Archean and Proterozoic tectono-magmatic activity along the southern margin of the Superior Province in northwestern Iowa, United States

1993 ◽  
Vol 30 (6) ◽  
pp. 1275-1285 ◽  
Author(s):  
Kenneth E. Windom ◽  
W. Randall Van Schmus ◽  
Karl E. Seifert ◽  
E. Timothy Wallin ◽  
Raymond R. Anderson
Keyword(s):  
United States ◽  
Iron Formation ◽  
Superior Province ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Minnesota River ◽  
Rock Types ◽  
Tectonic Environment ◽  
Juvenile Crust ◽  
Archean Greenstone Belt

A Precambrian igneous body of ultramafic and mafic rocks, named the Otter Creek layered igneous complex, occurs within the basement of northwestern Iowa, United States. It is marked by a circular magnetic anomaly, one of several that lie north and west of an inferred suture between the Archean Superior Province and Early Proterozoic juvenile crust. Sm–Nd whole-rock analyses for several rock types from the Otter Creek complex yield an isochron age of 2890 ± 90 Ma, with an εNd(t) of −0.9 ± 2.4. A block of older banded iron formation, itself intruded by lamprophyre dikes, is contained within the layered sequence. The iron formation – lamprophyre block has undergone high-temperature metamorphism followed by a retrograde event. A quartz monzodiorite gneiss, with a U–Pb age of 2523 ± 5 Ma, occurs near the layered complex, but the contact relations are not known. The layered series is overlain by Proterozoic keratophyre with a U–Pb age of 1782 ± 10 Ma. These felsic pyroclastic rocks are extremely depleted in K, Rb, Ba, and Cs. Our data are consistent with Archean greenstone-belt formation, including chemical sedimentation followed by mafic–ultramafic magmatism at approximately 2.9 Ga, followed by two later episodes of magmatism, one at approximately 2.5 Ga and the other at approximately 1.78 Ga. The Otter Creek complex is the first Archean greenstone reported south of the Great Lakes Tectonic Zone (GLTZ); its 2.9 Ga age is older than those reported for the granite–greenstone rocks north of the GLTZ. The southern portion of the Superior Province thus appears to have formed later, and in a different tectonic environment, than the high-grade gneisses of the Minnesota River Valley, but before the bulk of the granite–greenstone rocks exposed in northern Minnesota, Ontario, and eastern Manitoba.

Mineral chemistry, P-T pseudosection and in-situ U-Th-Pbtotal monazite geochronology of Banded Iron Formation from Bundelkhand craton North-Central India, and its geodynamic significance

2021 ◽  
Author(s):  
Mohd Baqar Raza ◽  
Pritam Nasipuri ◽  
Hifzurrahman
Keyword(s):  
Central India ◽  
Mineral Chemistry ◽  
Iron Formation ◽  
Age Group ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Third Age ◽  
The Third ◽  
Hydrothermal Activities

<p>The Banded Iron Formation (BIF) in Bundelkhand craton (BuC) occurred as supracrustals associated with TTG’s, amphibolites, calcsilicate rocks, and quartzite within the east-west trending Bundelkhand tectonic zone (BTZ). The BIFs near Mauranipur do not show any prominent iron-rich and silica-rich layer band and are composed of garnet, amphibole, quartz, and magnetite. The volumetrically dominant monoclinic-amphiboles are grunerite in composition. X<sub>Mg</sub> of grunerite varies between 0.39-0.37. The garnets are Mn-rich, the X<sub>Spss</sub> of garnet ranges from 0.26-0.20, X<sub>Pyp</sub> and X<sub>Grs </sub>vary between 0.10-0.06 and 0.07-0.05, respectively. P-T pseudosection analysis indicates that by destabilizing iron-silicate hydroxide phases through a series of dehydration and decarbonation reactions, amphibole and garnet stabilized in BIF at temperature 400-450°C and pressure 0.1-0.2 GPa.</p><p>Massive type BIFs have monazite grains that vary from 10 to 50 µm in size, yield three distinct U-Th-Pb<sub>total</sub> age clusters. 10-20 µm sized monazite grains yield the oldest age, 3098±95 Ma. 2478±37 Ma average age is obtained from the second group, which is relatively larger and volumetrically predominant. The third age group of Monaiztes gives an age of 2088±110 Ma. ~3100 Ma monazite suggests the older supracrustal rocks of Bundelkhand craton, similar to those obtained from Singhbhum and the Dharwar craton. The 2478±37 Ma age is constrained as the timing of metamorphism and stabilization of BuC. The third age group, 2088±110 Ma probably associated with renewed hydrothermal activities, leading to rifting and emplacement of mafic dykes in BuC.</p>

