Study of Upper Albian rudist buildups in the Edwards Formation using ground-based hyperspectral imaging and terrestrial laser scanning

Abstract

Ground-based hyperspectral imaging is used for development of digital outcrop models which can facilitate detailed qualitative and quantitative sedimentological analysis and augment the study of depositional environment, diagenetic processes, and hydrocarbon reservoir characterization in areas which are physically inaccessible. For this investigation, ground-based hyperspectral imaging is combined with terrestrial laser scanning to produce mineralogical maps of Late Albian rudist buildups of the Edwards formation in the Lake Georgetown Spillway in Williamson County, Texas. The Edwards Formation consists of shallow water deposits of reef and associated interreef facies. It is an aquifer in western Texas and was investigated as a hydrocarbon play in south Texas. Hyperspectral data were registered to a geometrically accurate laser point cloudgenerated mesh with sub-pixel accuracy and were used to map compositional variation by distinguishing spectral properties unique to each material. More calcitic flat-topped toucasid-rich bioherm facies were distinguished from overlying porous sucrosic dolostones, and peloid wackestones and packstones of back-reef facies. Ground truth was established by petrographic study of samples from this area. This research integrates high-resolution datasets to analyze geometrical and compositional properties of this carbonate formation at a finer scale than traditional methods have achieved and to model the geometry and composition of rudist buildups.

Detection of Magnesite and Associated Gangue Minerals using Hyperspectral Remote Sensing—A Laboratory Approach

“…The acquired hyperspectral images were preprocessed following the workflow of [33,40]. Moreover, the image pixels corresponding to the sample images were selected for further processing, excluding the background pixels.…”

“…[34] defined the zonation of limestone and dolostone using a HySpex-320m Specim hyperspectral short wave infrared (SWIR) hyperspectral scanner. [33] detected limestone, dolostone, chert-cemented dolostone, fossiliferous limestone, chert, and carbonate nodules in a sedimentary layer with 80% accuracy using a SWIR hyperspectral scanner. [35] determined the Ca/Mg content in dolomite and calcite using a SisuCHEMA hyperspectral scanner.…”

“…Compared to the traditional laboratory tests, high efficiency and non-destructive spectroscopic analysis using hand-held spectrometers or airborne hyperspectral remote sensing were proposed to expedite the mineral classification. Specifically, superior to multispectral remote sensing [22][23][24][25][26][27], hyperspectral images have been collected for mineralogy studies from space-borne [28][29][30], air-borne [31,32], or ground-based platforms [33][34][35]. For example, [30] explored hydrothermal alteration zones for the limestone area based on EO-1 Hyperion data and defined dolomite and chlorite distributions.…”

“…Those minerals have common absorption features manifested by CO 3 at 1800 and 2160 nm. The absorption feature at 2300 nm is controlled by the proportion between Mg and Ca contents [33]. The absorption feature causes a minor shift in spectral position, which is affected by its Mg and Ca content, where the absorption of magnesite is at 2300 nm, that of dolomite is at 2320 nm, and that of calcite is at 2340 nm [34].…”

Integrated Hyperspectral and Geochemical Study of Sediment-Hosted Disseminated Gold at the Goldstrike District, Utah

“…The reflectance curve contains physical and chemical properties of the material since chemical bonds absorb light at specific wavelengths [21]. Ground-based hyperspectral imaging has been widely used in geologic characterizations [15,[22][23][24][25][26][27][28], in which variations of the sub-centimeter or sub-millimeter scale can be resolved. This study used hyperspectral imaging to identify mineralogy as well as to extract relative abundances of the minerals.…”