Quantitative mapping of dolomitization using close-range hyperspectral imaging: Kimmeridgian carbonate ramp, Alacon, NE Spain

Geological models from outcrop analogues are often utilized as a guide, or soft constraint, for distributing reservoir properties in subsurface mod-els. In carbonate outcrops, combined sequence stratigraphic, sedimentological, and petrographic studies constrain the heterogeneity of geobodies and diagenetic processes, including dolomitization, at multiple scales. High-resolution digital outcrop modeling further aids geometric mapping, geo-body definition, and statistical analysis, though its usefulness for detailed mineralogical and lith-ological mapping is limited. Hyperspectral imaging offers enhanced spectral resolution for mapping subtle mineralogical differences. In both outcrops and subsurface, differences in carbonate compo-sition can provide key information for distributing porosity and permeability, yet this mapping is highly challenging in field studies due to access dif-ficulties, visible material differences, and sampling resolution. Spectral analysis of limestone- dolomite ratios conducted in laboratory studies indicates theoretical measures for quantitative identification and mapping of dolomite degrees within carbon-ate rocks. In this study, close-range hyperspectral imaging is applied to outcrops of the Alacon Mem-ber, Barranco del Mortero, northeastern Spain, to identify exposed limestone-dolomite geobod-ies and to quantify the degree of dolomitization across outcrop faces. Hyperspectral imaging is supplemented with photogrammetric outcrop modeling, field spectroscopy, and laboratory sam-ple analysis for empirical validation and uncertainty analysis. Hyperspectral mapping shows that ear-lier fieldwork utilizing visual inspection of difficult to access outcrop surfaces had overestimated the amount of dolomite in the outcrop. Results indi-cate that hyperspectral imaging identified dolomite bodies more accurately and reliably than conven-tional field methods and facilitates the mapping of dolomite contribution in areas modified by dedo-lomitization, where dolomite content changes by more than similar to 20%.