scholarly journals New insights on the geological and structural settings of the Musselwhite banded iron-formation-hosted gold deposit, North Caribou greenstone belt, Superior Province, Ontario

2015 ◽  
Author(s):  
W Oswald ◽  
S Castonguay ◽  
B Dubé ◽  
M Malo ◽  
P Mercier-Langevin ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Greenstone Belt ◽  
Iron Formation ◽  
Superior Province ◽  
Banded Iron Formation

Polymetamorphism in the Archean Hemlo – Heron Bay greenstone belt, Superior Province: P–T variations and implications for tectonic evolution

1993 ◽  
Vol 30 (5) ◽  
pp. 985-996 ◽  
Author(s):  
Yuanming Pan ◽  
Michael E. Fleet
Keyword(s):  
Greenstone Belt ◽  
Regional Metamorphism ◽  
Mineral Chemistry ◽  
Superior Province ◽  
Low Grade ◽  
Garnet Porphyroblasts ◽  
Metamorphic History ◽  
Tectonic Environment ◽  
History Of ◽  
Archean Greenstone Belt

The tectono-metamorphic history of the late Archean (2800–2600 Ma) Hemlo – Heron Bay greenstone belt in the Superior Province has been delineated from textural relationships, mineral chemistry, and P–T paths in metapelites, cordierite–orthoamphibole rocks, and metabasites from the White River exploration property, Hemlo area, Ontario. An early low-temperature, medium-pressure metamorphism (about 500 °C and 6–6.5 kbar (1 kbar = 100 MPa)) is indicated by the occurrence of relict kyanite and staurolite porphyroblasts and zoned garnet porphyroblasts in metapelites and the presence of zoned calcic amphiboles in metabasites. This early metamorphism appears to have been coeval with the previously documented D1 deformation that is associated with, for example, low-angle thrusts. A second regional metamorphism predominates in the Hemlo – Heron Bay greenstone belt and is generally of relatively low grade, at about 510–530 °C and 3.2–3.5 kbar, over most of the study area and increases to medium grade (550–650 °C and 4–5 kbar) towards the southern margin with the Pukaskwa Gneissic Complex and along the central axis enclosing the Hemlo Shear Zone. The second regional metamorphism was contemporaneous with the D3 deformation and was probably related to plutonism. This type of polymetamorphism in the Hemlo – Heron Bay greenstone belt may be equivalent to those in Phanerozoic subduction complexes and therefore supports the arc–arc accretion model for the development of the southern Superior Province. Although the Hemlo – Heron Bay greenstone belt most likely represents a single tectonic environment (an oceanic island arc), the restricted occurrence of the relict kyanite and staurolite indicates that the central portion of this Archean greenstone belt probably was at a deeper crustal level at the time of the first metamorphic event.

scholarly journals Fold pattern analysis around Kanjamalai Salem district Tamilnadu

2020 ◽  
Vol 2 (2) ◽  
pp. 74-32
Author(s):  
Thirukumaran V ◽  
Suresh R
Keyword(s):  
Interference Pattern ◽  
High Amplitude ◽  
Iron Formation ◽  
Amplitude Analysis ◽  
Banded Iron Formation ◽  
Rock Types ◽  
Folded Structure ◽  
History Of ◽  
Granulite Terrain ◽  
The Hill

