Table 3 Cross-correlations between geochemical, microstructural and optical signals in the studied fossil brachiopodCross-correlations are calculated between isotope composition (δ¹³C and δ¹⁸O), minor-element (Mn, Fe, and Mn) concentrations, MCLI, and AFR or ΑF-PCR of the fossil Terebratalia coreanica and Laqueus rubellus shells. Coefficient values in brackets are not statistically significant (p > 0.01)

 δ¹³C (‰VPDB)

1

 δ¹⁸O (‰VPDB)

0.9

1

 Mn (ppm)

−0.71

−0.71

1

 Fe (ppm)

−0.51

−0.43

0.61

1

 Sr (ppm)

[0.21]

[0.18]

[−0.42]

[−0.02]

1

 Mean CL intensity (MCLI: 0–255)

−0.53

−0.54

0.77

[0.34]

[−0.23]

1

 Altered fiber and puncta-filling cement ratio (AF-PCR: %)

−0.75

−0.76

0.75

0.6

[−0.15]

0.61

 δ¹³C (‰VPDB)

1

 δ¹⁸O (‰VPDB)

0.9

1

 Mn (ppm)

−0.77

−0.72

1

 Fe (ppm)

[−0.48]

[− 0.35]

0.54

1

 Sr (ppm)

0.54

0.55

−0.68

[− 0.19]

1

 Mean CL intensity (MCLI: 0–255)

−0.65

−0.64

0.80

[0.20]

−0.47

1

 Altered fiber and puncta-filling cement ratio (AF-PCR: %)

−0.79

−0.81

0.77

0.62

[−0.44]

0.63

 δ¹³C (‰VPDB)

1

 δ¹⁸O (‰VPDB)

0.91

1

 Mn (ppm)

[−0.65]

− 0.72

1

 Fe (ppm)

[−0.57]

[− 0.56]

0.76

1

 Sr (ppm)

[−0.15]

[− 0.20]

[− 0.16]

[0.17]

1

 Mean CL intensity (MCLI: 0–255)

[−0.32]

[−0.37]

0.69

[0.62]

[0.05]

1

 Altered fiber and puncta-filling cement ratio (AF-PCR: %)

−0.71

− 0.71

0.71

[0.57]

[0.31]

[0.55]