 | | Journal (article/letter/editorial) | | Mineralogist, Volume 59, pages 1190-1197, 1974 Lavasof Minnesota from the Keweenawan Clinopyroxenes T.qolsHI KoNna...Department of Geology, Uniuersity ol Minnesota, Duluth, Duluth. Minnesota 5 58 I 2 Abstract The Keweenawan(I-ate...Keweenawan(I-ate Precambrian) lava flows in northern Minnesota include the volcanic series: tholeiitic olivine...enrichment and is similar to that of the associated Beaver Bay Gabbro Complex and of the Skaergaard Intrusion...old, which underlies(Fig. 1) most of the shore of Lake Superior in northeasternMinnesota, U.S.A. (Green |  | | Journal (article/letter/editorial) | | Springer-Verlag 1970 Pyroxenes from the Beaver Bay Gabbro Complex of Minnesota TADASm KONDA Deparbment of Geology...University of Minnesota, Minneapolis, U.S.A. Received September 18, 1970 Abstract. Although the Beaver Bay ferrogabbro...pyroxenes from intermediate pigeonite (~gagF%0Can) to ferriferous pigeonite (Mg2~Fe65Cas) occur as intercumulus...non-layered Beaver River gabbro are included in the overall pyroxene fractionation trend of the Beaver Bay gabbro...gabbro complex. The pyroxene trend of the Beaver Bay gahbro complex is similar to those of the Skaergaard |  | | Journal (article/letter/editorial) | | Crystallization of pyroxenes in an iron-rich diabase from Minnesota. By I. D. MUIR, B.A., Ph.D., F.G.S. Department...University of Cambridge. [Read November 5, 1953.] HE Beaver Bay diabase forms an irregular sill-like intrusion...miles from Split Rock to Beaver Bay on the north shore of Lake Superior, Minnesota. It is intrusive into...several types of diabase from the Minnesota coast near Beaver Bay are given by Grout and Schwartz (1939)...collected from Highway 61 about l88 miles SW. of the Beaver Bay settlement. A similar rock (table I, anal. 2) |  | | Journal (article/letter/editorial) | | of pyroxenes in a ferrogabbro from Beaver Bay intrusion, Minnesota YASUO N A K A M U R A & TADASHI KONDA...pyroxenes in a ferrogabbro from I~.~ver Bay intrusion, Minnesota. Lithos 7, 7-14. Four different types...types of pyroxene found in a Beaver Bay ferrogabbro were analysed by microprobe. The cD-stallization sequence...coexisting orthopyroxene, Ca-poor clinopyroxene (pigeonite and ferropigeonite) and Ca-rich clinopyroxene...is reversed in the pyroxene assemblage in the Beaver Bay ferrogabbro (Muir 1954, Konda 1970). As pointed |  | | Journal (article/letter/editorial) | | plagioclase from the iron-rich facies of the Beaver Bay diabase has been described in detail, and textural...in table I. (i) Andesine fi'om the Beaver Bay diabase, Minnesota. This plagioclase comes from a specimen...coarsegrained iron-rich facies of the great pre-Cambrian Beaver Bay silt-like diabase intrusion (Grout and Schwartz...(CassMg~sF%t) with extremely fine exsolution lamellae, pigeonite (CagMg2~F%4) much of which has inverted to oIthopyroxene...Plagioclase. Wt. % An. Esterel . . . . . . . . . 40 Beaver Bay . . . . . . 44 New Amalfi EH52... 4689 New Amalfi |  | | Journal (article/letter/editorial) | | Hypabyssal Rocks of the Midcontinent Rift System in Minnesota, and Implications for a Keweenawan Magmatic “Family...Hypabyssal Rocks of the Midcontinent Rift System in Minnesota, and Implications for a Keweenawan Magmatic “Family...Hypabyssal Rocks of the Midcontinent Rift System in Minnesota, and Implications for a Keweenawan Magmatic "Family...Midcontinent Rift along the Min nesota shore of Lake Superior are a distinct suite within the rock associations...which are the voluminous flood basalts surrounding Lake Superior. These basalts are inferred to have formed |  | | Journal (article/letter/editorial) | | tie line for pyroxenes in iron rich diabase of Beaver Bay (Muir 1954). properties of the pyroxene (and...India' 2. Ferroaugite in iron rich