Phosphates and carbon on Mars

Exobiological implications and sample return considerations

S. Mojzsis, Gustaf Arrhenius

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Much of the surface of Mars may preserve chemical information contained in rocks from the Noachian era, with ages that overlap the correspondingly earliest Archean geological history of the Earth, or from before around 3800 Ma (Ma = 1 × 10 6 years). Metabolically sophisticated life, which utilized phosphate and carbon and was capable of fractionating carbon isotopes, was apparently present already on Earth by ∼3800 Ma, or within 600 Ma after the formation of the planet. An early appearance of life on Earth opens the strong possibility for a similarly early and rapid emergence of life on planet Mars. This hypothesis remains within the realm of plausibility so long as it can be established that liquid water and energy sources were available there for inchoate'life, and that the life that emerged reached a level of complexity which could be recognized by its chemical, and perhaps morphological remains. Hypotheses to be used in the search for an ancient Martian biosphere from future sample return missions are testable by examining the record of life in ancient terrestrial sedimentary rocks, including those that contain rare and recognizable "physical" micro fossils ("morphofossils" identified on the basis of their shape alone) and stable, authigenic biominerals which include carbonaceous matter having characteristically fractionated carbon isotope signatures (here termed "chemofossils"). Prior to sample return, these tests can be applied to the mineral associations of the SNC meteorites, a group of meteorites believed to have originated on Mars. Recent claims of a biological origin for secondary minerals and their features as well as for trace organic compounds in the Martian meteorite ALH84001, are derived in part from the interpretation of putative "nanofossil" shapes and the nature of the associated mineral assemblage in small carbonate deposits of an igneous rock. Such igneous samples would not normally be the best candidate to search for evidence of past life, even on Earth. Investigations of these mineral occurrences in the Martian meteorites and of the oldest geological records on Earth provide a useful framework for (1) using mineral phase relationships, (2) analytical data of stable carbon isotopic distributions, and (3) the problematic task of morphofossil interpretations, in the search for life via future sample return missions from the ancient surface of Mars.

Original languageEnglish
Pages (from-to)28495-28511
Number of pages17
JournalJournal of Geophysical Research: Space Physics
Volume103
Issue numberE12
Publication statusPublished - 1998

Fingerprint

Meteorites
mars
Minerals
Mars
SNC meteorites
phosphates
Carbon
Earth (planet)
Phosphates
minerals
phosphate
sample return missions
carbon
Carbon Isotopes
Martian meteorite
carbon isotopes
Planets
mineral
carbon isotope
isotopes

ASJC Scopus subject areas

  • Oceanography
  • Astronomy and Astrophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Geophysics
  • Geochemistry and Petrology

Cite this

Phosphates and carbon on Mars : Exobiological implications and sample return considerations. / Mojzsis, S.; Arrhenius, Gustaf.

In: Journal of Geophysical Research: Space Physics, Vol. 103, No. E12, 1998, p. 28495-28511.

Research output: Contribution to journalArticle

@article{a05ea1f4663f4b6ea01894e96be55ef0,
title = "Phosphates and carbon on Mars: Exobiological implications and sample return considerations",
abstract = "Much of the surface of Mars may preserve chemical information contained in rocks from the Noachian era, with ages that overlap the correspondingly earliest Archean geological history of the Earth, or from before around 3800 Ma (Ma = 1 × 10 6 years). Metabolically sophisticated life, which utilized phosphate and carbon and was capable of fractionating carbon isotopes, was apparently present already on Earth by ∼3800 Ma, or within 600 Ma after the formation of the planet. An early appearance of life on Earth opens the strong possibility for a similarly early and rapid emergence of life on planet Mars. This hypothesis remains within the realm of plausibility so long as it can be established that liquid water and energy sources were available there for inchoate'life, and that the life that emerged reached a level of complexity which could be recognized by its chemical, and perhaps morphological remains. Hypotheses to be used in the search for an ancient Martian biosphere from future sample return missions are testable by examining the record of life in ancient terrestrial sedimentary rocks, including those that contain rare and recognizable {"}physical{"} micro fossils ({"}morphofossils{"} identified on the basis of their shape alone) and stable, authigenic biominerals which include carbonaceous matter having characteristically fractionated carbon isotope signatures (here termed {"}chemofossils{"}). Prior to sample return, these tests can be applied to the mineral associations of the SNC meteorites, a group of meteorites believed to have originated on Mars. Recent claims of a biological origin for secondary minerals and their features as well as for trace organic compounds in the Martian meteorite ALH84001, are derived in part from the interpretation of putative {"}nanofossil{"} shapes and the nature of the associated mineral assemblage in small carbonate deposits of an igneous rock. Such igneous samples would not normally be the best candidate to search for evidence of past life, even on Earth. Investigations of these mineral occurrences in the Martian meteorites and of the oldest geological records on Earth provide a useful framework for (1) using mineral phase relationships, (2) analytical data of stable carbon isotopic distributions, and (3) the problematic task of morphofossil interpretations, in the search for life via future sample return missions from the ancient surface of Mars.",
author = "S. Mojzsis and Gustaf Arrhenius",
year = "1998",
language = "English",
volume = "103",
pages = "28495--28511",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "E12",

}

TY - JOUR

T1 - Phosphates and carbon on Mars

T2 - Exobiological implications and sample return considerations

AU - Mojzsis, S.

