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32 results on '"Belgacem, Ines"'

2. Image processing for precise geometry determination

Author

Belgacem, Ines, Jonniaux, Grégory, and Schmidt, Frédéric

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Reliable spatial information can be difficult to obtain in planetary remote sensing applications because of errors present in the metadata of images taken with space probes. We have designed a pipeline to address this problem on disk-resolved images of Jupiter's moon Europa taken with New Horizons' LOng Range Reconnaissance Imager, Galileo's Solid State Imager and Voyager's Imaging Science Subsystem. We correct for errors in the spacecraft position, pointing and the target's attitude by comparing them to the same reference. We also address ways to correct for distortion prior to any metadata consideration. Finally, we propose a vectorized method to efficiently project images pixels onto an elliptic target and compute the coordinates and geometry of observation at each intercept point.

Published
2020
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3. Regional study of Europa's photometry

Author

Belgacem, Ines, Schmidt, Frédéric, and Jonniaux, Grégory

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Data Analysis, Statistics and Probability
Abstract

The surface of Europa is geologically young and shows signs of current activity. Studying it from a photometric point of view gives us insight on its physical state. We used a collection of 57 images from Voyager's Imaging Science System and New Horizons' LOng Range Reconnaissance Imager for which we corrected the geometric metadata and projected every pixel to compute photometric information (reflectance and geometry of observation). We studied 20 areas scattered across the surface of Europa and estimated their photometric behavior using the Hapke radiative transfer model and a Bayesian framework in order to estimate their microphysical state. We have found that most of them were consistent with the bright backscattering behavior of Europa, already observed at a global scale, indicating the presence of grains maturated by space weathering. However, we have identified very bright areas showing a narrow forward scattering possibly indicating the presence of fresh deposits that could be attributed to recent cryovolcanism or jets. Overall, we showed that the photometry of Europa's surface is more diverse than previously thought and so is its microphysical state., Comment: 46 pages, 17 figures, 3 tables

Published
2020
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5. Spotlight on Corporate Fraud: How Is Takaful Insurance Stability Affected by Its Disclosure?

Author

Hemrit, Wael and Belgacem, Ines

Subjects
GENERALIZED method of moments, FINANCIAL security, FRAUD, INSURANCE companies, TAKAFUL
Abstract

This study examines the influence of fraud disclosure (FR_DISC) in annual reports on the financial stability of Takaful insurance (TKI) in Saudi Arabia over the period of 2014 to 2022. Moreover, the current study aims to explore the mediating impact of Shariah board size in shaping this relationship using agency theory and examines whether the different Islamic governance attributes could affect this stability differently. Using the dynamic generalized method of moments (GMM) approach to address the possibility of endogeneity, it was found that FR_DISC is significantly negatively related to the financial stability of a sample TKI. We also provide evidence that the larger the size of a Shariah board, the less FR_DISC affects TKI stability. Furthermore, significant negative influence of ownership concentration and the proportion of non-executives' independent board members on the stability of insurance companies was also observed. Overall, our analysis reveals several significant challenges if accounting and whistleblowing are to contribute to financial stability. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Merging datasets for photometric study

Author

Belgacem, Ines, Schmidt, Frederic, Jonniaux, Grégory, Belgacem, Ines, Idex Paris-Saclay - - IPS2011 - ANR-11-IDEX-0003 - IDEX - VALID, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Airbus Defence and Space [Toulouse], Airbus Defence & Space, Toulouse, France and the French National re-search Agency (ANR) as part of the « Investissement d’Avenir » program, through the 'IDI 2016' project funded by the IDEX, and ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011)

Subjects
[PHYS.ASTR.EP] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Physics::Space Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology
Abstract

International audience; We have developed tools to study the photometry of Europa using a Bayesian approach. We merged datasets from New Horizons' LORRI and Voyager's ISS cameras to maximize coverage. We encountered issues of absolute calibration and compatibility of the data and we propose here a way to efficiently merge datasets from different cameras. We also propose a way to estimate correction coefficients for the absolute calibration of each individual image at the same time as the photometric behavior. We use here the Hapke model and realize a Bayesian inversion of the Hapke parameters on 20 areas of interest on Jupiter's moon Europa as well as correction coefficients for a collection of 57 images from LORRI and ISS.

