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$\begin{figure} \par\includegraphics[width=7.7cm,clip]{8964fig1}\end{figure}$ Figure 1: Photoelectron spectrum of the San Carlos olivine before irradiation over a wide energy range. The peaks corresponding to C 1s, O 1s, Si 2p, Mg 1s, Mg 2p and Fe 2p_3/2 core levels and the Auger structure (O KLL, Mg KLL) are indicated.
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In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{8964fig2}\end{figure}$ Figure 2: Characteristic Fe 2p spectra of the three iron oxidation states. The peaks between 706 and 712 eV are due to Fe 2p_3/2 and those between 717 and 725 eV correspond to Fe 2p_1/2. The satellite peaks, which are characteristic of Fe²⁺ (small shoulder on the left of the main peak) and Fe³⁺ (bump in the middle of the two main peaks), are indicated by arrows. These features are used in the Non Linear Least Square Fit method to extract the relative proportion of each valence species of olivine.
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In the text

$\begin{figure} \par\includegraphics[width=7.75cm,clip]{8964fig3}\end{figure}$ Figure 3: XPS spectra of the Fe 2p region showing the progressive transformation of Fe²⁺ to Fe³⁺ during irradiation with He⁺ at 4 keV and a flux of 4 $\times$ 10¹⁴ ions cm^-2 s^-1: a) spectrum before irradiation, Fe²⁺ is the major valence state present at the olivine surface (85% of the iron), b) after irradiation with a fluence of 4 $\times$ 10¹⁷ He⁺ cm^-2, c) with a fluence of 14 $\times$ 10¹⁷ He⁺ cm^-2, the native oxide is progressively transformed to Fe³⁺ (38% of the iron in the Fe²⁺ state), d) after a fluence of 21 $\times$ 10¹⁷ He⁺ cm^-2 and e) a fluence of 29 $\times$ 10¹⁷ He⁺ cm^-2, Fe³⁺ is the dominant valence state present in the sample surface (12.7% and 23.3% of the iron in the Fe²⁺ state for the respective fluences). The Fe 2p_3/2 peak has moved from a binding energy of 710.3 eV to a binding energy of 711.7 eV after a fluence of 2.9 $\times$ 10¹⁸ He⁺ cm^-2.
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In the text

$\begin{figure} \par\includegraphics[width=7.75cm,clip]{8964fig4}\end{figure}$ Figure 4: Detail XPS spectra of the Fe 2p region showing a reduction of the iron species. The sample was irradiated with He⁺ at 4 keV and 1.1 $\times$ 10¹⁵ ion cm^-2 s^-1. A progressive reduction of the iron is indicated by the formation and development of the peak characteristic of the Fe⁰ state at 706.3 eV and a decrease of the Fe²⁺ peak: a) before the irradiation, Fe²⁺ is the dominant state present, b) 6.7 $\times$ 10¹⁷ He⁺ cm^-2, c) 23 $\times$ 10¹⁷ He⁺ cm^-2 and d) 38.6 $\times$ 10¹⁷ He⁺ cm^-2.
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In the text

$\begin{figure} \par\includegraphics[width=7.75cm,clip]{8964fig5}\end{figure}$ Figure 5: Evolution of the normalised area ratio, relative to Si 2p, as a function of the fluence. The olivine sample was irradiated by He⁺ at 4 keV (normal incidence) and with a flux of 4 $\times$ 10¹⁴ ions cm^-2 s^-1. The main observed effect is an increase in the Mg 1s/Si 2p ratio, which is associated with magnesium segregation at the surface.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig6}\end{figure}$ Figure 6: AFM images: a) before irradiation, b) in the center of the irradiated area after He⁺ irradiation (4 keV, fluence 1.1 $\times$ 10¹⁹ ions cm^-2), c) on the periphery of the irradiated area after He⁺ irradiation (4 keV, fluence 1.1 $\times$ 10¹⁹ ions cm^-2) and d) after He⁺ irradiation (1 keV, fluence 4.8 $\times$ 10¹⁸ ions cm^-2).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig7}\end{figure}$ Figure 7: AFM image ( top) and roughness profile across the interface along the black line ( bottom). The roughness of the irradiated area has increased by a factor of two.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig8}\end{figure}$ Figure 8: AFM image of the olivine surface irradiated with Ar⁺, at 1 keV and a fluence of 3.6 $\times$ 10¹⁶ ions cm^-2: a) just after irradiation and b) after one week of exposure to air.
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In the text

$\begin{figure} \par\includegraphics[width=7.7cm,clip]{8964fig9}\end{figure}$ Figure 9: XPS spectra of the C 1s region: a) after thermal annealing under an O₂ atmosphere, a weak carbon contamination band at a binding energy of. 285 eV is still present (dotted line), b) after thermal annealing under O₂ atmosphere and Ar⁺ irradiation, c) non-irradiated sample after exposure to a CO₂ atmosphere and d) irradiated sample after CO₂ atmosphere exposure, a peak at the binding energy 290 eV is formed (dashed line).
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In the text

$\begin{figure} \par\includegraphics[width=7.7cm,clip]{8964fig1}\end{figure}$	Figure 1: Photoelectron spectrum of the San Carlos olivine before irradiation over a wide energy range. The peaks corresponding to C 1s, O 1s, Si 2p, Mg 1s, Mg 2p and Fe 2p_3/2 core levels and the Auger structure (O KLL, Mg KLL) are indicated.
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$\begin{figure} \par\includegraphics[width=7.75cm,clip]{8964fig5}\end{figure}$	Figure 5: Evolution of the normalised area ratio, relative to Si 2p, as a function of the fluence. The olivine sample was irradiated by He⁺ at 4 keV (normal incidence) and with a flux of 4 $\times$ 10¹⁴ ions cm^-2 s^-1. The main observed effect is an increase in the Mg 1s/Si 2p ratio, which is associated with magnesium segregation at the surface.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig6}\end{figure}$	Figure 6: AFM images: a) before irradiation, b) in the center of the irradiated area after He⁺ irradiation (4 keV, fluence 1.1 $\times$ 10¹⁹ ions cm^-2), c) on the periphery of the irradiated area after He⁺ irradiation (4 keV, fluence 1.1 $\times$ 10¹⁹ ions cm^-2) and d) after He⁺ irradiation (1 keV, fluence 4.8 $\times$ 10¹⁸ ions cm^-2).
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig7}\end{figure}$	Figure 7: AFM image ( top) and roughness profile across the interface along the black line ( bottom). The roughness of the irradiated area has increased by a factor of two.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{8964fig8}\end{figure}$	Figure 8: AFM image of the olivine surface irradiated with Ar⁺, at 1 keV and a fluence of 3.6 $\times$ 10¹⁶ ions cm^-2: a) just after irradiation and b) after one week of exposure to air.
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