Basins, Stratigraphy and Geochronology

Lithostratigraphy is the systematic organization of rocks based on their lithological properties. Bruker’s tools for mineral identification enable a type of quantitative lithostratigraphy or lithotyping. Lithotyping is using classification techniques like cluster analysis or deep learning to group large datasets into meaningful lithofacies-like groupings. Those groupings can be used in stratigraphy and basin analysis to:

• Improve lithostratigraphy correlations by recognizing diagnostic patterns in lithotype occurrence that may not be obvious through optical observations of core, outcrop, or cuttings.

• Conduct high-resolution reconstructions of paleoenvironment by connecting lithotypes to facies or sub-facies, such as tracking underclay-paleosol relationships.

• Make regional sequence stratigraphic or predictive stratigraphic frameworks more robust by removing interruptive bias and increasing repeatability of stratigraphic observations from many wells.

• Collect lithologic data from cuttings and other hard to describe geologic samples, empowering deep-time studies in locations without core or outcrop.

• Create compelling visualizations that enable quick-look assessment of formation breaks, the occurrence of pay in all types of oil and gas wells.

The main technologies used to generate lithostratigraphy logs areautomated mineralogy,X-ray diffraction (XRD)andFTIR spectroscopy.Automated mineralogygenerated quantified maps of minerals from thin sections or grain mounts. Mineral textural information and mineral associations can be used to group results into lithotypes and generate lithology logs, and calculated density or rock property logs.X-Ray diffraction (XRD)andFourier Transform Infrared (FTIR) Spectroscopycan be used to identify minerals and the data can be grouped into lithotypes for logging.

Chronostratigraphy is concerned with establishing the general ages of stratified rocks. Studies of successions of rocks reveal depositional processes through investigations of chemistry, magnetism, fossils, striatal stacking patterns, and superposition relationships to reveal the temporal correlative relationships and the history of the earth. Geochronology is concerned with establishing the absolute age of any rock unit, and in sedimentary geology understanding the timing of processes such as erosion and deformation. The identification, isolation, and analysis of dateable minerals (e.g. zircon) is a primary tool used in both chronostratigraphy and geochronology. Bruker is innovating methods to streamline this process:

• TheM4 TORNADOmicro-XRF geochemical mapping of large samples allows for quick-look assessment of zircon fertility of samples either through geochemical proxies or by direct mineral identification withM4 AMICS.

• AMICS扫描电子显微镜provides automated mineralogical mapping of thin sections and polished grain mounts to identify and quantify dateable minerals.AMICScan be configured to identify target minerals and collect high-quality long-count spectra for quantification.

• BothSEM AMICSandM4 AMICSenables workers to precisely locate the spatial coordinates of dateable minerals on a slide, thin section, or grain mount. Those coordinates can be exported to a LA-ICPMS. This can reduce the total amount of sample processing and concentration needed, including hand picking of grains in mineral separates.