What the Heck is a Diamond Anvil Cell?

By Daniel Hummer, DCO Extreme Physics and Chemistry, Carnegie Institution of Washington, USA

In the Extreme Physics and Chemistry (EPC) community, our main goal is to learn about the structure, properties, and behavior of carbon-bearing materials at the extreme temperature and pressure conditions in the interior of Earth and other planetary bodies. Scientists have performed experiments at elevated temperatures for centuries, as there are many methods available for achieving high temperature. Attaining high pressure conditions in the laboratory, however, has historically proved much more problematic. High pressure experiments must take place in an enclosed space that is difficult to directly observe, and there are few techniques for producing the pressures found beneath Earth’s crust. The most widely used device for achieving very high pressures in a controlled laboratory setting is the diamond anvil cell (DAC).

Figure 1: Photo of a diamond anvil cell (DAC), with a blown up cross-section of the region where the experiment takes place. Depending on the DAC design, the diameter of the sample chamber is typically between 100 and 300 μm. Figure from Yang and Zhaohui [1].
Figure 1: Photo of a diamond anvil cell (DAC), with a blown up cross-section of the region where the experiment takes place. Depending on the DAC design, the diameter of the sample chamber is typically between 100 and 300 μm. Figure from Yang and Zhaohui [1].
A DAC consists of two round, metal plates on which two cut and polished diamonds are mounted (Fig. 1). The sample, as well as a standard reference material (see next section) is placed in a chamber with the diamonds on the top and bottom, and a gasket around the side. The diamonds act as anvils, pressing inward on the material between them. The gasket is a thin strip of metal, typically rhenium, with a hole drilled in the center. Note that the seats on which the diamonds sit (and the entire DAC assembly) have holes in the middle so that various beams of radiation, including X-ray diffraction and many types of spectroscopy, can be sent through the diamonds and into the sample chamber to probe the properties of whatever sample material is being studied. Several characteristics make diamond the ideal anvil material for in situ high-pressure experiments, including transparency across a broad range of the electromagnetic spectrum, chemical inactivity, stability at very high pressures, and extreme hardness.

The first researcher to implement the anvil design that modern DACs are based on was Percy Bridgman, a high pressure physicist at Harvard University [2]. His high pressure device, and the many discoveries it enabled, earned him the 1946 Nobel Prize in physics. The mineral that dominates Earth’s mantle, whose discovery would not have been possible without Bridgman’s work, was recently and very fittingly named bridgmanite in his honor [3], in place of its previous designation of “perovskite”. Nowadays, multiple DAC designs are available depending on the desired pressure range and analytical technique.

Before starting an experiment, we must load a “pressure medium” into the chamber to shield the sample from contact with the diamonds and gasket, and distribute the pressure evenly throughout the chamber. Because they are easily compressible and chemically inert, noble gases such as He, Ne, and Ar are often employed for this purpose, although other gases or even liquid water are occasionally used [4]. In order to enclose the samples and pressure medium within the sample chamber in an airtight fashion, we carefully put the samples, gasket, and diamonds in place, but we leave one diamond at a slight distance away from the gasket. Then, in a process called “gas loading,” we place the entire DAC in a gas-filled box so that the desired pressure medium can infiltrate the sample chamber. We then tighten the screws to close the gap between the diamonds and gasket, sealing the experimental chamber from the surrounding environment.

We can apply more pressure by turning the screws at the edge of the DAC, which forces the diamonds closer together. The secret of generating such high pressures is to take advantage of the fact that pressure is force per unit area: P = F/A. Although the screws apply only a moderate force, the flat surfaces of the diamond which face the sample chamber, called “culets”, have such a tiny area that very large pressures can be generated. The exact same principle makes ice-skating possible – a person transmits the entire weight of their body to the very small surface area of the blades, generating enough pressure to melt the ice under the blade and enable lubricated motion across the surface. A well-constructed and aligned DAC can produce pressures in excess of 300 GPa, close to the pressure of Earth’s inner core (Fig. 2) [5,6]. With special setups such as a double-stage, even higher pressures can be achieved – the highest recorded so far is an astounding 770 GPa, twice the pressure at the center of Earth [7]! However, in routine practice, increasing the pressure becomes rapidly more difficult once you surpass ~100 GPa.

Figure 2: A cross section of the Earth showing the major layers, and the depths and pressures corresponding to their boundaries. The center of the Earth is thought to be ~ 364 GPa. Figure from [6].
Figure 2: A cross section of the Earth showing the major layers, and the depths and pressures corresponding to their boundaries. The center of the Earth is thought to be ~ 364 GPa. Figure from [6].
How the heck do you know the pressure?

