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Feather 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. Plain Language Summary: Our research focused on a unique deformation feature in quartz, known as feather features (FFs), which are found where hypervelocity impacts of celestial bodies have occurred. These features include a main crack and several fine, feather‐like lines emanating from the main crack. We conducted shockwave experiments on granite, a common quartz‐bearing rock by simulating the shock conditions of impacts onto Earth's surface. We used various microscopic techniques to observe the experimentally shocked quartz. We show that FFs form under a wide range of pressures from 20,000× to 180,000× atmospheric pressure. The FFs can be divided into three types relating to the peak pressure, based on the orientation of the feather‐like lines with respect to the crystal lattice and the direction of shockwave propagation, and whether vitrification occurred. At pressures below ∼120,000× atmospheric pressure, the main crack and fine lines have specific orientations (type I), but these orientations change when the pressure is >120,000× atmospheric pressures (type II). The feather‐like lines transform from simple cracks to structures filled with glass at a peak pressure of >140,000–160,000× atmospheric pressure (type III). The nature of the FFs means that the three types of FFs are a useful shock barometer for ancient impact events. Key Points: Impact experiments revealed that feather features in quartz are produced at peak pressures of 2–18 GPaThe feather features can be divided into at least three types that relate to the peak pressureFeather features can be used as a shock barometer for estimating peak pressures in geological studies [ABSTRACT FROM AUTHOR]

Dry lakebeds might constitute large volatile reservoirs on Mars. Hypervelocity impacts onto ancient dry lakebeds would have affected the volatile distribution on Mars. We developed a new experimental method to investigate the response of evaporitic minerals (halite and gypsum) to impact shocks in an open system. This technique does not result in chemical contamination from the operation of the gas gun. The technique is termed the "two‐valve method," and the gun system is located in the Planetary Exploration Research Center, Chiba Institute of Technology, Japan. We detected the vaporization of halite at 31 GPa and devolatilization from gypsum at 11 GPa, suggesting that impact‐induced volatile release from dry lakebeds has periodically occurred throughout Martian history. The vaporization of halite deposits might have enhanced the production of perchlorates, which are found globally on Mars. The water loss from gypsum possibly explains the coexisting types of Ca‐sulfates found in Gale Crater. Plain Language Summary: We used a new experimental technique to investigate the result of a meteoroid impact into an evaporitic deposit on Mars. Although two‐stage light gas guns are ideal projectile launchers, the dirty gas from the gun has been a long‐standing limitation of this technique that so far greatly complicated analysis of the vapors that are generated due to such impacts. Our new method overcomes this limitation and allows us to measure impact‐generated vapor from evaporitic minerals. We detected NaCl vapor from halite and water vapor from gypsum at velocities lower than the typical impact velocities onto Mars. This suggests that volatile release from ancient dry lakebeds has periodically occurred throughout Martian history, due to stochastic meteoroid impacts. The nature of perchlorates and Ca‐sulfates found on Mars can be interpreted as the result of hypervelocity impacts onto dry lakebeds rich in evaporitic minerals. Key Points: Gas release from halite and gypsum was studied using a two‐stage light gas gun setup that avoids contamination of impact vapors from gun‐related gasesVaporization of halite at 31 GPa and devolatilization (water loss) from gypsum at 11 GPa were detectedImpacts might have resulted in efficient production of perchlorates in Martian soil and produced the anhydrite found in Gale Crater [ABSTRACT FROM AUTHOR]

Abstract: The shock-induced decarbonation of non-porous calcite was investigated in an open system over a wide range of peak shock pressures using a two-stage light gas gun and a quadrupole mass spectrometer. We developed a new experimental technique that avoids chemical contamination from the acceleration gas used in the gun. High-speed imaging and spectroscopic observations were conducted simultaneously to investigate the validity of the experimental procedure. The decarbonation efficiency along the Hugoniot curve changed at around 50GPa—the approximate incipient decarbonation pressure predicted by the previous theoretical studies. Decarbonation, albeit at a low efficiency, was detected at pressures below the 50GPa threshold, as observed in previous experimental studies, possibly as a result of energy localization due to a process like shear banding. A simple theoretical model for shock-induced decarbonation during isentropic release was constructed based on the entropy method and the lever rule, assuming the experimental conditions. The predicted amount of released CO2 as a function of the peak shock pressure agreed well with the experimental results at pressures exceeding 50GPa, strongly suggesting that the amount of shock-induced CO2 gas was determined only by the shock-induced entropy gain and by the entropies for incipient and complete decarbonation at the ambient pressure. In future experiments, the new method will be used for quantitative measurements of the chemical composition of impact-induced gases derived from other solid materials. The proposed method is useful in determining the peak shock pressure required for vaporization/devolatilization of geologic materials and for estimating the final chemical composition of impact-induced vapor clouds. [Copyright &y& Elsevier]