Absolute age determination isnecessary to check and calibratethe relative Martian chronologypresently available from meteoriticcrater counting

Cattani, F.

Cohen, Barbara A.

Gillot, P.Y.

Hildenbrand, A.

Quidelleur, X.

NASA Technical Reports Server

F. Cattani1,2, P.Y. Gillot1, X. Quidelleur1, A. Hildenbrand1, B.A. Cohen2
1Univ Paris Saclay, Univ Paris Sud, CNRS, GEOPS, Rue du Belvedere, Bat 504, F-91405 Orsay, France  2NASA Goddard Space Flight Center, Greenbelt MD 20771 
LPSC 50
Abstract ID: 1311
Contact: fanny.cattani@nasa.gov
In-situ K-Ar dating based on UV-Laser ablation coupled with a LIBS-QMS system 
development, calibration and application
40K
40Ar*
40Ca
β-
c.e.
c.e.
Half life = 1,249 Ga
γ
Mars Odyssey
Boynton et al. (2007)
Absolute age determination is 
necessary to check and calibrate 
the relative Martian chronology 
presently available from meteoritic 
crater counting. 
K-Ar dating method is particularly suitable for such purpose.
It is based on the radioactive decay of 40K, a major element universally 
distributed. Its daughter, 40Ar, noble gas, which accumulates as a function of time. 
The measurement of K and 40Ar can be used for in-situ dating planetary surface 
rocks as long as the sample mass from which they were extracted is known.
We present here an in-situ K-Ar dating prototype, KArMars1, based on
UV-laser ablation, K measurement by LIBS, and argon analysis by QMS. 
No data
Neukum and Ivanov (1994)
Principle
Instrument calibration, and checking measurements reliability 
for Martian analyses, requires terrestrial analogues.
For such purpose, analyses have been performed in order to 
qualify mineralogy, K%, and 40Ar content from a collection 
of old terrestrial rocks1.
500 µm
TL-18
Plg
PlgPlg
Px
Ox
Ox
Ox
Ox
Px
500 µm
TO-35
Plg
Plg
Plg
Ox
Px
Px
Ol
1 mm
30-01
Plg
Plg
Plg
Px
Px
Ox
500 µm
TL-19
Plg
Plg
Plg
Px
Px Ox
Px
ol
Chl
500 µm
AMP3.8
Amphibole inclusions
Amp
Amp
Amp
Plg
Plg
ADB
500 µm
Plg
px
px
Plg
Plg
Plg
Reference samples
Amphibolite Enderbite Basalts
Std
Ti
Ch
3
6
Pump
Gauge
Zr-Al getter pump
Valve
LCD SCD
5
4
QMS
Optic
Spectrometer
2
X-Y-Z
stages
Pyroelectric 
Laser Energy 
Sensor
1
Shutter
Pointer
UV Laser
1: Laser unit
2: Ablation and optical unit
3: Purification unit
4: Spectrometer unit
5: Pipette unit (a known amount of 
air to calibrate the QMS detectors)
LCD: large air pipette (FC calibration) 
SCD: small air pipette (EM calibration)
6: Pipette calibration unit
Schematic diagram of the experimental setup
Features and Calibration
Laser unit with a Q-switched Spectra Physics 
Nd-YAG / 14 ns / 10 Hz / 266 nm 
Evapore a specified amount of sample without significant argon diffusion.
R² = 0.9988
40
A
r i
nt
en
si
ty
 (1
0-
11
 A
)
Number of introduced air dose
35
0
5
10
15
20
25
30
0 1 2 3 4 5 6
a
40
Ar
 th
eo
ric
al
 (1
0-
11
 A
)
40Ar (10-11 A)
SCD#1
SCD#2
SCD#3
0
1
2
3
4
5
6
7
8
0 1 2 3 4 5 6 7 8
b
SXP Elite V QMS 
EM sensitivity 1.47×10−21A/atom
Several air pipette analyses were conducted and highlighted the 
linearity of the QMS instrument in the range 0.2 to 30×10-11A, 
corresponding to a range from 9.7×108 to 1.7×1011 atoms of 40Ar.
0
2
4
6
8
10
12
14
16
18
20
0 1 2 3 4 5 6 7 8 9
N
or
m
al
iz
ed
 in
te
ns
ity
 (1
0-
2  a
.u
.)
%K reference sample
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.27 0.32 0.37
K emission peak at 766 nm
K emission peak at 770 nm
15-yates-1-bio
SRM278
AGV-2
JA3
AMP3.8
plg
AMP3.8
amp
JB2 y = 0.0439 x0.6296
R² = 0.9782
y = 0.021 x0.6629
R² = 0.9756
Ocean Optics HR2000+ / gate: 385-835 nm / resolution: 0.23 nm
Univariate analysis was selected to define a correlation between the LIBS signal 
