The U.S. Department of Energy's Office of Scientific and Technical InformationThe Proterozoic Midcontinent Rift System of North America is remarkably similar to Phanerozoic rifted continental margins and flood basalt provinces. Like the younger analogues, the volcanism within this older rift can be explained by decompression melting and rapid extrusion of igneous material during lithospheric extension above a broad ...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 ...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 ...The U.S. Department of Energy's Office of Scientific and Technical InformationThe Keweenaw fault system along Lake Superior’s south shore in Michigan, USA is one of the most significant fault systems associated with North America’s Midcontinent Rift System.The major rift-bounding structure on the west side of the Midcontinent Rift System in Kansas is referred to as the Peace Creek Tectonic Zone (fig. 1; Berendsen and Blair, 1986). It is recognizable in the subsurface in southern Kansas, but cannot be mapped into the Salina basin, because of the paucity of available data.Objective: to test geophysical interpretations of the Proterozoic geology in northeastern Iowa by: 1) drilling a scientific borehole through Paleozoic cover to Proterzoic basement, 2) recover core from the Proterozoic basement sufficient for petrologic and radiometric analyses, and 3) obtain data on the overlying Paleozoic section to improve und...@article{osti_6422744, title = {Mid-Continent rift system: a frontier hydrocarbon province}, author = {Lee, C K and Kerr, Jr, S D}, abstractNote = {The Mid-Continent rift system can be traced by the Mid-Continent geophysical anomaly (MGA) from the surface exposure of the Keweenawan Supergroup in the Lake Superior basin southwest in the subsurface …Both sites are located along the 1200-mile Midcontinent Rift System, a tectonic fissure through the middle of North America. Building A Hydrogen Market.The 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 is a 1.1-b.y.-old structure extending from Kansas, through the Lake Superior region, and into southern Michigan. The rift is filled with thick sequences of basaltic ...Transcript. [A map of North America shows the Midcontinent Rift System as a red line curving through the Great Lakes and down through the midwestern United States.] 1.1 billion years ago, the North American continent began to split in half. [Black Hat stands at a lectern with a "Vote 2020" sign on it. He gestures to an image of the globe with a ...The Nebraska segment of the Mid-Continent Rift System parallels fabrics within the earlier Central Plains Orogen . 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 [39,40].Grenville orogenic belt. In Precambrian: Orogenic belts. …was the formation of the Midcontinent (or Keweenawan) rift system that extends southward for more than 2,000 …Ni-Cu-PGE sulfide mineralization in the Midcontinent rift system can be broadly classified into three types: (1) disseminated sulfide mineralization found within gabbroic to troctolitic sheet-like intrusions; (2) disseminated through massive sulfide occurrences associated with smaller, early rift, mafic to ultramafic intrusions that are conduit-related, and (3) relatively low sulfide, PGE ...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 …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 ...The Midcontinent Rift System: A major Proterozoic continental rift Author(s) ... John Mariano, 1997. "The Midcontinent Rift System: A major Proterozoic continental rift", Middle Proterozoic to Cambrian rifting, central North America, Richard W. Ojakangas, Albert B. Dickas, John C. Green. Download citation file: Ris (Zotero) Refmanager;Opening of the Midcontinent Rift System and, presumably, the East Continent Rift basin, occurred after the Shawinigan phase of the Grenvillian orogeny (~1190-1120 Ma) in the region that was ...The Midcontinent Rift System. Figure 2. Generalized map of the western Lake Superior region showing the distribution of major rock types of the Midcontinent rift and locations of known Ni-Cu sulfide mineralization in …14 Nis 1990 ... The Eischeid well was Amoco's first test of the petroleum potential of the Midcontinent Rift System (MRS), a failed rift in the crust that.The Hranice Abyss (Czech Republic), with a reached depth of 473.5 m, is the deepest mapped extent of such a system globally, although its maximum depth is unknown. Multiple geophysical data sets (gravity, electrical resistivity tomography, audiomagnetotellurics, and seismic refraction and reflection) are used to investigate the extent and ...