To perform a useful experiment, we need to independently measure the pressure the sample is experiencing. To do this, we must place in the sample chamber a reference material with a measurable property that responds to pressure in a well-known fashion. High-pressure researchers refer to this as a “pressure calibration” or “pressure scale”. There are two widely used methods for measuring pressure: ruby fluorescence, and the equation of state of a reference material.

Since rubies contain Cr3+ ions surrounded by oxide ions, electronic transitions among the Cr3+ valence electrons produce a fluorescent emission at about 694 nm at room pressure [8]. When the ruby is placed under pressure, the oxide ions move closer to the Cr3+ ions, systematically changing the electron energy levels and therefore shifting the wavelength of the fluorescence line. Thus, by shining a laser through a DAC onto a ruby crystal and measuring the wavelength of fluorescence, we can calculate the pressure inside our sample chamber. Mao et al. [8,9] were the first to calibrate how ruby fluorescence changes with pressure in 1978, and this calibration is still routinely used for pressures below ~60 GPa.

Figure 3: The intensity of ruby fluorescence vs. wavelength at two difference pressures within a DAC. Since the position of the peak maximum is very sensitive to pressure, the wavelength of the fluorescence line is useful as a pressure scale. Figure from Mao et al. [9].
Figure 3: The intensity of ruby fluorescence vs. wavelength at two difference pressures within a DAC. Since the position of the peak maximum is very sensitive to pressure, the wavelength of the fluorescence line is useful as a pressure scale. Figure from Mao et al. [9].
The other method for measuring pressure within a DAC uses the equation of state (EOS) of a reference material. The EOS of a material describes the relationship between its state variables: pressure, volume, and temperature (or in the case of an experiment at room temperature, just pressure and volume). If the volume decrease of a reference material is already well known as a function of pressure, then measuring the volume of that material within the DAC provides a measurement of pressure. In practice, volume is usually measured via the positions of X-ray diffraction peaks of a crystalline reference material. However, choosing a reference material requires care: it must not react with the sample or pressure medium at the experimental conditions, and the pressure-volume relationship must be well calibrated across the entire pressure range of the experiment.

The EOS of a variety of materials have been calibrated, but the most commonly used in DAC experiments are gold [10,11], platinum [12,13], magnesium oxide [14,15], sodium chloride [16,17], and neon [18]. Unfortunately, these pressure scales are not fully consistent with each other, making detailed comparison of experiments using different pressure scales cumbersome. Recently, a number of researchers have attempted to cross-calibrate and reconcile these various pressures scales [19-21].

Figure 4: The equation of state of MgO is plotted in volume-pressure space, with different curves representing different temperatures. Thus, a volume measurement of MgO within a DAC can be converted to pressure. Figure from Tange et al. [15]
Figure 4: The equation of state of MgO is plotted in volume-pressure space, with different curves representing different temperatures. Thus, a volume measurement of MgO within a DAC can be converted to pressure. Figure from Tange et al. [15]
How the heck do you heat stuff?

I have focused so far on generating and measuring high pressures, but since Earth scientists often want to measure sample properties that are a function of both pressure and temperature, it is crucial to be able to heat samples to a known temperature while under pressure within a DAC. There are two methods for doing this – a heating jacket and laser heating.

A heating jacket is a metal jacket placed around the circumference of a DAC, through which super-heated water is pumped, heating the entire DAC assembly. Because we can only heat water to approximately 200 oC in an enclosed environment, this heating method is somewhat limited [22]. However, the temperature stability and precision is better than with laser heating.

In order to heat a sample to thousands of degrees, we have to use laser heating. By aiming a high intensity laser beam through the diamond windows at the sample, the sample can heat to temperatures well above 3000 K through absorption of the radiation [23]. The intensity of the laser controls sample heating, and by collecting the blackbody spectrum and fitting it to Plank’s law, we know the sample temperature. However, strong thermal gradients within the sample chamber and uncertainties in fitting the blackbody spectrum often produce large error bars for temperature measurements made with this method. Techniques for improving thermal stability, minimizing thermal gradients, and maximizing accessible temperatures in laser heating are still active areas of research [24,25].

What the heck can you measure in a diamond anvil cell?

A wide variety of Earth materials can be placed under high pressure in a DAC, and many discoveries about Earth’s interior (and the interiors of other planetary bodies) have been made through DAC experiments. While a full accounting of techniques and results from DAC experiments would take volumes, we can briefly highlight here the types of measurements that are often made.

