Midcontinent rift system.

Introduction. Three major Precambrian crustal elements are inferred to underlie Phanerozoic strata in the eastern midcontinent of Laurentia: (1) the Grenville Front Tectonic Zone, the latest Mesoproterozoic to earliest Neoproterozoic western boundary of the Grenville orogen; (2) the East Continent Rift System, a southerly extension of the …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 ...Oct 1, 2022 · Generalized geology of the Lake Superior region with Midcontinent Rift-related intrusions, showing the location of the Tamarack intrusion, the Eagle intrusion, and the Duluth Complex relative to ... Dec 8, 2022 · 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. On the basis of similarities in lithology, stratigraphy, structure, and proximity to regional gravity anomalies, the Middle Run Formation and its apparent half-graben basin is proposed as evidence for the probable extension of the Midcontinent Rift System southward, from its normally accepted termination in southeastern Michigan, into ...

Imposed on this framework of crystalline rocks are the volcanic and sedimentary rocks of the Midcontinent rift system. Both the main trend of the rift and related volcanic and plutonic outliers reflect the pre-existing tectonic framework of the older orogens. Chemically the volcanic rocks of the rift are tholeiites.

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 through Wisconsin, Minnesota, Iowa, Nebraska, and Kansas. Outcrop and well penetrations of the late rift Keweenawan sedimentary rocks reveal ...

The Tamarack Intrusive Complex (TIC, 1105.6 ± 1.2 Ma) in NE Minnesota, was emplaced during the early stages of the development of the Midcontinent Rift System (MRS, "Early Stage": 1110-1106 Ma).Country rocks of the TIC are those of the Paleoproterozoic Thomson Formation, part of the Animikie Group including sulfide-bearing metasedimentary black shale.By using a combination of physical sedimentological and geochemical proxies, it is possible to reconstruct the provenance, weathering intensity, and depositional setting for sedimentary rocks associated with the 1.1 Ga failed Midcontinental Rift system on the Keweenaw Peninsula, Michigan, USA. Conglomerates from the syn-rift Portage Lake ...The 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 ...Prominent examples of rift failure include the North Sea, the West African Rift System and the Midcontinent Rift underlying the Great Lakes of North America. Rifting stopped in these cases because ...

MRS Midcontinent Rift System PLV Portage Lake Volcanics SBAS Satellite Based Augmentation Systems USCG United States Coast Guard USGS United States Geological Survey . viii . Abstract The Keweenaw Fault (KF) has been interpreted as arift-bounding normal fault along the southern margin of the Midcontinent Rift System; later inverted …

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 ...

Feb 7, 2022 · 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 ... 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 ...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 ...The resistivity signature of the 1.1 Ga Mid-continent Rift System is examined in detail, in particular as relates to rift geometry, extent, and segmentation. An unrecognized expanse of (concealed) Proterozoic deltaic deposits in Kansas is identified and speculated to result from axial drainage along the southwest rift arm akin to the Rio Grande ...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, Nebraska, and Kansas. The aeromagnetic anomaly signature of the rift ... 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 ...

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 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.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 ...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 Midcontinent Rift System (MRS) is a major Precambrian magmatic province on the North American continent. It formed when the North American craton began to split apart during the Mesoproterozoic era (1,100 Ma). As a result of the extension and possibly the effects of a rising mantle plume, a thick layer of basalt and numerous reverse and normal faults were formed. The basalt layer is ...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).

2. Simplified map of the Midcontinent Rift defined from gravity sur­ veys 4 3. Detailed structural interpretation of the Superior Zone of the Mid-continent Rift System 5 4. General geology of the western Lake Superior Basin part of the Mid-continent Rift System 6 5. General stratigraphic section in the western part of the Lake Superior Basin 7Jan 25, 2018 · The Midcontinent Rift System, which curves for more than 2000 km across the Upper Midwest, is one of the world’s great continental rifts. Rifting began about 1.1 billion years ago, when the Earth’s crust began to split along the margin of the Superior craton.

