Structural development of the Snow Lake Allochthon and its role in the evolution of the southeastern Trans-Hudson Orogen in Manitoba, central Canada

1999 ◽  
Vol 36 (11) ◽  
pp. 1881-1899 ◽  
Author(s):  
Jürgen Kraus ◽  
Paul F Williams
Keyword(s):  
Structural Development ◽  
Southeastern Part ◽  
External Zone ◽  
Local Boundary ◽  
Tectonic Model ◽  
Adjacent Part ◽  
Central Canada ◽  
Tectonic Transport ◽  
The One ◽  
Superior Craton

The Snow Lake Allochthon is a zone of tectonic interleaving of sedimentary rocks of an inverted marginal basin (Kisseynew Domain) with island-arc and oceanic rocks. It is located in the southeastern part of the exposed internal zone of the Paleoproterozoic Trans-Hudson Orogen in Manitoba, Canada, near the external zone (Superior collision zone or Thompson Belt), which constitutes the local boundary between the Trans-Hudson Orogen and the Archean Superior Craton. The Snow Lake Allochthon formed, was deformed, and was metamorphosed up to high grade at low to medium pressure during the Hudsonian orogeny as a result of the collision of Archean cratons ~1.84-1.77 Ga. Four generations of folds (F1-F4) that formed in at least three successive kinematic frames over a period of more than 30 Ma are described. Isoclinal to transposed southerly verging F1-2 structures are refolded by large, open to tight F3 folds and, locally, by open to tight F4 folds. The axes of the F1-2 folds are parallel or near parallel to the axes of F3 folds, owing to progressive reorientation of the F1-2 axes during south- to southwest-directed tectonic transport, followed by F3 refolding around the previous linear anisotropy. A tectonic model is presented that reconciles the distinct tectono-metamorphic developments in the Snow Lake Allochthon and the adjacent part of the Kisseynew Domain on the one hand, and in the Thompson Belt on the other, during final collision of the Trans-Hudson Orogen with the Superior Craton.

scholarly journals BOUNDARY OPERATORS IN QUANTUM FIELD THEORY

2000 ◽  
Vol 15 (28) ◽  
pp. 4539-4555
Author(s):  
GIAMPIERO ESPOSITO
Keyword(s):  
Field Theory ◽  
Mathematical Theory ◽  
The Other ◽  
Quantum Field ◽  
Local Boundary ◽  
Elliptic Theory ◽  
Boundary Operators ◽  
The One ◽  
Well Posed ◽  
Pseudodifferential Boundary

The fundamental laws of physics can be derived from the requirement of invariance under suitable classes of transformations on the one hand, and from the need for a well-posed mathematical theory on the other hand. As a part of this programme, the present paper shows under which conditions the introduction of pseudodifferential boundary operators in one-loop Euclidean quantum gravity is compatible both with their invariance under infinitesimal diffeomorphisms and with the requirement of a strongly elliptic theory. Suitable assumptions on the kernel of the boundary operator make it therefore possible to overcome problems resulting from the choice of purely local boundary conditions.

scholarly journals STRUCTURAL DEVELOPMENT CHANGES OF RUSSIAN AGRARIAN SECTOR WITHIN THE FRAMEWORK OF IMPLEMENTATION OF NATIONAL PRIORITIES

2020 ◽  
Author(s):  
M. A. Kholodova ◽  
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Agricultural Sector ◽  
Mining Industry ◽  
Comparative Characteristic ◽  
Structural Development ◽  
State Management ◽  
Agrarian Sector ◽  
The One ◽  
Agrarian Structure

Purpose: to study the problem of structural changes in the development of the agricultural sector in Russia within the framework of the national priorities implementation. Materials and methods: the synthetic tools of the study are based on the methods of economic statistics, which helped to analyze the structural dynamics of the country's agricultural sector. The object of the research was the agrarian structure of the Russian agricultural sector. The statistical analysis was carried out in the context of individual categories of farms. Results. The problems of structural changes in the agricultural sector of Russia within the framework of the implementation of national priorities are dealt with. For this, the methodology for calculating structural changes in agriculture and the mining industry, as well as the agricultural sector in the context of certain categories of farms, was used. The analysis is carried out for agricultural organizations, peasant (farmer) households. The problem of structuring the agrarian sector of the Russian economy is considered as a systemic task of state management of the industry, reduced to the formation of optimal proportions between the elements of the agrarian structure and their development. The results of agrarian reforms in agriculture for the period 2006–2019 are presented. A comparative characteristic of the options for organizing large-scale agro-industrial production in Russia and abroad is given. Conclusions. The presented dynamics of structural changes in agriculture on the basis of linear and quadratic coefficients makes it possible to determine the effectiveness of the state agricultural policy in the context of the implementation of national priorities. It has been substantiated that in the mid-term strategic development the intensity of structural changes in agriculture will be determined by the development trends of the small-format sector of the economy, including the one through the system of agricultural cooperation.

scholarly journals On the Crank-Nicolson difference scheme for the time-dependent source identification problem

2021 ◽  
Vol 102 (2) ◽  
pp. 35-44
Author(s):  
A. Ashyralyev ◽  
◽  
M. Urun ◽  
◽  
◽  
...  
Keyword(s):  
Difference Scheme ◽  
Source Identification ◽  
Identification Problem ◽  
Stability Estimates ◽  
Differential Problem ◽  
Order Of Accuracy ◽  
Local Boundary ◽  
Non Local ◽  
The One ◽  
Crank Nicolson

In this study the source identification problem for the one-dimensional Schr¨odinger equation with non-local boundary conditions is considered. A second order of accuracy Crank-Nicolson difference scheme for the numerical solution of the differential problem is presented. Stability estimates are proved for the solution of this difference scheme. Numerical results are given.

The magnitude 8.3 June 23 2001 southern Peru earthquake and tsunami

2003 ◽  
Vol 36 (3) ◽  
pp. 189-207
Author(s):  
Mark Stirling ◽  
Robert Langridge ