Esposito, R., Klebesz, R., Bartoli, O., Klyukin, Y.I., Moncada, D., Doherty, A.L., and Bodnar, R.J. (2012) Application of the Linkam TS1400XY heating stage to melt inclusion studies. Central European Journal of Geosciences, 4(2), 208-218.”

Also, I would like to let you notice that in Steele-MacInnis et al. (2011, Table 1 and Fig. 3) and Esposito et al. (2011, Table 5) we have done a mass balance calculation of the total CO2 of an MI (CO2 dissolved in the glass plus CO2 in vapor-bubble), and the use of your technique could have greatly improved the precision of the calculation. Please, read the text for more details or contact me if you would like to have additional information about this.

If you would like, I am opened and available for future contributions or suggestions.

Hope this helps and sorry if I have been too wordy

Rosario

Steele-MacInnis, M.J., Esposito, R., and Bodnar, R.J. (2011) Thermodynamic model for the effect of post-entrapment crystallization on the H2O-CO2 systematics of volatile saturated silicate melt inclusions. . Journal of Petrology, 52(12), 2461-2482.

Esposito, R., Bodnar, R.J., Danyushevsky, L., De Vivo, B., Fedele, L., Hunter, J., Lima, A., and Shimizu, N. (2011) Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy). Journal of Petrology, 52(12), 2431-2460.

Dear Prof. Kitchen, I checked those publications under your name. The dykes you mentioned looks very interesting. Please share those with me on my email randive101@yahoo.co.in. Thanks and regards.

Hi, Robin! I hope this artical will be interesting for you:

Smith, E.M., Kopylova, M.G., Dubrovinsky, L., Navon, O., Ryder, J., Tomlinson, E.L., 2011. Transmission X-ray diffraction as a new tool for diamond fluid inclusion studies. Mineralogical Magazine 75, 2657-2675. http://minmag.geoscienceworld.org/content/75/5/2657.abstract

check also the following papers:

Harris, A. J. L., Neri, M. (2002): Volumetric observations during paroxysmal eruptions at Mount Etna: pressurized drainage of a shallow chamber or pulsed supply? J. Volcanol. Geotherm. Res., 116, 79-95, doi:10.1016/S0377-0273(02)00212-3.

Calvari S., Neri M., Pinkerton H. (2003): Effusion rate estimation during the 1999 summit eruption on Mt. Etna, and growth of two distinct lava flow fields. J. Volcanol. Geotherm. Res., 119/1-4, 107-123, doi:10.1016/S0377-0273(02)00308-6.

Behncke, B., Neri, M., and Nagay, A., (2005), Lava flow hazard at Mount Etna (Italy): New data from a GIS-based study, in Manga, M., and Ventura, G., eds., Kinematics and dynamics of lava flows: Geol. Soc. Am. Spec. Pap. 396, 187-205, doi: 10.1130/0-8137-2396-5.189.

Behncke B., Neri M., Pecora E., Zanon V. (2006), The exceptional activity and growth of the Southeast Crater, Mount Etna (Italy), between 1996 and 2001. Bull. Volcanol., 69, 149-173, DOI 10.1007/s00445-006-0061-x.

Neri M., F. Casu, V. Acocella, G. Solaro, S. Pepe, P. Berardino, E. Sansosti, T. Caltabiano, P. Lundgren, R. Lanari (2009), Deformation and eruptions at Mt. Etna (Italy): a lesson from 15 years of observations. Geophys. Res. Lett., 36, L02309, doi:10.1029/2008GL036151.

Vicari, A., Ganci, G., Behncke, B., Cappello, A., Neri, M., Del Negro, C. (2011), Near-real-time forecasting of lava flow hazards during the 12-13 January 2011 Etna eruption, Geophys. Res. Lett., 38, L13317, doi:10.1029/2011GL047545.

Neri M., Acocella V., Behncke B., Giammanco S., Mazzarini F., Rust D. (2011), Structural analysis of the eruptive fissures at Mount Etna (Italy). Ann. Geophys., 54, 5, 464-479, doi: 10.4401/ag-5332.

To identify igneous carbonate in carbonatite usually requires several methods to be certain. Optically, calcite crystals may show a variety of euhedral forms, but igneous zoning is usually rare, although sometimes visible in cathodoluminescence. When analysed by electron microprobe, trace elemnts are often characteristic and usually include, measurable strontium up to the percent level (this is not usually the case in sedimentary rocks). Sometimes the carbonates are associated with elevated rare earth elements, although these are more likely to be contained in accompanying apatite or other REE minerals like pyrochlore or perovskite. Isotopic features include oxygen isotopes close to the field defined for primary carbonatites (d18O 6 to 9 per mil), and carbon isotopes close to mantle values (d13C -5 to -7.5 per mil).

An old but useful reference illustrating igneous calcite and apatite morphologies including cathodoluminescence is here :

A recent review of carbonatites is available for download for free at http://www.minsocam.org/msa/rim/RiM75/RIM075_C10_novideo.pdf