Fig. 1. The spectra of calcite and three spectra with different feature types around 2.33 μm

Fig. 2. The grey image of band 207 (Wavelength 2.33 μm)

Fig. 3. To mix with calcite under variable abundance
(a): galena4; (b): mordeni1; (c): czoisite

Fig. 4. The spectral curve after continuum removal processing
(a): galena4; (b): mordeni1; (c): czoisite

Fig. 5. Three endmember spectra and different reflectivity
(a): None feature; (b): Reflection feature; (c): Absorb feature

Fig. 6. Continuum removed curve of spectra with different reflectivity under different features
(a): None feature; (b): Reflection feature; (c): Absorb feature

Fig. 7. CRBD change with reflectivity and abundance fractions under different features
(a): None feature; (b): Reflection feature; (c): Absorb feature

Fig. 8. CRBD variation of mixed spectra by three endmembers under different spectral abundance
(a): CRBD of mixed spectra by three endmembers; (b): Linear interpolation of CRBD of three endmembers; (c): Difference of (a) and (b)

Fig. 9. CRBD change with carbonate mineral abundance and corresponding fitting equation
(a): CRBD variation with carbonate mineral abundance; (b): Fitting equation of CRBD variation boundary

Fig. 10. The inversion results by the fitting equations
(a): Inversion by applying the high-value variation fitting equation; (b): Inversion by applying linear changing trend to image data;(c): Inversion by applying the low-value variation fitting equation