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 mid-continent rift system failed, for reasons that are not completely clear, but we'll talk about one possible factor in a couple days. So it never reached the stage of true ocean crust, like the Red Sea, but was always like the complex system of troughs, mountain chains, and volcanoes that mark the East African rift today. ...The Midcontinent Rift System Figure 2. Generalized map of the western Lake Superior region showing the distribution of major rock types of the Midcontinent rift and locations of known Ni-Cu sulfide mineralization in Minnesota and Wisconsin.The Keweenawan Midcontinent rift system was imposed upon the terrane suture in our study area at ca. 1100 Ma. This event nearly separated the ancient continent and imparted enormous volumes of mafic magma to various depths in the crust (Hinze et al., 1997; Nicholson et al., 1997; Vervoort et al., 2007; Stein et al., 2015), engendering numerous high-grade base and precious metal deposits ...Precise resolution of the timing of igneous activity is crucial to understanding the dynamic processes associated with continental rifting. Mafic intrusive rocks constitute a major portion of the exposed 1100 Ma (Keweenawan) Midcontinent Rift system in northeastern Minnesota; however, prior to this study, geochronological data were insufficient to allow rigorous interpretation of intrusive ...The Midcontinent Rift (MCR) in midwestern Canada and the U.S. stopped short of actually splitting North America, and today offers a snapshot of an ancient stage of the continental rifting process. (Photo at left) Northwestern University graduate students Emily Wolin and Jessica Lodewyk install a SPREE seismic station in northern Wisconsin.you time lyrics
The East Continent Rift Basin (ECRB) is a newly recognized, dominantly sedimentary-volcanic Proterozoic rift basin that apparently represents the southern extension of the Keweenawan Midcontinent Rift. The ECRB extends from central Michigan at least as far south as south-central Kentucky. The inferred age of the rift fill is approximately 1,000 Ma.This project is focused on the sediment-hosted copper deposits of the Midcontinent Rift, with three main objectives: 1) describe the ore mineralogy and geochemistry of the White Pine and Copperwood deposits, 2) evaluate whether hydrothermal alteration in footwall rocks can be used as a vector towards ore, and 3) provide a careful scoping study to evaluate whether unconventional platinum-group ...Midcontinent Rift System Bibliography. Steven Hauck. 1995. See Full PDF Download PDF. See Full PDF Download PDF. Related Papers. The Journal of Geology. Detrital Zircon Provenance of the Mesoproterozoic Midcontinent Rift, Lake Superior Region, U.S.A. 2013 • Alexandros Konstantinou.Comparisons between the Midcontinent rift system and the Voisey Bay and Noril'sk settings point to several similarities that suggest that the Midcontinent rift is a likely setting for Ni-Cu mineralization. The continental rifting and associated voluminous igneous activity in all three regions formed in response to the rise of a hot plume of ...Magmatic Ni-Cu-PGE mineralization in the ~ 1.1 Ga Midcontinent Rift System ( Fig. 1 ) in North America can be broadly divided into three types (see a recent rev iew by Ripley, 2014 ).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). To the south, it is buried by younger sediments ...igneous activity and sedimentation along the midcontinent rift system at about 1100 Myr ago. This appears to be the youngest Precambrian igneous activity in the midcontinent region. To the east of the midcontinent region is the Grenville Province, which represents a major crustal event. The Grenville Province is large andThe Mesoproterozoic Midcontinent Rift System (MRS) of North America hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface. Historically, hydrothermal deposits, such as Michigan's native copper deposits and the White Pine sediment-hosted stratiform ...RESEARCH. Architecture of the hidden Penokean terrane suture and Midcontinent rift system overprint in eastern Minnesota and western Wisconsin from magnetotelluric profiling. R.L. Wunderman1,*, P.E. Wannamaker2,†, and C.T. Young1,§ 1DEPARTMENT OF GEOLOGICAL AND MINING ENGINEERING AND SCIENCES, MICHIGAN TECHNOLOGICAL UNIVERSITY, 1400 TOWNSEND DRIVE, HOUGHTON, MICHIGAN 49931, USA 2ENERGY ...oklahoma state baseball 2023
igneous activity and sedimentation along the midcontinent rift system at about 1100 Myr ago. This appears to be the youngest Precambrian igneous activity in the midcontinent region. To the east of the midcontinent region is the Grenville Province, which represents a major crustal event. The Grenville Province is large andThe Mid-Continent Rift System (MCRS) is a 3000-km long failed rift system that formed within the Precambrian continent of Laurentia and nearly split North America apart about 1.1 billion years ago. The MCRS can also be classified as a Large Igneous Province (LIP), made up of two distinct magmatic phases [Stein et al., 2015]. The first, large-scale syn-rift magmatism, is characterized by a ...Midcontinent Rift System in Northeastern Kansas Timothy S. Woelk 1 and William J. Hinze 2. 