Table 4 Wavelength ratio at 1600 cm⁻¹ for the minerals identified in samples 0641 and 1273

Calcite

2873 (vibration 2ν₃ carbonate group)

2515 (vibration 2ν₂ + ν₄ carbonate group)

1798 (vibration 2ν₁ + ν₄ carbonate group)

1425, 1397 (ν₃, symmetric stretching vibration of the carbonate group)

878 (ν₂, out-of-plane bending vibration of the carbonate group)

710 (ν₄, out-of-plane stretching vibration of the carbonate group)

Whewellite/Weddellite (calcium oxalate mono- and dihydrate)

3541, 3400 (stretching vibration of hydroxyl groups)

1627 (COO group asymmetric stretching vibration)

1324 (COO group asymmetric stretching vibration)

789 (-COO group vibration)

Clay/plagioclase minerals

3380 (stretching vibrations of water)

994 (stetching vibration of Si–O silicate bonds)

910 (internal hydroxyl deformation vibration)

542 (OH bending vibration)

Quartz

1089 (stetching vibration of Si–O silicate bonds with E symmetry)

798, 778 (Qtz double)

512 (Si–O bond deformation vibration)

Goethite

3185 (stretching vibration of hydroxyl group)

892 (shoulder) (OH bending vibration)

790 (shoulder) (OH bending vibration)

Hematite

524 (an-isodimensional Fe–O bond stretching vibration)

557 (isodimensional Fe–O bonds’ stretching vibration)