Synthesis of regional scale geophysical geochemical and geologic

Synthesis of regional scale geophysical, geochemical and geologic models Heather Bedle University of Oklahoma • Load crustal and mantle tomographic models, seismic reflection data, gravity, and magnetic data into Petrel ( a 3 D geological modeling software). Also incorporate thermal and geochemical models (if available). • Have acquired a few seismic reflection datasets. Some of these datasets are legacy and missing some important loading and acquisition information, so still a work in process. • Next step will to locate thermal, gravity and magnetic information. Possibly well logs, and geologic maps, LIDAR? • Once datasets are properly synthesized, data can be co-rendered and concurrently synthesized, hopefully revealing new insights into the upper mantle and crustal evolution. • Variation in resolution of datasets • Relating geophysics-geology-geochemistry • Can also include large scale insights (Kevin Chamberlain’s observations of differences between regions)

Initial S-velocity tomographic model test input B A C A) S-velocity model NA 07 (Bedle and van der Lee, 2009) revealed some insights into the Wyoming craton structure as compared to adjacent cratons. 1 D comparison of cratonic S-velocity structure is shown in (B). Initial loading of tomographic model into Petrel revealed issues with interpolation and resolution (C), methods to fix the algorithm and apply to other higher-resolution tomographic models is being investigated.

NA 07 into 3 D modeling software - Petrel 120 km depth

NA 07 into 3 D modeling software - Petrel 120 km depth

NA 07 into 3 D modeling software – co-rendered with magnetic anomalies 120 km depth

NA 07 into 3 D modeling software - Petrel SLC 90 km depth

NA 07 into 3 D modeling software - Petrel Worthington e Wyoming 90 km depth with variance co-render

Next step: WUS 08 and other IRIS published tomographic models • • Used USArray TA stations Reparametrized model space to 75 km grid Goal is to load multiple P- and S- models into a software platform where they can be directly compared, manipulated, and synthesized Bedle (2008)

Seismic Reflection data • Working to get active and passive seismic results loaded • 2 D lines: • COCORP (20 s) – Wyoming, Montana • WY 1 & WY 2 – southern Wind River 160 km • WY 3, 4, 5, 6 - Laramie • MT 3 -7 – northern MT, Sweetgrass Arch, Bearpaw Mtns • MT 8 -12 –cross Wy craton, trans-Hudson boundary • Powder River Basin (14 -18 s) • Link stratigraphy to mantle processes? • 2 D and 3 D: Teapot Dome (3 s) – just north of Casper. • Probably not too useful, but if anyone is grappling with shallow crustal issues near the Arch/Proto. Boundary, I’d be glad to help Worthington et al. (2016)

Legacy WY-2 COCORP reflection seismic data WY-2 COCORP seismic reflection data extends to 20 s depth (~33 km). Modern reprocessing and analysis may be able to provide new insights into the deep Archean crustal structure.

Need more data!!! • Looking for results of: • CDROM, Deep Probe, BASE • 2 D- Bighorn Basin (6 s) • Other types of data to synthesize: • Gravity • UTEP site down in December • Geochem? • Xenolith data points • Detailed crustal maps? • Receiver function results Worthington et al. (2016) • Other regional (finer resolution) tomographic models? • Rayleigh wave tomography of crust? (Shen et al. , 2013) • Teleseismic P-wave? (Humphries et al. , 2015) • Shear Rayleigh wave model (Dave and Li, 2018) • What do models from different datasets reveal (ex. surface & body)? GOALS: 1) Bridge the gap between small-scale surface observations and large-scale lithosphere models 2) Combine geochemical, geological (structure and stratigraphy), and geophysics to allow direct comparison for improved synthesis

References Papers: • Bedle, H. , 2008. Studies on the S-velocity structure of the North American upper mantle (dissertation) • Bedle, H. , and S. van der Lee, 2009. S velocity variations beneath North America, J. Geophys. Res. , 114, B 07308, doi: 10. 1029/2008 JB 005949 • Dave, R. , and A. Li, 2016. Destruction of the Wyoming craton: Seismic evidence and geodynamic processes, Geology, vol. 44, iss. 11, p 883 -886, doi: 10. 1130/G 38147. 1 • Humphries, E. D. , B. Schmandt, M. J. Bezada, J. Perry-Houts, 2015. Recent craton growth by slab stacking beneath Wyoming, EPSL, v 429, p 170 -180, doi: 10. 1016/j. epsl. 2015. 07. 066 • Shen, W. , Ritzwoller, M. H. , and Schulte-Pelkum, V. , 2013. A 3 -D model of the crust and uppermost mantle beneath the central and western US by joint inversion of receiver functions and surface wave dispersion: Journal of Geophysical Research, v. 118, p. 262– 276, doi: 10. 1029 /2012 JB 009602 • Worthington, L. L. , K. C. Miller, E. A. Erslev, M. L. Anderson, K. R. Chamberlain, A. F. Sheehan, W. L. Yeck, S. H. Harder, and C. S. Siddoway, 2016. Crustal structure of the Bighorn Mountains region: Precambrian influence on Laramide shortening and uplift in north-central Wyoming, Tectonics, 35, 208– 236, doi: 10. 1002/2015 TC 003840 Data: • Petrel license courtesy of Schlumberger to the University of Oklahoma • Kingdom license courtesy of IHS to the University of Oklahoma • COCORP 2 D seismic project funded by the National Science Foundation, and Continental Dynamics Program, data available through Cornell • Teapot Dome 2 D and 3 D data available courtesy of DOE and RMOTC • NA 07 (Bedle, 2009), and WUS 08 (Bedle, 2008)