A GIS-based method for archival and visualization of microstructural data from drill core samples.

Core samples obtained from scientific drilling could provide large volumes of direct microstructural and compositional data, but generating results via the traditional treatment of such data is often time-consuming and inefficient. Unifying microstructural data within a spatially referenced Geographic Information System (GIS) environment provides an opportunity to readily locate, visualize, correlate, and explore the available microstructural data. Using 26 core billet samples from the San Andreas Fault Observatory at Depth (SAFOD), this study developed procedures for: 1. A GIS-based approach for spatially referenced visualization and storage of microstructural data from drill core billet samples; and 2. Producing 3D models of sample billets and thin section positions within each billet, which serve as a digital record after irreversible material loss and fragmentation of physical billets. This approach permits spatial registration of 2D thin section ‘base maps’ within the core sample billets, where each billet is represented by 3D solid surface (produced via SFM photogrammetry) and internal structure models (acquired with micro-CT scans) created prior to sectioning. The spatial positions of the base maps were established within locally defined coordinate systems in each core billet’s solid surface model. The GIS database structure provided interactive linkage to the results of various analyses performed throughout the map at a wide range of scales (e.g. SEM and CL images as well as text and numerical data) within each thin section. The viability of the proposed framework was demonstrated via display of integrated microstructural data, creation of vector point information associated with features of interest in CL imagery, and development of a model for extraction and unsupervised classification of a multi-generation calcite vein network from the CL imagery. The results indicate that a GIS can facilitate the spatial treatment of 2D and 3D data even at centimeter to nanometer scales, building upon existing work which is predominantly limited to the 2D space of single thin sections. Conversely, the research effort also revealed several challenges, particularly involving intensive 3D representations and complex matrix transformations required to create geographically translated forms of the within-billet coordinate systems, which are suggested for consideration in future studies

Automated analysis of pottery by QEM-EDS: A case study from Mansiri, Sulawesi

The analysis of raw materials and manufacturing techniques is central to the investigation of pottery assemblages. While various analytical techniques exists, petrography generally remains the go-to method to analyse the fabric of pottery. It combines relatively cheap and simple sample preparation protocol with the ability to yield very detailed information related to provenance and manufacturing technique. Here, we test the utility of performing QEM-EDS on archaeological pottery from the Mansiri site, Sulawesi, to complement petrographic observations. We identify the main non-plastic inclusions as plagioclase, quartz, calcic amphibole, iron oxides and volcanic rock fragments, consistent with the pottery being made locally. Quantitative analysis of inclusion size and direction suggests that the non-plastic inclusions were not manually added, and that in contrast to other Neolithic Sulawesi sites, coiling with beating/paddle and anvil was used to manufacture the pots

Documenting archaeological thin sections in high-resolution: A comparison of methods and discussion of applications

Optical thin section observations represent the core empirical basis for most micromorphological interpretations at archaeological sites. These observations, which often vary in size and shape, are usually documented through digital graphic representations such as photomicrographs, scans, or figures. Due to variability in documentation practices, however, visual thin section data can be captured with a range of methods and in many different formats and resolutions. In this paper, we compare and evaluate five common image‐based methods for documenting thin sections in high‐resolution: a flatbed scanner, a film scanner, a macro photography rig, and conventional stereo and light microscopes. Through the comparison results, we demonstrate that advances in digital imaging technology now allow for fast and high‐resolution visual recording of entire thin sections up to at least ×30 magnification. We suggest that adopting a digital micromorphological documentation practice has several advantages. First, a digital thin section may be observed more efficiently and consistently, for example, on a computer screen, and the spatial configuration of large or complex features may be more accurately documented. Second, they allow for the establishment of digital repositories that may promote scientific reproducibility and inter‐laboratory communication, as well as lay the foundations for more consensus‐based educational training of archaeological micromorphology.publishedVersio

