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| Titel |
Rock Formation and Cosmic Radiation Exposure Ages in Gale Crater Mudstones from the Mars Science Laboratory |
| VerfasserIn |
Paul Mahaffy, Ken Farley, Charles Malespin, Ralph Gellert, John Grotzinger |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090187
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| Publikation (Nr.) |
 EGU/EGU2014-4407.pdf |
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| Zusammenfassung |
| The quadrupole mass spectrometer (QMS) in the Sample Analysis at Mars (SAM) suite of the
Mars Science Laboratory (MSL) has been utilized to secure abundances of 3He, 21Ne, 36Ar,
and 40Ar thermally evolved from the mudstone in the stratified Yellowknife Bay formation in
Gale Crater. As reported by Farley et al. [1] these measurements of cosmogenic and
radiogenic noble gases together with Cl and K abundances measured by MSL’s alpha
particle X-ray spectrometer enable a K-Ar rock formation age of 4.21+0.35 Ga to be
established as well as a surface exposure age to cosmic radiation of 78+30 Ma.
Understanding surface exposures to cosmic radiation is relevant to the MSL search
for organic compounds since even the limited set of studies carried out, to date,
indicate that even 10’s to 100’s of millions of years of near surface (1-3 meter)
exposure may transform a significant fraction of the organic compounds exposed to
this radiation [2,3,4]. Transformation of potential biosignatures and even loss of
molecular structural information in compounds that could point to exogenous or
endogenous sources suggests a new paradigm in the search for near surface organics that
incorporates a search for the most recently exposed outcrops through erosional
processes.
The K-Ar rock formation age determination shows promise for more precise in situ
measurements that may help calibrate the martian cratering record that currently relies on
extrapolation from the lunar record with its ground truth chronology with returned
samples.
We will discuss the protocol for the in situ noble gas measurements secured
with SAM and ongoing studies to optimize these measurements using the SAM
testbed.
References: [1] Farley, K.A.M Science Magazine, 342, (2013). [2] G. Kminek et al.,
Earth Planet Sc Lett 245, 1 (2006). [3] Dartnell, L.R., Biogeosciences 4, 545 (2007). [4]
Pavlov, A. A., et al. Geophys Res Lett 39, 13202 (2012). |
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