1. USArray and the Great Plains
A summary of
the Pre-EARTHSCOPE WORKSHOP
Kansas State University
April, 2003
Mary Hubbard, Steve Gao, Kelly Liu,
Jack Oviatt, and Kirsten Nicolaysen

2. Identified areas of interest (including the RM transition)
GREAT PLAINS WORKSHOP
Meeting format
Identified areas of interest (including the RM transition)
Submitted projects
Future plans

3. 40 participants
3 day event
Invited talks, volunteered posters, large group brainstorming, small working group sessions
Follow-up meeting

4. SELECTED TARGET AREAS RIFT FEATURES TERRANE BOUNDARIES
BASINS AND UPLIFTS
ROCKY MOUNTAIN-GREAT PLAINS TRANSITION
KIMBERLITES AND ANOMALOUS INTRUSIVES

5. Rift Features Mid Continent rift Reel Foot fault zone Rio Grande rift
Why thick crust?
Does the mantle have normal or low velocity?
What are fabrics in crust and mantle that might affect anisotropy?
Lingering thermal effect?
Reel Foot fault zone
Rio Grande rift

6. Terrane Boundaries
Need to understand evolution of cratons and pre-collisional environment
Where are terrane boundaries - how many collisions?
Timing of collisions
Sense of movement on boundaries
Influence of terrane structures on Phanerozoic deformation
Preservation of ancient slabs

7. Basins and Uplifts
What are primary causes of basin formation in the mid-continent (Illinois basin and Michigan basin)?
What is relation to deep structure?
When did basins form?
What caused Black Hills uplift?
Is there a relation to the ancient craton vs. platform settings?

8. Rocky Mountain to Great Plains transition
What is timing of surface uplift
Does uplift history vary from north to south
What is relationship of crustal thickness to uplift
How do mantle variations compare to surface response
Is there a Farallon slab?

9. Kimberlites and Anomalous Intrusives
Magma source
Depth of source
Time of emplacement
Cause of intrusives
Relation to other tectonic activity

10. Submitted Projects
Illinois Basin - crust/mantle using industry seismic (McBride)
Lithospheric structure across Wy, Trans-H, Sup Provinces (South Dakota project: Collaborative)
Bighorns (Erslev, Sheehan et al.)

11. SOUTH DAKOTA PROJECT
Integrated geologic and geophysical study aimed at understanding continental assembly, and the relationship between modern crustal and mantle properties to past tectonic activity

12. SOUTH DAKOTA PROJECT Geologic study of Black Hills exposures
Image transition from thin to thick crust
Cenozoic uplift
Farallon slab
Multi-university, student/faculty research with outreach component
(map from Karlstrom et al., 1999)

13. FUTURE PLANS Resubmittal of early proposals
Superior Working group meeting in 2005 (Tikoff, Holms et al.?)
Southern Great Plains Project (Keller et al.)
Geotraverse???

14. THE MID-CONTINENT:

15. AN OROGENY WAITING TO HAPPEN!

16. THANK YOU!