1 ARCO Oil & Gas Company and 2 Purdue University This article available as an Acrobat PDF file (6.7 Mb). Introduction. One of the major tectonic features of North America is the 1,100-Ma Midcontinent Rift System (MCR). The Midcontinent Rift System (MRS) is an approximately 2,200 km curvilinear Mesoproterozoic rift that stretches from Kansas northeast to the Lake Superior region where it turns southeast and extends through lower Michigan. Although rocks of the MRS are largely buried beneath younger rocks except around the margins and on islands of Lake ...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 ...Volcanism in the Midcontinent rift system lasted between 1108 and 1086 Ma. Rates of flood-basalt eruption and subsidence in the western Lake Superior region appear to have been greatest at the ...Paces J B, Miller J D. Precise U-Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights into physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga midcontinent rift system. J Geophys Res, 1993, 98: 13997–14013THE MIDCONTINENT RIFT SYSTEM | Annual Review of Earth and Planetary Sciences. Publications A-Z. Journal Information. About. Subscribe. Give. Home. Annual Review of Earth and Planetary Sciences. Volume 13, 1985.The Middle Proterozoic Midcontinent Rift System is one of the world's great continental rifts. This 1,100-Ma rift, which extends more than 2,000 km across the North American craton, is a major ...bellingham craigslist missed connections
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 data demonstrate the dominantly mafic composition of the ...The 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. It is the most prominent feature of gravity and magnetic anomaly maps of ...Aug 3, 2020 · The Midcontinent Rift System (MRS) of North America is one of the world’s largest continental rifts and has an age of 1.1 Ga (giga-annum). The MRS hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface. Midcontinent Rift. The Midcontinent Rift (MCR), a 3000-km-long band of more than 2 million km 3 of buried igneous and sedimentary rocks that outcrop near Lake Superior, has been extensively studied, as reviewed by Ojakangas et al. (2001) and S. Stein et al. (2018). To the south, it is buried by younger sediments, but easily traced because the rift-filling volcanic rocks are dense and highly ...The Eagle Ni-Cu-(platinum-group element, PGE) deposit in northern Michigan is associated with mafic-ultramafic intrusions that formed during the early stages of picritic magmatism in the ~1.1 Ga Midcontinent Rift System (a, b in Fig. 1).Ding et al. (2010, 2011) have described the general setting of the deposit, age, characteristics of the parental magmas, and their petrochemical evolution.The Midcontinent Rift of North America is a ca. 1.1 Ga, 3000-km-long failed rift that nearly split the Precambrian continent of Laurentia. Unlike most continental rifts, which are filled with a mixture of volcanic rocks and sediments, the Midcontinent Rift contains a large volume of flood basalts that were emplaced during both syn- and post …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 ...The Keweenaw Peninsula lies on the southern flank of the Mid-Continent Rift system (MCR) of North America. The MCR extends for about 2,000 kilometres from Kansas northeast through Lake Superior, then southeast through the lower peninsula of Michigan where it ends abruptly near Detroit, Michigan. The MCR began forming around 1,100 million years ...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 Midcontinent Rift System (MRS) is a 1.1 Ga sequence of voluminous basaltic eruptions and multiple intrusions followed by widespread sedimentation that …The Midcontinent Rift System (MRS) is an example of a matic-dominated continental rift where silicic magmatism is locally significant. The best-preserved example of this is on the NE limb of the rift along the North Shore of Lake Superior where rhyolites comprise a large percentage (up to 25%; Green, J.C., Fitz, T.J., 111, 1993. Extensive ...1. Introduction [2] The recent discovery of the Eagle Ni-Cu-PGE deposit in Upper Michigan represents a major breakthrough in the exploration for magmatic sulfide deposits in the Midcontinent Rift System (MRS) ().Prior to the Eagle discovery, sulfide mineralization in the MRS was known to occur mainly in the basal zones of large layered mafic intrusions within the Duluth and Mellen complexes ...African Rift System. The Anza graben is the southeastern continuation of the Cretaceous oil- and gas-prolific Central African Rift System, which extends into Kenya from the Melut and Muglad Basins of Southern Sudan where Cretaceous working petroleum systems have been proved and oil discovered. From: Developments in Earth Surface Processes, 2013.The Midcontinent Rift System (MRS) is expressed geophysically by a semi-linear, regional gravity high that trends across the Midcontinent and Great Lakes region of North America. The gravity high is interrupted by two prominent, semi-circular gravity lows, which have been interpreted from modeling and seismic-reflection sections as basement ...Previous Cu isotope work has documented a clear disparity between d65Cu values of sheet-style (-0.5 to 0.5‰) and conduit-style (0.5-2.0‰) intrusions associated with the Midcontinent rift system.The Midcontinent rift system is one of only seven basins globally that host a giant … Expand. Save. Reconstructing Nitrogen Sources to Earth's Earliest Biosphere at 3.7 Ga. E. Stüeken Toby J. Boocock K. Szilas S. Mikhail N. Gardiner. Geology, Environmental Science. Frontiers in Earth Science.jack lockton
