The Wollaston Lake fold-belt system, Saskatchewan–Manitoba

1968 ◽  
Vol 5 (6) ◽  
pp. 1489-1504 ◽  
Author(s):  
P. L. Money
Keyword(s):  
Regional Metamorphism ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Intermediate Type ◽  
Fold Belt ◽  
System A ◽  
Fold Belts ◽  
Group A ◽  
Group Form ◽  
Belt System

The Wollaston Lake fold-belt system, a major feature of the Churchill (structural) Province, consists of coalescing fold belts that collectively have been traced for about 400 miles. The fold belts, formed during the Hudsonian orogeny ~1750 million years ago, consist of tightly to isoclinally folded metamorphic and migmatitic rocks. They are bounded mainly by granitic rocks (in the broad sense) that are probably in part younger and in part older. The metamorphic rocks comprising them have been assigned locally to the Daly Lake, Sandfly Lake, or Meyers Lake Groups. The Daly Lake Group (a miogeosynclinal type of assemblage) has an uncertain relationship to the Sandfly Lake Group (eugeosynclinal assemblage); it was probably not deposited contemporaneously with the Meyers Lake Group. The Meyers Lake Group, which has a considerable resemblance to 'stable shelf1 assemblages, although it is less mature, overlies the Sandfly Lake Group, probably unconformably. Metamorphic rocks lithologically similar to those assigned to the Daly Lake Group form most of the fold-belt system. Rocks similar to those assigned to the other groups are of limited extent. The rocks within the fold-belt system have undergone regional metamorphism of the andalusite–sillimanite or low pressure intermediate type and in general now belong to the amphibolite facies. Mineralization within the fold-belt system, consisting of syngenetic (?) sphalerite, galena, and copper minerals, was widespread, but is not yet known to be of economic importance. The most prominent zone of magnetic anomalies in the Precambrian of Saskatchewan coincides in part with the fold-belt system.

Whole-Rock Rb/Sr Ages of Metamorphic Rocks from Northern Ellesmere Island, Canadian Arctic Archipelago. I. The Gneiss Terrain between Ayles Fiord and Yelverton Inlet

1975 ◽  
Vol 12 (1) ◽  
pp. 90-94 ◽  
Author(s):  
A. K. Sinha ◽  
Thomas Frisch
Keyword(s):  
Regional Metamorphism ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Metamorphic Rocks ◽  
Canadian Arctic Archipelago ◽  
Fold Belt ◽  
Late Precambrian

The first Precambrian ages from the Northern Ellesmere Fold Belt are reported. Six rocks from the largest gneiss terrain in northern Ellesmere Island yield a Late Precambrian age (minimum 742 ± 12 m.y.) of regional metamorphism. Relatively high initial 87Sr/86Sr suggests that the rocks were derived from crustal materials.

Correlation of Major Aphebian Rock Units in the Northeastern Canadian Shield

1972 ◽  
Vol 9 (12) ◽  
pp. 1650-1669 ◽  
Author(s):  
G. D. Jackson ◽  
F. C. Taylor
Keyword(s):  
Regional Metamorphism ◽  
Volcanic Rocks ◽  
Structural Data ◽  
Granulite Facies ◽  
Canadian Shield ◽  
Shelf Zone ◽  
Fold Belt ◽  
Entire Area ◽  
Fold Belts ◽  
Basic Volcanic

Several groups of Aphebian layered rocks in the northeastern Canadian Shield have been correlated because of lithologic and stratigraphic similarities and alignment of groups and structural trends. Most of these layered rocks lie in three distinct fold belts which from south to north have been named the Dorset, Foxe, and the Committee Fold Belts.The widespread occurrence of Aphebian outliers between the fold belts indicates that Aphebian strata probably originally covered the entire area from the Circum–Ungava Geosyncline or Fold Belt east to the Dorset Fold Belt and north to the Committee Fold Belt. The name Baffin Geosyncline is proposed for this depositional zone. Aphebian layered rocks in the two last-named fold belts were probably deposited in marginal mio-eugeosynclinal zones of the main geosyncline and are mainly meta-shale, meta-graywacke, and metamorphosed basic volcanic rocks and associated basic and ultrabasic intrusions. The Aphebian rocks of the Dorset and Foxe Fold Belts were deposited in the central shelf zone of the Baffin Geosyncline and are mainly meta-shale, meta-graywacke, rusty quartz-rich gneiss, marble, and quartzite.The Aphebian layered rocks have been intruded by large granitic plutons and have been metamorphosed to amphibolite and granulite facies of regional metamorphism. Age determinations and structural data indicate that a mid-Aphebian orogeny affected much of the northern part of this region 2000–2200 m.y. ago, and that the whole region was strongly affected by the Hudsonian orogeny.

