Scientific goals of Phobos samples laboratory studies (Phobos-soil program) Eric M. Galimov, Yuri A. Kostitsyn V.I. Vernadsky Institute of Geochemistry

Scientific goals of Phobos samples laboratory studies

(Phobos-soil program)

Eric M. Galimov, Yuri A. Kostitsyn

V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI) RAS

13 October 2010

Phobos and MarsData from Phobos-2 SC, 1989

Phobos image from Mars Reconnaissance Orbiter space craft, 23 March 2008

What do we know about Phobos?

27×22×19 kmmass 1.082×1014 gspec.gravity ~1.85 g/cm3

Our questions to Phobos10.04.2008

NASA

Is there a genetic link between Phobos and Mars?

8

6

4

2

0

-2

-4

-6

0 5 10 15

Primitivewater

SNC meteorites

OrdinaryChondrites

Earth

Moon

CarbonaceousChondrites

CHCMCR

CV

CO

d17

O,

‰

d18O, ‰

Oxygen isotopic composition of Moon and Earth is the same in terms of D17O value. Moon data scatters along Terrestrial Fractionation Line (TFL) with a slope ≈0.52

Martian meteorites data (SNC) are located above TFLby 0.3‰ of D17O

CAI and carbonaceous chondrites data are scattered along line with a slope ≈1

Are Phobos and Mars identical in oxygen isotopic composition?

SIMS Cameca-1280

18O/17O/16O:1s = 0.05 ‰

for spot size ~15 m

It is very likely, that SNC-meteorites (Shergottites, Nakhlites and Shassignites) – are samples of Martian magmatic rocks

Phobos?

Sun

CI - chondrites

VenusEarth

Mars10 -15

10 -13

10 -11

10 -9

10 -7

10 -5

10 -3

10 30 50 70 90 110

Ne Ar Kr Xe

m /m1 2

a.e.m .

Yu.A.Shukoliukov, 1991Mgas/Mbody

Our questions to Phobos


How primitive is Phobos material? Phobos=CI?

T=

4.5

6 G

a

Sm/Nd=0.325

147Sm 143Nd

Kostitsyn, 2004

M.Boyet, R.W.Carlson. Science. 2005. Vol.309. P.576-581.

146Sm 142Nd

Chondrites: Sm/Nd=0.325 (Jacobsen&Wasserburg, 1980)

Earth: Sm/Nd=0.350 (Kostitsyn, 2004)

SNC: Sm/Nd≈0.340 (Caro et al., 2008)

Phobos: Sm/Nd = ?




Does it contain some relict components?

Bir

ck,

20

04

Ca Ti

Cr Ni

Isotopic anomalies in the earliest minerals – Ca-Al inclusions (CAI) of Allende chondrite

Excess of r-isotopes!

Isotopic anomalies in SiC and graphite grains of carbonaceous chondrite Murchison (CM2)

Mo Xe

Ba Nd

Bir

ck,

20

04

Excess of s-isotopes!

Cameca Nano-SIMS 50L

18O/17O/16O:1s = 0.5 – 1.5 ‰

For spot 10 × 10 m

Minimal spot size50 × 50 nm





What types of processes could alter Phobos’ material?






Events chronology on Phobos: Long-living (Sm-Nd, U-Pb, Rb-Sr, K-Ar, Lu-Hf, Re-Os) and short-living isotopic systems

Short-living nuclides in the Sun system

Parent Daughter T1/2, Ma Initial ratios Source

10Be 10B 1.5 10Be/9Be=9×10−4 McKeegan et al. 2000

26Al 26Mg 0.73 26Al/27Al=5.1×10−5 Lee et al. 1977

41Ca 41K 0.1 41Ca/40Ca=1.4×10−8 Sahijpal et al. 1998

53Mn 53Cr 3.7 53Mn/55Mn=4.4×10−5 Birck and Allegre 1985

60Fe 60Ni 1.5 60Fe/56Fe≈1.5×10−6 Birck and Lugmair 1988

92Nb 92Zr 36 92Nb/93Nb≈1×10−5 Schönbächler et al. 2002

107Pd 107Ag 6.5 107Pd/108Pd=2.4×10−5 Chen and Wasserburg 1990

129I 129Xe 16 129I/127I≈1×10−4 Reynolds 1963

146Sm 142Nd 103 146Sm/144Sm≈0.005–0.015 Lugmair et al. 1983; Prinzhofer et al. 1989

182Hf 182W 9.4 182Hf/180Hf≈1×10−4 Yin et al. 2002

244Pu a,SF 81 244Pu/238U≈0.004–0.007 Rowe and Kuroda 1965

53Mn – 53Cr

Shukoliukov, Lugmair, 2004

(HED)

(SNC)

Phobos?






Events chronology on Phobos

Is there organic material on Phobos?

N

CHN

C

NH2

C

CN

CH

N

C

C

O

C

CH

OH OH

HH H

C O P O

H

H

OH

O

P O P OH

O

OH

OH

O

Adenosine Triphosphate (ATP)

Adenine

Ribose

Phosphates

Main directions of Phobos samples laboratory treatment

Acceptance and storage

Physical, petrographic and mineralogical

studies

Chemical analysis Isotopic studies

Organic material studies

Physical, petrographic and mineralogical studies

Preliminary diagnostic of obtained material, assessment of its mass; physical, granulometric features, phase composition. Techniques and equipment:• Optical microscopes• X-ray difractometer • Scanning electron microscope with energy-dispersive

spectroscopy detector (EDS) and electron backscattered diffraction detector (EBSD)

Samples preparation to various types of analysis:thin sections, polished section, defragmentation, mineral isolation, etc. Techniques and equipment:• SelFrag-Lab - high-voltage pulses selective fragmentation

Chemical analysis

In-situ techniques (almost non-destructive)• X-ray microprobe• Electron microscopy with energy-dispersive detector • Secondary ion mass-spectrometry (SIMS)• Laser ablation with inductively coupled plasma mass-

spectrometry (LA-ICP-MS)

Destructive techniques (application depends from quantity of obtained material)• Using powdered samples (XRF, INNA)• Using samples solutions (ICP-MS, ICP-AES, AAS)• Using vacuum heating or crushing (gas mass-spectrometry

including noble gas analysis)

Isotopic studies Stable isotope variations H, O, C, N, S, Fe, Cr (MAT-253 with

sample preparation systems, MC-ICP-MS Neptune)

Long-living decay systems: U-Th-Pb, Rb-Sr, Sm-Nd, Lu-Hf, Re-Pt-Os, K-Ar (Triton, Neptune, ARGUS)

Short-living decay systems: 26Al-26Mg, 182Hf-182W, 53Mn-53Cr, 129I-129Xe, 244Pu-136Xe (Neptune, HELIX)

Organic matter studies Organic molecules composition and structure (HPLC/HRMS

Exactive with extraction systems)

Isotopic composition of organic matter: H, O, C, N, S (MAT-253 and sample preparation systems)






Events chronology on Phobos

Is there organic material on Phobos?

Thank you

Documents

Scientific goals of Phobos samples laboratory studies (Phobos-soil program) Eric M. Galimov, Yuri A. Kostitsyn V.I. Vernadsky Institute of Geochemistry