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).To the south, it is buried by younger sediments, but easily ...The Midcontinent Rift System (MRS) of North America is one of the world's largest continental rifts and has an age of 1.1 Ga (giga-annum). The MRS hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface. As part of the construction of a database summarizing information on mineral deposits in the MRS ...The Midcontinent rift system is a 1.1-b.y.-old structure extending from Kansas, through the Lake Superior region, and into southern Michigan. The rift is filled with thick sequences of basaltic ...The overall structure of the suite is that of a sill with a dike-like keel. In places the intrusion forms a sill, and the base of the sill is imaged in the reflection data. This rift event is contemporaneous with formation of the Midcontinent rift system, Pikes Peak Batholith and the intrusion of diabase sills in California, Nevada and Arizona.The Midcontinent Rift System Figure 2. Generalized map of the western Lake Superior region showing the distribution of major rock types of the Midcontinent rift and locations of known Ni-Cu sulfide mineralization in Minnesota and Wisconsin. Rifts Connected to the Mid-continent Rift System. A rift may extend from the western end of the Southern Oklahoma Aulacogen westward into Colorado. The Pikes Peak Granite is alkalic and was intruded about 1.04 by ago (Barker et al., 1975), possibly along a rift.Enter the email address you signed up with and we'll email you a reset link.and conduit-style (0.5-2.0‰) intrusions associated with the Midcontinent Rift System. The application of metal isotopes to the study of magmatic Ni-Cu-platinum group element (PGE) deposits is ...The Humboldt Fault (red) and Midcontinent Rift System (green) in Kansas and Nebraska. The Humboldt Fault or Humboldt Fault Zone, is a normal fault or series of faults, that extends from Nebraska southwestwardly through most of Kansas. Kansas is not particularly earthquake prone, ranking 45th out of 50 states by damage caused.The Mesoproterozoic Midcontinent Rift System (MRS) of North America hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface. Historically, hydrothermal deposits, such as Michigan's native copper deposits and the White Pine sediment-hosted stratiform ...New teleseismic data and images have prompted new models for the evolution of the Midcontinent rift system (Zhang et al., 2016; Stein et al., 2018; Bollmann et al., 2019) and an increasing ...North America's Midcontinent Rift (MCR) is an unusual combination, because its 3000-km length formed during a continental breakup event 1.1 Ga, but it contains an enormous volume of igneous rocks that are mostly flood basalt.Picrites and tholeiites from the Mamainse Point Formation, a 5.3 km thick section of Keweenawan (1100 Ma) volcanic and sedimentary fill on the eastern flank of the central portion of the Midcontinent rift system, contain a nearly continuous record of rift magmatic activity. Picrites occur primarily in the lowermost two units of the formation. In this study, they are compared to rarely exposed ...Collaborative Research: Geophysical Investigation of the Mid-Continent Rift System. NSF Org: EAR Division Of Earth Sciences: Awardee: UNIVERSITY OF OKLAHOMA: Initial Amendment Date: September 24, 2012: Latest Amendment Date: September 18, 2014: Award Number: 1147761: Award Instrument:jackson goddardThe Nonesuch Formation, a black siltstone, was deposited in the Lake Superior portion of the mid-continent rift system during middle Proterozoic rifting. Despite its age of nearly 1.1 Ga, the Nonesuch Formation contains liquid petroleum and solid pyrobitumen. Numerical modeling techniques were used in this study to constrain the thermal history ...The Midcontinent Rift System (MRS) is an approximately 2,200 km curvilinear Mesoproterozoic rift that stretches from Kansas northeast to the Lake Superior region where it turns southeast and extends through lower Michigan. Although rocks of the MRS are largely buried beneath younger rocks except around the margins and on islands of Lake ...The Midcontinent rift system is a 1.1-b.y.