Shock Recovery Experiments Research Articles

Detailed Occurrence of Feather Features in Quartz in Experimentally Shocked Granite

AbstractFeather features (FFs) in quartz consist of a planar fracture (PF) and associated fine lamellae (FF lamellae; FFL) and have been observed in various natural impact structures. However, the mechanisms and conditions of FF formation are poorly understood. We conducted shock recovery experiments on granite using decaying compressive pulses to investigate the formation conditions of FFs. We characterized the recovered samples using an optical microscope equipped with a universal stage, a scanning electron microscope combined with an electron back‐scattered diffraction detector, and a transmission electron microscope. We found that FFs are formed over a wide range of peak pressures (2–18 GPa) and that FFs can be divided into at least three types (I–III) based on the crystallographic orientation of the PFs and FFL, the angle between the orientation of the FFL and the propagation direction of the compression wave, and the presence/absence of amorphous silica in the FFL. The peak pressures that produce type I–III FFs are estimated to be <12, 12–14, and >16 GPa, respectively. We propose that FFs can be used as a shock barometer for quartz‐bearing rocks.

Tuning of lower to higher crystalline nature of β-L-Glutamic acid by shock waves

Understanding the crystallographic phase stability and solid – state new phases as well as their functions of materials under shock wave loaded conditions always generate a great deal of special enthusiasm among the researchers due to the emergence of lots of known and unknown behaviors of materials. Hence, such kind of shock recovery experiments is becoming one of the most promising research areas in materials science branch. In the present course of work, we have made systematic investigation for the assessment of crystallographic phase stability of β-L-Glutamic acid crystal under shocked conditions employing X-ray diffraction technique. From the diffraction measurements, it has been observed that the test materials turn from a lower crystalline nature to a higher crystalline nature due to the occurrence of dynamic recrystallization and reduction of structural complexity of the title material. Based on the diffraction assessments, it is confirmed that the test sample has not undergone any crystallographic phase changes even though it has several polymorphs.

Shock-recovered maskelynite indicates low-pressure ejection of shergottites from Mars.

Diaplectic feldspathic glass, commonly known as maskelynite, is a widely used impact indicator, notably for shergottites, whose shock conditions are keys to their geochemistry and launch mechanism. However, classic reverberating shock recovery experiments show maskelynitization at higher shock pressures (>30 gigapascals) than the stability field of the high-pressure minerals found in many shergottites (15 to 25 gigapascals). Most likely, differences between experimental loading paths and those appropriate for martian impacts have created this ambiguity in shergottite shock histories. Shock reverberation yields lower temperature and deviatoric stress than single-shock planetary impacts at equivalent pressure. We report the Hugoniot equation of state of a martian analog basalt and single-shock recovery experiments, indicating partial-to-complete maskelynitization at 17 to 22 gigapascals, consistent with the high-pressure minerals in maskelynitized shergottites. This pressure explains the presence of intact magmatic accessory minerals, used for geochronology in shergottites, and offers a new pressure-time profile for modeling shergottite launch, likely requiring greater origin depth.

Experimentally Shock‐Induced Melt Veins in Basalt: Improving the Shock Classification of Eucrites

AbstractBasaltic rocks occur widely on the terrestrial planets and differentiated asteroids, including the asteroid 4 Vesta. We conducted a shock recovery experiment with decaying compressive pulses on a terrestrial basalt at the Chiba Institute of Technology, Japan. The sample recorded a range of pressures, and shock physics modeling was conducted to add a pressure scale to the observed shock features. The shocked sample was examined by optical and electron microscopy, electron back‐scattered diffractometry, and Raman spectroscopy. We found that localized melting occurs at a lower pressure (∼10 GPa) than previously thought (>20 GPa). The shocked basalt near the epicenter represents “shock degree C” of a recently proposed classification scheme for basaltic eucrites and, as such, our results provide a pressure scale for the classification scheme. Finally, we estimated the total fraction of the basaltic eucrites classified as shock degree C to be ∼15% by assuming the impact velocity distribution onto Vesta.