diabase of Beaver Bay (Muir 1954)' 3. Ferroaugite in syenite, Okonjeje...analysis of ferroaugite in iron rich diabase, Beaver Bay, Minnesota (Muir 1954) 1a-2a. Atomic ratio on the basis...ferroaugite reported from Fe-rich diabase of Beaver Bay (Muir 1954) but the pyroxene reported here is...presented in Table 2 along with chemical data for the Beaver Bay pyroxene for a comparison.Atomic percentagesof |  | | Journal (article/letter/editorial) | | of the data on natural pyroxenes suggests that pigeonite crystallizes from magmas within its own stability...temperatures. Crystallization of ortho pyroxene and pigeonite from basalt magmas is discussed on the basis of...best-studied Mg-Fe forms 41964), BOYD and the be pigeonite in than does orthopyroxene all in that stability...terrestrial clinopyroxene those This petrologists pigeonite rocks of orthopyroxene result was because...necessary natural pyroxenes of the recent "pigeonite" is with Mg: various experimentally is also |  | | Journal (article/letter/editorial) | | OccunruNcns Hallimond (1914) first noted iron-rich pigeonite in the Scottish Tertiary tocks, presenting an...This rock can be classified in modern terms as a pigeonite ferrodacite, by use of the hitherto unpublished...phenocrysts; secondly, pigeonite sometimes forms cores to augite phenocrysts and; thirdly, pigeonite itself sometimes...sometimes contains hypersthene cores. Both augite and pigeonite vary in composition (Table 2, group 1). In part...enrichment in Fe relative to Mg. However, one pigeonite crystal (Table 2, no. 3a) is considerably more |  | | Journal (article/letter/editorial) | | lamellae indicative of formation by inversion of pigeonite, and the other, free from this type of exsolution... FERRODIORITE FROM SKYE 29 of pigeonite. The inverted pigeonite is often rimmed by directly precipitated...with the compositions of these minerals in the Beaver Bay diabase (Muir, 1954), the upper part of the Bushveld...of the Beaver Bay and the Upper Bushveld rocks. 5 IO- //.~j IS- O u_ x~, 9 ~ 0 BEAVER BAY ~ diobasr...late-stage Bushveld rocks (Boshoff, 1942), the Beaver Bay iron-rich diabase (Muir, 1954), and the fayalite |  | | Journal (article/letter/editorial) | | IryPERSTHENE, PIGEONITE AND AUGITE IN CRYSTALLIZING MAGMAS: MICROPROBESTUDY OF A PIGEONITE ANDESITE FROM...difierent coexisting pyroxenes, hypersthene, pigeonite and augite phenocrysts and ferropigeonite and...and ferroaugite of the groundmass in a pigeonite andesite from Weiselberg have been determined with the...ratio, to pigeonite-augite of relatively high Fe/Mg ratio. Eight pairs of hypersthene-pigeonite of difierent...suggested that changeover from hypersthene to pigeonite during the crystallization sequence is a result |  | | Report (issue) | | GABBRO COMPLEX NEAR DULUTH, MINNESOTA UNIVERSITY OF MINNESOTA MINNESOTA GEOLOGICAL SURVEY P A U L K...near Duluth, Minnesota BY RICHARD B. TAYLOR THE MINNEAPOLIS· 1964 UNIVERSITY OF MINNESOTA PRESS PRINTED...6Z LIST OF FIGURES 1. lVIap of northeastern Minnesota, showing generalized geology Z Z. Anorthositic...hypersthene host, the result of inversion from pigeonite . . . . . . . . . . . . . . . . . . . . . . ....Geologic map of Duluth and vicinity, St. Louis County, Minnesota LIST OF TABLES 1. Stratigraphic Succession |  | Chalokwu, Christopher I., Grant, Norman K., Ariskin, Alexei A., Barmina, Galina S. (1993) Simulation of primary phase relations and mineral compositions in the Partridge River intrusion, Duluth Complex, Minnesota: implications for the parent magma composition. Contributions to Mineralogy and Petrology, 114 (4) 539-549 doi:10.1007/bf00321758 | Journal (article/letter/editorial) | | the Partridge River intrusion, Duluth Complex, Minnesota: implications for the parent magma composition...Auburn, AL 36849 USA 2 Department of Geology,Miami University,Oxford,OH 45056, USA 3 VernadskyInstitute...Duluth Complex and from the nearby Portage Lake area of the Lake Superior region. The parental magma was...and T-59, respectively); 5, 6, Keweenawan Portage Lake lava (Wilband and Wasuwanich 1980; samples WOT87...composition of the Keweenawan Silver Bay intrusions, northeastern Minnesota (Chalokwu and Miller 1992) compared |  | | Book | | (Superior Province) ......... 