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Aqueous Processes from Diverse Hydrous Minerals in the Vicinity of Amazonian-Aged Lyot Crater

Pan, Lu and Ehlmann, Bethany L. (2018) Aqueous Processes from Diverse Hydrous Minerals in the Vicinity of Amazonian-Aged Lyot Crater. Journal of Geophysical Research. Planets, 123 (7). pp. 1618-1648. ISSN 2169-9097. doi:10.1029/2017JE005461.

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Amazonian‐aged Lyot crater is the best‐preserved and deepest peak‐ring impact crater (diameter, D = 220 km) in the northern lowlands of Mars. Morphological features including scouring channels emanating from its ejecta and small channels within the crater have been examined previously to understand hydrological activity associated with the crater. In this study, we analyze images acquired by the Compact Reconnaissance Imaging Spectrometer for Mars on board the Mars Reconnaissance Orbiter to investigate the mineralogical record in Lyot and its surroundings, which are presently enriched in ground ice, to understand the associated aqueous processes, their relative timing, and a possible role for ground ice in hydrous mineral formation. We find diverse hydrous minerals, including Fe/Mg phyllosilicates, chlorite, illite/muscovite, and prehnite in Lyot crater walls, central peak, and ejecta, as well as in two craters to the west of Lyot. The exposure and distribution of the hydrous minerals suggest that they are related to the impact process, either exposed by the excavation of hydrothermally altered rocks or formed through syn‐depositional hydrothermal alteration immediately after impacts. The Lyot impact induced channel formation to the north, but no mineralogical evidence of aqueous alteration associated with the channels is observed. The sinuous channels within Lyot, diverted by bedrock units with hydrous mineral detections, did not cause mineralization but likely represent the last stage of water activity in Lyot crater. The separate episodes of water activity indicate flow of liquid water on Mars' surface during the Amazonian but limited to no aqueous alteration to generate hydrous minerals.

Item Type:Article
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URLURL TypeDescription
Pan, Lu0000-0002-8151-2125
Ehlmann, Bethany L.0000-0002-2745-3240
Additional Information:© 2018 American Geophysical Union. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. Received 9 OCT 2017; Accepted 24 MAY 2018; Accepted article online 31 MAY 2018; Published online 10 JUL 2018. All the imagery data presented in this work are archived on the Planetary Data System ( We acknowledge funding from NASA Mars Data Analysis Program grant NNX12AJ43G to B. L. E. and from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska‐Curie grant agreement 751164 to L. P. The manuscript was greatly enhanced by reviews from L. Ojha and an anonymous reviewer. We thank the CRISM team for targeting and providing the data set. We would also like to thank Jeffrey Plaut for sharing the map for SHARAD ice detection in Deuteronilus Mensae, and Jay Dickson for the help in processing the CTX mosaic.
Group:Astronomy Department
Funding AgencyGrant Number
Marie Curie Fellowship751164
Subject Keywords:Mars remote sensing; Hydrous minerals; Amazonian climate; Impact cratering
Issue or Number:7
Record Number:CaltechAUTHORS:20180601-131750060
Persistent URL:
Official Citation:Pan, L., & Ehlmann, B. L. (2018). Aqueous processes from diverse hydrous minerals in the vicinity of Amazonian‐aged Lyot crater. Journal of Geophysical Research: Planets, 123, 1618–1648.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86745
Deposited By: Tony Diaz
Deposited On:01 Jun 2018 20:40
Last Modified:15 Nov 2021 20:41

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