A common type of experiment is to place a mineral or other composition that we know is abundant in Earth under pressure, and look for phase transitions (i.e., rearrangements of the atomic structure that would produce a new mineral). This is typically done by shining monochromatic X-rays onto the sample, and looking for sudden changes in the X-ray diffraction pattern as pressure is increased. For example, by placing the aforementioned mantle mineral “perovskite” (now called bridgmanite [3]) under conditions of ~125 GPa and ~2500 K, two independent teams found a change in crystal structure producing a new material called “post-perovskite”. [26,27] This discovery helped explain unusual seismic observations in the lowermost part of the mantle.

 Figure 5: Illustration of the phase transition in MgSiO3 from the perovskite structure (a) to the post-perovskite structure (b) when pressurized above 125 GPa. Gray octahedra represent SiO6 groups, and red spheres represent Mg. Figure from [28].
Figure 5: Illustration of the phase transition in MgSiO3 from the perovskite structure (a) to the post-perovskite structure (b) when pressurized above 125 GPa. Gray octahedra represent SiO6 groups, and red spheres represent Mg. Figure from [28].
It is also routine to measure the EOS of newly discovered Earth materials, which simply involves measuring the material’s volume as a function of pressure. Such experiments tell us about the density of different layers in the Earth. EOS measurements are typically made via X-ray diffraction, which can be used to track the decrease in interatomic distances in crystals [10-21], but volume measurements of the entire sample can now also be made directly using X-ray tomography [29]. Sometimes, abrupt changes in volume can be seen even without a change in atomic structure. These are often the result of changes in the electronic configuration of the material, which are referred to as “spin transitions”. These can be examined more precisely by irradiating the sample with high energy X-rays, and measuring the wavelengths of emitted X-rays (i.e., X-ray emission spectroscopy) [30,31].

With special setups, other material properties can be measured, such as thermal conductivity [25], electrical conductivity [32], and magnetization [33]. Such experiments inform us about how heat flows from one part of the Earth to another, and how the Earth’s magnetic field is generated. When fluids such as water are placed in a DAC, various spectroscopic techniques can be used to measure the solubility of minerals in the fluid as a function of pressure [34], and learn about the arrangement of atoms in the fluid [35].

By using a variety of combinations of DAC models, pressure scales, analytical techniques, and heating methods, members of the EPC community are testing the properties of numerous carbon-bearing minerals and fluids at a wide array of deep Earth conditions. With new techniques continuously under development, be on the lookout for studies that push experimental boundaries and uncover processes occurring thousands of kilometers beneath our feet, because it’s wicked awesome stuff.

Who the heck would I like to acknowledge?

The author is very grateful for helpful comments from Sami Mikhail (University of St. Andrews, UK), Dana Thomas (Stanford University, USA), Katie Pratt (University of Rhode Island, USA), Peter Barry (University of Oxford, UK), and Karen Lloyd (University of Tennessee, USA) which greatly improved the content and presentation of this article.

Where the heck are those references?

[1] Yang, S. and Zhaohui, D. (2011) Novel pressure-induced structural transformations of inorganic nanowires, in Nanowires – Fundamental Research, ed. Abbass Hashim, InTech, Rijeka, Croatia.

[2] Bridgman, P.W. (1931) The Physics of High Pressure, ed. G. Bell, London, England.

[3] Tschauner, O., Ma, C., Beckett, J.R., Prescher, C., Prakapenka, V.B., Rossman, G.R. (2014) Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite. Science, 346, 1100-1102.

[4] Bassett, W.A., Shen, A.H., Bucknum, M., Chou, I.M. (1993) A new diamond-anvil cell for hydrothermal studies to 2.5 GPa and from -190 oC to 1200 oC. Review of Scientific Instruments, 64, 2340-2345.

[5] Li, J. and Fei, Y. (2007) Experimental constraints on core composition, in Treatise On Geochemistry, Elsevier Ltd.

[6] Duffy, T.S. (2011) Probing the core’s light elements. Nature, 479, 480-481.

[7] Dubrovinsky, L., Dubrovinskaia, N., Bykov, M., Prakapenka, V., Prescher, C., Glazyrin, K., Liermann, H.P., Hanfland, M., Ekholm, M., Feng, Q., Pourovskii, L.V., Katsnelson, M.I., Wills, J.M., Abrikosov, I.A. (2015) The most incompressible metal osmium at static pressures above 750 gigapascals. Nature, 525, 226-229.