2.12.1.1 The Bad Vermilion Lake Complex, Ontario ........................... 2.12...Bell River and Dore Lake Complexes, Quebec ................. 2.12.1.4 Big Trout Lake, Ontario ...........Intrusion, Labrador . 170 3.12.3 The Duluth Complex, Minnesota ..... 171 3.12.4 The Glen Mountains Layered Complex...Inclusions ....................... 6.3.1 Beaver Bay Complex, Minnesota ..... 6.3.2 Anorthosite Inclusions in...colours darting through the limpid crystal of the lake, and flashing from the cliffs more especially when |  | | Book (volume) | | .... 92 Jadeite ......... 99 Augite.109 Pigeonite ......... 143 Omphacite ......... 154 Fassaite...Johannsenite Aegirine Spodumene J adeite Augite Pigeonite Omphacite Fassaite (Mg,Fe+2)2Si206 Ca(Mg,Fe+2)Si206...are monoclinic in the high-temperature form (pigeonite) and orthorhombic in the low-temperature form...The structures of the two monoclinic phases, pigeonite and clinoenstatite, have the space group P2i/c...principal com¬ binations are: augite with (001) pigeonite lamellae (x and y coincident), augite with (100) |  | | Journal (article/letter/editorial) | | lamellae (which can be exceedingly fine) as augite, pigeonite, or ortho-pyroxene on the basis of their orientation...diffraction patterns to be expected from inverted pigeonite crystals were not discussed in the previous paper...considered. According to Poldervaart and Hess (1951) pigeonite on inver- EXSOLUTIONIN PYROXENES 381 sion...always retains the b and c axial directions of the pigeonite. On the other hand Brown (1957) found that the...15~ c-axis oscillation photograph of inverted pigeonite from 1849 (perpendicular feldspar rock), taken |  | Czamanske, Gerald K., Bennett, Pauline C., Zientek, Michael L., Weiblen, Paul W., Havach, George A., Foose, Michael P. (1986) Comprehensive bibliographies on mineralized and unmineralized layer mafic intrusions in the United States. Open-File Report Vol. 1986 (86-589) US Geological Survey doi:10.3133/ofr86589a | Report (issue) | | California. Department of Geology, University of Minnesota, Minneapolis *U.S. Geological Survey, Res ton...Weiblen, Department of Geology, University of Minnesota These bibliographies have been compiled at the...prospector with potential. The Duluth Complex, Minnesota, and the Stillwater Complex, Montana, are given...references cited in Minnesota Geological Survey Bulletin 46, entitled "Bibliography of Minnesota Geology, 1951-1980...noteworthy were the contributions of Lynn Swanson, Minnesota Geological Survey; Laurel Burns, Alaska Geological |  | | Journal (article/letter/editorial) | | the Partridge River Intrusion, Duluth Complex, Minnesota: 1. Relationships between Mineral Compositions...The Keweenawan Duluth complex, in northeastern Minnesota, has been the focus of geologic investigation...wedge of plutonic rocks along the north shore of Lake Superior llounal of Pnrohgy, Vol. 31. Pan 2, pp...shown by square is in T60N, Rl 1W, northeastern Minnesota. Bottom: Summary megascopic log of core showing...from the strongly differentiated troctolitic Sanju Lake intrusion (see Weiblen & Morey, 1980). Downloaded |  | | Journal (article/letter/editorial) | | sufficient to clarify the relationship between pigeonite and the various polymorphs of MgSiO3. It is probable...that there is a first-order inversion between pigeonite and protoenstatite, and possible phase