Kanjamalai one of the fascinating location in Southern Granulite Terrain (SGT) for studying Archaean geology and structures as the entire hill is made up of variety of rock types like two pyroxene granulite, amphibolites, quartzo - feldsapthic gneisses, banded iron formation, and intrusive rocks like dunite, peridotite and pegmatite and beautifully carved structures. The entire hill resembles a canoe shape with doubly plunging fold structure with E-W elongation. The entire hillock seems to sit pretty on mylonitised hornblende biotite gneisses which also have a common N70-95 degree trend and sub vertical dip with NE plunge which is in contradiction to centrally plunging lineations of the hill. The SW part of Kanjamalai near Chinasrirangapadi was displaying beautiful fold structures, with interference pattern out of which six domains were selected for detailed study and analysis. The multiple generation folded structure will have a clue in reconstructing the deformation history of this Kanjamalai. The observed f1, f2 and f3 folds show significant Type III interference pattern as that of Ramsay and 01 and 03 type folds of Bernhard Grasemann.   Wavelength –amplitude analysis was made to generalize and regroup the observed folds in to high amplitude, high wavelength or open folds, low wavelength and Mesoscopic folds. And visual harmonic analysis was made to analyse the symmetry of the folds and analyze the geometry, symmetry and harmony and genesis of the fold in terms of relative timing of the events.

Block and shear-zone architecture of the Minnesota River Valley subprovince: implications for late Archean accretionary tectonics

1996 ◽  
Vol 33 (6) ◽  
pp. 831-847 ◽  
Author(s):  
D. L. Southwick ◽  
Val W. Chandler
Keyword(s):  
Regional Scale ◽  
Shear Zones ◽  
River Valley ◽  
Superior Province ◽  
Tectonic Zone ◽  
Minnesota River ◽  
The North ◽  
Geophysical Anomalies ◽  
Superior Craton ◽  
Minnesota River Valley

The Minnesota River Valley subprovince of the Superior Province is an Archean gneiss terrane composed internally of four crustal blocks bounded by three zones of east-northeast-trending linear geophysical anomalies. Two of the block-bounding zones are verified regional-scale shears. The geological nature of the third boundary has not been established. Potential-field geophysical models portray the boundary zones as moderately north-dipping surfaces or thin slabs similar in strike and dip to the Morris fault segment of the Great Lakes tectonic zone at the north margin of the subprovince. The central two blocks of the subprovince (Morton and Montevideo) are predominantly high-grade quartzofeldspathic gneiss, some as old as 3.6 Ga, and late-tectonic granite. The northern and southern blocks (Benson and Jeffers, respectively) are judged to contain less gneiss than the central blocks and a larger diversity of syntectonic and late-tectonic plutons. A belt of moderately metamorphosed mafic and ultramafic rocks having some attributes of a dismembered ophiolite is partly within the boundary zone between the Morton and Montevideo blocks. This and the other block boundaries are interpreted as late Archean structures that were reactivated in the Early Proterozoic. The Minnesota River Valley subprovince is interpreted as a late accretionary addition to the Superior Province. Because it was continental crust, it was not subductible when it impinged on the convergent southern margin of the Superior Craton in late Archean time, and it may have accommodated to convergent-margin stresses by dividing into blocks and shear zones capable of independent movement.

Earth’s Middle Ages: What Came after the GOE

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Middle Ages ◽  
Atmospheric Oxygen ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Dissolved Iron ◽  
Great Oxidation Event ◽  
Low Levels ◽  
Substantial Rise

This chapter considers the aftermath of the great oxidation event (GOE). It suggests that there was a substantial rise in oxygen defining the GOE, which may, in turn have led to the Lomagundi isotope excursion, which was associated with high rates of organic matter burial and perhaps even higher concentrations of oxygen. This excursion was soon followed by a crash in oxygen to very low levels and a return to banded iron formation deposition. When the massive amounts of organic carbon buried during the excursion were brought into the weathering environment, they would have represented a huge oxygen sink, drawing down levels of atmospheric oxygen. There appeared to be a veritable seesaw in oxygen concentrations, apparently triggered initially by the GOE. The GOE did not produce enough oxygen to oxygenate the oceans. Dissolved iron was removed from the oceans not by reaction with oxygen but rather by reaction with sulfide. Thus, the deep oceans remained anoxic and became rich in sulfide, instead of becoming well oxygenated.