[8] Mao, H.K., Bell, P.M., Shaner, J.W., Steinberg, D.J. (1978) Specific volume measurements of Cu, Mo, Pd, and Ag and calibration of the ruby R1 fluorescence pressure gauge from 0.06 to 1 Mbar. Journal of Applied Physics, 49, 3276-3283.

[9] Mao, H.K., Xu, J., Bell, P.M. (1986) Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research, 91, 4673-4676.

[10] Anderson, O.L., Isaak, D.G., Yamamoto, S. (1989) Anharmonicity and the equation of state for gold. Journal of Applied Physics, 65, 1534–1543.

[11] Shim, S., Duffy, T.S., Takemura, K. (2002). Equation of state of gold and its application to the phase boundaries near 660km depth in the Earth’s mantle. Earth and Planetary Science Letters, 203, 729– 739.

[12] Holmes, N.C., Moriarty, J.A., Gathers, G.R., Nellis, W.J. (1989) The equation of state of platinum to 660 GPa (6.6 Mbar). Journal of Applied Physics, 66, 2962–2967.

[13] Yokoo, M., Kawai, N., Nakamura, K.G., Kondo, K., Tange, Y., Tsuchiya, T. (2009), Ultrahigh-pressure scales for gold and platinum at pressures up to 550 GPa. Physical Review B, 80(10), 104114.

[14] Speziale, S., Zha, C., Duffy, T.S., Hemley, R.J., Mao, H.K. (2001) Quasi-hydrostatic compression of magnesium oxide to 52 GPa: implications for the pressure–volume–temperature equation of state. Journal of Geophysical Research, 106, 515–528.

[15] Tange, Y., Nishihara, Y., Tsuchiya, T. (2009) Unified analyses for P-V-T equation of state of MgO: A solution for pressure-scale problems in high P-T experiments, Journal of Geophysical Research, 114, B03208.

[16] Ono, S. (2010) The equation of state of B2-type NaCl. Journal of Physics: Conference Series, 215, 012196.

[17] Sakai, T., Ohtani, E., Hirao, N., Ohishi, Y. (2011) Equation of state of the NaCl-B2 phase up to 304 GPa. Journal of Applied Physics, 109(8), 084912.

[18] Dewaele, A., Datchi, F., Loubeyre, P., Mezouar, M. (2008), High pressure–high temperature equations of state of neon and diamond. Physical Review B, 77(9), 094106.

[19] Fei, Y., Li, J., Hirose, K., Minarik, W., Van Orman, J., Sanloup, C., van Westrenen, W., Komabayashi, T., Funakoshi, K. (2004) A critical evaluation of pressure scales at high temperatures by in situ X-ray diffraction measurements. Phyiscs of the Earth and Planetary Interiors, 143-144, 515-526.

[20] Fei, Y., Ricolleau, A., Frank, M., Mibe, K., Shen, G., Prakapenka, V. (2007) Toward an internally consistent pressure scale. Proceedings of the National Academy of Sciences, 104, 9182-9186.

[21] Dorfman, S.M., Prakapenka, V.B., Meng, Y., Duffy, T.S. (2012) Intercomparison of pressure standards (Au, Pt, Mo, MgO, NaCl, and Ne) to 2.5 Mbar. Journal of Geophysical Research, 117, B08210.

[22] Moore, M.J., Sorensen, D.B., DeVries, R.C. (1970) A simple heating device for diamond anvil high pressure cells. Review of Scientific Instruments, 41, 1665-1666.

[23] Huang, X.L., Li, F.F., Zhou, Q., Wu, G., Huang, Y.P., Wang, L., Liu, B.B., Cui, T. (2015) In situ synchrotron X-ray diffraction with laser-heated diamond anvil cells study of Pt up to 95 GPa and 3150 K. RSC Advances, 5, 14603-14609.

[24] Meng, Y., Hrubiak, R., Rod, E., Boehler, R., Shen, G. (2015) New developments in laser-heated diamond anvil cell with in situ synchrotron X-ray diffraction at High Pressure Collaborative Access Team. Review of Scientific Instruments, 86, 072201.

[25] Rainey, E.S.G. and Kavner, A. (2014) Peak scaling method to measure temperatures in the laser-heated diamond anvil cell and application to the thermal conductivity of MgO. Journal of Geophysical Research, 119, 8154-8170.

[26] Murakami, M., Hirose, K., Kawamura, K., Sata, N., Ohishi, Y. (2004) Post-perovskite phase transition in MgSiO3. Science, 304, 855-858.

