Midcontinent rift system
The 1100 Ma Midcontinent rift system of North America is one of the world's great igneous provinces, containing over one million km of mafic volcanic and plutonic rocks. Volcanic rocks range from picrite to rhyolite, although tholeiitic basalt predominates. Plutonic rocks range from peridotite to granite, with plagioclase-rich gabbros and ...As summarized in several reviews (e.g., Van Schmus and Hinze, 1985, Hinze et al., 1997, Ojakangas et al., 2001, Hinze and Chandler, 2020, Woodruff et al., 2020), the Midcontinent rift system is a >2500-km-long, arcuate structure, defined by broadly coincident gravity, magnetic, and seismic reflection signatures, that formed at ~1100 Ma in response to upwelling of a mantle plume beneath the ...Introduction. The North American Midcontinent Rift System (MRS) is a major magmatic continental rift that stretches approximately 2200 km from Kansas northeast to the Lake Superior region, where it curves southward and is inferred to extend into lower Michigan (Figure 1; Ojakangas et al., 2001a).Because much of the MRS lies beneath Phanerozoic and surficial cover, it was first recognized by a ...
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The Fracture Pattern of North-central Kansas and Its Relation to Hydrogen Soil Gas Anomalies Over the Midcontinent Rift System Volume 88, Issue 25 of Open-file report: Authors: Kansas Geological Survey, Scott Kenneth Johnsgard: Publisher: University of Kansas, Geology, 1988: Length: 112 pages : Export Citation: BiBTeX EndNote RefManEnter the email address you signed up with and we'll email you a reset link.Aug 3, 2018 · The Midcontinent Rift system and surrounding Precambrian rocks are known to host highly significant mineral resources. Our project objectives are to increase understanding of this system through the integration of new and legacy geophysical data with geochemical and borehole data, map the lithology and structure of PreCambrian rocks, and develop an integrated 3D geologic model of the region. The Midcontinent Rift System (MRS) of central North America is a 1.1-Ga, 2500-km long structural feature that has been interpreted as a triple-junction rift developed over a mantle plume. As much ...The U.S. Department of Energy's Office of Scientific and Technical InformationPaces, J.B., and Bell, K., 1989, Non-depleted sub-continental mantle beneath the Superior Province of the Canadian Shield: Nd-Sr isotopic and trace element evidence from Midcontinent Rift basalts: Geochimica et Cosmochimica Acta, v. 53, p. 2023-2035.Midcontinent Rift System. Keweenawan. North America. Precambrian. Proterozoic. Middle Proterozoic. Natural Resources Research Institute. NRRI. University of Minnesota Duluth. UMD. Appears in collections Technical Reports [503] Series/Report Number. NRRI Technical Report; NRRI/TR-95/33. Description.The continental lithosphere which hosts the Midcontinent Rift (MCR) system comprises a crustal assemblage ranging in age from 3.6 to 1.5 Ga. The most voluminous igneous activity along the MCR occurred within Late Archean (2.7 Ga) crust, presumably due to magmatism associated with a rising mantle plume. Two major arms of the rift extend to the ...Gravity map showing Midcontinent Rift (MCR), Fort Wayne Rift (FWR), and East Continent Gravity High (ECGH), computed by upward continuing complete Bouguer anomaly (CBA) data to 40 km and subtracting result from CBA (as shown in the supporting information). Grenville-age Appalachian inliers with Laurentia and Amazonia affinities are shown as ...The prerift crust, however, was thinned 25-30 km beneath the central rift (compared with its flanks), providing evidence for crustal extension by factors of about 3-4. The Midcontinent rift system differs from Phanerozoic rifts in having total crustal thicknesses equal to or greater than the surrounding (presumably unextended) regions.The Fracture Pattern of North-central Kansas and Its Relation to Hydrogen Soil Gas Anomalies Over the Midcontinent Rift System Volume 88, Issue 25 of Open-file report: Authors: Kansas Geological Survey, Scott Kenneth Johnsgard: Publisher: University of Kansas, Geology, 1988: Length: 112 pages : Export Citation: BiBTeX EndNote RefManMidcontinent Rift System The map area can be divided into two stuctural domains, each displaying contrasting structures developed mostly during and shortly after formation of the Midcontinent rift system. The southern half of the area is dominated by a great monoclinal sequence of strata of the Montreal River monocline (Cannon and others, 1993b).Geophysical evidence in the Mid-Continent has led to delineation of a rift system active during the Proterozoic Y Era. The Mid-Continent rift system can be traced by the Mid-Continent gravity high and corresponding aeromagnetic anomaly signature from the surface exposure of the Keweenawan Supergroup in the Lake Superior basin southwest in the subsurface through Wisconsin, Minnesota, Iowa ...1. Introduction. The shallow, dense igneous rocks of North America's 1.1‐Ga