Advances in the Geochronology of the Rice Lake – Beresford Lake Area, Southeastern Manitoba

1971 ◽  
Vol 8 (5) ◽  
pp. 572-579 ◽  
Author(s):  
Andrew Turek ◽  
Zell E. Peterman
Keyword(s):  
Greenstone Belt ◽  
Regional Metamorphism ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Lake Area ◽  
The South ◽  
Quartz Veins ◽  
The North ◽  
Granite Emplacement ◽  
Second Period

The Rice Lake – Beresford Lake area consists of an easterly trending Precambrian greenstone belt which is flanked on the north by granitic rocks and on the south by granitic and metamorphic rocks. Analyses of an intrusive, late tectonic quartz monzonite at Black Lake, yield an isochron age of 2735 ± 55 m.y. with an initial 87Sr/80Sr composition 0.7019 ± 0.0008. This age is a minimum for the granitic rocks to the south of the greenstone belt and is the oldest age obtained in this area. On the other hand, analyses of a quartz diorite pluton intrusive into the greenstones give a metamorphic age of 2555 ± 70 m.y. with an initial 87Sr/86Sr of 0.7016 ± 0.0012. Mylonite zones are developed along the northern and southern boundaries of the greenstone belt. Analyses of whole-rock samples from these zones yield an age of 2345 ± 100 m.y. with initial 87Sr/88Sr 0.7044 ± 0.0024, and is the youngest age obtained in the area.These new data, combined with our previous work, indicate three major events. The first and oldest event is 2730 ± 50 m.y. and is interpreted as a period of regional metamorphism, granite emplacement, and the emplacement of gold–quartz veins which postdate the greenstones. A second period of metamorphism and granite emplacement occurred at 2530 ± 40 m.y. and it affected the area as a whole, as evidenced by updated mineral ages. The third and youngest event, 2345 ± 100 m.y., is recorded by the mylonites and may represent epeirogenic movement in the area.

scholarly journals Isotopic age determinations from South Greenland and their geological setting

1965 ◽  
Vol 53 ◽  
pp. 1-56
Author(s):  
D Bridgwater
Keyword(s):  
Biotite Granite ◽  
Canadian Shield ◽  
Granitic Rocks ◽  
Isotopic Age ◽  
Fold Belt ◽  
South West ◽  
Intrusive Rocks ◽  
Igneous Activity ◽  
Fold Belts ◽  
Age Determinations

A brief geological review of the area between Sermiligârssuk and Kap Farvel is given using the following five main divisions of the Precambrian of South Greenland: 1) pre-Ketilidian (? 2000-2700 m. y.) 2) Ketilidian (? 1700-2000 m. y.) 3) post-Ketilidian = Kuanitic (? 1650-1700 m. y.) 4) Sanerutian (? 1500-1650 m. y.) 5) Gardar (1020-?1500 m.y.). In the area described these divisions are characterized by: 1) gneisses, 2) geosynclinal sedimentation and lava extrusion, metamorphism and plutonism, 3) basic and intermediate dyking, 4) renewed plutonism, and emplacement of synplutonic basic, intermediate and granitic rocks, 5) post-orogenic sedimentation, lava extrusion and a predominantly alkali suite of intrusive rocks. Isotopic age determinations are available from the two youngest of the above divisions in South Greenland; dates for the three older divisions are suggested by comparison of the development of South Greenland with other fold belts together with sparse data from elsewhere in Greenland. It is suggested that the pre-Ketilidian gneisses represent the remnant of an old fold belt formed approximately 2400-2700 m. y. ago which has been reactivated during the Ketilidian and Sanerutian plutonic episodes in South Greenland. It is further suggested that the Ketilidian, post-Ketilidian and Sanerutian episodes are phases in the evolution of one fold belt which started at approximately 2000 m. y. ago and represents the beginning of the Svecofennid chelogenic cycle in South Greenland. The Gardar magmatism is regarded as a typical post-orogenic alkali suite and it is thought that the Gardar activity at about 1200 m. y. may represent compensatory tensional conditions on the margins of the developing Grenville fold belt which probably passed south of Greenland. Eight K/Ar age determinations (Geochron Laboratories) give the following results: Sanerutian hypersthene gabbro, 1645 m. y. (biotite) and 1700 m. y. (augite); Sanerutian granite, 1620 m. y. (biotite) ; early Gardar dolerite, 1435 m. y. (augite); Gardar syenite, 1128 m. y. (biotite) and 1355 m. y. (augite); inclusion of anorthosite fragment in a Gardar dyke, 1025 m. y. (biotite) and 1075 m. y. (augite). Four Rb/Sr age determinations (Moorbath) give the following results: Ketilidian pegmatite affected by Sanerutian metamorphism, 1630 m. y; Sanerutian granite, 1615 m. y.; Sanerutian granite probably affected by Gardar event, 1220 m. y.; Gardar biotite granite, 1150 m. y. Results from other areas in Greenland are discussed and it is suggested that a large part of the south-west coastal strip is pre-Ketilidian in age and that the Nagssugtoqidian fold belt was formed at approximately the same time as the Ketilidian-Sanerutian fold belt in South Greenland, that is at the beginning of the Svecofennid chelogenic cycle. It is suggested that the main episodes described from South Greenland correspond to events in the Canadian shield as follows: pre-Ketilidian plutonism = Kenoran; Ketilidian-Sanerutian and Nagssugtoqidian = Hudsonian; Gardar = post-Hudsonian, pre-Grenville igneous activity. Tectono-igneous cycles are used in conjunction with basic dykes and age determinations as a method of dividing the Precambrian.