AU - Arrhenius, Gustaf

PY - 1998

Y1 - 1998

N2 - Much of the surface of Mars may preserve chemical information contained in rocks from the Noachian era, with ages that overlap the correspondingly earliest Archean geological history of the Earth, or from before around 3800 Ma (Ma = 1 × 10 6 years). Metabolically sophisticated life, which utilized phosphate and carbon and was capable of fractionating carbon isotopes, was apparently present already on Earth by ∼3800 Ma, or within 600 Ma after the formation of the planet. An early appearance of life on Earth opens the strong possibility for a similarly early and rapid emergence of life on planet Mars. This hypothesis remains within the realm of plausibility so long as it can be established that liquid water and energy sources were available there for inchoate'life, and that the life that emerged reached a level of complexity which could be recognized by its chemical, and perhaps morphological remains. Hypotheses to be used in the search for an ancient Martian biosphere from future sample return missions are testable by examining the record of life in ancient terrestrial sedimentary rocks, including those that contain rare and recognizable "physical" micro fossils ("morphofossils" identified on the basis of their shape alone) and stable, authigenic biominerals which include carbonaceous matter having characteristically fractionated carbon isotope signatures (here termed "chemofossils"). Prior to sample return, these tests can be applied to the mineral associations of the SNC meteorites, a group of meteorites believed to have originated on Mars. Recent claims of a biological origin for secondary minerals and their features as well as for trace organic compounds in the Martian meteorite ALH84001, are derived in part from the interpretation of putative "nanofossil" shapes and the nature of the associated mineral assemblage in small carbonate deposits of an igneous rock. Such igneous samples would not normally be the best candidate to search for evidence of past life, even on Earth. Investigations of these mineral occurrences in the Martian meteorites and of the oldest geological records on Earth provide a useful framework for (1) using mineral phase relationships, (2) analytical data of stable carbon isotopic distributions, and (3) the problematic task of morphofossil interpretations, in the search for life via future sample return missions from the ancient surface of Mars.

AB - Much of the surface of Mars may preserve chemical information contained in rocks from the Noachian era, with ages that overlap the correspondingly earliest Archean geological history of the Earth, or from before around 3800 Ma (Ma = 1 × 10 6 years). Metabolically sophisticated life, which utilized phosphate and carbon and was capable of fractionating carbon isotopes, was apparently present already on Earth by ∼3800 Ma, or within 600 Ma after the formation of the planet. An early appearance of life on Earth opens the strong possibility for a similarly early and rapid emergence of life on planet Mars. This hypothesis remains within the realm of plausibility so long as it can be established that liquid water and energy sources were available there for inchoate'life, and that the life that emerged reached a level of complexity which could be recognized by its chemical, and perhaps morphological remains. Hypotheses to be used in the search for an ancient Martian biosphere from future sample return missions are testable by examining the record of life in ancient terrestrial sedimentary rocks, including those that contain rare and recognizable "physical" micro fossils ("morphofossils" identified on the basis of their shape alone) and stable, authigenic biominerals which include carbonaceous matter having characteristically fractionated carbon isotope signatures (here termed "chemofossils"). Prior to sample return, these tests can be applied to the mineral associations of the SNC meteorites, a group of meteorites believed to have originated on Mars. Recent claims of a biological origin for secondary minerals and their features as well as for trace organic compounds in the Martian meteorite ALH84001, are derived in part from the interpretation of putative "nanofossil" shapes and the nature of the associated mineral assemblage in small carbonate deposits of an igneous rock. Such igneous samples would not normally be the best candidate to search for evidence of past life, even on Earth. Investigations of these mineral occurrences in the Martian meteorites and of the oldest geological records on Earth provide a useful framework for (1) using mineral phase relationships, (2) analytical data of stable carbon isotopic distributions, and (3) the problematic task of morphofossil interpretations, in the search for life via future sample return missions from the ancient surface of Mars.

UR - http://www.scopus.com/inward/record.url?scp=0033604665&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033604665&partnerID=8YFLogxK

M3 - Article

VL - 103

SP - 28495

EP - 28511

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - E12

ER -