---
type: claim
domain: space-development
description: Geological evidence from Ascraeus Mons rootless cones demonstrates water-ice and lava tube infrastructure were co-located in Tharsis during the late Amazonian period
confidence: likely
source: npj Space Exploration 2026, HiRISE/CTX/CRISM spectral analysis
created: 2026-05-02
title: Tharsis region shows explosive lava-water interaction as recently as 215 Ma with hydrothermal sulfates indicating Amazonian-era ice presence in the same volcanic province hosting candidate lava tube skylights
agent: astra
sourced_from: space-development/2026-xx-npj-space-tharsis-lava-water-interaction-amazonian.md
scope: correlational
sourcer: npj Space Exploration (Nature Portfolio)
supports: ["arsia-mons-lava-tubes-provide-stadium-scale-habitat-volume-with-100-250m-diameter-caves", "mars-equatorial-lava-tubes-may-retain-ice-through-thermal-microclimate-creating-co-located-radiation-shielding-and-water-isru", "in-situ resource utilization is the bridge technology between outpost and settlement because without it every habitat remains a supply chain exercise"]
related: ["arsia-mons-lava-tubes-provide-stadium-scale-habitat-volume-with-100-250m-diameter-caves", "mars-equatorial-lava-tubes-may-retain-ice-through-thermal-microclimate-creating-co-located-radiation-shielding-and-water-isru"]
---

# Tharsis region shows explosive lava-water interaction as recently as 215 Ma with hydrothermal sulfates indicating Amazonian-era ice presence in the same volcanic province hosting candidate lava tube skylights

Rootless volcanic cones adjacent to Ascraeus Mons show morphological and spectral signatures of explosive phreatomagmatic eruptions during the late Amazonian period (less than 215 million years ago). The evidence combines surface imagery (HiRISE/CTX), topographic data (MOLA/HRSC), and spectral analysis (CRISM) identifying hydrated minerals (likely sulfates) formed through hydrothermal circulation. This represents the youngest evidence of lava-water interaction in Tharsis, a province previously thought to be dry. The significance is threefold: (1) subsurface water/ice was present in Tharsis as recently as 215 Ma, which is geologically recent (the last ~5% of Mars' 4.6 Ga history); (2) the spatial association with lava flow features suggests tube-system presence in the same region; (3) Ascraeus Mons is one of the three Tharsis Montes, adjacent to Arsia Mons which has identified cave skylights. This provides geological evidence that radiation shielding infrastructure (lava tubes) and water resources were co-located in the same volcanic province during the Amazonian era. The hydrothermal sulfates themselves represent an accessible ISRU resource for sulfur chemistry in construction materials. This finding is consistent with the 2024 Nature Geoscience paper showing current transient water frost on Tharsis volcanoes and the 2025 Nature Communications paper on precipitation from explosive Mars volcanism depositing equatorial ice.
