Publication details
Correlation potential of spectral reflectance logs compared to gamma-ray and magnetic susceptibility
| Authors | |
|---|---|
| Year of publication | 2008 |
| Type | Article in Proceedings |
| Conference | Outcrops Revitalized: Tools, Techniques and Applications; SEPM Research Conference |
| MU Faculty or unit | |
| Citation | |
| Field | Geology and mineralogy |
| Keywords | visible light spectral reflectance; sediment colour; stratigraphy |
| Description | Spectral reflectance analysis and digital image analysis make it possible to relate sediment colour to variation in organic carbon, carbonate content, magnetic susceptibility (MS) or directly to concentrations of particular minerals, implying a great potential for time series analysis and stratigraphic correlation. We examined visible light reflectance spectra from three sections with different lithology and age (Lower Devonian carbonates, recent lake deposits, Czech Republic; Upper Pleistocene loess, eastern Kazakhstan) using portable spectral photometer. The aim was to examine the potential of spectrophotometric logs to reveal important stratigraphic trends and boundaries on different scales. The reflectance data were logged in 2 to 10 cm interval and converted to CIE L*a*b* values, brightness and percent reflectance in seven colour spectral bands (violet to red). The colour data were compared to MS and spectral gamma ray (GRS) logs, background lithology and stratigraphy. Linear regression analysis reveals that the colorimetric data are uncorrelated with MS and GRS (R2 < 0.1). However, the spectrophotometric, MS and GRS logs can be subdivided into easily correlatable blocky, funnel-like and bell-like segments, symmetrical sinusoids and isolated peaks on different thickness scales. All the major stratigraphic features such as major disconformities, paleosol complexes in loess and annual lake layers can be easily discerned on the spectrophotometric logs, MS logs and to a lesser degree on the GRS logs. The results show that the spectrophotometric logs can have a strong potential for preliminary stratigraphic correlation in various lithologies although the role of particular colour activators may not be clearly known. |