Diverse Volcanism and Volcanotectonics on Ancient Mars

Professor Michalski, Joseph Ryan   (Principal Investigator (PI))

60

2024-01-01

5155380

Diverse Volcanism and Volcanotectonics on Ancient Mars

Volcanism, Plate tectonics, Mars, Continents, Space Exploration

Planetary SciencesEarth Sciences

Physical Sciences (P)

RFS2324-7S02

RGC Research Fellow Scheme (RFS) 2023/24

2023

On-going

1. Why perform this project? Plate tectonics is the dominant process governing all of Earth’sgeology, but we do not understand how it started because most of the ancient crust on thisplanet has been lost to erosion and crustal recycling. A recognizable form of modern platetectonics took hold on Earth c.a. 3 billion years ago, but before this time there would havebeen various forms of volcano-tectonic processes resulting in crustal formation andresurfacing that ultimately led to plate tectonics. While those geological clues are lost onEarth, they may be preserved on Mars, where~70% of the crust is >3 billion years old and~45% of the crust is >3.6 billion years old. A fundamental question is: what volcanotectonicprocesses operated in the first billion years of martian geologic history and whatcan those processes teach us about the same period of time on Earth?2. Why this project? Volcanism is one of the fundamental geological processes in the solarsystem. Catastrophic or gradual volcanic resurfacing is the primary mechanism throughwhich planets lose their heat. Magmatism and crustal evolution resulted in continents onthis planet, but it is unclear if evolved (felsic) crust ever formed on Mars (or other planets).Furthermore, the most ancient period of volcanism on Mars remains a mystery. Whilemodels of magmatism and heat loss correlate with observed volcanism for the most recent~3.5 billion years, model-predicted and empirically observed evidence for volcanismdramatically diverge for the period >3.5 billion years ago, termed the Noachian on Mars.It is possible that our concept of the style and type of ancient volcanism for Mars is flawed.This work will challenge the paradigm of ancient martian volcanism, and these results willby analogy shine light on early forms of volcanism on Earth.3. Problems addressed: This proposed work will explore and quantify early (>3 billion yearsold) volcanism and resurfacing on Mars through systematic morphometric andmorphological analysis of ancient volcanic structures. Preliminary results reveal 60-100newly identified, diverse volcanic structures such as domes, stratovolcanoes, pyroclasticsshields and calderas. Morphometrics reveal height-diameter trends for a diverse quite ofunderrecognized volcanic structures such as domes, stratovolcanoes, pyroclastic shieldsand calderas. Infrared remote sensing shows that some of these structures have silica-rich,dacitic compositions thought to be unusual or effectively nearly absent on Mars – but thiswork shows they are likely more common than expected. This project will reveal newinformation about volcanic diversity, resurfacing and crustal evolution on Mars.4. Problems addressed: Volcanic structures will be placed into a geotectonic context throughsystematic mapping of tectonic structures, especially thrust faults (compressional), rifts(extensional) and transtensional or transpressional (oblique) structures. Preliminary resultsshow some interesting spatial associations between volcanism, crustal shortening andtranstensional basins. Indicators of fault offset such as craters overthrust by thrust faultswill be used to determine minimum offset.5. Outcomes: The work proposed here goes far beyond systematic mapping of volcanicfeatures on Mars. This project has a good chance to produce transformative research resultsthat would shift or break the current paradigms about volcanic processes and crustalevolution on Mars, especially in the first billion years of the planet’s history. Specifically,this work presents an opportunity to reveal styles of volcanism when crustal heat flow washigher, evidence for formation of felsic crust through diverse volcanism, and associationsbetween volcanoes and tectonic features that could have been an early stage of volcanotectonics,analogous to what ultimately became plate tectonics on this planet.6. Outcomes: The morphometric data produced in this study will shed new light on formationof volcanic landforms and structures in lower gravity, and under lower atmosphere