-old structure extending from Kansas, through the Lake Superior region, and into southern Michigan. The rift is filled with thick sequences of basaltic volcanic rocks and clastic sediments. For most of its extent it is buried beneath Paleozoic rocks but can be traced by its strong gravity and magnetic ...Enter the email address you signed up with and we'll email you a reset link.The Midcontinent rift system cuts across terranes ranging in age from 3.6 to 1.65 Ga. The location of the rift south of Lake Superior in Minnesota, Michigan, Wisconsin, Iowa, Nebraska, and Kansas is inferred from gravity and magnetic data. Pseudosections 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 ...The Coldwell Complex represents the largest alkaline intrusion associated with the Midcontinent Rift System in North America. This complex contains a plethora of rock types that have previously been subdivided into three intrusive centers. A detailed U-Pb zircon/baddeleyite age study of five samples indicates that the majority of the complex was emplaced into "cold" Archean crust at 1108± ...The Midcontinent Rift System (MRS) of North America is one of the world’s largest continental rifts and has an age of 1.1 Ga (giga-annum). The MRS hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface.Abstract. Continental rifting at 1.1 Ga produced approximately 1.3 × 10 6 km 3 of igneous rocks over a rift length of 2200 km (Midcontinent Rift System, MRS). These constitute one of the largest as well as oldest flood basalt provinces. Both geophysical (Hutchinson et al. 1990) and geochemical evidence (Nicholson and Shirey 1990) suggest that ...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 …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 beds.The Midcontinent Rift System (MCRS) is a 1.1 billion-year-old failed rift system that spans much of the North American continental interior. The MCRS is exposed at Lake Superior and is buried in the subsurface along its southwest-extending arm through southeastern Nebraska. Due to the presence ofA geophysical profile of the southern margin of the midcontinent rift system in western Lake SuperiorThe tholeiitic Eastern Gabbro is a composite pluton that wraps around the eastern and northern margins of the Coldwell Complex, the latter of which is an undeformed and unmetamorphosed suite of alkaline igneous rocks that intruded the Archean rocks of the Schreiber–Hemlo greenstone belt as part of the North American Midcontinent rifting …dmv cheat sheet free pdf
We report the ages of detrital zircons (207 Pb/ 206 Pb LA-ICPMS; n p 1188) from 12 clastic units that are representative of the Mesoproterozoic Midcontinent Rift System (MRS) of North America.Magmatism of the MRS spanned 1115-1085 Ma. The Puckwunge, Nopeming, and Bessemer basal sandstones and the Oronto and Bayfield Group sandstones …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.Mar 1, 2002 · 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 ... Compressional-wave seismic velocity (velocity) and bulk density (density) data were compiled from published sources for rock suites and earth materials that are significant for geophysical modeling of the Mesoproterozoic Midcontinent Rift System in the Lake Superior region. The data include laboratory measurements of outcrop and drill core samples, seismic refraction studies, and a sonic log ...The Keweenaw Peninsula lies on the southern flank of the Mid-Continent Rift system (MCR) of North America. The MCR extends for about 2,000 kilometres from Kansas northeast through Lake Superior, then southeast through the lower peninsula of Michigan where it ends abruptly near Detroit, Michigan. The MCR began forming around 1,100 million years ...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.His presentation illustrates, using a giant crowbar, the completion of the Midcontinent Rift, which is a large crack that started to form about 1.1 billion ...26 Eyl 2016 ... The Midcontinent Rift was discovered by geophysicists who noticed that gravity was stronger in some parts of the upper Midwest than in others.A geophysical profile of the southern margin of the midcontinent rift system in western Lake SuperiorThe 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.gooden drew
The Midcontinent Rift System (MRS) is a Late Mesoproterozoic (∼1.1 Ga) sequence of volcanic and sedimentary rocks exposed in the Lake Superior Region of North America. The MRS continues to be the focus of much research due to its economic mineral deposits as well as its archive of Precambrian life and tectonic processes. In order to constrain the post-depositional thermal history of the MRS ...The Midcontinent Rift System is a 1,500-km (900-mi) long Middle Proterozoic aborted rift extending from the Lake Superior region southwestward into Kansas (Sims, 1990). The rift can be divided into three distinct segments (Dickas and Mudrey, 1989) separated from each other by accommodation structures.Recent drilling of the midcontinent rift system in northeastern Kansas reveals a transposed Keweenawan stratigraphy of mafic volcanic rocks overlying thick clastic sedimentary rocks. A reprocessed version of COCORP Kansas Line 1 indicates that the drillhole penetrated a series of west-dipping reflectors associated with a reverse fault …Magmatism that accompanied the 1.1 Ga Midcontinent rift system (MRS) is attributed to the upwelling and decompression melting of a mantle plume beneath North America. Five distinctive flood-basalt compositions are recognized in the rift-related basalt succession along the south shore of western Lake Superior, based on stratigraphically correlated major element, trace element, and Nd isotopic ...