A new volcanic province: evidence from glacial erratics in western North Greenland

2000 ◽  
pp. 35-41 ◽  
Author(s):  
Peter R. Dawes ◽  
Bjørn Thomassen ◽  
T.I. Hauge Andersson
Keyword(s):  
Volcanic Rocks ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Common Component ◽  
Volcanic Province ◽  
North West ◽  
North East ◽  
The North ◽  
Surficial Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Thomassen, B., & Andersson, T. H. (2000). A new volcanic province: evidence from glacial erratics in western North Greenland. Geology of Greenland Survey Bulletin, 186, 35-41. https://doi.org/10.34194/ggub.v186.5213 _______________ Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

Preparation and characterization of magnetic photocatalyst from the banded iron formation for effective photodegradation of methylene blue under UV and visible illumination

2021 ◽  
Vol 9 (2) ◽  
pp. 105127
Author(s):  
Moustafa M.S. Sanad ◽  
Mohsen M. Farahat ◽  
Soliman I. El-Hout ◽  
Said M. El-Sheikh
Keyword(s):  
Methylene Blue ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Magnetic Photocatalyst

scholarly journals Serpentine–Hisingerite Solid Solution in Altered Ferroan Peridotite and Olivine Gabbro

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 47 ◽  
Author(s):  
Benjamin Tutolo ◽  
Bernard Evans ◽  
Scott Kuehner
Keyword(s):  
Iron Formation ◽  
Olivine Gabbro ◽  
Banded Iron Formation ◽  
Silicate System ◽  
Duluth Complex ◽  
Sheet Silicate ◽  
Structure Modulation ◽  
Compositional Variability ◽  
Common Observation ◽  
End Members

We present microanalyses of secondary phyllosilicates in altered ferroan metaperidotite, containing approximately equal amounts of end-members serpentine ((Mg,Fe2+)3Si2O5(OH)4) and hisingerite (□Fe3+2Si2O5(OH)4·nH2O). These analyses suggest that all intermediate compositions can exist stably, a proposal that was heretofore impossible because phyllosilicate with the compositions reported here have not been previously observed. In samples from the Duluth Complex (Minnesota, USA) containing igneous olivine Fa36–44, a continuous range in phyllosilicate compositions is associated with hydrothermal Mg extraction from the system and consequent relative enrichments in Fe2+, Fe3+ (hisingerite), Si, and Mn. Altered ferroan–olivine-bearing samples from the Laramie Complex (Wyoming, USA) show a compositional variability of secondary FeMg–phyllosilicate (e.g., Mg–hisingerite) that is discontinuous and likely the result of differing igneous olivine compositions and local equilibration during alteration. Together, these examples demonstrate that the products of serpentinization of ferroan peridotite include phyllosilicate with iron contents proportionally larger than the reactant olivine, in contrast to the common observation of Mg-enriched serpentine in “traditional” alpine and seafloor serpentinites. To augment and contextualize our analyses, we additionally compiled greenalite and hisingerite analyses from the literature. These data show that greenalite in metamorphosed banded iron formation contains progressively more octahedral-site vacancies (larger apfu of Si) in higher XFe samples, a consequence of both increased hisingerite substitution and structure modulation (sheet inversions). Some high-Si greenalite remains ferroan and seems to be a structural analogue of the highly modulated sheet silicate caryopilite. Using a thermodynamic model of hydrothermal alteration in the Fe–silicate system, we show that the formation of secondary hydrothermal olivine and serpentine–hisingerite solid solutions after primary olivine may be attributed to appropriate values of thermodynamic parameters such as elevated a S i O 2 ( a q ) and decreased a H 2 ( a q ) at low temperatures (~200 °C). Importantly, recent observations of Martian rocks have indicated that they are evolved magmatically like the ferroan peridotites analyzed here, which, in turn, suggests that the processes and phyllosilicate assemblages recorded here are more directly relevant to those occurring on Mars than are traditional terrestrial serpentinites.

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