DOI: 10.1016/j.tecto.2020.228369
论文题名: Tectonic implications of the gravity signatures of the Midcontinent Rift and Grenville Front
作者: Elling R.P. ; Stein S. ; Stein C.A. ; Keller G.R.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 778 语种: 英语
中文关键词: Grenville Front
; Midcontinent Rift
英文关键词: Geophysical prospecting
; Lakes
; Sailing vessels
; Seismic response
; Gravity anomalies
; Gravity effects
; Grenville Front
; Lake Superior
; Midcontinent Rift
; Potential field datum
; Sheet structure
; Tectonic implications
; Seismic waves
; continental drift
; gravity anomaly
; magnetic anomaly
; rifting
; seismic data
; tectonic evolution
; Alabama
; Canada
; Michigan
; United States
英文摘要: North America's Midcontinent Rift (MCR) and Grenville Front (GF) jointly record aspects of the complex history of the assembly of Rodinia. The ~1100 Ma MCR, remaining from a failed major rifting event, is exposed along Lake Superior and well defined by gravity, magnetic, and seismic data. The GF, which results from collisions with Laurentia, is exposed in and identified by seismic and potential field data in Canada. In the eastern U.S., lineated gravity highs extending southward from Michigan to Alabama, along the trend of the front in Canada, have been interpreted either as a buried Grenville Front or as part of the MCR's east arm. We explore this issue by examining the gravity signatures of the MCR and GF. Both the MCR's arms have pronounced gravity highs, with the west arm's greater than the east arm's. Combining the gravity observations with seismic data suggests that the west arm contains 20–25 km thickness of volcanics, whereas the east arm contains 10–15 km of volcanics. Along the Grenville Front in Canada, thickened crust along the northern portion causes a broad gravity low, whereas the stacked thrusts along the southern portion cause essentially no gravity signature. Hence the lineated gravity highs in the eastern U.S. appear similar to those along the remainder of the MCR, and unlike those on either portion of the GF. These data favor the gravity anomalies traditionally interpreted as the Grenville Front in the eastern U.S. as instead being part of the MCR's east arm. A thrust sheet structure like that of the southern Canadian Grenville Front - which would have essentially no gravity effect - could also be present along the MCR's east arm, as implied by recent EarthScope seismic data. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170575
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: Dept. of Earth & Planetary Sciences, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3130, United States; Dept. of Earth & Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607-7059, United States; School of Geology and Geophysics, University of Oklahoma, 100 E. Boyd, Norman, OK 73019, United States
Recommended Citation:
Elling R.P.,Stein S.,Stein C.A.,et al. Tectonic implications of the gravity signatures of the Midcontinent Rift and Grenville Front[J]. Tectonophysics,2020-01-01,778