[27] Oganov, A.R., Ono, S. (2004) Theoretical and experimental evidence for a post-perovskite phase of MgSiO3 in Earth’s D” layer. Nature, 430, 445-448.

[28] Shim, S.H. (2008) The postperovskite transition. Annual Review of Earth and Planetary Sciences, 36, 569-599.

[29] Wang, J., Yang, W., Wang, S., Xiao, X., De Carlo, F., Liu, Y., Mao, W.L. (2012) High-pressure nanotomography using an iterative method. Journal of Applied Physics, 111, 112626.

[30] Badro, J., Fiquet, G., Guyot, F., Rueff, J.P., Struzhkin, V.V., Vanko, G., Monaco, G. (2003) Iron partitioning in Earth’s lower mantle: toward a deep lower mantle discontinuity. Science, 300, 789-791.

[31] Badro, J., Rueff, J.P., Vanko, G., Monaco, G., Fiquet, G., Guyot, F. Electronic transition in perovskite: possible nonconvecting layers in the lower mantle. Science, 305, 383-386.

[32] Seagle, C.T., Cottrell, E., Fei, Y., Hummer, D.R., Prakapenka, V.B. (2013) Electrical and thermal transport properties of iron and iron-silicon alloy at high pressure. Geophysical Research Letters, 40, 5377-5381.

[33] Giriat, G., Wang, W., Attfield, J.P., Huxley, A.D., Kamenev, K.V. (2010) Turnbuckle diamond anvil cell for high-pressure measurements in a superconducting quantum interference device magnetometer. Review of Scientific Instruments, 81, 073905.

[34] Schmidt, C., Rickers, K. (2015) In-situ determination of mineral solubilities in fluids using a hydrothermal diamond-anvil cell and SR-XRF: solubility of AgCl in water. American Mineralogist, 88, 288-292.

[35] Bassett, W.A., Wu, T.C., Chou, I.M., Haselton, H.T., Frantz, J., Mysen, B.O., Huang, W.L., Sharma, S.K., Schiferl, D. (1996) The hydrothermal diamond anvil cell and its applications, in Mineral Spectroscopy: A Tribute to Roger G. Burns, ed. M.D. Dyar, C. McCammon and M.W. Schaefer, The Geochemical Society, Special Publication No. 5.

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The Awakening of Momotombo Volcano, Nicaragua

Contribution by Gino González Ilama, University of Costa Rica

Introduction

Central America is home to more than 50 active volcanoes, with many large eruptions over the course of history. The volcanism in the region is widespread, including effusive, explosive and phreatic eruptions occurring today. The main source of volcanic eruptions in Central America is the subduction of the Cocos and Nazca plates beneath the Caribbean plate.

Momotombo volcano is located 40 km to the NW of Managua, the capital of Nicaragua. In 1609 this volcano was responsible for an important migration of civilians to Leon City, due to several events which affected the old town including earthquakes, ash fall and even lava flow.

After 110 years of silence, on December 1st, 2015, Momotombo volcano began to erupt again with large scale lava flow on the NE flank. Some of this lava flow was visible from Managua (about 40 km away on the other side of the Managua Lake).

With this in mind, we visited the volcano 12 days after the first event. Our purpose was to measure thermal anomalies with the FLIR camera (Forward Looking Infrared Camera), take samples of the lava flow and describe the event.

fig. 1.jpg

Figure 1. Location and tectonic context of Momotombo volcano. The area marked with MO denotes the location of the sampling site along the new lava flow.

Results

The lava flow descended on the NE flank, partially over the lava flow of 1905. This flow traveled 2 km from the top, with a volume of lava flow around 6×106 m3. This flow was delimited by consolidated levées, denoted by the FLIR camera.

fig. 2

Figure 2. Eruptions and lava flows of Momotombo volcano. a) effusive eruption, December 3rd, 2015. Photo credit AP; b) Lava flows of 1905 and 2015; c) explosive eruption of February 21st, 2016. Photo credit Álvaro Sánchez.

Macroscopically, the rocks are porphyritic basalt-andesite, with olivine (5%) and plagioclase (35%), and 15% porous.

The type of the lava flow is aa and has two parts: upper part was rough and sharp, and the lower part was continues hot. Also, many features related with the movement of the flow and change in the velocity and topography can be observed at that time on the site.

With the Flir Camera we measured around 700 °C, principally in the pipes, with some minerals in the boundaries.