The mid-Paleozoic deformation in the Hazen fold belt, Ellesmere Island, Arctic Canada

1990 ◽  
Vol 27 (10) ◽  
pp. 1359-1370 ◽  
Author(s):  
Eva M. Klaper
Keyword(s):  
Large Scale ◽  
Ellesmere Island ◽  
Small Scale ◽  
Northwestern Part ◽  
Fold Belt ◽  
Southeastern Part ◽  
Lower Paleozoic ◽  
Slip Mechanism ◽  
Fold Belts ◽  
Surface Geology

The mid-Paleozoic deformation of lower Paleozoic subgreenschist-facies sediments of the Hazen fold belt in northern Ellesmere Island is represented predominantly by chevron-style folding. Folded multilayers display cleavage fans suggesting synchronous fold and cleavage formation. Bedding-parallel slip indicates a flexural slip mechanism of folding. The geometry of several large-scale anticlinoria has been interpreted as being due to formation of these structures over detachments and thrust ramps.The constant fold geometry, the parallel orientation of faults and large- and small-scale folds, and the axial-plane foliation are related to a single phase of folding with a migrating deformation front in the Hazen fold belt during the mid-Paleozoic orogeny. The minimum amount of shortening in the Hazen and Central Ellesmere fold belts has been estimated from surface geology to increase from 40–50% of the original bed length in the external southeastern part to 50–60% in the more internal northwestern part of the belts.The convergent, thin-skinned nature of the Hazen and Central Ellesmere fold belts indicates that the postulated transpressive plate motions during the accretion of Pearya did not affect the study area.

Tasman Fold Belt System in Tasmania

1978 ◽  
Vol 48 (3-4) ◽  
pp. 159-205 ◽  
Author(s):  
Emyr Williams
Keyword(s):  
Fold Belt ◽  
Belt System

scholarly journals Identifikasi Keterdapatan Mineral Radioaktif pada Urat-Urat Magnetit di Daerah Ella Ilir, Melawi, Kalimantan Barat

EKSPLORIUM ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 33
Author(s):  
Ngadenin Ngadenin ◽  
Frederikus Dian Indrastomo ◽  
Widodo Widodo ◽  
Kurnia Setiawan Widana
Keyword(s):  
Iron Ore ◽  
Biotite Granite ◽  
Ore Deposits ◽  
Geological Mapping ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
West Kalimantan ◽  
The North ◽  
Iron Ore Deposits ◽  
Radioactive Minerals

