Sakamaki et al. Progress in Earth and Planetary Science (2016) 3:38
DOI 10.1186/s40645-016-0114-5

Progress in Earth andPlanetary SciencePREFACE

Open AccessPreface for the article collection “HighPressure Earth and Planetary Science in thelast and next decade”
Tatsuya Sakamaki1*, Akio Suzuki1 and Bjorn Mysen2

Keywords: High pressure, Early earth, Magma, Fluid, Mantle, Core, Synchrotron X-ray

Preface
A special session entitled “Early Earth - from accumulation to formation-” was held on May 24, 2015 during
the Japan Geoscience Union (JpGU) annual meeting.
This session aimed to bring together high-pressure/hightemperature experiment on physics and chemistry ofdeep Earth materials, natural observation, and theoretical modeling within the principal subject areas of “EarlyEarth” research. Twenty-six oral and seven poster presentations were given at this session (Fig. 1). Two review
and seven research articles from that session are includedin this SPEPS. These articles cover Earth’s formation/evolution (de Vries et al. 2016; Kondo et al. 2016), magma
and fluid in the interior of the Earth (Mysen 2015; Ohiraet al. 2016; Poli 2016; Reynard 2016), Earth’s deep mantle(McCammon et al. 2016; Zhang et al. 2016), and methods
using synchrotron radiation (Yu et al. 2016).
Giant impact events during planetary accretion caused
large degrees of melting of the early Earth. De Vries etal. (2016) simulated the volumes of melt, pressure, andtemperature conditions of metal-silicate equilibration
after each impact, and demonstrated that the pressure
evolution during metal-silicate equilibration during accretion depends strongly on the lifetime of impactgenerated magma oceans compared to the time interval
between large impacts. Kondo et al. (2016) estimatedmajor element composition of an early Earth reservoir(EER) with the aid of 142Nd/144Nd isotope systematics todetermine the age and pressure–temperature conditions
to form the EER. They concluded that the EER formed
within 33.5 Myr of Solar System formation and at* Correspondence: sakamaki@m.tohoku.ac.jp
1
Department of Earth Science, Tohoku University, 6-3, Aramaki Aza-Aoba,
Aoba-ku, Sendai 980-8578, Japan
Full list of author information is available at the end of the article

near-solidus temperatures and pressures of shallow
upper mantle conditions. The picritic to komatiitic crust(EER) most likely would have been ejected from theEarth by the last giant impact or preceding impacts.
They concluded, therefore, the EER was lost, leaving theEarth more depleted than its original composition.
The existence of magma and fluid is one of the mostunique features of the Earth. These materials are principal agents of mass and energy transfer in and on theEarth and are, therefore, responsible for the many
unique features of formation, evolution, and present day
processes of the Earth. In subduction zone environments, fluids are particularly important. With thisconsideration in mind, Poli (2016) studied the melting
carbonated epidote eclogites. The subsolidus breakdownof epidote in the presence of carbonates at depths
exceeding 120 km provides a major source of C–O–H
volatiles at sub-arc depth. In warm subduction zones,
the possibility of extracting carbonatitic liquids from avariety of gabbroic rocks and epidosites offers new
scenarios on the metasomatic processes in the lithospheric wedge of subduction zones and a new mechanism for recycling carbon. Reynard (2016) reviewed themantle hydration and Cl-rich fluids in the subduction
forearc. Mysen (2015) reported the Zr4+ transportcapacity of water-rich fluids. His results imply that fluid
released during high-temperature/high-pressure dehydration of hydrous mineral assemblages in the Earth’s
interior under some circumstances may carry significant
concentrations of Zr.
In order to further our understanding of the nature ofdense silicate melts that may be present at the base of
the mantle, Ohira et al. (2016) used Brillouin scattering
spectroscopic methods to pressures of 196.9 GPa toconduct in situ high-pressure acoustic wave velocity© The Author(s). 2016 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.

Sakamaki et al. Progress in Earth and Planetary Science (2016) 3:38

Page 2 of 3Fig. 1 Poster used for the special call for excellent papers on hot topics: “High-Pressure Earth and Planetary Science in the last and next decade”.
From left to right: the surface of Mars, Earth, and Moon

measurements of SiO2–Al2O3 glasses. Compared toprevious acoustic wave velocity data on SiO2 andMgSiO3 glasses, Al2O3 appears to promote a lowering of
the pressure at which the abrupt increase of dV S/dP isobserved. This suggests that the Al2O3 in silicate melts
may help to stabilize gravitationally those melts in thelower mantle.
The properties of mantle minerals in the deep Earthare important research target. McCammon et al. (2016)
reported Debye sound velocities by using nuclear inelastic scattering for one majorite composition and fivebridgmanite compositions measured in a diamond anvil
cell at pressures up to 89 GPa at room temperature.
They calculated partial and total density of states (DOS)for MgSiO3 and FeSiO3 bridgmanite by using density
functional theory. It was demonstrated that Debye soundvelocities calculated from the reduced DOS with thesame approach as for the experimental data give thesame sound velocities for each phase irrespective of
which partial DOS is used. Zhang et al. (2016) reported
accurate unit cell parameters of individual mineralphases in a mineral assemblage contained in a diamondanvil cell (DAC) with the aid of multigrain X-ray diffraction (XRD) technique. Coexisting post-perovskite (ppv)and H-phase were synthesized at 119 GPa and 2500 K
from (Mg0.85Fe0.15) SiO3 in a laser-heated DAC. Their
unit cell parameters were determined using multigrain
XRD with 5 μm spatial resolution, to advance our understanding of compositional variations across the centerarea in a laser-heated sample.
Synchrotron X-ray is an important tool in highpressure Earth science. Yu et al. (2016) reviewed thehigh-pressure X-ray microtomography (HPXMT), which