After the lava flow…

Now (February/March 2016), the Momotombo volcano has changed its behavior presenting episodes of explosive activity, and the big deal will be: Why has it changed from effusive to explosive? It is difficult to explain, but maybe this explosive activity is due to the formation of a plug in the conduit or a summit dome and this could have increase the gas pressure in the conduit (F. Lucchi, written communication).

Along with this change in the activity, hazards have also changed. This is because explosive activity is generating pyroclastic density currents, driving more than 2 km at times, and ash plumes of more than 2 km height.

In this perspective, Momotombo volcano is a good example of how volcanoes wake up, and how they can change activity and hazard with each eruption.

fig. 3.jpg

Figure 3. View of Momotombo volcano and pipes in the lava flow. a) View of Momotombo volcano; b) thermal image of Momotombo volcano, the hottest color is the levées; c) pipe in the lava flow; d) thermal image of the pipe in other hot points.

fig. 4
Figure 4. Lava flow of Momotombo volcano and different features: a) collecting samples in the MO point indicated in Fig.1; b) macroscopic texture of the rock sample; c) and d) different structures related with the lava flow movement.

A birdseye view of the sampling site

The area within the Furnas Volcano (São Miguel, Azores) influenced by secondary geothermal manifestations is not particularly big. You can walk all of it in about 30 minutes. Despite this the diversity of geothermal activity is impressive. The entire area is situated few tens of meters from the caldera lake, and effluents from the hydrothermal area flow directly into the lake waters. The hydrothermally altered ground in the main area is about the size of a football field, and contain solfataras, boiling pools, numerous fumaroles, boiling mud pools and several degassing and hot spots in the entire zone.

Screen Shot 2016-02-24 at 1.35.18 PM

Satellite view (Google Maps) of the Furnas caldera lake in São Miguel, Azores

There are also numerous diffuse degassing areas on the shores of the lake, and underwater degassing and hot fluids vents are evident venturing few feet into the water.

21825766822_f8a1aeae0d_o

View of the geothermally influenced area of Furnas Volcano from the nearby parking lot. Credit DCO/Katie Pratt

For the sampling we selected an area representative of the diverse environments, yet safe enough for numerous people to work at the same time. Geothermally altered grounds, especially if still active, can be extremely unstable, and often be made of a thin crust covering large pools of near-boiling waters. For everyone safety we decided to limit our sampling to and area considered relatively stable.

Panorama_sampling_location_limits.png

A Birdseye view of the sampling location obtained by photomosaic. Credit Donato Giovannelli

As you can see in the picture above, the area we selected (delimited by the red line) contains different features, including soils not influenced by the geothermal activity (F). The large red square marked with *, represent the area were DCOECS15 participants Matteo Masotta, with the help of local expert and DCOECS15 participant Vittorio Zanon, performed the stratigraphy already appeared on this blog.

The sampling site, Furnas, Azores
The sampling site looking back towards the lake from the fumarole. Credit DCO/Katie Pratt

The sampled locations within this plot were: A the sediments of a hot pool; B the fluids and sediments of a bubbling fumarole; while D, C and E represented different point along the outflow channel connecting the fumarole and hot pool with the lake, located outside the field of view of the previous picture on the right side; F was a control site not directly influenced by the geothermal activity.

Sampling_station_mosaic

Diversity of the sampling environments. Credit Donato Giovannelli

For each site we performed a large number of measurements and collected numerous samples for further laboratory analyses. Among others, this included CO2 fluxes for the entire area, gas composition measurement and isotopes, mineralogical analyses, major and minor elements, geochemistry, quality and quantity of the organic matter and a suite of microbiological analyses. Sometime in the near future my colleagues will start to blog about the results that we are slowly compiling in a large database.

Alysia Cox takes samples. Credit: DCO/Katie Pratt
Alysia Cox takes samples. Credit: DCO/Katie Pratt

Stratigraphy of lacustrine deposits outcropping at the fumarole field at Furnas

While we were sampling at the hydrothermal field at Furnas, workshop participant Matteo Masotta (Istituto Nazionale di Geofisica e Vulcanologia, Italy), in collaboration with Vittorio Zanon (University of Azores) analyzed the stratigraphy of the area.

Furnas Lake Stratigraphy
From Matteo Masotta (INGV)

From Matteo:

The fumarole field of Furnas Lake Volcano is imposed on a sequence of lacustrine sediments deposited in recent times. The stratigraphy of this lacustrine deposit has been investigated in detail in an outcrop occurring at the north side of the fumarole field (Figure 1a). The deposit consists mostly of muds deposited either by direct sedimentation from the lake water table variations or by lahars (Figure 1b).