Published
2019

18. Estimation of Hapke's Parameters on Selected Areas of Eurapa Using a Bayesian Approach

Author

Belgacem, Ines, Schmidt, Frédéric, Jonniaux, Grégory, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Airbus Defence and Space [Toulouse], Airbus Defence & Space, ToulouseFrench National re-search Agency (ANR) as part of the « Investissement d’Avenir » program, through the 'IDI 2016' project funded by the IDEX, ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), Belgacem, Ines, and Idex Paris-Saclay - - IPS2011 - ANR-11-IDEX-0003 - IDEX - VALID

Subjects
[PHYS.ASTR.EP] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology
Abstract

International audience; Exploring the icy satellites of the outer planets is a major step in the search for habitabil-ity in our Solar System. This work focuses on Jupiter’s icy moon Europa and the images captured by the Long-Range Reconnaissance Imager (LORRI) on-board the New Horizons spacecraft. Images of the surface were combined to derive photometric and reflectance models.

Published
2018

19. Etude photométrique des lunes glacées de Jupiter

Author

Belgacem, Ines, Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université Paris Saclay (COmUE), and Frédéric Schmidt

Subjects
Vision-based navigation, Inversion Bayésienne, Traitement d'images, Space technology, Callisto, Photométrie, Bayesian inversion, Reflectance, BRDF, Planétologie, Surface, Photometry, Europe, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Image processing, Navigation basée vision, Ganymede, Planetary science, Technologie spatiale, Réflectance, Europa, Ganymède
Abstract

Jupiter's icy moons are of great interest in the search for habitability in our Solar System. They probably all harbor liquid water ocean underneath their icy crust. Their surfaces present different stages of evolution – Callisto is heavily cratered and the oldest, Ganymede shows a combination of dark cratered terrain and younger bright plains and Europa’s surface is the youngest with signs of recent and maybe current activity. This work focuses on photometry, i.e. the study of the light scattered by a surface in relation to the illumination and observation geometry. Photometric studies give us insight on the physical state and microtexture of the surface (compaction, internal structure, shape, roughness, transparency…). A good photometric knowledge is also of crucial importance in the correction of datasets for any mapping or spectroscopic study as well as for the future missions of this decade – NASA’s Europa Clipper and ESA’s JUpiter ICy moons Explorer.Two pieces of information are necessary to conduct a photometric study – reflectance data and geometric information (illumination, viewing conditions). For the former, we have used and calibrated images from past space missions – Voyager, New Horizons and Galileo. For the latter, we have developed tools to correct these images metadata (e.g. spacecraft position and orientation) to derive precise geometric information. Moreover, we have developed a Bayesian inversion tool to estimate Hapke’s photometric parameters on regions of Europa, Ganymede and Callisto. We estimate all parameters on our entire dataset at once. Finally, we discuss the possible links between the photometric parameters, the surface microtexture and endogenic/exogenic processes.; Les satellites glacés de Jupiter sont d'un grand intérêt scientifique dans la recherche d'habitabilité au sein de notre système solaire. Elles abritent probablement toutes trois des océans d'eau liquide sous leur croûte glacée. Leurs surfaces présentent différents stades d’évolution – celle de Callisto est très ancienne et entièrement recouverte de cratères, celle de Ganymede est un mélange de terrains sombres et cratérisés et de plaines claires et plus jeunes et la surface d’Europa est la plus jeune et présente des signes d’activité récente. Cette thèse porte sur la photométrie, c’est à dire l’étude de l’énergie lumineuse réfléchie par une surface, en fonction des géométries d’éclairement et d’observation. Les études photométriques permettent de déterminer l’état physique et la microtexture des surfaces (porosité, structure interne, forme des grains, rugosité, transparence…). Une bonne connaissance photométrique est également d'une importance cruciale dans la correction des jeux de données pour toute étude cartographique ou spectroscopique ainsi que pour les futures missions de cette décennie : Europa Clipper de la NASA et JUpiter ICy Moons Explorer de l’ESA.Deux types d’information sont nécessaires pour réaliser une étude photométrique : des données de réflectance et des données géométriques (conditions d’illumination et d'observation). Pour obtenir les premières, nous avons utilisé et calibré des images de missions spatiales passées - Voyager, New Horizons et Galileo. Pour obtenir les secondes, nous avons développé des outils permettant de corriger les métadonnées de ces images (ex : la position et l'orientation des sondes) afin d’obtenir des informations géométriques précises. Nous avons, d’autre part, développé un outil d’inversion pour estimer les paramètres photométriques de Hapke sur des régions d’Europa, Ganymede et Callisto sur l’ensemble du jeu de données en un seul calcul. Enfin, nous discutons des liens possibles entre les paramètres photométriques estimés, la microtexture de la surface et les processus endogènes/exogènes mis en jeu.