failed Midcontinent Rift (MCR) System create a striking magnetic anomaly and gravity high that demarcate the rift axis (Chase & Gilmer, 1973; Hinze et al., 1992; King & Zietz, 1971).The system consists of two arms that converge in the Lake Superior region—one extending southeast through Michigan and one extending ...Open the PDF Link PDF for Segmented structure of the middle Proterozoic Midcontinent Rift System, North America in another window Add to Citation Manager Integrated geophysical modeling of the North American Midcontinent Rift System: New interpretations for western Lake Superior, northwestern Wisconsin, and eastern MinnesotaThe ca. 1100 Ma old Midcontinent Rift System (MRS) 1 is arguably the most significant non-orogenic tectonic feature of mid-North America because of its major disturbance of the lithosphere, vast extent, impact on latter tectonism of the region, and its earth resources.The Midcontinent Rift System (MRS) of central North America is a 1.1-Ga, 2500-km long structural feature that has been interpreted as a triple-junction rift developed over a mantle plume.Introduction. Two prominent Precambrian features of central North America (Fig. 1) record opposite ends of the Wilson cycle. One, the Midcontinent Rift (MCR), is a 3000-km long horseshoe-shaped band of more than 2 million km 3 of buried igneous and sedimentary rocks that outcrop near Lake Superior (Ojakangas et al., 2001; S. Stein et al., 2018).Nov 1, 2020 · The Midcontinent Rift System (MRS) of North America represents a major thermal-tectonic rifting event ca. 1.1 Ga marked by a huge volume of igneous rock emplaced in a relatively short time span of ~30 million years, followed by deposition of a thick package of clastic sediments with subsequent faulting (Wold and Hinze, 1982). Previous Cu isotope work has documented a clear disparity between δ65Cu values of sheet-style (–0.5 to 0.5‰) and conduit-style (0.5–2.0‰) intrusions associated with the Midcontinent Rift ...Rift-wide correlation of 1.1 Ga Midcontinent rift system basalts: implications for multiple mantle sources during rift development. 1997 • Steven Shirey. Download Free PDF View PDF. The Journal of Geology. Detrital Zircon Provenance of the Mesoproterozoic Midcontinent Rift, Lake Superior Region, U.S.A.MIDCONTINENT RIFT SYSTEM BIBLIOGRAPHY By Steven A. Hauck December 1995 Technical Report NRRI/TR-95/33 Funded by the Natural Resources Research Institute In ...
The Midcontinent Rift System (MRS), a 2,700 km long, horseshoe shaped, intra-continental, thermo-tectonic structure of Middle Proterozoic age, extends from central Kansas to at least southern Ohio by way of the Lake Superior basin. Its western arm, geophysically identified as the Midcontinent Gravity High, has recently been clarified ...The U.S. Department of Energy's Office of Scientific and Technical InformationThe Midcontinent Rift System (MRS), a 2,700 km long, horseshoe shaped, intra-continental, thermo-tectonic structure of Middle Proterozoic age, extends from central Kansas to at least southern Ohio by way of the Lake Superior basin. Its western arm, geophysically identified as the Midcontinent Gravity High, has recently been clarified ...The MCR probably formed as part of the rifting of Amazonia (Precambrian northeast South America) from Laurentia (Precambrian North America) and became inactive once seafloor spreading was established. A cusp in Laurentia's apparent polar wander path near the onset of MCR volcanism, recorded by the MCR's volcanic rocks, likely reflects the rifting.Some mafic–ultramafic intrusions in the North American Midcontinent Rift System host disseminated to massive sulfides of magmatic origin. Massive sulfides are also present in the immediate sedimentary country rocks to some of these intrusions, such as Partridge River, Tamarack, and Eagle. Our working hypothesis is that the country rock-hosted massive sulfides are also of magmatic origin. To ...
One notable example of a failed rift elsewhere on the globe is the Midcontinent Rift, which curves for about 1,900 miles (3,000 km) across the Upper Midwest of North America, according to a 2022 ...The project objective is to assess the Duluth Complex and related mafic-ultramafic intrusions in the 1.1 Ga Midcontinent Rift System in the Lake Superior region. Our current activities focus on a Keweenawan igneous intrusion to determine how much platinum-group elements are present, how much could be found, and how it formed.Nov 1, 2020 · The Midcontinent Rift System (MRS) of North America represents a major thermal-tectonic rifting event ca. 1.1 Ga marked by a huge volume of igneous rock emplaced in a relatively short time span of ~30 million years, followed by deposition of a thick package of clastic sediments with subsequent faulting (Wold and Hinze, 1982). …
Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. The Midcontinent Rift System, which curves for more than 2000 km acr. Possible cause: CLASTIC ROCKS MIDCONTINENT RIFT SYST, IA. CLASTIC ROCKS MIDCONTINENT RIFT SYST, IA. .