The sequence opens at the base, with a ~60 cm-thick, massive layer of hydrothermally altered consolidated silt. The surface temperature of the basal layer ranges between 40˚C at the base and 30˚C at the top. The basal layer fades upward into a softer, equally altered, ~20 cm-thick layer of consolidated silt. A ~20 cm-thick layer of less altered brown silt extends on top of these two layers. This layer contains cm-sized, altered white pumices and lithic clasts. Above this layer, three thin (<10 cm) layers of finely stratified ash lay over the basal sequence and contain rare, mm-sized lithic clasts. The stratigraphic sequence closes at the top with another massive, 30-50 cm-thick, partially pedogenized silty layer, overlaid by a 20-40 cm-thick vegetated soil.

Why Open Science?

A lot has been said about Open Source, Open Data and Open Science (just google it to see the sheer amount of pages coming up), and data sharing and open access publishing mandate is something all major funding sources are implementing (see the OSTP Open Data Mandate from the US government. Similar mandate are now present also in Europe and other nations).

In some disciplines this is no news. The molecular biology community has been ahead of the open science and open data game for years, as the deposition into public and open database of all sequences is a prerequisite for publishing (and this extends to organisms, plasmids, and other biological constructs). Open Source software development (especially science oriented in this context) is another good example.

Besides the funding agency pressure, and the hot topic wave following the open movement you should opt for a open model for many other reasons. Recently, I watched a wonderful talk on line by Matthew Todd, the founder of the Open Source Malaria project. If you never heard of this project watch the video below, head to the http://opensourcemalaria.org website and check one of their experiments. Perhaps you could contribute to the fight against malaria (and you can do it even if you are not a scientist, as explained here.

As Matthew explains toward the end of the video, Open Science is transparent, is immortal and it’s fast. If you think about this for some time, it can really change your perspective on the issue. And while the Open Science model still has its loose ends (see here and here for a quick hints to some of the problems), I believe Open Science is the way of the future.

At the last Deep Carbon Observatory Early Career Scientist Workshop we thought it was time to do the same, and share with everyone our science, and the making of it. During the workshop we designed and performed a multidisciplinary co-located sampling effort, aimed at characterizing multiple aspect of carbon science at a single geographic location (Furnas Volcano, São Miguel, Azores, Portugal). We decided that beside the final publication, also the experiments, the analyses and the raw data should be part of the public domain, to help scientist and educators to build on our work, as fast and efficiently as possible.

Keep following us to see the hows and whys of our collective open science project!

Second DCO Early Career Scientist Workshop Report

The report originally featured on the Deep Carbon Observatory website.

The Second DCO Early Career Scientist Workshop (DCOECS15) took place from 31 August- 5 September 2015 on the island of São Miguel in the Azores. The workshop included both classroom sessions at the University of the Azores, and field trips to various geologically active areas of the island.

Building on the success of last year’s workshop at the University of Costa Rica, as well as the 2014 DCO Summer School in Yellowstone National Park, the DCOECS15 organizing committee put together an ambitious program for the 45 early career scientists arriving in Ponta Delgada from 18 countries and 37 institutions. The workshop began with an introduction to the four DCO scientific communities and an evening icebreaker at the University.

A large proportion of the scientific program was devoted to the participants themselves, with each one presenting both oral and poster presentations. Early career scientists from all four DCO Communities (Deep Energy, Reservoirs and Fluxes, Deep Life, and Extreme Physics and Chemistry) presented short talks on their work. These talks, intentionally broad, allowed cross-disciplinary interests to blossom. Evening poster sessions further facilitated these interactions.

To complement these sessions, the organizing committee programmed several additional activities and talks. Fátima Viveiros (University of the Azores, Portugal), co-organizer and local coordinator of the workshop, shared her many years of experience working in the field in the Azores. Workshop Principal Investigator Donato Giovannelli (Rutgers University, USA/ISMAR-CNR, National Research Council of Italy) talked about open access publishing opportunities, advantages, and outlets, as well as metadata curation. Katie Pratt (DCO Communications Director, University of Rhode Island, USA) led sessions on social media for scientists and filming in the field. She also made several GoPro cameras available to workshop participants, and used the resulting footage to create a video from the workshop.

DCO Early Career Scientist Workshop 2015

Click on the image to view a Flikr gallery of images from the workshop.