Electron probe micro-analysis of the Woodford Shale, south central Oklahoma

Thesis (M.S.)--University of Oklahoma, 2011.Includes bibliographical references (leaves 117-123).Three samples from the Wyche-1, Late Devonian Woodford Shale, OU-DevonSchlumberger research core were analyzed with a Cameca SX-50 electron probe microanalyzer with the aim of characterizing the mineralogy of very fine grained shale samples perpendicular to their laminations and with a vertical resolution < 100 micrometers. The samples chosen for analysis were the remaining pieces of core material that had been prepared by Sierra (2011) for geomechanical experimentation. Micro-mineralogy of the samples was accomplished from chemical analyses performed by Wavelength Dispersive X-ray Spectrometry (WDS) and the resulting data were plotted as micro-mineralogy logs. Elemental Capture Spectroscopy logs (ECS - trade mark of Schlumberger), generated from capture gamma-ray spectroscopy in cased and uncased boreholes, can be thought of as analogous to micro-mineralogy logs, but with coarser vertical resolutions between 1.5 ft (uncased boreholes) to 2.5 ft (cased boreholes) (Schlumberger, 2000). Additional techniques performed with the aim to complement the WDS analysis included Backscattered Electron (BSE) imaging, which was taken throughout each sample and along each WDS spot analysis transect line, Energy Dispersive X-ray Analysis (EDXA) to characterize mineral phases when examining samples in live-time BSE imaging, X-ray intensity mapping of a selected area within a calcite-clay laminated couplet, and plane/cross polarized light microscopy of "sister" petrographic thin sections. Overlapping BSE images acquired along each WDS analysis transect line were stitched into a photomontage producing an image log analogous to lower vertical resolution image logs produced using borehole imaging tools. To finalize each micro-mineralogy log for visual analysis, the micro-mineralogy log, BSE photomontage, and digitally-scanned image of a complete thin section were scaled and cross-correlated. Analysis of all the data sets for each sample allowed for micro-stratigraphic observations and interpretations. Cross plots of micro-mineralogy log organics versus individual mineral phases allowed for trends to be observed showing decreases in organic content within more brittle calcite-cemented quartz laminations and increases in organic content within more ductile clay laminations. Such brittle-ductile couplet combinations offer the potential for lamination scale reservoir-source amalgamations if targeted for hydraulic fracture. Tasmanites algal cyst identification, the diagenetic precipitation of quartz and pyrite within such palynomorphs, and the variety of observed cyst compaction features offered evidence for inferences about changes in rate of deposition, radiolarian test origins for internal cyst diagenetic quartz, and activity pulses by bacterial sulfate reducing organisms based on internal cyst pyrite precipitation. The presence of fine calcite grains with distinct circular morphologies also presented evidence for calcareous algae or calcareous coral-spore deposition. Observations of minor detrital apatite bone fragments as well as organic-rich apatite grains provided inferences for anoxic ocean water conditions. Based on the methods employed in this thesis, I recommend that electron probe micro-analysis of core, sidewall core, and cutting samples be integrated into the reservoir characterization of gas shales because microprobes have spatial resolution on scales at or near the realm of shale grains and can more accurately provide high resolution mineralogic data for geomechanical modeling upon which many hydraulic fracture completions of gas shale reservoirs are now based

Building stone assessment of the Ardrossan Sarcophagus

BGS has been asked by Patrick Murray, acting on behalf of Ardrossan Castle Heritage Society, to examine a stone coffin known as The Ardrossan Sarcophagus (Figure 1). The sarcophagus, which is presently housed at North Ayrshire Heritage Centre in Saltcoats, is believed to date from medieval times. Ardrossan Castle Heritage Society are conducting research to identify the origins of the sarcophagus, and to explore its historical background and significance

Technical note : TRACKFlow, a new versatile microscope system forfission track analysis

We here present TRACKFlow, a new system with dedicated modules for the fission track (FT) laboratory. It is based on the motorised Nikon Eclipse Ni-E upright microscope with the Nikon DS-Ri2 full frame camera and is embedded within the Nikon NIS-Elements Advanced Research software package. TRACKFlow decouples image acquisition from analysis to decrease schedule stress of the microscope. The system further has the aim of being versatile, adaptable to multiple preparation protocols and analysis approaches. It is both suited for small-scale laboratories and is also ready for upscaling to high-throughput imaging. The versatility of the system, based on the operators’ full access to the NIS-Elements package, exceeds that of other systems for FT and further expands to stepping away from the dedicated FT microscope towards a general microscope for Earth Sciences, including dedicated modules for FT research. TRACKFlow consists of a number of user-friendly protocols which are based on the well plate design that allows sequential scanning of multiple samples without the need of replacing the slide on the stage. All protocols include a sub-protocol to scan a map of the mount for easy navigation through the samples on the stage. Two protocols are designed for the External Detector Method (EDM) and the LA–ICP–MS apatite fission track (LAFT) approach, with tools for repositioning and calibration to the external detector. Two other tools are designed for large crystals, such as the Durango age standard and U-doped glass external detectors. These protocols generate a regular grid of points and inspect if each point is suitable for analysis. Both protocols also include an option to image each withheld point. One more protocol is included for the measurement of etch pit diameters and one last protocol prepares a list of coordinates for correlative microscopy. In a following phase of development TRACKFlow can be expanded towards fully autonomous calibration, grain detection and imaging

Mineral texture identification using local binary patterns equipped with a Classification and Recognition Updating System (CARUS)

In this paper, a rotation-invariant local binary pattern operator equipped with a local contrast measure (riLBPc) is employed to characterize the type of mineral twinning by inspecting the texture properties of crystals. The proposed method uses photomicrographs of minerals and produces LBP histograms, which might be compared with those included in a predefined database using the Kullback–Leibler divergence-based metric. The paper proposes a new LBP-based scheme for concurrent classification and recognition tasks, followed by a novel online updating routine to enhance the locally developed mineral LBP database. The discriminatory power of the proposed Classification and Recognition Updating System (CARUS) for texture identification scheme is verified for plagioclase, orthoclase, microcline, and quartz minerals with sensitivity (TPR) near 99.9%, 87%, 99.9%, and 96%, and accuracy (ACC) equal to about 99%, 97%, 99%, and 99%, respectively. According to the results, the introduced CARUS system is a promising approach that can be applied in a variety of different fields dealing with classification and feature recognition tasks. © 2022 by the authors