ABSTRAKElla Ilir secara administratif terletak di Kabupaten Melawi, Kalimantan Barat. Geologi regional daerah Ella Ilir tersusun atas batuan malihan berumur Trias–Karbon yang diterobos oleh batuan granitik berumur Yura dan Kapur. Keterdapatan mineral radioaktif di daerah tersebut terindikasi dari radioaktivitas urat-urat magnetit pada batuan malihan berumur Trias–Karbon dengan kisaran nilai 1.000 c/s hingga 15.000 c/s. Tujuan dari penelitian ini adalah menentukan jenis cebakan mineral bijih dan mengidentifikasi keterdapatan mineral radioaktif pada urat-urat bijih magnetit di daerah Ella Ilir. Metode yang digunakan adalah pemetaan geologi, pengukuran radioaktivitas, analisis kadar uranium, dan analisis mineragrafi beberapa sampel urat bijih magnetit. Litologi daerah penelitian tersusun oleh kuarsit biotit, metatuf, metabatulanau, metapelit, granit biotit, dan riolit. Sesar sinistral barat-timur dan sesar dekstral utara-selatan merupakan struktur sesar yang berkembang di daerah ini. Komposisi mineral urat-urat magnetit terdiri dari mineral-mineral bijih besi, sulfida, dan radioaktif. Mineral bijih besi terdiri dari magnetit, hematit, dan gutit. Mineral sulfida terdiri dari pirit, pirhotit, dan molibdenit sedangkan mineral radioaktif terdiri dari uraninit dan gumit. Keterdapatan urat-urat bijih magnetit dikontrol oleh litologi dan struktur geologi. Urat-urat magnetit pada metabatulanau berukuran tebal (1,5–5 m), mengisi rekahan-rekahan yang terdapat di sekitar zona sesar. Sementara itu, urat-urat magnetit pada metapelit berukuran tipis (milimetrik–sentimetrik), mengisi rekahan-rekahan yang sejajar dengan bidang sekistositas. Cebakan mineral bijih di daerah penelitian adalah cebakan bijih besi atau cebakan bijih magnetit berbentuk urat karena proses hidrotermal magmatik.ABSTRACTElla Ilir administratively located in Melawi Regency, West Kalimantan. Regional geology of Ella Ilir area is composed of metamorphic rocks in Triassic–Carboniferous age which are intruded by Jurassic and Cretaceous granitic rocks. Radioactive minerals occurences in the area are indicated by magnetite veins radioactivities on Triassic to Carboniferous metamorphic rocks whose values range from 1,000 c/s to 15,000 c/s. Goal of the study is to determine the type of ore mineral deposits and to identify the presence of radioactive mineral in magnetite veins in Ella Ilir area. The methods used are geological mapping, radioactivity measurements, analysis on uranium grades, and mineragraphy analysis of severe magnetite veins samples. Lithologies of the study area are composed by biotite quartzite, metatuff, metasilt, metapellite, biotite granite, and ryolite. The east-west sinistral fault and the north-south dextral fault are the developed fault structures in this area. Mineral composition of magnetite veins are consists of iron ore, sulfide, and radioactive minerals. Iron ore mineral consists of magnetite, hematit, and goetite. Sulfide minerals consist of pyrite, pirhotite, and molybdenite, while radioactive minerals consist of uraninite and gummite. The occurences of magnetite veins are controlled by lithology and geological structures. The magnetite veins in metasilt are thick (1.5–5 m), filled the fractures in the fault zone. Meanwhile, the magnetite veins in metapellite are thinner (milimetric–centimetric), filled the fractures that are parallel to the schistocity. The ore deposits in the study area are iron ore deposits or magnetite ore deposits formed by magmatic hydrothermal processes. 

Unusual Inheritance in the ABO Blood Group System: A Group O Child from A Group A(2)B Mother

Vox Sanguinis ◽  
1978 ◽  
Vol 35 (3) ◽  
pp. 176-180
Author(s):  
Maria Dolores Valdes ◽  
Caroline Zoes ◽  
Alice Froker
Keyword(s):  
Blood Group ◽  
Abo Blood Group ◽  
Blood Group System ◽  
Group System ◽  
System A ◽  
Group A

A special issue on the metallogeny of the Tasman fold belt system of eastern Australia; preface

1995 ◽  
Vol 90 (6) ◽  
pp. 1381-0 ◽  
Author(s):  
J. L. Walshe ◽  
K. G. McQueen ◽  
S. F. Fox
Keyword(s):  
Fold Belt ◽  
Special Issue ◽  
Eastern Australia ◽  
Belt System

scholarly journals A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

2016 ◽  
Vol 46 (4) ◽  
pp. 491-508 ◽  
Author(s):  
Benjamim Bley de Brito Neves ◽  
◽  
Edilton José dos Santos ◽  
Reinhardt Adolfo Fuck ◽  
Lauro César Montefalco Lira Santos ◽  
...  
Keyword(s):  
Granitic Rocks ◽  
Lower Plate ◽  
Low Grade ◽  
Northeast Brazil ◽  
The South ◽  
Magmatic Arc ◽  
Continental Plate ◽  
Borborema Province ◽  
Northern Portion ◽  
Fold Belts

ABSTRACT: Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma) exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB) belt. Three igneous supersuites are recognized: a) epidote-bearing granodiorites and tonalites ("Conceição" type); b) high-K calc-alkaline granites ("Itaporanga" type); c) biotite granodiorites of trondhjemite affinity ("Serrita" type). A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil.

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