Sedimentology and Structure Working Group

Sedimentology and Structure Working Group of the Intermountain West Project

Research Topics

Basin Analysis Within the Intermountain West

• Stratigraphy and depositional environments: Geologic mapping, measured sections, field samples, and drillhole data are paired with accessory geochronology, paleontology, geochemistry, geophysics, and/or provenance data, etc., to enhance regional stratigraphic frameworks. Emphasis is placed upon depositional settings that facilitate physical or chemical accumulation of potential economic deposits of critical minerals or energy resources and secondary processes that mobilize and concentrate resources within specific rock assemblages.
• Stratigraphic architecture and sedimentary processes: Spatial and temporal variations within and between alluvial, fluvial, eolian, lacustrine, and marine deposits, as well as their bounding stratigraphic surfaces, are analyzed to understand the drivers of sedimentation, mineralization, alteration, and resource migration in the geologic record.
• Paleodrainage evolution and source-to-sink studies: New and existing geochronology, isotope, and paleocurrent data are analyzed to determine sediment sources and paleodrainage pathways across the Cordillera that control the dispersion and distribution of soft rock economic deposits across the continent from eroded hard rock or reworked point sources.
• Paleogeography and landscape evolution: Paleo-landscape models are constructed to test the links and feedbacks between tectonic activity, structural deformation, uplift, basin accommodation, and drainage evolution. These connections help define a systems-based framework to guide exploration for undiscovered critical minerals and energy resources and reinterpretation of previously identified deposits through coordinated study with our colleagues in the Energy and Mineral Resources Mission Area.

Structural Analysis Within the Intermountain West

• Structural analysis: Petrographic and outcrop assessment of deformation fabrics, mineralogical changes, and rheology of sheared and brecciated rocks are combined with meso- and macro-scale mapping of structures and shear-sense data to reconstruct deformational history and understand the role of deformation in generating and controlling critical mineral deposits.
• Data synthesis: Petrographic analyses, field measurements, and map geometries of structures are integrated at regional scale to derive holistic, kinematic interpretations of a wide variety of tectonic and magmatic systems that generate deformation and host potential critical mineral deposits or control distribution of energy or water resources.
• Fault kinematics: Dynamics of fault partitioning, fault-tip propagation, reactivation, strain transfer, and complex, coseismic fault geometries are analyzed to better understand the effects of faults in orogenic systems and the impacts upon the geometry of basin-fill deposits that host critical mineral, energy, and water resources.  
• Balanced cross-sections: Schematic representations of structural and stratigraphic geometries are built to characterize 3-D geologic frameworks and test structural models of basin geometry and resource distribution at depth below surface cover materials.
• Metamorphism and mylonitic shear zones: In coordination with the Igneous and Metamorphic Working Group, petrochronology, isotope analysis, and geothermobarometry are paired with geologic mapping and microstructural analysis to test basement rock tectono-magmatic associations with localized, mid-crustal shear and build tectonic models explaining crustal assembly and deformation within zones of critical mineral potential.
• Integration of geophysical data to improve structural understanding: Airborne data acquisitions by EarthMRI targeting zones of known or suspected critical mineral potential are paired with traditional mapping to interpret complex cross-cutting relationships that are important for understanding tectonic history and resource genesis and distributions.
• Big data analysis: Statistical trends in large datasets of contact, fault, fold, foliation, and lineation orientations across entire structural provinces are analyzed for patterns and variations to assess deformation models and geometric constraints upon critical mineral and energy resource potential.