Martian Groundwaters Through Time and Their Impact on the Mars System: an Appraisal Bethany L

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Martian Groundwaters Through Time and Their Impact on the Mars System: An Appraisal Bethany L. Ehlmann, California Institute of Technology

Note added: This slide package was presented at the Ninth International Conference on Mars and is being shared, with permission from the plenary presenter. The original file has been compressed in size and converted to .pdf – please contact the presenter if interested in the original presentation.

HiRISE false color, mineralized boxwork in the Nili Fossae Noachian Basement Paleohabitats of Ancient Mars

oxygenation

Amador & Ehlmann, in press, Astrobiology (U. Arizona Press) Paleohabitats of Ancient Mars Obliquity changes force frequent climate changes generates 500-kyr intermittency of habitability, oxygenationimportant for surface environments

Earth Mars

~1° causes ice ages 10° - 60° Mars

Laskar et al., 2004, Icarus

Amador & Ehlmann, in press, Astrobiology (U. Arizona Press) Paleohabitats of Ancient Mars

oxygenation

Amador & Ehlmann, in press, Astrobiology (U. Arizona Press) Paleohabitats of Ancient Mars

oxygenation

NASA/JPL/JHUAPL/MSSS/BROWN UNIVERSITY EUNGCHOPAN/ISTOCK/THINKSTOCK

Mars’ late valleys and deltas are like charismatic megafauna

Important, likeable, and relateable But there is also a whole (eco)system in the background that is equally or more important Paleohabitats of Ancient Mars

oxygenation

by Dana Berry for National Geographic

Martian groundwaters played– and may still play a crucial role – in • Water availability and geochemical cycling • Climate • Providing habitats for life (and thus should be targets in the search) New Information Since 8th Mars Conference (July 2014) • orbital datasets (new images, new analyses) • in situ exploration • novel modeling • a growing understanding of the geobiology and preservation of subterranean ecosystems on Earth New Information Since 8th Mars Conference (July 2014) • orbital datasets (new images, new analyses) Part 1: Paleo • in situ exploration • novel modeling • a growing understanding of the geobiology and preservation of subterranean ecosystems on Earth Groundwater habitats – with clear surface connectivity

Silica hot springs Alkaline Springs in Lakes Acid Springs in Lakes/Playas

alunite

kaolinite

Carbonate(serpentine?)/ Nili Patera smectite 500 m Skok et al., 2010, Nat. Geo. Michalski et al., 2014, Nat Geo; 2019, JGR

10 cm

McLaughlin Crater

Andrews-Hanna et al., 2010, JGR; Home Plate, Gusev Wray et al., 2011, JGR; Ehlmann, Arvidson et al., 2010, JGR Swayze et al., 2016, Am. Min. Fumarole/Sinter System at Home Plate, Gusev like El Tatio, Chile

Ruff et al., 2016, Nat. Comm. Some Terra Sirenum Acid Lakes Deposits have a Groundwater Connection to a Magma Source

kaolinite-alunite sediments Leask et al., 2019, LPSC; in prep. Some Terra Sirenum Acid Lakes Deposits have a Groundwater Connection to a Magma Source

1 km

Leask et al., 2019, LPSC; in prep. Some Terra Sirenum Acid Lakes Deposits have a Groundwater Connection to a Magma Source

1 km

Leask et al., 2019, LPSC; in prep. Groundwater habitats – surface connectivity not fully known

Impact crater central peaks Fe/Mg smectite ridges in Jarosite ridges at NE Syrtis (zeolites, chlorites) Noachian terrains, Nili Fossae

2 km 500 m 1 km Ehlmann et al, 2009, JGR; Marzo et Mustard et al., 2009, JGR; Saper & Ehlmann & Mustard, 2012, GRL; al., 2010, Icarus, Mangold et al., Mustard, 2013, GRL; Pascuzzo et al., Quinn & Ehlmann, 2019, JGR 2012, PSS; Sun & Milliken, 2015, JGR 2019, Icarus