Shock Recovery With Decaying Compressive Pulses: Shock Effects in Calcite (CaCO3) Around the Hugoniot Elastic Limit

AbstractShock metamorphism of minerals in meteorites provides insights into the ancient Solar System. Calcite is an abundant aqueous alteration mineral in carbonaceous chondrites. Return samples from the asteroids Ryugu and Bennu are expected to contain calcite‐group minerals. Although shock metamorphism in silicates has been well studied, such data for aqueous alteration minerals are limited. Here, we investigated the shock effects in calcite with marble using impact experiments at the Planetary Exploration Research Center of Chiba Institute of Technology. We produced decaying compressive pulses with a smaller projectile than the target. A metal container facilitates recovery of a sample that retains its pre‐impact stratigraphy. We estimated the peak pressure distributions in the samples with the iSALE shock physics code. The capability of this method to produce shocked grains that have experienced different degrees of metamorphism from a single experiment is an advantage over conventional uniaxial shock recovery experiments. The shocked samples were investigated by polarizing microscopy and X‐ray diffraction analysis. We found that more than half of calcite grains exhibit undulatory extinction when peak pressure exceeds 3 GPa. This shock pressure is one order of magnitude higher than the Hugoniot elastic limit (HEL) of marble, but it is close to the HEL of a calcite crystal, suggesting that the undulatory extinction records dislocation‐induced plastic deformation in the crystal. Finally, we propose a strategy to re‐construct the maximum depth of calcite grains in a meteorite parent body, if shocked calcite grains are identified in chondrites and/or return samples from Ryugu and Bennu.

Experimental simulations of shock textures in BCC iron: implications for iron meteorites

Neumann band in iron meteorites, which is deformation twins in kamacite (Fe–Ni alloy), has been known to be a characteristic texture indicating ancient collisions on parent bodies of meteorites. We conducted a series of shock recovery experiments on bcc iron with the projectile velocity at 1.5 km/s at various initial temperatures, room temperature, 670 K, and 1100 K, and conducted an annealing experiment on the shocked iron. We also conducted numerical simulations with the iSALE-2D code to investigate peak pressure and temperature distributions in the nontransparent targets. The effects of pressure and temperature on the formation and disappearance of the twins (Neumann band) were explored based on laboratory and numerical experiments. The twin was formed in the run products of the experiments conducted at room temperature and 670 K, whereas it was not observed in the run product formed by the impact at 1100 K. The present experiments combined with the numerical simulations revealed that the twin was formed by impacts with various shock pressures from 1.5–2 GPa to around 13 GPa. The twin in iron almost disappeared by annealing at 1070 K. The iron meteorites with Neumann bands were shocked at this pressure range and temperatures at least up to 670 K, and were not heated to the temperatures above 1070 K after the Neumann band formation.

Structural changes in shocked tektite and their implications to impact-induced glass formation

AbstractHeavy meteorite impacts on Earth’s surface produce melt and vapor that are quenched rapidly and scattered over wide areas as natural glasses with various shapes and characteristic chemistry, which are known as tektites and impact glasses. Their detailed formation conditions have long been debated using mineralogical and geochemical data and numerical simulations of impact melt formations. These impact processes are also related to the formation and evolution of planets. To unravel the formation conditions of impact-induced glasses, we performed shock recovery experiments on a tektite. Recovered samples were characterized by X-ray diffraction, Raman spectroscopy, and X-ray absorption fine structure spectroscopy on the Ti K-edge. Results indicate that the densification by shock compression is subjected to post-shock annealing that alters the density and silicate-framework structures but that the local structures around octahedrally coordinated Ti ions remain in the quenched glass. The relationship between the average Ti-O distance and Ti K pre-edge centroid energy is found to distinguish the valance state of Ti ions between Ti4+ and Ti3+ in the glass. This relationship is useful in understanding the formation conditions of impact-derived natural glasses. The presence of Ti3+ in tektites constrains the formation conditions at extremely high temperatures or reduced environments. However, impact glasses collected near the impact sites do not display such conditions, but instead relatively mild and oxidizing formation conditions. These different formation conditions are consistent with the previous numerical results on the crater size dependence.