relations...established the crystal structure of clinoenstatite and pigeonite. Their clinoenstatite was prepared by inverting...enstatite from the Bishopville meteorite, and the pigeonite was a natural ferropigeonite from an andesite...such pyroxenes are shown in Fig. 9. The bronzite-pigeonite trend and that portion of the augite trend more |  | | Book (volume) | | intrusion, east Greenland. Crossed polars x60. A. B. Pigeonite inverted to orthopyroxene with exsolved augite...pyroxene. Bushveld complex. Crossed polars x60. C. Pigeonite inverted to orthopyroxene with exsolved augite...Introduction 3 Magnesium-Iron Pyroxenes Orthopyroxenes Pigeonite 162 Calcium Pyroxenes Diopside-Hedenbergite...augite magnesium pigeonite hedenbergite ferriferous pigeonite intermediate pigeonite V 0 10 MgSiO3...Pyroxenes Orthopyroxenes (Enstatite-Orthoferrosilite) Pigeonite (Mg,Fe2 + ,Ca)(Mg,Fe2 +)Si 2 O 6 (Mg,Fe2 +) 2 |  | | Journal (article/letter/editorial) | | presence of sub-microscopicexsolution lamellae of pigeonite, a feature consistent with the transitional nature...augites of sub-microscopic exsolution lamellae of pigeonite. / In the Lower and Middle Zones of the Skaergaard...exsolution of pigeonite. The chemistry of the augites indicates that the percentage of pigeonite can be only...impossible to state with certainty whether the pigeonite has inverted to hypersthene, but the obviously...when the temperature was sufficiently low for pigeonite to become metastable. It is interesting to note |  | | Report (issue) | | BIBLIOGRAPHY OF MINNESOTA 1951-1980 GEOLOGY ves ai é Lita: ae i if “Pe va MINNESOTA GEOLOGICAL...DIRECTOR BULLETIN BIBLIOGRAPHY SURVEY 46 OF MINNESOTA GEOLOGY 1951-1980 COMPILED G.B. MOREY, NANCY...NANCY BY BALABAN, AND LYNN Gn UNIVERSITY OF MINNESOTA ST. PAUL e 1981 SWANSON ISSN 0076-9169 @...@ ISBN 0-934938-01-6 The University of Minnesota is committed to the policy that all persons shall have...bibliography brings Minnesota Geological Survey Bulletin 34, ‘‘Bibliography of Minnesota Geology,’’ by T |  | | Book | | Hypabyssal Rocks of the Midcontinent Rift System in Minnesota, and Implications for a Keweenawan Magmatic “Family...cabin on a lake outside Knoxville. He also might occasionally sneak his boat out onto the lake to fish for...Suite; HI = Hettasch Intrusion; ML = Makhavinekh Lake Pluton; NAC = Nain Anorthosite Complex; old name...abundance), augite, orthopyroxene, and inverted pigeonite in variable proportions. These minerals also may...v. 29, p. 275— 289. Ryan, B., 1991, Makhavinekh Lake pluton, Labrador, Canada: Geological setting, subdivisions |  | | Journal (article/letter/editorial) | | Hornblende, andesine, quartz, and alkali feldspar Pigeonite, augite, and labradorite Orthopyroxene, augite...augite Micropegmatite, ferroaugite, and andesine Pigeonite, augite, and andesine the lower and central zones...coincides with the inversion of Orthopyroxene to pigeonite. The upper zone is composed of rocks in which...coincides with the inversion of Orthopyroxene to pigeonite. In the dyke, the boundary between the main and...and fayalite zones marks the disappearance of pigeonite and the appearance of fayalite as a primary phase |  | | Journal (article/letter/editorial) | | phase of inverted pigeonite. In cases of doubt the data are omitted. Inverted pigeonite is not considered...and a contact metamorphic Iron Formation Montana, USA [ C M I F ] (Vaniman et al., 1980) some orthopyroxenes...(ultra-)mafic rocks and at higher fe-ratios for the Beaver Bay Intrusion (Nakamura and Konda, 1974). Asterisks:...CMIF: contact metamorphic Iron Formations, Montana USA (Vaniman et al., 1980). In fig. 4 all orthopyroxene...Maximum Ca solubility in OPX at its inversion to pigeonite at 1 arm. (Ross and Huebner, 1979); 2. Ditto, |
|
Beaver Bay, Lake County, Minnesota, USA