The geochemistry and structural significance of a set of Middle Precambrian diabase dikes from the Highland Range, southwestern Montana

1989 ◽  
Vol 26 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Eric Lee Johnson ◽  
Susan M. Swapp
Keyword(s):  
Thermal Effects ◽  
Calcic Plagioclase ◽  
Southwestern Montana ◽  
The North ◽  
Metamorphic Assemblage ◽  
The One ◽  
Tobacco Root Mountains ◽  
East West ◽  
Metasomatic Event ◽  
Structural Significance

The Middle Precambrian diabase dikes of the Highland Range in southwestern Montana are moderate- to high-TiO2 continental tholeiites and are related along a differentiation trend involving strong iron enrichment. Postmagmatic metamorphism and K, Rb, and Sr metasomatism have altered the chemical composition of the igneous rocks of some of the samples. The metamorphic assemblage in the diabase dikes belongs to the low-pressure calcic plagioclase – actinolite hornfels facies, and we suggest that thermal effects associated with the intrusion of the Boulder Batholith are responsible for the metamorphic overprints in these rocks.Combined chemical data from the diabase dikes in the Highland Range, the Ruby Range, and the Tobacco Root Mountains produce smooth differentiation trends for most major oxides and trace elements, and we conclude that one magma was responsible for the dikes in the three ranges. Discrepancies in Rb–Sr age dates obtained for the dikes in the Tobacco Root Mountains can be explained if a Rb, Sr, and K metasomatic event like the one observed in the Highland Range had occurred in the Tobacco Root Mountains as well.Structurally, the diabase dikes in the Highland Range intruded into both east–west- and northwest-trending fractures at the same time. All dikes dip steeply to the north or northeast and are believed to have intruded into tensionally opened fractures related to the opening of the Belt Basin.

The late Precambrian mafic dikes of the southern Tobacco Root Mountains, Montana: geochemistry, Rb–Sr geochronology and relationship to belt tectonics

1978 ◽  
Vol 15 (4) ◽  
pp. 467-479 ◽  
Author(s):  
Joseph L. Wooden ◽  
Charles J. Vitaliano ◽  
Steven W. Koehler ◽  
Paul C. Ragland
Keyword(s):  
Mantle Material ◽  
Mountain Area ◽  
Precambrian Rocks ◽  
Southwestern Montana ◽  
Late Precambrian ◽  
High K ◽  
Major Period ◽  
Tobacco Root Mountains ◽  
Low K ◽  
East West

During late Precambrian time three sets of mafic dikes were emplaced in southwestern Montana south of the east–west Helena embayment of the Belt Basin. The oldest dikes, intruded approximately 1455 Ma ago into both the southern Tobacco Root Mountains and the adjoining Ruby Range, are low K tholeiite in composition. The two other sets of dikes were intruded at approximately the same time, about 1120–1130 Ma ago. Both are high K quartz normative types: one is strongly enriched in Fe and is most similar to ferrobasalt or ferrogabbro in composition, the other is low in iron and differentiated along strong alkali and silica enrichment trends. The 1455 Ma old dikes and the iron-enriched 1120 Ma dikes have initial Sr ratios in the range 0.7020–0.7030 that indicate probable derivation from mantle material that has maintained a low Rb–Sr ratio (0.024) for much of the Earth's history. This mantle source is much lower in Rb–Sr ratio than that proposed for the source of dikes in the Beartooth–Bighorn Mountain area to the southeast. The iron-poor 1130 Ma old magma has an initial ratio of 0.709, which suggests contamination by crustal Sr.A strong correlation appears to exist between the timing of mafic intrusive events in the older Precambrian rocks to the south of the Belt Basin and tectonic-intrusive events within the basin. Intrusive events are recorded at 1455–1430 Ma ago both inside and outside the basin. A 1330 Ma old mafic intrusive event in the Beartooth Mountains is associated with a period of metamorphism and (or) a period of deposition in the basin. The 1120–1130 Ma old dikes are correlated with mafic flows and sills and another major period of deposition within the Belt Basin.

Das Nord-Süd-Verhältnis zu Beginn der neunziger Jahre: Neue Strukturen eines alten Konflikts?

