The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record
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The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record. / Costa, Maria M.; Jensen, Ninna K.; Bouvier, Laura C.; Connelly, James N.; Mikouchi, Takashi; Horstwood, Matthew S. A.; Suuronen, Jussi-Petteri; Moynier, Frederic; Deng, Zhengbin; Agranier, Arnaud; Martin, Laure A. J.; Johnson, Tim E.; Nemchin, Alexander A.; Bizzarro, Martin.
I: Proceedings of the National Academy of Sciences of the United States of America, Bind 117, Nr. 49, 2020, s. 30973-30979.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record
AU - Costa, Maria M.
AU - Jensen, Ninna K.
AU - Bouvier, Laura C.
AU - Connelly, James N.
AU - Mikouchi, Takashi
AU - Horstwood, Matthew S. A.
AU - Suuronen, Jussi-Petteri
AU - Moynier, Frederic
AU - Deng, Zhengbin
AU - Agranier, Arnaud
AU - Martin, Laure A. J.
AU - Johnson, Tim E.
AU - Nemchin, Alexander A.
AU - Bizzarro, Martin
PY - 2020
Y1 - 2020
N2 - Combining U-Pb ages with Lu-Hf data in zircon provides insights into the magmatic history of rocky planets. The Northwest Africa (NWA) 7034/7533 meteorites are samples of the southern highlands of Mars containing zircon with ages as old as 4476.3 +/- 0.9 Ma, interpreted to reflect reworking of the primordial Martian crust by impacts. We extracted a statistically significant zircon population (n = 57) from NWA 7533 that defines a temporal record spanning 4.2 Gyr. Ancient zircons record ages from 4485.5 +/- 2.2 Ma to 4331.0 +/- 1.4 Ma, defining a bimodal distribution with groupings at 4474 +/- 10 Ma and 4442 +/- 17 Ma. We interpret these to represent intense bombardment episodes at the planet's surface, possibly triggered by the early migration of gas giant planets. The unradiogenic initial Hf-isotope composition of these zircons establishes that Mars's igneous activity prior to similar to 4.3 Ga was limited to impact-related reworking of a chemically enriched, primordial crust. A group of younger detrital zircons record ages from 1548.0 +/- 8.8 Ma to 299.5 +/- 0.6 Ma. The only plausible sources for these grains are the temporally associated Elysium and Tharsis volcanic provinces that are the expressions of deep-seated mantle plumes. The chondritic-like Hf-isotope compositions of these zircons require the existence of a primitive and convecting mantle reservoir, indicating that Mars has been in a stagnant-lid tectonic regime for most of its history. Our results imply that zircon is ubiquitous on the Martian surface, providing a faithful record of the planet's magmatic history.
AB - Combining U-Pb ages with Lu-Hf data in zircon provides insights into the magmatic history of rocky planets. The Northwest Africa (NWA) 7034/7533 meteorites are samples of the southern highlands of Mars containing zircon with ages as old as 4476.3 +/- 0.9 Ma, interpreted to reflect reworking of the primordial Martian crust by impacts. We extracted a statistically significant zircon population (n = 57) from NWA 7533 that defines a temporal record spanning 4.2 Gyr. Ancient zircons record ages from 4485.5 +/- 2.2 Ma to 4331.0 +/- 1.4 Ma, defining a bimodal distribution with groupings at 4474 +/- 10 Ma and 4442 +/- 17 Ma. We interpret these to represent intense bombardment episodes at the planet's surface, possibly triggered by the early migration of gas giant planets. The unradiogenic initial Hf-isotope composition of these zircons establishes that Mars's igneous activity prior to similar to 4.3 Ga was limited to impact-related reworking of a chemically enriched, primordial crust. A group of younger detrital zircons record ages from 1548.0 +/- 8.8 Ma to 299.5 +/- 0.6 Ma. The only plausible sources for these grains are the temporally associated Elysium and Tharsis volcanic provinces that are the expressions of deep-seated mantle plumes. The chondritic-like Hf-isotope compositions of these zircons require the existence of a primitive and convecting mantle reservoir, indicating that Mars has been in a stagnant-lid tectonic regime for most of its history. Our results imply that zircon is ubiquitous on the Martian surface, providing a faithful record of the planet's magmatic history.
KW - Mars
KW - meteorites
KW - zircon
KW - geodynamics
KW - MARTIAN MANTLE
KW - MAGMA OCEAN
KW - HISTORY
KW - ORIGIN
KW - CRUST
KW - SYSTEMATICS
KW - CONVECTION
KW - MINERALOGY
KW - AGE
U2 - 10.1073/pnas.2016326117
DO - 10.1073/pnas.2016326117
M3 - Journal article
C2 - 33199613
VL - 117
SP - 30973
EP - 30979
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 49
ER -
ID: 255735189