"The rift system is splitting Africa and rifting Arabia away from it, forming new ocean basins in the Red Sea and Gulf of Aden," explained Seth Stein, ... Detailed mapping of the underground Midcontinent Rift using gravity data from G. Randy Keller, professor of geophysics at the University of Oklahoma in Norman and director of the Oklahoma ...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).Abstract. Two prominent Precambrian geologic features of central North America are the Midcontinent Rift (MCR) and Grenville Front (GF). The MCR, an extensive band of buried igneous and sedimentary rocks outcropping near Lake Superior, records a major rifting event at ca. 1.1 Ga that failed to split North America.Lake Superior is the largest freshwater lake in the world by surface area and the third-largest by volume, holding 10% of the world's surface fresh water. Located in central North America, it is the northernmost and westernmost of the Great Lakes of North America, straddling the Canada-United States border with the Canadian province of Ontario to the north and east and the U.S. states of ...The Keweenaw Fault (KF) has been interpreted as a -bounding normal fault along the rift southern margin of the southwest arm of t he Midcontinent Rift System (MRS) , which was later inverted into a reverse fault by a tectonic compression event (Cannon, 1994; Hinze and Braile, 1990).Exposures in the Lake Superior region, and associated geophysical evidence, show that a 2000 km-long rift system developed within the North American craton ??? 1109-1087 Ma, the age span of the most of the volcanic rocks. This system is characterized by immense volumes of mafic igneous rocks, mostly subaerial plateau basalts, generated in two major pulses largely by a hot mantle plume.They are essential for the U.S. economy; however the U.S. imports about 90 percent of the platinum-group elements that we need to use. 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...

The 1.1 Ga Middle Proterozoic Midcontinent Rift System (MRS) is a major intracontinental, thermo-tectonic structure that is traced by gravity and magnetic data, subsurface drilling, and outcrop control over a length of 2,000 km within the central United States (Van...

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 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 kimberlites of Riley and Marshall Counties are located just east of the mid-continent rift system in north-eastern Kansas (Fig. 1) and intrude Permian age limestone and shale of the Chase ...Geophysical investigations and crustal structure of the North American Midcontinent Rift systemThe 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 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 through Wisconsin, Minnesota, Iowa, Nebraska, and Kansas. ... This new round of wildcatting is located on the Midcontinent rift trend, a …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 ...Generalized geology of the Lake Superior region with Midcontinent Rift-related intrusions, showing the location of the Tamarack intrusion, the Eagle intrusion, and the Duluth Complex relative to ...The Midcontinent Rift's present structure results from the combined effects of a sequence of rifting, volcanism, sedimentation, subsidence, compression, erosion, and any later effects (Stein et al., 2015; S. Stein et al., 2018). The large positive gravity anomalies along the MCR primarily reflect the large volume of high-density igneous rocks ...

It is also associated with the Proterozoic Midcontinent Rift System, which extends into northern Kansas about fifty miles west of the Nemaha. [2] Along the Nemaha Ridge is a series of faults referred to as the "Nemaha Fault Zone".In the United States, the Duluth Complex in Minnesota, comprised of a group of mafic intrusions related to the 1.1 Ga Midcontinent Rift system, represents a major Ni resource of 8 Mt Ni, but deposits generally exhibit low grades (0.2 percent Ni, 0.66 percent Cu) and remain in the process of being proven economic.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 ...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...Instagram:https://instagram. kelley cooperprofessional work attirecottagecore starter house minecraftrti model tiers 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 through Wisconsin, Minnesota, Iowa, Nebraska, and Kansas. ... This new round of wildcatting is located on the Midcontinent rift trend, a …The Mesoproterozoic Midcontinent Rift System (MRS), formed about 1.1 Ga, is a large arcuate structure located in central North America.It is the most striking anorogenic geologic feature observed within the Precambrian basement rocks forming the North American craton. polymc hackedmedia law programs Time resolution of geologic events on the Keweenaw Peninsula and implications for development of the Midcontinent Rift system. Author links open overlay panel D.W. Davis 1, J.B. Paces * 2. Show more. Add to Mendeley. Share. ... Evolution of the Midcontinent Rift: a perspective from the stratigraphy and chemistry of the Mamainse … gradley dick 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.The Paleoproterozoic (2.5-1.7 Ga) Midcontinent rift system of the northeastern Fennoscandian Shield V. F. Smolkin. V. F. Smolkin Search for other works by this author on: ... Varzuga belt is an intracontinental paleorift system formed during four stages: prerifting (2.55-2.30 Ga), early rifting (2.30-2.20 Ga), late rifting (2.20-1.95 Ga ...