Geophysical investigations and crustal structure of the North American Midcontinent Rift system (W.J. Hinze et al.). The igneous petrology and magmatic evolution of the Midcontinent rift system (K.W. Klewin, S.B. Shirey). The Midcontinent rift in the Lake Superior region with emphasis on its geodynamic evolution (W.F. Cannon).The Midcontinent Rift System (MRS) of central North America is a 1.1-Ga, 2500-km long structural feature that has been interpreted as a triple-junction rift developed over a mantle plume. As much ...The Midcontinent Rift System (MRS) of central North America is a 1.1-Ga, 2500-km long structural feature that has been interpreted as a triple-junction rift developed over a mantle plume. As much as 20 km of subaerial lava flows, mainly flood basalts, are overlain by as much as 10 km of sedimentary rocks that are mostly continental fluvial red ...
Stein proposes a three-armed rift system, formed of the Midcontinent Rift and the two arms that split Laurentia and Amazonia. “In a lot of locations, when the continents break apart you seem to ...Open the PDF Link PDF for Segmented structure of the middle Proterozoic Midcontinent Rift System, North America in another window Add to Citation Manager Integrated geophysical modeling of the North American Midcontinent Rift System: New interpretations for western Lake Superior, northwestern Wisconsin, and eastern MinnesotaPseudosections of magnetotelluric (MT) responses for the eight high-frequency controlled-source audio (CSA) MT soundings plus the 14 wideband MT soundings across the Midcontinent rift system and ...
Abstract and Figures. This chapter discusses the The Midcontinent Rift system and surrounding Precambrian rocks are known to host highly significant mineral resources. Our project objectives are to increase understanding of this system through the integration of new and legacy geophysical data with geochemical and borehole data, map the lithology and structure of PreCambrian …The continental lithosphere which hosts the Midcontinent Rift (MCR) system comprises a crustal assemblage ranging in age from 3.6 to 1.5 Ga. The most voluminous igneous activity along the MCR occurred within Late Archean (2.7 Ga) crust, presumably due to magmatism associated with a rising mantle plume. Two major arms of the rift extend to the ... Moho reflections recorded in Lake Superior ovThe Mid-continent rift system can be traced by the Mid-c The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton, began to split apart during the Mesoproterozoic era of the Precambrian, about 1.1 billion years ago. The rift failed, leaving behind ...Clastic Rocks, Midcontinent Rift System, Iowa I1. Abstract. The Middle Proterozoic Midcontinent Rift System (MRS) of North America is a failed rift that formed in response to region-wide stresses about 1,100 Ma. In Iowa, the MRS is buried beneath 2,200–3,500 ft of Paleozoic and Mesozoic sedimentary rocks and Quaternary glaciogenic deposits. The continental lithosphere which hosts the Midcontinent Rift (M The failed rift, known as the Midcontinent Rift, occurred about 1.1 billion years ago, and underlies Lake Superior and much of Iowa, Minnesota, and Michigan. Although the rift did not succeed in dividing the continent, it did bring vast quantities of minerals to the upper layers of the Earth’s crust, including iron-rich minerals that could ... True amplitude processing of The Great Lakes International MuPrice, K.L. & McDowell, S.D. (1993) Illite/smecrift arm to the east. The Nebraska segment of the Mid-Cont rift arm to the east. The Nebraska segment of the Mid-Continent Rift System parallels fabrics within the earlier Central Plains Orogen [35]. In the southern part of the study area, within eastern Kansas, the Mid-Continent Rift System is cut by a series of NW-SE trending dextral strike-slip faults, on which there have been historical earthquakes ... New results from the ca. 1.1 Ga Midcontinent The Midcontinent Rift System of North America is a ∼1.1 Ga large igneous province comprising mainly flood basalts and intrusive rocks. We present new data for the Pillar Lake Volcanics and Inspiration Sill from the northern edge of the Midcontinent Rift in the northwestern Nipigon Embayment. The Pillar Lake Volcanics comprise a ∼20-40 m thick, flat-lying sequence of mafic pillowed and ... The Duluth Complex (Minnesota, USA) is one of the largest m[The Middle Proterozoic Midcontinent Rift System i@article{osti_6434014, title = {Mid-continent rift system: a fron We present a detailed velocity model across the 1.1 billion year old Midcontinent Rift System (MRS) in central Lake Superior. The model was derived primarily from onshore-offshore large-aperture seismic and gravity data. High velocities obtained within a highly reflective half-graben that was imaged on coincident seismic reflection …