Potassium isotope composition of Mars reveals a mechanism of planetary volatile retention

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F21%3A00000123" target="_blank" >RIV/00025798:_____/21:00000123 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.pnas.org/content/118/39/e2101155118" target="_blank" >https://www.pnas.org/content/118/39/e2101155118</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1073/pnas.2101155118" target="_blank" >10.1073/pnas.2101155118</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Potassium isotope composition of Mars reveals a mechanism of planetary volatile retention

Popis výsledku v původním jazyce

The abundances of water and highly to moderately volatile elements in planets are considered critical to mantle convection, surface evolution processes, and habitability. From the first fly-by space probes to the more recent ‘Perseverance’ and ‘Tianwen-1’ missions, ‘follow the water’, and more broadly ‘volatiles’, has been one of the key themes of martian exploration. Ratios of volatile relative to refractory elements (e.g., K/Th, Rb/Sr) are consistent with a higher volatile content for Mars than for Earth, despite the contrasting present-day surface conditions of those bodies. This study presents K isotope data from a spectrum of martian lithologies as a new isotopic tracer for comparing the inventories of highly and moderately volatile elements and compounds of planetary bodies. Here, we show that meteorites from Mars have systematically heavier K isotopic compositions than the bulk silicate Earth (BSE), implying a greater loss of K from Mars than from Earth. The average ‘bulk silicate’ d41K values of Earth, Moon, Mars, and the asteroid 4-Vesta, correlate with surface gravity, the Mn/Na ‘volatility’ ratio, and most notably, bulk planet H2O abundance. These relationships indicate that planetary volatile abundances result from variable volatile loss during accretionary growth, where larger mass bodies preferentially retain volatile elements over lower mass objects. There is likely a threshold on the size requirements of rocky (exo)planets to retain enough H2O to enable habitability and plate tectonics, with mass exceeding that of Mars.

Název v anglickém jazyce

Potassium isotope composition of Mars reveals a mechanism of planetary volatile retention

Popis výsledku anglicky

The abundances of water and highly to moderately volatile elements in planets are considered critical to mantle convection, surface evolution processes, and habitability. From the first fly-by space probes to the more recent ‘Perseverance’ and ‘Tianwen-1’ missions, ‘follow the water’, and more broadly ‘volatiles’, has been one of the key themes of martian exploration. Ratios of volatile relative to refractory elements (e.g., K/Th, Rb/Sr) are consistent with a higher volatile content for Mars than for Earth, despite the contrasting present-day surface conditions of those bodies. This study presents K isotope data from a spectrum of martian lithologies as a new isotopic tracer for comparing the inventories of highly and moderately volatile elements and compounds of planetary bodies. Here, we show that meteorites from Mars have systematically heavier K isotopic compositions than the bulk silicate Earth (BSE), implying a greater loss of K from Mars than from Earth. The average ‘bulk silicate’ d41K values of Earth, Moon, Mars, and the asteroid 4-Vesta, correlate with surface gravity, the Mn/Na ‘volatility’ ratio, and most notably, bulk planet H2O abundance. These relationships indicate that planetary volatile abundances result from variable volatile loss during accretionary growth, where larger mass bodies preferentially retain volatile elements over lower mass objects. There is likely a threshold on the size requirements of rocky (exo)planets to retain enough H2O to enable habitability and plate tectonics, with mass exceeding that of Mars.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Proceedings of the National Academy of Sciences of the United States of America

ISSN

0027-8424

e-ISSN

—

Svazek periodika

118

Číslo periodika v rámci svazku

39 : e2101155118

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

7

Strana od-do

nestránkováno

Kód UT WoS článku

000704004200006

EID výsledku v databázi Scopus

2-s2.0-85115306605