Carbonate, serpentine Ca sulfate, clay, oxide Hematite-sulfate mineralization

10 cm 5 mm

Ehlmann et al., 2010, GRL; Leveille et al., 2012; Siebach et Grotzinger et al., 2005; McLennan et Ehlmann & Mustard, 2012, GRL; al., 2014; Stack et al., 2014; al., 2005; Tosca et al., 2005 Viviano-Beck et al., 2013, JGR Nachon et al., 2014; Multiple generations, multiple chemistries of fluid flow in Gale basin

from R. Kornyak, GSA, 2015; AGU, 2015 from Kornyak et al., 2019, Earth & Space Sci Multiple generations, multiple chemistries of fluid flow in Gale basin

from Kornyak et al., 2019, Earth & Space Sci Multiple generations, multiple chemistries of fluid flow in Gale basin

Intruding veinlets and rip up from Kornyak et al., 2019, Earth & Space Sci clasts suggest a history: (1) sediment deposition (lacustrine); (2) gray vein precipitation (Mg- rich); (3) second generation injection of Ca sulfates by higher fluid pressures, crystallization pressure-driven fracturing (4) Third (or second) generation of Fe‐,K‐, and F‐rich dark‐toned veins

• Drivers of diversity? Drivers of change/episodicity? • The relative influences of weathering, magmatic volcanic volatiles, and subsurface magmatic sources in contributing to groundwater chemistry is a key open issue, even at the landing sites. Multiple Generations of Groundwater in the Gale basin after Gale Lake, incl. Amazonian

3 wt. % jarosite in Mojave:

→Diagenesis with liquid water in the Amazonian

Martin et al., 2017, GRL Kah et al., 2018, Terra Nova Huge Hesperian Groundwater-Formed in Acid Environment, Northeast Syrtis

Quinn & Ehlmann, 2019, JGR

Scene ~3 km wide with 400 m of relief Huge Hesperian Groundwater-Formed in Acid Environment

Quinn & Ehlmann, 2019, JGR

Jarosite-filled fractures in sulfate sedeiments

Scene ~3 km wide with 400 m of relief Huge Hesperian Groundwater-Formed in Acid Environment

Quinn & Ehlmann, 2019, JGR

Then filling fracturing

Scene ~3 km wide with 400 m of relief New Information Since 8th Mars Conference (July 2014) • orbital datasets (new images, new analyses) • in situ exploration • novel modeling • a growing understanding of the geobiology and preservation of subterranean ecosystems on Earth Groundwater Implications: Habitability

Paleorecord of environments with water, energy, nutrients

• Radiolytic H2 • Chemolithoautotrophic (H2, CH4, sulfur redox, iron redox)

Tarnas et al., 2018, EPSL and this conf. (also Onstott et al., 2006, Astrobio.) Gas production from subsurface water Rock Reactions

NASA/JPL-Caltech/MSSS Gas production from subsurface water Rock Reactions

Bristow et al., 2015, Am. Min.

Tosca et al., 2018, Nat. Geo.

NASA/JPL-Caltech/MSSS Groundwater implications: climate and geochemical cycles

Wordsworth et al., 2017, GRL (also Chassefiere & LeBlanc, 2011; Kite et al., 2018, Nat. Geo.; Turbot, Forget et al., this conf.) Questions: • Rates of production, release, loss, transformation of warming gases • Their warming impact • Reduced gases coupled with other phenomena (obliquity, volcanic aerosols, ice aerosols, impacts) New Information Since 8th Mars Conference (July 2014) • orbital datasets (new images, new analyses) • in situ exploration • novel modeling • a growing understanding of the geobiology and preservation of subterranean ecosystems on Earth Subsurface life is abundant when you know where to look General cells/gram decrease with increasing depth and temperature, and decreasing porosity BUT are highly variable.

Energy flux across chemical redox interfaces and physical interfaces play a significant part in explaining high biomass occurrences.

They do not correlate with rock type or water saturation or organic carbon content Magnabosco et al., 2018, Nat. Geosci.; Onstott et al., 2019, Astrobiology

Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 28 Where is rock-hosted life thriving?