can provide the high-pressure community with a unique
opportunity to image the three-dimensional volume,
texture, and microstructure of materials under highpressure and temperature by combining the strong
synchrotron X-ray source and fast switching between
white (for X-ray diffraction) and monochromatic (forabsorption imaging) modes.
Finally, we dedicate this SPEPS to Dr. E. Ohtani(professor emeritus at Tohoku University), who mademeaningful contributions to vast research areas frompartial melting of deep silicate Earth, element partitioning, and role of hydrous circulation of water and hydrogen in the early deep Earth to core/mantle equilibria
together with equation-of-state of silicate mantle andmetal core materials. It is striking how many current
research directions were initiated by Professor Ohtani
decades ago and how involved he remains even today.
There is hardly any subject where he and his collaborators contributed often the original and often the mostimportant experimental data and demonstrated how
these can be used to model the physics and chemistry of
the materials and processes in the interior of the Earthand terrestrial planets. We hope that this SPEPS will also
convey this message.
Acknowledgements
This special issue is based on a special session entitled “Early Earth - fromaccumulation to formation-” held on May 24, 2015 at the Japan Geoscience
Union (JpGU) annual meeting in Makuhari. The session consisted of 26 oral
and seven poster presentations, and included 11 presentations from outsideJapan. The session was highly successful, with energetic discussions, andresulted in nine articles being submitted to this special issue. Travel expenses
of invited speakers from outside Japan were supported by JpGU, and we
thank PEPS staff for logistical help provided to foreign participants. We
would like to acknowledge the authors and reviewers for their valuablecontributions. We thank Prof. Yasufumi Iryu for serving as a General Chief

Sakamaki et al. Progress in Earth and Planetary Science (2016) 3:38

Page 3 of 3Editor. We also thank Ms. Tomoyo Asada and other PEPS staff for theirsupport during the submission and revision of manuscripts, and the PEPS
editorial board for helpful and swift editorial handling of manuscripts.
Funding
Not applicable.
Authors’ contributions
All authors wrote this manuscript and approved the final manuscript.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Department of Earth Science, Tohoku University, 6-3, Aramaki Aza-Aoba,Aoba-ku, Sendai 980-8578, Japan. 2Geophysical Laboratory, Carnegie
Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC
20015, USA.
Received: 29 November 2016 Accepted: 29 November 2016

Referencesde Vries J, Francis N, Jay Melosh H, Jacobson SA, Morbidelli A, Rubie DC (2016)
Impact-induced melting during accretion of the Earth. Prog Earth Planet Sci
3:7. doi:10.1186/s40645-016-0083-8
Kondo N, Yoshino T, Matsukage KN, Kogiso T (2016) Major element composition ofan early enriched reservoir: constraints from 142Nd/144Nd isotope systematics inthe early Earth and high-pressure melting experiments of a primitive peridotite.
Prog Earth Planet Sci 3:25. doi:10.1186/s40645-016-0099-0
McCammon C, Caracas R, Glazyrin K, Potapkin V, Kantor A, Sinmyo R, Prescher C,Kupenko I, Chumakov A, Dubrovinsky L (2016) Sound velocities ofbridgmanite from density of states determined by nuclear inelastic scatteringand first principles calculations. Prog Earth Planet Sci 3:10. doi:10.1186/s40645-016-0089-2
Mysen B (2015) An in-situ experimental study of Zr4+ transport capacity ofwater-rich fluids in the temperature and pressure range of the deep crustand upper mantle. Prog Earth Planet Sci 2:38. doi:10.1186/s40645-015-0070-5
Ohira I, Murakami M, Kohara S, Ohara K, Ohtani E (2016) Ultrahigh-pressure
acoustic wave velocities of SiO2-Al2O3 glasses up to 200 GPa. Prog EarthPlanet Sci 3:18. doi: 10.1186/s40645-016-0097-2
Poli S (2016) Melting carbonated epidote eclogites: carbonatites from subducting
slabs. Prog Earth Planet Sci 3:27. doi:10.1186/s40645-016-0105-6
Reynard B (2016) Mantle hydration and Cl-rich fluids in the subduction forearc.
Prog Earth Planet Sci 3:9. doi: 10.1186/s40645-016-0090-9
Yu T, Wang Y, Rivers ML (2016) Imaging in 3D under pressure: a decade ofhigh-pressure X-ray microtomography development at GSECARS. Prog EarthPlanet Sci 3:17. doi:10.1186/s40645-016-0093-6
Zhang L, Meng Y, Mao H-K (2016) Unit cell determination of coexisting postperovskite and H-phase in (Mg, Fe) SiO3 using multigrain XRD: compositionalvariation across a laser heating spot at 119 GPa. Prog Earth Planet Sci 3:13.
doi: 10.1186/s40645-016-0091-8

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