S37. Understanding the regional 3D structural evolution of the Intermountain West through time

Developing integrated regional- to national-scale map databases and earth models requires greatly improved understanding of the structure of the earth in three dimensions. To meet this challenge in the intermountain west, the USGS seeks a postdoctoral researcher in structural geology and tectonics to aid in reconstructing the 3D evolution of regional-scale structures. As part of their duties the postdoctoral researcher will contribute to construction of geologic map databases and 3-D/4-D framework models within a transect from the Rio Grande rift to the Basin and Range. Within this framework they will be expected to develop a complimentary research agenda that advances our understanding of tectonics in the intermountain west.

Geologic map data are a fundamental starting point for earth-science research and resource assessments. However, existing regional-scale geologic map coverage of the Western U.S. Cordillera is inconsistent, mismatched across administrative borders, and often decades out-of-date. These datasets are neither synthesized or integrated, resulting in conceptual and boundary discontinuities within the data that limit its scientific and predictive capabilities. The USGS Intermountain West project was launched to modernize our understanding of the geology within a transect extending from the Rio Grande rift through the Basin and Range. The goal is to produce a digital geologic map and 3D geologic model built by synthesizing existing geologic maps with targeted new mapping, subsurface data, and ancillary data sets (e.g., geochronology and geochemistry). This data set will provide a foundation for geologic research and resource assessments and serve as a platform for developing new workflows for digital data compilation and serving data to stakeholders and the public.

The Intermountain West transect encompasses the full range of orogenic episodes and tectonic deformation that characterize the western United States, from the Proterozoic to the present-day. Sedimentary basins formed during both compression and extension are critical repositories of energy resources and groundwater. Faults served to both localize ore-forming fluids and structurally disrupt or bury mineral deposits formed at earlier times. The modern landscape of some of our most iconic National Parks is the product of erosion modulated by tectonics and climate, and active faults pose hazards to life and property. Recent advances in analytical tools and numerical models have enhanced our ability to quantify rates and kinematics of deformation both now and in the distant past. The successful postdoctoral applicant will propose research that develops and utilizes regional 3D models of geologic structures to understand phenomena like those mentioned above. Possible research topics may include, but are by no means limited to, the following:

—From the Cretaceous to the early Cenozoic, the transect area was subject to both Sevier thin-skinned deformation and Laramide reverse faulting. How do the timing, spatial extent, and kinematics of these different styles of shortening compare within the transect area? Do they overlap spatially and temporally or are they distinct?

—Continental extension and magmatism are closely related, but the extent to which each is a cause or consequence of the other is often unclear. By integrating new regional models of extensional faulting with ongoing efforts to refine the timing of magmatism, can we evaluate links between continental extension and magmatism in the Basin and Range and Rio Grande rift? How do the records of deformation and magmatism in these provinces compare?

—It is often hypothesized that modern orogens are sensitive to climatic controls. Are there differences in the style of deformation recorded in fault kinematics or regional cross sections, or differences in the history of subsidence recorded in ancient basins, that might record the impacts of ancient climate on orogenic evolution?

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.

Proposed Duty Station: Lakewood, CO

Areas of PhD: Structural geology, tectonics, or related disciplines; expertise in 3D modeling is desirable but not necessary (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet the qualifications for: Research Geologist

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Human Resources Office Contact: Audrey Tsujita, 916-278-9395, atsujita@usgs.gov