and a known concentration using calibration curves based on standards 
analyses (glasses and reference samples).
The non-linear trend can be explained by self-absorption, the decreasing plasma 
luminosity and/or matrix effects2-4.
LOD766: 0.14%
LOQ766: 0.52%
LOD770: 0.05%
LOQ770: 0.19%
Limits of detection and quantification
R² = 0.9919
0
1
2
3
4
5
6
0 20 40 60 80 100
Ab
la
te
d 
m
as
s 
(1
0-
5  g
)
Ablation time (10 laser pulses/s)
Several analyses of reference 
plagioclases allowed us to deﬁne 
the relation between the ablation 
time and the ablated mass. 
Indeed, the relation is obtained by 
comparison between QMS signal 
and the known content of 40Ar* 
atoms per gram ot the reference. 
The ablated mass determination depends on laser parameters, and on the 
mineral analyzed. The profilometry technique can define this mass5-7 but this 
technique can be affect by several parameters1. 
In this study the mass determination is based on the QMS measurements.
15-yates-1-bio ablated during 60s by laser power at 260 mW
100 µm
100 µm
AMP3.8
15-yates-1-bio
AMP3.8 ablated during 40s by laser power at 260 mW
µm
0
100
200
300
400
NM
µm0 800600400200
µm
600
400
200
0
Profilometry image
0
100
200
300
NM
µm
µm
0
600
400
200
0
800600400200
Profilometry image
µm
310
360
410
310 360 410
TL-19
AMP3.8
ADB
TO-35
TL-18
30- 01
mix phases
amphibole
plagioclase
Viluy basalts
plagioclase
+1
0%
-10
%
0
1000
2000
3000
0 1000 2000 3000
Re
fe
re
nc
e 
ag
e 
(M
a)
KArMars age (Ma)
40K atoms (1011 atoms)
0
2
4
6
8
10
12
0 5.02.5
40
A
r a
to
m
s 
(1
09
 a
to
m
s) TL-19 plagioclase
Age KArMars
359 ± 20 Ma
MSWD = 2.95; n = 10 
Reference Age
plagioclase
378.0 ± 5.4 Ma 0
2
4
6
8
10
12
0 5.02.5
TO-35 microlites
Age KArMars
406 ± 210
MSWD = 0.17; n = 5
Reference Age
plagioclase
373.5 ± 5.3 Ma
0
2
4
6
8
10
12
0 5.02.5
TL-18 plagioclase
Age KArMars
362 ± 15 Ma
MSWD = 1.85; n = 13 
Reference Age
plagioclase
380.7 ± 5.4 Ma
40K atoms (1011 atoms)
0
2
4
6
8
10
12
0 5.02.5
30-01 plagioclase
Age KArMars
351 ± 33 Ma
MSWD = 0.28; n = 4 
Reference Age
plagioclase
370.3 ± 5.3 Ma40
A
r a
to
m
s 
(1
09
 a
to
m
s)
0
10
20
30
40
50
60
70
80
0 0.5 1.0 1.5 2.0
AMP3.8 amphibole
Age KArMars
2913 ± 292 Ma
MSWD = 0.14; n = 5
Reference Age
amphibole
2649 ± 38 Ma
ADB
2.0 4.0
0
10
20
30
40
60
50
0
ADB plagioclase
Age KArMars
1382 ± 46 Ma
MSWD = 5.29; n = 11
Reference Age
plagioclase
1447 ± 21 Ma0
10
20
30
40
50
60
70
80
0 0.5 1.0 1.5 2.0
AMP3.8 mix phases
Age KArMars
2585 ± 138 Ma
MSWD = 0.20; n = 14 
40
A
r a
to
m
s 
(1
09
 a
to
m
s)
0
10
20
30
40
50
60
70
80
0 0.5 1.0 1.5 2.0
AMP3.8 plagioclase
Age KArMars
2218 ± 135 Ma
MSWD = 0.39; n = 4
Reference Age
plagioclase
2052 ± 29 Ma40
A
r a
to
m
s 
(1
09
 a
to
m
s)
40K atoms (1011 atoms) 40K atoms (1011 atoms)
Application
UV laser ablations were performed on AMP3.8, ADB, and 
30-01, TL-18, TL-19, TO-35 (basalt from Viluy) used here
as unknowns. The error bars on each point are defined by
the uncertainties on K% (between 5 and 40%), mass 
(around 4%) and 40Ar (less than 2%) measurements1.
In order to reduce this uncertaincy, KArMars ages of these 
samples have been determined using the isochron 
approach8 with the following equation:
here 40Ari represents the intercept on the y axis (b) and 
(λe/λ)(eλt-1) represent the slope (m) which is a function of 
the age. Thus  sckcscjjjjjjjjjjjjjjjjjjjjjjjjjjj
That allows to obtain an uncertainty and an accuracy 
lower than 10%. This is even observed for relatively young 
and low K samples from Viluy basalts, which are at the 
limit of detection of the instruments1.
40Ar = 40Ari + (λe / λ) x 40K (eλt
 