• Follow the interfaces – Permeability – Redox

107 cells/cm2 Rock hosted life thrives off of chemical 3 5 and 10 - 10 physical cells/gram gradients focused by fractures where reactants and products can exchange over long time scales

Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 29 Ex. #1: Buried Chesapeake Impact Structure

• Typical decline in biomass Modern seafloor seds. with depth in seafloor sediments reverses in permeable impact-fractured rocks

• Strategy: Follow the Buried permeability! seafloor seds. (products of 2-3 order of photosynthate consumed) magnitude increase in cell No cell counts in count in granite block permeable impacted Impact- bedrock fractured rock Cockell et al., 2009, GSA 0.5x104 special pub. Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 30 Example: Modern Clay/Fe-ox. Mineralization in Icelandic Basalt

Trias et al, 2017, Nat Comm. (Suppl) Fluorescence showing DNA In the Holocene Hellisheidi cores through Feed-zones (made of fracture and rubbles) Icelandic basalt, microbial cells are provided flow pathway for CO2 charged associated with clay minerals and Fe oxides ground waters in vesicles Dissolving the rock and feeding microbes (including iron-oxidizers) with aromatic Microbial activity facilitates the creation of compounds and metals 20 µm permeability by dissolution of primary Cells found in Fe oxides, clay minerals materials (contrast with the “self-sealing” idea of mineralization in hydrothermal systems)

Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 31 Ex. #2: Oman Olivine-Carbonate Preserved Biomass

Isotopic and organic biosignatures (lipids) preserved in carbonates 13 Diagnostically heavy in δ C- from carbon limitation Hydroxyarchaeol with PE headgroup Squalene δ13C ~ 14‰

Archaeal Methanogen lipid-derived hydrocarbons intact lipids

PMI δ13C ~ 10‰

Rempfert et al. (in prep) Intact polar lipids captured in precipitating retention carbonate, Samail Ophiolite, Oman Extracted hydrocarbons Biomarker: Bacterial (sulfate-reducer?) core lipids ~100 Ma, Preservation of Terrestrial carbonated lipid degradation products in serpentinites, carbonate veins from a Chimaera seeps, Turkey fossilized serpentinizing SE serpentine system, Iberian Margin V carbonate vein Klein et al. (2015) (for more detail, see Extras) Zwicker et al. (2018) slide provided by A. Templeton, K. Rempfert Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 32 Example: Ancient Biosignatures of Rock-Hosted Life: ~120Ma Deep Carbonate/Serpentine-Hosted

>700m deep

Lipid analysisstandard

samples Klein et al. 2015, PNAS standard Fossil Lost City Hydrothermal standard System, deep rocks. 125 - 113Ma) Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 33 The Strategy for Biosignatures: How to Find Rock Hosted Life on Mars Step Spatial Scale Key Measurement Requirements 1. Identify rocks with <100 m Ability to identify water-related mineral Orbital data, incl. ancient subsurface sampling deposits from orbit, determine Midway, NE Syrtis habitats stratigraphic context just outside Jezero 2. Locate interfaces that Meter- to cm- Ability to identify redox and permeability represent favorable scale interfaces by identification of distinct In situ remote locations for rock life lithologic units sensing

3. Search for Centimeter- and Ability to identify silica, carbonate, In situ remote mineralization from fluid millimeter-scale sulfate, phyllosilicate, and oxides that sensing flow at interfaces may mineralize microbial life 4. Search for organics, <100 μm Ability to detect organics, chemical, mineralization, and sampling mineralogic, and/or isotopic differences In situ isotopic anomalies at the between interface rocks and surrounding petrology interface rocks indicative of biosignatures 5. Map putative <1 μm sampling Ability to identify microbial textures and biosignatures in 3- in 3-D distinguish biotic and abiotic processes Sample dimensions, tracking to definitively confirm fossil rock-hosted Return chemical and organic life variations with texture rover icon made by Freepik from www.flaticon.com - thanks! Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 34 Could rock-hosted life be preserved at Mars 2020 sites? Yes! With multiple opportunities!

Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 35 Conclusions: Paleo-Rock Hosted Life

Why focus the search on rock-hosted life on Mars? • Mars is different from Earth and its specific geologic history suggests the best places for life are the longest-lived stable habitats: groundwater aquifers Is there enough subsurface life that Mars-2020 could find? • Yes! Found on Earth at >106 cells/cm3 (SHERLOC threshold: 103); also lipid, isotopic, morphologic evidence in returned samples

Is there a search strategy to direct the rovers? Yes! • Follow the interfaces (redox, permeability) to find the highest concentrations of organic matter. Measure in situ or in returned samples