Published
2019

20. A new look at Europa's photometry in preparation of the JUICE mission

Author

Belgacem, Ines, Schmidt, F., Jonniaux, Grégory, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Airbus Defence and Space [Toulouse], Airbus Defence & Space, Toulouse, FranceFrench National re-search Agency (ANR) as part of the « Investissement d’Avenir » program, through the 'IDI 2016' project funded by the IDEX, and ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

21. Photometric study of Europa with Hapke model

Author

Belgacem, Ines, Schmidt, Frederic, Jonniaux, Grégory, Belgacem, Ines, Idex Paris-Saclay - - IPS2011 - ANR-11-IDEX-0003 - IDEX - VALID, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Airbus Defence and Space [Toulouse], Airbus Defence & SpaceFrench National re-search Agency (ANR) as part of the « Investissement d’Avenir » program, through the 'IDI 2016' project funded by the IDEX, and ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011)

Subjects
[PHYS.ASTR.EP] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology
Abstract

International audience; In the context of ESA's future mission JUICE, this work is the start of a broad investigation on the reflectance models of Jupiter's icy moons. It focuses on Europa and Hapke photometric model using images from the LORRI instrument on New Horizons. The parameters are estimated using a Bayesian approach that has been developed for similar work on Mars. We show that it is possible to constrain Hapke parameters on restricted areas of Europa and that they can be fairly different depending on the regions of interest. However, this study shows limitations that we hope to overcome by including more data from other missions such as Voyager.

Published
2018

22. Towards photometry of Europa

Author

Belgacem, Ines, Schmidt, F., Jonniaux, G., Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Airbus Defence and Space [Toulouse], Airbus Defence & Space, Toulouse, FranceFrench National re-search Agency (ANR) as part of the « Investissement d’Avenir » program, through the 'IDI 2016' project funded by the IDEX, ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), Belgacem, Ines, and Idex Paris-Saclay - - IPS2011 - ANR-11-IDEX-0003 - IDEX - VALID

Subjects
[PHYS.ASTR.EP] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology
Abstract

International audience; Exploring the icy satellites of outter planets is a major step in the search for habitability in our Solar System. This work focuses on Jupiter's icy moon Europa and the images captured by the Long-Range Reconnaissance Imager on-board the New Horizons spacecraft. It is aimed at combining images of the satellite in order to derive photometric reflectance models (i.e. angular response of a surface). It will later be extended to the other two icy Jovian satellites, Ganymede and Callisto and larger data sets.

