Hyperspectral image analysis of different carbonate lithologies (limestone, karst and hydrothermal dolomites): the Pozalagua Quarry case study (Cantabria, North‐west Spain)

Abstract

Ground-based hyperspectral imaging combined with terrestrial lidar scanning is a novel technique for outcrop analysis, which has been applied to Early and Late Albian carbonates of the Pozalagua Quarry (Cantabrian Mountains, Spain). An image processing workflow has been developed for differentiating limestone from dolomite, providing additional sedimentary and diagenetic information, and the possibility to quantitatively delineate diagenetic phases in an accurate way. Spectral absorption signatures can be linked to specific sedimentary or diagenetic products, such as recent and palaeokarst, hydrothermal karst, (solution enlarged) fractures and different dolomite types. Some of the spectral signatures are related to iron, manganese, organic matter, clay and/or water content. Ground-truthing accessible parts of the quarry showed that the classification based on hyperspectral image interpretation was very accurate. This technique opens the possibility for quantitative data evaluation on sedimentary and diagenetic features in inaccessible outcrops. This study demonstrates the potential of ground-based imaging spectroscopy to provide information about the chemical-mineralogical distribution in outcrops, which could otherwise not be established using conventional field methods.

Close Range Hyperspectral Imaging Integrated With Terrestrial Lidar Scanning Applied to Rock Characterisation at Centimetre Scale

“…In the limestone spectra, different organic content modifies the intensity of the carbonate absorption features. The zebra dolomite contains more iron and manganese compared to the coarse crystalline dolomite that results in a flattened carbonate absorption feature at 2150 nm (Kurz et al, 2012). Figure 3 shows a result of the hyperspectral mapping.…”

“…Ground based hyperspectral imaging is a new technique in remote sensing, where a lightweight hyperspectral imager mounted on a tripod is used to map mineral variation in vertically-oriented rock faces, at high resolution. (Kurz et al 2012). To relate the image to a real world coordinate system, the hyperspectral imagery is integrated with terrestrial laser scanning (TLS) (Kurz et al 2011).…”

An Alternative Quality Control Technique for Mineral Chemistry Analysis of Portland Cement-Grade Limestone Using Shortwave Infrared Spectroscopy

“…For the purpose of the present study, each carbonate rock type was grouped by five selective hand specimen samples. They consist of dark gray limestones (samples B20, B28, B33, B45, and B49), light gray limestones (samples B1, B26, B32, B36, and B41) and dolomitic limestones (samples F17, F18, F20, F23, and F26) ( Figure 2 wavelength region centered at 2.530-2.541 μm and 2.333-2.340 μm and 2.503-2.520 μm and 2.312-2.323 μm, respectively [39,41,[45][46][47][48][49], due to the vibrational processes of carbonate ions CO [39,41,46]. The presence of clay and other phyllosilicate minerals in an intimate mixture with carbonates can be identified based on their vibrational absorption features around 2.20 μm and 2.30 μm [40][41][42].…”

A Review of Hyperspectral Imaging in Close Range Applications

“…Reference areas for endmember collection can be marked prior to hyperspectral data collection and located within the hyperspectral imagery during data processing. Alternatively, geometric data such as photorealistic lidar/photogrammetric models can be used to locate reference areas after data fusion with the hyperspectral imagery (Kurz et al 2012b). In-situ spectral measurements using high resolution single pixel spectrometers are another possibility to create a reference spectral library of the materials of interest (e.g.…”

“…A number of new and innovative applications have been demonstrated indicating the high potential of the methods in disciplines such as geosciences (e.g. Kurz et al 2012b, Murphy et al 2015, Zaini et al 2014, environmental applications (e.g. Jay et al 2016), medical applications (e.g.…”