Shock experiments on basalt—Ferric sulfate mixes and their possible relevance to the sulfide bleb clusters in large impact melts in shergottites

AbstractLarge impact‐melt pockets in shergottites contain both Martian regolith components and sulfide/sulfite bleb clusters that yield high sulfur concentrations locally compared to bulk shergottites. The regolith may be the source of excess sulfur in the shergottite melt pockets. To explore whether shock and release of secondary Fe‐sulfates trapped in host rock voids is a plausible mechanism to generate the shergottite sulfur bleb clusters, we carried out shock recovery experiments on an analog mixture of ferric sulfate and Columbia River basalt at peak pressures of 21 and 31 GPa. The recovered products from the 31 GPa experiment show mixtures of Fe‐sulfide and Fe‐sulfite blebs similar to the sulfur‐rich bleb clusters found in shergottite impact melts. The 21 GPa experiment did not yield such blebs. The collapse of porosity and local high‐strain shear heating in the 31 GPa experiment presumably created high‐temperature hotspots (~2000 °C) sufficient to reduce Fe3+ to Fe2+ and to decompose sulfate to sulfite, followed by concomitant reduction to sulfide during pressure release. Our results suggest that similar processes might have transpired during shock production of sulfur‐rich bleb clusters in shergottite impact melts. It is possible that very small CO presence in our experiments could have catalyzed the reduction process. We plan to repeat the experiments without CO.

Experimental and atomic observations of phase transformations in shock-compressed single-crystal Fe

The phase transformations in Fe have been of technological and sociological importance in the development of human civilization. The α→ε (BCC→HCP) martensitic transformation is the best known phase transformation of Fe and has been extensively studied. However, the mechanisms of α→ε and ε→α transformation upon shock loading and release are not yet understood owing to its short life and reversibility. In this study, we designed experimental and atomic methods for observing the shock-induced phase transformations in [001] and [111] single-crystal Fe, using shock recovery experiments and molecular dynamic simulations. It was found that the orientation relationships in the [001] and [111] single-crystal Fe are consistent with previously proposed transformation mechanisms. The α→ε transformation was attributed to the (110) slip system, while the reverse transformation was attributed to the (112) slip system. Furthermore, it was postulated that the rod-like microstructures observed in the shock-recovered samples were caused by the wave interactions during the unloading. However, the rod-like shapes in the [001] Fe were caused by the activation of dislocations in the b1 = ka[11–2] and b2 = ka[112] Burgers vectors. Only the b3 = ka[112] dislocation was activated in the [111] Fe sample.

Chondrule Flattening by Shock Recovery Experiments on Unequilibrated Chondrites

AbstractShock recovery experiments were conducted using ALH‐78084 H3 and Y‐793375 L3 chondrites in the shock pressure range of 11–43 GPa to reproduce shock‐induced melting and chondrule flattening. Shock‐induced melt and chondrule flattening in 15 H3, 23 L3, and 23 LL3 ordinary chondrites were also investigated for comparisons. The shock experiments proved that, at least in unequilibrated ordinary chondrites, shock‐induced melting occurred beyond 11 GPa. The melting occurs at the boundary between chondrule and matrix. The melts included fine‐grained silicate minerals, glasses, and ameba or spherical metallic Fe–Ni or metallic Fe–Ni–iron sulfide with a eutectic texture that coincided with shock‐induced melts in the investigated H/L/LL3 ordinary chondrites. Shock experiments also proved that shock‐induced flattening of chondrules occurs and the flattening degree increases with increasing shock pressure. Considering the shock experiments not only of ordinary chondrites but also of carbonaceous chondrites, the flattening degree is not significantly affected by the density, porosity, and chondrule/matrix ratio of chondrites. The long axes of chondrules in shocked ALH‐78084 H3 and Y‐793375 L3 chondrites have preferred orientations and the degree increases with increasing shock pressure. It is difficult to estimate quantitatively the shock pressure recorded in unequilibrated ordinary chondrites using the empirical formula between the aspect ratio of chondrules and shock pressure. Nevertheless, the investigated L/LL3 ordinary chondrites with shock‐induced melts had higher aspect ratios (median, 1.36) and more strongly preferred orientations than those without shock‐induced melts (median, 1.25).

A shock recovery experiment and its implications for Mercury's surface: The effect of high pressure on porous olivine powder as a regolith analog

We conducted classic dynamic high - pressure experiments on porous San Carlos (SC) olivine powder to examine if and how different shock stages modify corresponding reflectance mid – infrared (MIR) spectra. Microscopic investigation of the thin sections produced of our shocked samples indicates local peak pressures of >60 GPa along with all lower grade shock stages. Spectral analyses of optically identified shock areas were documented and compared in terms of Christiansen Feature (CF) and the position of olivine – diagnostic Reststrahlenbands (RBs). We found that one RB (fundamental vibrations of the orthosilicate - ion) of olivine occurring at 980 cm−1 (corresponding to ≈ 10.2 μm) shows the least energetic shift in the investigated MIR spectra and could therefore serve as a proxy for the presence of olivine in remote sensing application. Furthermore, a peak located at ≈ 1060 cm−1 (≈ 9.4 μm) shows a significant intensity change probably related to the degree of shock exposure or grain orientation effects, as we observe a decline in intensity of this band from our averaged reference olivine spectra of our IRIS database (diffuse reflectance measurement) down to spectra of grains showing mosaicism and recrystallized areas. We also report the presence of a weak band in some of the olivine spectra located at ≈ 1100 cm−1 (9.1 μm) that has an influence on the position of the CF when spectral data of olivine are averaged.

