Mars Pathfinder

Analysis of Martian Samples by the Alpha Proton X-Ray Spectrometer: Preliminary Results
Comparison with SNCs and the Earth

Mars				Earth
	A-3, Rock "Barnacle Bill"	A-5, Soil	SNCs (Mars Meteorites)	Continental Crust		Oceanic Crust
				Average	Sediments
	weight %	weight %	weight %	weight %	weight %	weight %
MgO	3.1	8.6	9.3 - 31.6	3.1	3.1	7.7
Al2O3	12.4	10.1	0.7 - 12.0	15.2	13.0	15.6
SiO2	55.0	43.8	38.2 - 52.7	60.2	50.0	50.7
K2O*	1.4	0.7	0.022 - 0.19	2.9	2.0	0.17
CaO	4.6	5.3	0.6 - 15.8	5.5	8.4	11.4
TiO2	0.7	0.7	0.1 - 1.8	0.7	0.7	1.5
MnO*	0.9	0.6	0.44 - 0.55	0.1	0.1	0.16
FeO	12.7	17.5	17.6 - 27.1	6.05	5.5	9.9
FeO/MnO	14.1	29.2	37.0 - 51.5	-	-	-

*Values for potassium (K) and manganese (Mn) are probably too high and subject to revision after further analysis.

Elements

Element	A-2, Soil	A-4, Soil	A-5, Soil	A-3, Rock "Barnacle Bill"	A-7, Rock "Yogi"
	weight %	weight %	weight %	weight %	weight %
Carbon [C] (see note 2)	-	-	-	-	-
Oxygen [O] (see note 2)	42.5	43.9	43.2	45.0	44.6
Sodium [Na]	3.2	3.8	2.6	3.1	1.9
Magnesium [Mg]	5.3	5.5	5.2	1.9	3.8
Aluminum [Al]	4.2	5.5	5.4	6.6	6.0
Silicon [Si]	21.6	20.2	20.5	25.7	23.8
Phosphorus [P]	-	1.5	1.0	0.9	0.9
Sulphur [S]	1.7	2.5	2.2	0.9	1.7
Chlorine [Cl]	-	0.6	0.6	0.5	0.6
Potassium [K] (see note 4)	0.5	0.6	0.6	1.2	0.9
Calcium [Ca]	4.5	3.4	3.8	3.3	4.2
Titanium [Ti]	0.6	0.7	0.4	0.4	0.5
Chromium [Cr]	0.2	0.3	0.3	0.1	0.0
Manganese [Mn] (see note 4)	0.4	0.4	0.5	0.7	0.4
Iron [Fe]	15.2	11.2	13.6	9.9	10.7
Nickel [Ni]	-	-	0.1	-	-
Sum	100.0	100.0	100.0	100.0	100.0

Notes:

1. Analysis based on X-ray data.
2. Direct results on carbon and oxygen will be available from the analysis of the alpha spectra at a later date.
3. Oxygen is calculated from oxide stoichiometry, assuming sulphur in the form of SO3 and iron in the form of FeO.
4. Values for potassium and manganese are upper limits; more accurate numbers will be available after further analysis.

Oxides

Oxide	A-2, Soil	A-4, Soil	A-5, Soil	A-3, Rock "Barnacle Bill"	A-7, Rock "Yogi"
	weight %	weight %	weight %	weight %	weight %
Na2O	4.3	5.1	3.6	4.2	2.5
MgO	8.7	9.0	8.6	3.1	6.3
Al2O3	8.0	10.4	10.1	12.4	11.4
SiO2	46.1	43.3	43.8	55.0	50.9
SO3	4.3	6.2	5.4	2.2	4.2
K2O	0.6	0.7	0.7	1.4	1.1
CaO	6.3	4.8	5.3	4.6	5.8
TiO2	1.1	1.1	0.7	0.7	0.8
MnO	0.5	0.5	0.6	0.9	0.5
FeO	19.5	14.5	17.5	12.7	13.8

Notes:

1. Analysis based on X-ray data.
2. Values for potassium and manganese are upper limits; more accurate numbers will be available after further analysis.
3. Minor elements such as phosphorus, chlorine and chromium are omitted from this table.