- 1)
Where λ is the total decay constant of 40K, and λe is the decay constant of 40K to 40Ar*
t = 1/λ x ln [m (λ / λe) + 1]. 
Perspectives
PLS method9
The intensity of each elemental peak is not a simple function 
of elemental abundance. Furthermore, LIBS data is sensitive to 
the composition of the sample. PLS method helps understand 
the bulk composition of the sample and refine the K 
calibration curve better than univariate analysis.
[1] Cattani F. et al. (2019) Chem. Geol. [2] Cho Y. et al. (2015) s. Spectrochim. Acta B At. Spectrosc. 106, 28–35. [3] Cremers D.A. and Radziemski L.J., “Handbook of LIBS”, 2006. [4] Guezenoc J. et al.
(2017) Spectrochim. Acta B At. pectrosc. 134, 6–10. [5] Cohen B.A. et al. (2014) Geoﬆand. Geoanal. Res. 38, 421–439. [6] Cho Y. et al. (2016) Planet. Space Sci. 128, 14–29. [7] Cho Y. and Cohen B.A.
(2018) Rap. Com. Mass Spectrom. 32, 1755–1765. [8] Bogard D.D. (2009) Meteorit. Planet. Sci. 44, 3–14. [9] Clegg S. et al. (2017) Spectrochim. Acta B At. pectrosc. 129, 64–85.
KArLE device
DALI project
The agency’s Development and Advancement of Lunar Instrumentation, or DALI, program recently awarded funding to 
mature spacecraft-based instruments for use in future lander missions. 
Knowing the precise ages afforded through potassium-argon dating would help scientists understand the Moon’s history, its 
formation, the effects of bombardment, and by extension, the history of the solar system. KArLE is an especially good 
match to the DALI call because all of the necessary components have been proven on flight missions. 
As part of the DALI project, we need to miniaturise KArLE and calibrate the instruments for the moon.
B.A. Cohen’s team develops a device based on the same principle, KArLE5, at NASA GSFC
https://ntrs.nasa.gov/search.jsp?R=20190002336 2019-08-30T21:20:15+00:00Z


In-Situ K-Ar Dating Based on UV-Laser Ablation Coupled with a LIBS-QMS System Development, Calibration and Application

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