TY - JOUR
T1 - The basement revealed
T2 - Tectonic insight from a digital elevation model of the Great Unconformity, USA cratonic platform
AU - Marshak, Stephen
AU - Domrois, Stefanie
AU - Abert, Curtis
AU - Larson, Timothy
AU - Pavlis, Gary
AU - Hamburger, Michael
AU - Yang, Xiaotao
AU - Gilbert, Hersh
AU - Chen, Chen
N1 - Funding Information:
National Science Foundation award 1053551 (for the EarthScope OIINK array) partially supported this work. We thank many colleagues for helpful discussions, Steve Whitmeyer, Randy Keller, and an anonymous reviewer for insightful comments, and the Illinois State Geological Survey for providing computational support.
Publisher Copyright:
© 2017 Geological Society of America.
PY - 2017/5/1
Y1 - 2017/5/1
N2 - Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a > 0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
AB - Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a > 0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
UR - http://www.scopus.com/inward/record.url?scp=85017547825&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85017547825&partnerID=8YFLogxK
U2 - 10.1130/G38875.1
DO - 10.1130/G38875.1
M3 - Article
AN - SCOPUS:85017547825
SN - 0091-7613
VL - 45
SP - 391
EP - 394
JO - Geology
JF - Geology
IS - 5
ER -