Real-time observation of twinning-detwinning in shock-compressed magnesium via time-resolved in situ synchrotron XRD experiments

Both engineered and natural materials may be subjected to extremes of elevated pressure, temperature, and strain rate due to shock loading; examples include ballistic impact of projectiles on armor, planetary impacts, and high-speed machining operations. Experimental techniques for ascertaining the macroscopic response of materials to shock loading are well established, but insight into fundamental mechanisms of deformation requires the ability to characterize the evolution of microstructure in real time. Experiments in which specimens are recovered and characterized after shock loading have been widely used to understand structure-property relationships. But these shock recovery experiments only reveal information at the end state of the material, from which the evolution of the structure during unloading must be inferred. There is always the possibility that the structure of the material continues to evolve during unloading, leading to a potential misunderstanding of the structural evolution during shock compression and release. In this paper we describe the results of shock recovery and time-resolved in situ x-ray diffraction studies of deformation twinning in an extruded fine-grained AMX602 magnesium alloy. The samples were shock compressed along the plate normal and extrusion directions, then released back to ambient conditions. Analysis of the microstructure before and after shock loading indicates a substantial change in crystallographic texture reflecting substantial deformation twinning. Texture evolution from in situ synchrotron x-ray diffraction measurements show significant twinning during shock compression followed by detwinning during stress release. These results not only provide insight into the complex twinning-detwinning behavior of this particular alloy, but also illustrate the utility of in situ characterization for bridging the knowledge gap between shock recovery experiments and the transient behavior of materials during shock loading more generally.

Effect of impact shock on extremophilic Halomonas gomseoemensis EP-3 isolated from hypersaline sulphated lake Laguna de Peña Hueca, Spain

The geologic histories of planetary surfaces reveal that Earth and Mars have been pummeled by cataclysmic impact events. The surface of Mars has been perused to have an impact origin for its hemispheric dichotomy. The spallation during impact events causes the interplanetary transfer of material from Mars to Earth or Mars to Phobos/Deimos. Assessing the survival of micro-organisms in impact conditions is critical for the development of planetary protection strategies for future missions. Shock waves are generated during such major impact events. The objective of the present investigation was to explore the microbial diversity of the hypersaline sulphated Laguna de Peña Hueca, Spain and to study the effect of shock waves on extremophilic bacteria isolated from the lake. Peña Hueca is a hypersaline sulphated lagoon rich in Mg–Na–SO4–Cl, epsomite and hexahydrate and it potentially serves as Planetary field analogue site for Martian chloride deposits and salt-rich subsurface brines of Ocean worlds like Enceladus and Europa. The microbial community structure of the lagoon was studied by 16S rRNA metagenomic sequencing. The phylogenetic studies indicated the presence of phyla Euryarchaeota, Proteobacteria, and Bacteroides in the hypersaline brines of the lagoon. The anoxic sediments of Peña Hueca showed the presence of Haloanaerobiaeta and Hadesarchaeota including the anoxic genus of Haloanaerobium, Desulfosalsimonas and Desulfovermiculum. The effect of impact shock on the halophilic bacterium Halomonas gomseomensis EP-3 isolated from Laguna de Peña Hueca was studied in a Reddy shock tube. The halophilic bacterium was exposed to shock waves at a peak shock pressure of 300 ​kPa and a temperature of 400 ​K. The results of shock recovery experiments of halophilic bacteria reveal 97% killing at 300 ​kPa and Mach number of 1.47 in comparison with Bacillus sp. This study indicates that gram-positive spore-forming Bacillus sp. are better adapted to survival in impact shock waves in comparison to non-sporulating halophiles. In the current study, we present the first report on response of halophiles in impact shock. Furthermore, we demonstrate a novel application of the simple handheld Reddy shock tube in astrobiology. The survival studies of halophiles isolated from terrestrial analogue sites in impact shock can provide valuable insights in astrobiology and microbial physiology in impact shock stress.

