Dear researchers,
I have two questions:
1. I want to evaluate the maximum burial depth of a Lower Cretaceous mudstone from Germany with the Kübler index. Mostly you can find correlations with diagenetic zones and/or maximum temperatures. Is there a direct correlation with the burial depth without assuming a certain geothermal gradient to back calculate the maximum depth?
2. Most of the correlations end at a Kübler index of 1 but the half width at half height of my mudrocks is around 1.3 to 1.4. Is it feasible to use the Kübler index for such a wide peak?
Best regards
Christian Günther
Dear Christian,
If the KI is so high, it probably indicates there is a significant contribution from a swelling component which broadens the 10A-reflection. Hence you are not measuring the KI of an "illite" but of an interstratified illite/smectite mineral with probably quite some smectite layers.
Dear Rieko,
thank you for your answer. A XRD analysis indicated that the smectite content is nearly negligible. After further evaluations of the diffractogramms the Kübler index is about 0,8 to 0,9.
The attached manuscript addresses this issue. It is a submitted draft and you can probably find the final publication on the Internet. The topic falls between metamorphic geology and sedimentology.
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India