Proterozoic history of the midcontinent region of North America
Journal Article
·
· Geology; (United States)
Age and petrographic data from the buried basement of the midcontinent region of North America, integrated with information from exposed rocks and magnetic- and gravity-anomaly maps, allow much of the Proterozoic history of the region to be assembled. Between 1780 and 1720 Ma, a major orogen developed along the southern margin of the continent and is exposed in Arizona and Colorado. These rocks are volcanogenic and, for the most part, juvenile additions to the crust; they can be traced beneath the plains as far as eastern Kansas and Nebraska. Another orogen formed farther to the south about 1700-1630 Ma and is exposed in southern Arizona and New Mexico; rocks of this age and type have been traced as far east as central Missouri but may extend as far as central Michigan. A major geophysical feature of the midcontinent is a system of northwest-trending magnetic and gravity anomalies in Missouri, Kansas, and Nebraska; the origin of these is not currently understood. The tectonic history of the midcontinent between 1480 and 1340 Ma was dominated by extensional formation of two widespread granite-rhyolite terranes that evidently were formed from, and overlie, the orogenic provinces. The older, formed 1450-1480 Ma, underlies the eastern midcontinent, whereas the younger, formed 1340-1400 Ma, underlies the southwestern midcontinent. The latest Proterozoic events were the formation of the midcontinent rift system and the collisional Grenville and Llano provinces about 1100 Ma. 60 references, 2 figures.
- Research Organization:
- Univ. of Kansas, Lawrence
- OSTI ID:
- 5503475
- Journal Information:
- Geology; (United States), Journal Name: Geology; (United States) Vol. 14:6; ISSN GLGYB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Middle proterozoic tectonic activity in west Texas and eastern New Mexico and analysis of gravity and magnetic anomalies
Early Proterozoic transcontinental orogenic belts in the United States
Geology and geophysics of Proterozoic basement rocks in the eastern midcontinent of the United States
Conference
·
Mon Feb 28 23:00:00 EST 1994
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:6899559
Early Proterozoic transcontinental orogenic belts in the United States
Conference
·
Sun Jan 31 23:00:00 EST 1993
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5932944
Geology and geophysics of Proterozoic basement rocks in the eastern midcontinent of the United States
Conference
·
Tue Dec 31 23:00:00 EST 1991
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5707421