Shock wave induced defect engineering on structural and optical properties of pure and dye doped potassium dihydrogen phosphate crystals

Abstract Based on the importance of the shock recovery experiments, the authors report the structural and optical properties of pure and 0.001 M dye-doped potassium dihydrogen phosphate (KDP) crystals for virgin and shock wave loaded samples. Rhodamine B and Methylene blue dyes are selected as dopants to be doped with KDP crystal for the present investigation. The test crystals of pure and doped KDP crystals are grown by slow evaporation technique and cut and polished crystals of (200) face are used for the present investigation. Table-top pressure driven shock tube is utilized for the shock wave generation and the used functional Mach number is 1.7. Virgin and shock wave loaded test crystals’ surface morphology, structural properties and optical transmissions are observed using optical microscope, powder X-ray diffractometer and UV-Visible spectrometer, respectively. Crystalline nature and optical transmission of pure and doped KDP crystals are found to have reduced by the impact of shock waves. It occurs due to the enhancement of defect concentration on the surface of the test crystals. From the observed results, we assert that the pure KDP crystal is relatively more stable to shock wave induced damage compared to doped KDP crystals as reflected by structural and optical studies.

Shock-synthesized quasicrystals.

Quasicrystals (QCs) are unique materials, whose crystallographic identity has been controversial for many years. Using recent advances in shock synthesis, Hu et al. [(2020), IUCrJ, 7, 434-444] reproduce for the first time the formation conditions of the icosahedral Al62Cu31Fe7 QC (i-phase II) found in the Khatyrka meteorite. The authors demonstrate that shock-recovery experiments provide a novel strategy for preparing and exploring QCs.

First synthesis of a unique icosahedral phase from the Khatyrka meteorite by shock-recovery experiment.

Icosahedral quasicrystals (i-phases) in the Al-Cu-Fe system are of great interest because of their perfect quasicrystalline structure and natural occurrences in the Khatyrka meteorite. The natural quasicrystal of composition Al62Cu31Fe7, referred to as i-phase II, is unique because it deviates significantly from the stability field of i-phase and has not been synthesized in a laboratory setting to date. Synthetic i-phases formed in shock-recovery experiments present a novel strategy for exploring the stability of new quasicrystal compositions and prove the impact origin of natural quasicrystals. In this study, an Al-Cu-W graded density impactor (GDI, originally manufactured as a ramp-generating impactor but here used as a target) disk was shocked to sample a full range of Al/Cu starting ratios in an Fe-bearing 304 stainless-steel target chamber. In a strongly deformed region of the recovered sample, reactions between the GDI and the steel produced an assemblage of co-existing Al61.5Cu30.3Fe6.8Cr1.4 i-phaseII + stolperite (β, AlCu) + khatyrkite (θ, Al2Cu), an exact match to the natural i-phase II assemblage in the meteorite. In a second experiment, the continuous interface between the GDI and steel formed another more Fe-rich quinary i-phase (Al68.6Fe14.5Cu11.2Cr4Ni1.8), together with stolperite and hollisterite (λ, Al13Fe4), which is the expected assemblage at phase equilibrium. This study is the first laboratory reproduction of i-phase II with its natural assemblage. It suggests that the field of thermodynamically stable icosahedrite (Al63Cu24Fe13) could separate into two disconnected fields under shock pressure above 20 GPa, leading to the co-existence of Fe-rich and Fe-poor i-phases like the case in Khatyrka. In light of this, shock-recovery experiments do indeed offer an efficient method of constraining the impact conditions recorded by quasicrystal-bearing meteorite, and exploring formation conditions and mechanisms leading to quasicrystals.

Shock-induced phase transition of g-C3N4 to a new C3N4 phase

In this study, phase transition of graphitic carbon nitride (g-C3N4) was investigated using the shockwave compression technique. Firstly, the shock Hugoniot data of g-C3N4 were obtained using a bore propellant gun and a light gas gun under impact velocities of 1.208–4.982 km/s, revealing one phase transition pressure of g-C3N4 at 22.4 GPa. Then, a series of shock recovery experiments was carried out with a pressure range of 17.0–62.1 GPa. The recovered samples were characterized by various techniques, including X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The measured d-values of the recovered samples were compared with those from the previous reported results, revealing a new carbon nitride phase synthesized by the shockwave compression technique. The new phase is indexed as a triclinic cell with a = 0.481 nm, b = 0.353 nm, c = 0.285 nm, α = 67.52°, β = 100.75°, γ = 106.47°, and Vcell = 0.043 nm3. EDX and XPS spectra reveal the existence of C and N elements with an atomic ratio of 0.754, also confirming the presence of a new C3N4 phase obtained via a g-C3N4 phase transition induced by shockwave compression with a pressure range of 29.3–62.1 GPa. These sample results are in good agreement with the shock Hugoniot data.