Co-organizers Cody Sheik (University of Minnesota Duluth, USA), Dana Thomas (Stanford University, USA), Alysia Cox (Montana Tech of the University of Montana, USA) and Daniel Hummer (Carnegie Institution of Washington, USA) coordinated a series of breakout sessions and activities throughout the week, culminating in the defining feature of DCOECS15: a day of sampling at Furnas Volcano hydrothermal field.

This activity was possible thanks to the experience and vision of both PI Donato Giovannelli and the local committee at the University of the Azores: Fátima Viveiros, Vittorio Zanon, César Andrade, Catarina Silva, Joana Pacheco, Lucia Moreno, Diana Linhares, and Ana Hipólito. With permits in hand, the organizers coordinated sampling of sediments, liquids, and gases at six defined sites in the Furnas Lake hydrothermal field. All samples are currently undergoing analysis; the results of this work are expected to be published in 2016.

“The organizing committee and I are thrilled that the sampling activity, and indeed the workshop in general, went so well,” said Giovannelli. “We can’t wait to follow the samples over the next few months, and hopefully publish our work in an open access format some time next year.”

This second ECS workshop cemented within DCO a burgeoning community of scientists who represent the future of deep carbon science.

Organizing Committee
Donato Giovannelli, Rutgers University, USA/ISMAR-CNR, National Research Council of Italy
Fátima Viveiros, CVARG, University of the Azores, Portugal
Katie Pratt, University of Rhode Island, USA
Cody Sheik, University of Minnesota Duluth, USA
Daniel Hummer, Carnegie Institution of Washington, USA
Alysia Cox,  Montana Tech of the University of Montana, USA
Dana Thomas, Stanford University, USA

Local Committee (University of the Azores)
César Andrade
Ana Hipólito
Diana Linhares
Lucía Moreno
Joana Pacheco
Catarina Silva
Vittorio Zanon

Participants
Armando Azua-Bustos, Blue Marble Institute of Science, Chile
Peter Barry, University of Oxford, UK
Tamara Baumberger, University of Bergen, Norway
Eglantine Boulard, Institut Neel, France
Leonardo Coppo, West Systems
Melitza Crespo-Medina, Inter-American University of Puerto Rico
Giuseppe d’Errico, Polytechnic University of Marche, Italy
Sébastien Facq, University of Cambridge, UK
Rebecca Fischer, Smithsonian Institution/University of California Santa Cruz, USA
Antonina Lisa Gagliano, INGV Palermo, Italy
Siddharth Gautam, Ohio State University, USA
Frédéric Girault, École Normale Supérieure de Paris, France
Ian Glenn, University of Utah, USA
Gino Gonzalez, University of Costa Rica
Jinxiang Huang, Macquarie University, Australia
Ana Patrícia Jesus, German University of Technology, Oman
Riikka Kietäväinen, Geological Survey of Finland
Kate Kiseeva, University of Oxford, UK
Doug LaRowe, University of Southern California, USA
Matteo Masotta, Bayerisches Geoinstitut, Germany
Jill McDermott, University of Toronto, Canada
Sami Mikhail, University of St Andrews, UK
Quin Miller, University of Wyoming, USA
Olivier Nadeau, University of Ottawa, Canada
Maggie Osburn, Northwestern University, USA
Elizabeth Padilla-Crespo, UPRM/UIPR, Puerto Rico
Roy Price, SUNY Stony Brook, USA
Esther Schwarzenbach, Virginia Tech, USA
Aleksandr Serovaiskii, Russian Gubkin State University, Russia
Andrew Steen, University of Tennessee, USA
Vikram Vishal, Stanford University, USA
Marion Le Voyer, University of Maryland, USA
Mustafa Yucel, Middle East Technical University, Turkey

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What is DCOECS15 and what’s this blog all about?

At the beginning of September 2015, a group of 47 Early Career Scientists (ECS) met at the University of the Azores, Portugal, for a workshop sponsored by the Deep Carbon Observatory (DCO). Hence, DCOECS15. The workshop was the third in a series of ECS events hosted by DCO (read more here and here), but this time the organizing committee tried something new.

DSCF1827_smallWe got permits to sample at Furnas hydrothermal field on São Miguel island, and knowing that we were bringing some very talented scientists to the workshop, we asked them to help plan and implement a day of sampling.

At the end of the workshop, we sent the recovered samples (fluids, sediments, and gases) home with 12 of the attendees. The goal of this blog is to chart the sample analysis as we work toward generating both an open access publication and an openly available dataset.

Check out our next post for a full report from the workshop!