Table 3 Comparison between XRD and SEM-EDS results for the fracture infill in sample S8.

From: Determining rock discontinuity fracture aperture and infilling characteristics using 3D X ray tomography with automated approach and multi method validation

Phase / Element

XRD

SEM-EDS (wt%)

Interpretation

Calcite (\(\hbox {CaCO}_{3}\))

Major (PDF 05-0586)

Ca: 19.4, O: 49.4

Cementing phase

Quartz (\(\hbox {SiO}_{2}\))

Minor (PDF 46-1045)

Si: 16.6, O: 49.4

Detrital grains / residual phase

Biotite / mica group

Minor (PDF 80-1106)

Al: 6.4, K: 3.1, Mg: 1.2, Fe: 3.9

Phyllosilicate (authigenic or inherited)

Potassium (K)

–

3.1

Supports K-mica (biotite/illite) presence

Magnesium (Mg)

–

1.2

Consistent with biotite or chlorite

Iron (Fe)

–

3.9

Typical of Fe-bearing micas (biotite)

Aluminum (Al)

–

6.4

Component of feldspars or micas

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