Fine‐structures of planar deformation features in shocked olivine: A comparison between Martian meteorites and experimentally shocked basalts as an indicator for shock pressure

AbstractWe performed shock recovery experiments on an olivine‐phyric basalt at shock pressures of 22.2–48.5 GPa to compare with shock features in Martian meteorites (RBT 04261 and NWA 1950). Highly shocked olivine in the recovered basalt at 39.5 and 48.5 GPa shows shock‐induced planar deformation features (PDFs) composed of abundant streaks of defects. Similar PDFs were observed in olivine in RBT 04261 and NWA 1950 while those in NWA 1950 were composed of amorphous lamellae. Based on the present results and previous studies, the width and the abundance of lamellar fine‐structures increased with raising shock pressure. Therefore, these features could be used as shock pressure indicators while the estimated pressures may be lower limits due to no information of temperature dependence. For Martian meteorites that experienced heavy shocks, the minimum peak shock pressures of RBT 04261 and NWA 1950 are estimated to be 39.5–48.5 GPa and 48.5–56 GPa, respectively, which are found consistent with those estimated by postshock temperatures expected by the presence of brown olivine. We also investigated shock‐recovered basalts preheated at 750 and 800 °C in order to check the temperature effects on shock features. The results indicate a reduction in vitrifying pressure of plagioclase and a pressure increase for PDFs formation in olivine. Further temperature‐controlled shock recovery experiments will provide us better constraints to understand and to characterize various features found in natural shock events.

On the formation of diaplectic glass: Shock and thermal experiments with plagioclase of different chemical compositions

AbstractThis contribution addresses the role of chemical composition, pressure, temperature, and time during the shock transformation of plagioclase into diaplectic glass—i.e., maskelynite. Plagioclase of An50‐57 and An94 was recovered as almost fully isotropic maskelynite from room temperature shock experiments at 28 and 24 GPa. The refractive index (RI) decreased to values of a quenched mineral glass for An50‐57 plagioclase shocked to 45 GPa and shows a maximum in An94 plagioclase shocked to 41.5 GPa. The An94 plagioclase experiments can serve as shock thermobarometer for lunar highland rocks and howardite, eucrite, and diogenite meteorites. Shock experiments at 28, 32, 36, and 45 GPa and initial temperatures of 77 and 293 K on plagioclase (An50‐57) produced materials with identical optical and Raman spectroscopic properties. In the low temperature (<540 K) region, the formation of maskelynite is entirely controlled by shock pressure. The RI of maskelynite decreased in heating experiments of 5 min at temperatures of >770 K, thus, providing a conservative upper limit for the postshock temperature history of the rock. Although shock recovery experiments and static pressure experiments differ by nine orders of magnitude in typical time scale (microseconds versus hours), the amorphization of plagioclase occurs at similar pressure and temperature conditions with both methods. The experimental shock calibration of plagioclase can, together with other minerals, be used as shock thermobarometer for naturally shocked rocks.

Evaluation of the shock-induced phase transition in β-Ga2O3

A series of shock recovery experiments were conducted on single-crystal β-Ga2O3 involving the impact of a flyer plate accelerated by a single-stage powder-propellant gun. The samples that recovered from shock were characterized by X-ray diffraction (XRD) analysis and Raman spectroscopy. The XRD results of the β-Ga2O3(010) sample shocked at a pressure of 16 GPa indicated that a transition from the β to α phase occurred. In contrast, no phase transition was detected for the sample shocked at 11 GPa. Analysis of the shocked samples suggests that the onset pressure for the transition from the β- to α-Ga2O3 phase lies between 11 and 16 GPa. Although the transition from the β- to α-Ga2O3 phase was accomplished in only a tiny part of the shocked sample, our results combined with numerical simulation results indicate that the shock-induced phase transition from β- to α-Ga2O3 was initiated within several hundred nanoseconds.