Published
2017

25. A buried aeolian lag deposit at an unconformity between the Murray and Stimson formations at Marias Pass, Gale Crater, Mars

Author

Newsom, H., Edgett, K, Fey, D, Wiens, R., Frydenvang, J., Banham, S, Gupta, S., Williams, A. J., Grotzinger, J., Mangold, N., Schieber, J., Rivera-Hernandez, F, Belgacem, Ines, The University of New Mexico [Albuquerque], Malin Space Science Systems (MSSS), Los Alamos National Laboratory (LANL), University of Copenhagen = Københavns Universitet (KU), Imperial College London, Towson University [Towson, MD, United States], University of Maryland System, California Institute of Technology (CALTECH), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Department of Geological Sciences [Bloomington], Indiana University [Bloomington], Indiana University System-Indiana University System, University of California [Davis] (UC Davis), University of California, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and University of California (UC)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

27. ASK Space.

Author

van der Horst, Alexander, Brown, Daniel, Alston, William, Delhaize, Jacinta, Veras, Dimitri, Dartnell, Lewis, and Belgacem, Ines

Published
2021

28. Recent observations by Curiosity's Mars Hand Lens Imager (MAHLI) of rock strata and eolian sediment on the lower north slope of Aeolis Mons, Gale Crater, Mars

Author

Edgett, Kenneth S., Yingst, R, Edgar, L. A., Gasda, P., Banham, S, Grotzinger, J., Newsom, H., Bridges, N., Watkins, J, Herkenhoff, K., Minitti, M., Kennedy, M, Krezoski, G, Fey, D, Belgacem, Ines, Gupta, S., Kah, L, Lewis, K, Mcbride, M., Schieber, J., Stack, K., Williams, R, Malin Space Science Systems (MSSS), Los Alamos National Laboratory (LANL), California Institute of Technology (CALTECH), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Becker Technology, BC Cancer Research Centre, BC Cancer Agency (BCCRC), Department of Geological Sciences [Bloomington], Indiana University [Bloomington], Indiana University System-Indiana University System, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

29. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

Author

Clegg, Samuel M., primary, Wiens, Roger C., additional, Anderson, Ryan, additional, Forni, Olivier, additional, Frydenvang, Jens, additional, Lasue, Jeremie, additional, Cousin, Agnes, additional, Payré, Valérie, additional, Boucher, Tommy, additional, Dyar, M. Darby, additional, McLennan, Scott M., additional, Morris, Richard V., additional, Graff, Trevor G., additional, Mertzman, Stanley A., additional, Ehlmann, Bethany L., additional, Belgacem, Ines, additional, Newsom, Horton, additional, Clark, Ben C., additional, Melikechi, Noureddine, additional, Mezzacappa, Alissa, additional, McInroy, Rhonda E., additional, Martinez, Ronald, additional, Gasda, Patrick, additional, Gasnault, Olivier, additional, and Maurice, Sylvestre, additional

Published
2017
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30. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

Author

Clegg, Samuel M., Wiens, Roger C., Anderson, Ryan B., Forni, Olivier, Frydenvang, Jens, Lasue, Jeremie, Cousin, Agnes, Payre, Valerie, Boucher, Tommy, Dyar, M. Darby, McLennan, Scott M., Morris, Richard V., Graff, Trevor G., Mertzman, Stanley A., Ehlmann, Bethany L., Belgacem, Ines, Newsom, Horton, Clark, Ben C., Melikechi, Noureddine, Mezzacappa, Alissa, Mclnroy, Rhonda E., Martinez, Ronald, Gasda, Patrick, Gasnault, Olivier, Maurice, Sylvestre, Clegg, Samuel M., Wiens, Roger C., Anderson, Ryan B., Forni, Olivier, Frydenvang, Jens, Lasue, Jeremie, Cousin, Agnes, Payre, Valerie, Boucher, Tommy, Dyar, M. Darby, McLennan, Scott M., Morris, Richard V., Graff, Trevor G., Mertzman, Stanley A., Ehlmann, Bethany L., Belgacem, Ines, Newsom, Horton, Clark, Ben C., Melikechi, Noureddine, Mezzacappa, Alissa, Mclnroy, Rhonda E., Martinez, Ronald, Gasda, Patrick, Gasnault, Olivier, and Maurice, Sylvestre

Abstract

The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the, spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides (SiO2, TiO2, A1(2)O(3), FeOT, MgO, CaO, Na2O, K2O), have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with a calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was significantly over-estimated by the previous model, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. The uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data. (C) 2017 Elsevier B.V. All rights reserved.

Published
2017

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