HiRISE | Sulfate Deposits in Iani Chaos (ESP_092877

NASA/JPL-Caltech/UArizona

Sulfate Deposits in Iani Chaos
ESP_092877_1780 Science Theme:

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This HiRISE image shows light-toned layered deposits within Iani Chaos. Many of the same deposits occur within the depressions of Iani Chaos, as well as several nearby similar regions like Aram and Aureum Chaos.

The chaos regions are thought to have formed when large volumes of water at the surface and within the subsurface were catastrophically released from confined regions, causing collapse of the terrain to form broken blocks and fractured mounds and mesas. The light-toned deposits later filled in larger gaps between the chaos blocks, including the deposit in this HiRISE image. Many of these light-toned layered deposits in the chaos regions have sulfate signatures as detected in CRISM data, indicating they formed by water activity.

Written by: Cathy Weitz (22 September 2026)

This is a stereo pair with ESP_084847_1780.

Acquisition date
20 May 2026

Local Mars time
14:34

Latitude (centered)
-1.829°

Longitude (East)
344.132°

Spacecraft altitude
271.5 km (168.7 miles)

Original image scale range
57.4 cm/pixel (with 2 x 2 binning) so objects ~172 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
19.4°

Phase angle
61.2°

Solar incidence angle
43°, with the Sun about 47° above the horizon

Solar longitude
285.7°, Northern Winter

For non-map projected images
North azimuth: 97°
Sub-solar azimuth: 330.5°

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USAGE POLICY
All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL-Caltech/UArizona

POSTSCRIPT
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.