1992 ◽  
Vol 36 (1) ◽  
pp. 8-18
Author(s):  
Hans Diefanbacher ◽  
Ulrich Ratsch
Keyword(s):  
Developing Countries ◽  
Global Climate Change ◽  
Development Policy ◽  
Global Climate ◽  
Terms Of Trade ◽  
The North ◽  
Lost Decade ◽  
The One ◽  
The Relationship ◽  
East West

AbstractThe paper of Hans Diejenbacher and Ulrich Ratschstrats from the thesis that although the eighties have been a lost decade for the developing countries, the structures of the conflict between the North and the South have changed drastically. Those changes are exemplified by six different problern areas: the danger of an irreversible global climate change, the deterioration of the terms of trade for the developing countries, the impoverishment of the least development countries, the relationship between foreign debts and inflation, the crisis of development policy, and the effects of the changing east-west-conflict. The description of those conflict areas Ieads to the question how it could be possible to overcome the discrepancy between the knowledge about these problems on the one hand and the willingness to initiate political change on the other band.

From Helsinki to “Mars”

2021 ◽  
Vol 23 (4) ◽  
pp. 34-94
Author(s):  
Douglas Selvage
Keyword(s):  
Soviet Union ◽  
North Atlantic ◽  
The United States ◽  
Status Quo ◽  
Eastern Bloc ◽  
Soviet Bloc ◽  
The North ◽  
The Soviet Union ◽  
The One ◽  
East West

Abstract After the signing of the Final Act of the Conference on Security and Cooperation in Europe (CSCE) at Helsinki on 1 August 1975, the Soviet Union sought to compel the West to accept its vision for détente. This meant, on the one hand, the acceptance of the political and social status quo within the Soviet bloc and, on the other hand, the “completion” of the existing political détente with “military détente”—namely, East-West arms control agreements that preserved or augmented existing Warsaw Pact advantages. To this end, the KGB and its Soviet-bloc partners undertook two parallel campaigns of active measures, “Synonym” and “Mars.” Despite tactical successes, both campaigns failed to achieve their goals. The United States, supported by other Western governments, continued to pressure the Eastern-bloc governments on human rights violations, and the North Atlantic Treaty Organization (NATO) continued to modernize its forces in Europe, most importantly with the stationing of U.S. Euromissiles in 1983 in accordance with NATO's dual-track decision of December 1979.

Simulation of the internal temperature in the Passol Laboratory, University of Debrecen

2012 ◽  
Vol 3 (1) ◽  
pp. 63-73 ◽  
Author(s):  
I. Csáky ◽  
F. Kalmár
Keyword(s):  
Temperature Variation ◽  
Air Temperature ◽  
Indoor Air ◽  
Storage Capacity ◽  
Building Structures ◽  
Internal Temperature ◽  
The One ◽  
Heavy Structure ◽  
East West ◽  
Made In

Abstract Nowadays the facades of newly built buildings have significant glazed surfaces. The solar gains in these buildings can produce discomfort caused by direct solar radiation on the one hand and by the higher indoor air temperature on the other hand. The amplitude of the indoor air temperature variation depends on the glazed area, orientation of the facade and heat storage capacity of the building. This paper presents the results of a simulation, which were made in the Passol Laboratory of University of Debrecen in order to define the internal temperature variation. The simulation proved that the highest amplitudes of the internal temperature are obtained for East orientation of the facade. The upper acceptable limit of the internal air temperature is exceeded for each analyzed orientation: North, South, East, West. Comparing different building structures, according to the obtained results, in case of the heavy structure more cooling hours are obtained, but the energy consumption for cooling is lower.

MBAH HENDRO KUSUMO BIN SYECH AHMAD MUTAMAKKIN: JEJAK SYIAR ISLAM DI WILAYAH PATI

EMPIRISMA ◽  
2008 ◽  
Vol 27 (2) ◽  
Author(s):  
Fathimatuz Zahra Dan Abdul Azis
Keyword(s):  
Central Region ◽  
Marital Relationship ◽  
Southern Region ◽  
North Coast ◽  
The North ◽  
Trace Back ◽  
Northern Regions ◽  
The One

Pati is a region on the north coast, according to the hypothesis of the researcher, the region is divided into three categories. The northern regions are more religious, the central is more plural, while the southern region is in the middle. In the central region there are many relics of tombs believed to be the those of the Muslim proselytizers in the area of Pati. The one that attracts the researcher is a tomb in the Gambiran area, where there are five local Muslim saints buried, one of them belons to mbah Hendro Kusumo, the son of Syech Ahmad Mutamakkin. This article attempts to trace back the spreading of Islam in Pati based on the existence of thetomb of Mbah Hendro Kusumo. It wants to answer question of whethere the existence of his tomb is due to his studying there or marital relationship, and how it relates to the spreading of Islam.Keywords: Mbah Hendro Kusumo, Traces of Islamic Dakwah, Islam

