Sedimentology of Archean Turbidites at Yellowknife, Northwest Territories

1972 ◽  
Vol 9 (7) ◽  
pp. 882-902 ◽  
Author(s):  
John B. Henderson

The Burwash Formation is a major formation of the Archean Yellowknife Supergroup at Yellowknife. It consists of about 15 000 ft (4572 m) of interbedded graywackes and mudstones and shows many of the features characteristic of turbidites. Analysis of the internal sedimentary structures and paleocurrent data on the sediments indicate that the sediments were derived from the west, possibly from an area now occupied by an extensive granitic terrain, and accumulated in depositional fan valleys on a submarine fan complex near the margin of a large Archean sedimentary basin that lies to the east of Yellowknife. The high proportion of volcanic rock fragments, particularly silicic–volcanic lithic clasts, along with abundant quartz and feldspar and the minor but ubiquitous granitic rock fragments in the graywackes, indicates a mixed silicic–volcanic and granitic provenance. The modal and chemical composition, and volumetric abundance, of these sediments denotes the presence, and considerable extent, of sialic crust prior to the deposition of the Burwash Formation.

1992 ◽  
Vol 29 (6) ◽  
pp. 1274-1295 ◽  
Author(s):  
John Irwin Garver

Basin analysis of Albian–Cenomanian rocks of the Tyaughton and Methow basins suggests that the two basins were filled by three principle petrofacies during a regionally significant contractional event. The Volcanic petrofacies, which occurs only in the Tyaughton basin, comprises west-derived volcaniclastic strata. This petrofacies is dominated by intermediate volcanic clasts and minor metavolcanic, sedimentary, and plutonic clasts. This petrofacies and correlatives to the west (Taylor Creek volcanics and the Gambier Group) are inferred to have been a volcanic cover and volcaniclastic apron to the Insular terrane.The Cherry petrofacies occurs in both the Tyaughton and the Methow basins. Paleocurrents suggest that these chert-rich sediments were shed both east and west off a topographic high that separated the two basins. The Cherry petrofacies is dominated by chert-lithic detritus with subordinate sedimentary and volcanic rock fragments. Locally, the petrofacies is characterized by clasts of chert, greenstone, serpentinite, and blueschist; all these lithologies are common in the unconformably underlying Bridge River terrane, which is inferred to have been the dominant source terrane.Rocks that contain the Arkosic petrofacies are 3–8 km thick in the Methow basin, but only a thin unit is present in the Tyaughton basin. This petrofacies is rich in quartz and feldspar, with lesser quantities of volcanic lithic and metamorphic lithic fragments. Detrital muscovite, which is the hallmark of this petrofacies, is interpreted to have been derived from granitic and metasedimentary rocks to the east. This petrofacies is interpreted to have been largely derived from the Omineca Crystalline Belt, which was rapidly uplifting during this time. The three petrofacies in the two basins provide the first provenance link between the Insular terrane to the west to what was then North America (Omineca Crystalline Belt and the Intermontane Belt) to the east; juxtaposition is inferred to have occurred in a contractional setting.


1977 ◽  
Vol 8 ◽  
pp. 45-49
Author(s):  
Richard J. Hodgkinson ◽  
Christopher D. Walley

Carbonate and clastic sediments of Jurassic and Cretaceous age are exposed along the fault-scarp of Djebel Nefusa in north-western Libya. Previous geological investigations have been mainly restricted to the eastern sector of the scarp. Recent studies by the authors in the western sector of Djebel Nefusa and on equivalent sediments in southern Tunisia have allowed the first regional interpretation of these rocks.The area studied lies geographically and geologically at the edge of the Saharan Platform, a large cratonic block, composed of rocks of Precambrian-Palaeozoic age. To the north and east lies a downfaulted sedimentary basin (Gabes-Sabratha Basin) containing a large thickness of Mesozoic sediments. The location of the sections measured along Djebel Nefusa are depicted in Fig.1.The stratigraphic nomenclature of the rock succession of Djebel Nefusa was first established in the east and continued laterally towards the west by later workers. Difficulties in the application of this nomenclature are presented by the recognition of facies changes previously overlooked by earlier investigators. However, as a framework for understanding these changes and the sedimentary processes which caused them, the stratigraphy erected by Magnier (1963) is adopted.


2019 ◽  
Vol 44 (1) ◽  
pp. 77 ◽  
Author(s):  
A. Jayanegara ◽  
V. Ardani ◽  
H. A. Sukria

The objective of this experiment was to evaluate chemical composition, in vitro fermentation and digestibility of dried and ensiled indigofera, papaya and moringa leaves. The leaves were subjected to artificial drying in an oven at 60oC for 24 h and ensiling treatment for 30 d under room temperature. Dried and ensiled samples were determined for chemical composition, silage fermentation characteristics and in vitro rumen fermentation and digestibility. The experimental design was a factorial design 3 × 2 in which the first factor was different leaves (indigofera, papaya and moringa) and the second factor was conservation treatments (drying and ensiling). Determination of chemical composition was performed in duplicate whereas in vitro evaluation was conducted in three replicates. Results showed that ensiling treatment decreased CP contents of indigofera and moringa but not papaya leaves. Ensiling also decreased NDF and NDICP contents of all experimental leaves in comparison to drying treatment. The pH of all silages was high and they were characterized with high ammonia concentrations. Ensiled indigofera tended to have lower IVDMD and IVOMD as compared to dried indigofera (P<0.1). It can be concluded that ensiling of high protein forages leads to considerable extent of proteolysis.


