Archean to Anthropocene: Field Guides to the Geology of the Mid-Continent of North America
This volume of 25 field guides plus one paper on field instruction was prepared in conjunction with the 2011 GSA Annual Meeting in Minneapolis, Minnesota. The diverse slate of field trips spans a geologically broad range of topics, including the Precambrian geology of the southern Canadian Shield; the economic geology of the Lake Superior region; Phanerozoic strata in Minnesota, Wisconsin, Iowa, and North Dakota; glacial geology; hydrogeology and limnology; undergraduate and K12 geoscience field education; archaeological investigations in the upper Mississippi River valley; and geology by bicycle.
Late Paleoproterozoic deformational, metamorphic, and magmatic history of east-central Minnesota
-
Published:January 01, 2011
-
CiteCitation
Terry Boerboom, Daniel Holm, Randy Van Schmus, 2011. "Late Paleoproterozoic deformational, metamorphic, and magmatic history of east-central Minnesota", Archean to Anthropocene: Field Guides to the Geology of the Mid-Continent of North America, James D. Miller, George J. Hudak, Chad Wittkop, Patrick I. McLaughlin
Download citation file:
- Share
Abstract
This field trip examines deformed Archean basement, and variably metamorphosed supracrustal rocks and an exhumed midcrustal batholith of late Paleoproterozoic age in east-central Minnesota. Collectively, these rocks reveal an approximately 100 m.y. geologic history of crustal growth and stabilization of this part of the craton. The Penokean orogen in Minnesota consists of a northern foreland basin (the Animikie basin), a medial fold-thrust belt, and a southern high-grade metamorphic and plutonic terrane, representing two major orogenic events: the Penokean (geon 18) and Yavapai (geon 17) orogenies. The 1870–1830 Ma Penokean orogenic rocks are part of a belt of juvenile crust accreted onto the southern margin of Laurentia-Baltic continent during the late Paleoproterozoic. Metamorphism along the southern margin of the Archean Superior province has been historically attributed to the Penokean Orogeny, in a corridor of amphibolite-facies rocks which record 1.86–1.80 Ga (geon 18) metamorphic ages that correspond to the culmination of arc accretion. However, a widespread geon 17 amphibolite-facies metamorphic overprint is also recorded along the regions of greatest thickening of the Penokean crust, which corresponds to the tectonically buried Archean-Proterozoic continental margin. This was also the locus of emplacement of the voluminous east-central Minnesota batholith, composed of some twenty separate intrusions that range from mafic to dominantly felsic-intermediate compositions. Most of these are Yavapai in age, with emplacement ages between 1787 and 1772 Ma.
- amphibolite facies
- batholiths
- Canadian Shield
- facies
- field trips
- fold and thrust belts
- guidebook
- high-grade metamorphism
- intrusions
- magmatism
- metamorphic rocks
- metamorphism
- Minnesota
- North America
- orogeny
- overprinting
- Paleoproterozoic
- Penokean Orogeny
- Precambrian
- Proterozoic
- road log
- Superior Province
- supracrustals
- tectonic elements
- tectonics
- United States
- upper Precambrian
- east-central Minnesota