Preaching and Sermons

2017 ◽  
Author(s):  
Robert H. Ellison
Keyword(s):  
Eighteenth Century ◽  
North Atlantic ◽  
Religious Revival ◽  
Early Nineteenth Century ◽  
Denominational Identity ◽  
The North ◽  
The North Atlantic ◽  
The One ◽  
The Impact

Prompted by the convulsions of the late eighteenth century and inspired by the expansion of evangelicalism across the North Atlantic world, Protestant Dissenters from the 1790s eagerly subscribed to a millennial vision of a world transformed through missionary activism and religious revival. Voluntary societies proliferated in the early nineteenth century to spread the gospel and transform society at home and overseas. In doing so, they engaged many thousands of converts who felt the call to share their experience of personal conversion with others. Though social respectability and business methods became a notable feature of Victorian Nonconformity, the religious populism of the earlier period did not disappear and religious revival remained a key component of Dissenting experience. The impact of this revitalization was mixed. On the one hand, growth was not sustained in the long term and, to some extent, involvement in interdenominational activity undermined denominational identity; on the other hand, Nonconformists gained a social and political prominence they had not enjoyed since the middle of the seventeenth century and their efforts laid the basis for the twentieth-century explosion of evangelicalism in Africa, Asia, and South America.

scholarly journals A Low frequency Southern Sky Survey Using the Mauritius Radio Telescope

2002 ◽  
Vol 199 ◽  
pp. 25-31
Author(s):  
N. Udaya Shankar
Keyword(s):  
Radio Telescope ◽  
Low Frequency ◽  
Fourier Synthesis ◽  
North East ◽  
The North ◽  
Sky Survey ◽  
Correlation Receiver ◽  
Complex Correlation ◽  
Right Ascension ◽  
East West

The Mauritius Radio Telescope (MRT) is a Fourier synthesis instrument which has been built to fill the gap in the availability of deep sky surveys at low radio frequencies in the southern hemisphere. It is situated in the north-east of Mauritius at a southern latitude of 20°.14 and an eastern longitude of 57°.73. The aim of the survey with the MRT is to contribute to the database of southern sky sources in the declination range −70° ≤ δ ≤ −10°, covering the entire 24 hours of right ascension, with a resolution of 4' × 4'.6sec(δ + 20.14°) and a point source sensitivity of 200 mJy (3σ level) at 151.5 MHz.MRT is a T-shaped non-coplanar array consisting of a 2048 m long East-West arm and a 880 m long South arm. In the East-West arm 1024 fixed helices are arranged in 32 groups and in the South arm 16 trolleys, with four helices on each, which move on a rail are used. A 512 channel, 2-bit 3-level complex correlation receiver is used to measure the visibility function. At least 60 days of observing are required for obtaining the visibilities up to the 880 m spacing. The calibrated visibilities are transformed taking care of the non-coplanarity of the array to produce an image of the area of the sky under observation.This paper will describe the telescope, the observations carried out so far, a few interesting aspects of imaging with this non-coplanar array and present results of a low resolution survey (13' × 18') covering roughly 12 hours of right ascension, and also present an image with a resolution of 4' × 4'.6sec(δ + 20.14°) made using the telescope.

scholarly journals Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

2021 ◽  
Author(s):  
Xiaoyi Shen ◽  
Chang-Qing Ke ◽  
Bin Cheng ◽  
Wentao Xia ◽  
Mengmeng Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Reanalysis Data ◽  
Mean Value ◽  
Ocean Model ◽  
North Coast ◽  
Average Value ◽  
The North ◽  
Wind Sea ◽  
The One

AbstractIn August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled ice-ocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978 (mean value of 1.1 m, compared to the average value of 2.8 m during 1978–2017) and the modest southerly wind caused by a positive North Atlantic Oscillation (mean value of 0.82, compared to the climatological value of −0.02) were responsible for the formation and maintenance of this polynya. The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind. Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

scholarly journals Optimal design of the solar tracking system of parabolic trough concentrating collectors

2020 ◽  
Vol 15 (4) ◽  
pp. 613-619
Author(s):  
Li Kong ◽  
Yunpeng Zhang ◽  
Zhijian Lin ◽  
Zhongzhu Qiu ◽  
Chunying Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Tracking System ◽  
Low Cost ◽  
Parabolic Trough ◽  
The North ◽  
Tracking Mode ◽  
Solar Tracking ◽  
East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

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