Onstott, Ehlmann et al. 2019, Astrobiology www.liebertpub.com/doi/pdf/10.1089/ast.2018.1960 - 36 New Information Since 8th Mars Conference (July 2014) • orbital datasets (new images, new analyses) Part 2: Modern • in situ exploration • novel modeling • a growing understanding of the geobiology and preservation of subterranean ecosystems on Earth Activity (and Habitats?) on Modern Mars: Hints of Methane Great panel, talks, posters, this conf. And now ~20 ppb. Modern Aquifers? RSLs Great panel, talks, posters, this conf. Timing and temperature could be consistent with a role for liquid water (Stillman et al., 2014, Icarus; McEwen et al., 2014, Nat. Geosci.) or deliquescence but rechardge is challenging

Thermal infrared measurements placed a very small upper bound on water content (Edwards & Piqueux, 2016, GRL)

Reanalysis of spectra showed original perchlorate detections were likely and caused by an artifact of on-the-ground CRISM data processing (Ojha et al., 2015, Nat. Geosci.; Leask et al., 2018, GRL; Vincendon et al., 2019, Icarus)

The timing and style of RSL emplacement is consistent with dust avalanching (Dundas et al., 2017, Nat. Geosci.)

Needed: multiple time of day, IR water detection at small pixel size NASA/Caltech-JPL/U Arizona Modern Aquifers? Polar subsurface lakes? Separately, diurnal magnetic field variation from InSight due to An underground water? Russell et al., this conf pond?

Radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials

Orosei et al., Science, 2018

perchlorate ice mixes

90 mW/m2 Challenges with regard to geothermal gradient, unless a local magmatic source Sori & Bramson et al., 2019, GRL

Many bright Plaut et al., 2007, Science reflectors too explain Martian Groundwaters: Key Findings, Key Questions, Needed Measurements and Models

1. Why were there • Partial progress possible from groundwaters? What orbit (e.g., higher res controlled the geography, MIR+SWIR mineralogy) but timing, and chemistry? landed missions demanded for 2. Much of mineral final answers formation was ancient but • → Demands high resolution how much was recent petrology (mineralogy + (Amazonian), driven by texture), isotopes and age overprinting dating from multiple landed groundwaters? missions (or multiple sample 3. How did communication returns) between the surface and • New geophysical detection subsurface influence the approaches for modern Mars climate system via groundwaters? Followup RSL for shallow aquifers? Essential pre-cursor volatile sequestration and prior to any Mars deep drilling release? investigation) 4. Is there groundwater • Modeling/experiment on ice-water today in hidden aquifers? transitions in modern climate regimes Outstanding questions

• Exploration demands in situ petrography for minerals, chemistry, isotopes, organics, and their textural relations [41]. For the paradigm-altering search for life on Mars, an exploration strategy that targets ancient subsurface life and scales spatially may stand the best chance for finding life on Mars. Efforts should focus initially on identifying rocks with evidence for groundwater flow and low-temperature mineralization, then identifying redox and permeability interfaces preserved within rock outcrops, and finally focusing on finding minerals associated with redox reactions and associated carbon and diagnostic chemical and isotopic biosignatures. This approach on Earth yields preserved life. Deep drilling is unnecessary as the outcrops preserving Mars’ ancient subsurface habitable environments are exposed by tectonics and refreshed today by modern wind erosion. They are there for ready exploration by landed missions and human explorers. Key Investigations for Early Mars

Mars Rock Record Allows Examination of these crucial questions • Petrology at Multiple Sites: How frequently was there liquid water on Mars and in What environments? • Follow the Volatiles to Track Geochemical and Climate Change: Inventories, Isotopes, and Submeter Scale Stratigraphies • Isotopes in the rock record track atmospheric loss identify atmospheric gas constituents • Timing is Everything: Understanding of Processes on Mars and Across the Inner Solar System by Measuring Ages • On Mars, can access stratigraphies before and after the magnetic field decline, before/after impacts, relative to stellar evolution and at different points in atmospheric loss • The Coupling of Interior and Surface Evolution

As on Earth, different time periods and are environments accessible at different geographical locations, single site sample return is insufficient alone to address all key questions posed here. Reconnaissance and measurements (but not at flagship level) will be required EXTRAS Timiskaming, Matijevic Hill region of Cape York (Opportunity Sol 3135)

45 Arvidson et al., 2014, Science; Clark et al., 2016, Am. Min.; Mittlefehldt, et al., 2019, LPSC