2012 ◽  
Vol 40 (2) ◽  
pp. 163 ◽  
Author(s):  
Ireneusz Dariusz OCHMIAN

The studies were conducted in the period of 2010-2011, in the Laboratory of Orcharding at the West Pomeranian University of Technology in Szczecin, and related to the bushes of the highbush blueberry of the Duke cultivar. The authors examined the impact of foliar calcium fertlizers (Calcinit, Calcium chloride, Fruton Calcium Calcium, Folanx®Ca29 Lebosol Calcium Forte Calcium Forte) on the fruit size and firmness, their chemical composition, content of macronutrients in the foliage and fruits, and their colour. It was found that the applied fertlizers have varied impact on the examined attributes. The bushes sprayed with the Lebosol Calcium Forte and Calcinit preparations had big fruits with a high content of K and Mg, and dark foliage. The application of the Lebosol Calcium Forte fertilizer increased the content of polyphenols and vitamin C in the fruits. The smallest amounts of such compounds were determined in the fruits sprayed with the Calcinit fertilizer. The highest firmness and resistance to mechanical damage were achieved in the case of the fruits collected from the bushes sprayed with the foliar fertlizers containing calcium chloride, such as Fruton Calcium and Folanx Ca29. It was determined that the application of the calcium preparations resulted in the increase of the calcium content in the fruits and foliage. The highest amounts of this element were determined in the case of the plants sprayed with the Folanx Ca29 and Lebosol Calcium Forte preparations.


1994 ◽  
Vol 31 (2) ◽  
pp. 435-446 ◽  
Author(s):  
Pierre A. Cousineau ◽  
Pierre St-Julien

Two new formations, the Frontière and Etchemin formations, have been found to lie below the Beauceville and Saint-Victor formations, the two known formations of the Magog Group. The Frontière Formation, at the base of the group, is made up of centimeter-thick beds of medium- to coarse-grained litharenite and of greyish green mudstone; the sandstone, greyish green, contains abundant felsic volcanic rock fragments and chromite grains. The Etchemin Formation is composed mostly of centimeter-thick dusky yellow green siliceous mudstone; at the base, there is also a purple mudstone, and meter-thick beds of dusky green volcaniclastic rocks rich in intermediate to felsic volcanic rock fragments and crystals of feldspar and quartz occur near its top. The Beauceville Formation consists of interbedded centimeter-thick beds of black clayslate and centimeter- to meter-thick beds of black volcaniclastic rocks. The Saint-Victor Formation consists of classic turbidite beds with few meter-thick yellowish volcaniclastic rock beds similar to those of the Beauceville Formation; the sandstone is a litharenite rich in quartz grains and sedimentary rock fragments. Most rocks of the Frontière and Etchemin formations as well as the volcaniclastic rocks of the Beauceville and Saint-Victor formations were derived from a magmatic arc located to the southeast. However, the shale of the Beauceville Formation and the turbidites of the Saint-Victor Formation were derived from an orogenic source located to the northwest. The Magog Group is located between the Saint-Daniel Mélange and the Ascot Complex interpreted as remnants of an accretionary prism and a magmatic arc, respectively. The sediments of this group were thus deposited in a fore-arc basin active during the Taconian orogeny of the Middle to Late Ordovician.


1996 ◽  
Vol 5 (3) ◽  
Author(s):  
Adam Slater

Fostering a strong export sector is essential for the kind of small, open economy like post-communist Czechoslovakia (latterly the Czech and Slovak Republics). The CSFR export sector has to a considerable extent the defied expectations, of many of the more pessimistic commentators in regard to the expansion of exports to the West, as many industries with a previously poor record on the EC market have attained very rapid growth rates of exports to that market. Nevertheless, the evidence of section 3 points to a weakening of the reorientation process in 1992, and raises questions about the future of many of the industries which formerly exported largely to the CMEA area. Whilst the overall level of exports has been largely maintained in the transition period, export growth to the West has not allowed most of the CMEA-oriented industries to maintain their shares in total exports.


Author(s):  
Elena V. Ponomareva ◽  
◽  
Svetlana V. Ryzhkova ◽  

The paper considers three types of reservoirs in the Bazhenov formation: fractured, fractured-cavernous, and fractured-porous. Analysis of modern ideas about the Bazhenov Formation lithology and results of the formation testing in the southeastern and southern parts of the West Siberian sedimentary basin allowed to conclude that productive horizon Yu0 is confined to a reservoir of mainly fractured-porous type within the Koltogor-Nyrolka trench and adjacent positive tectonic elements.


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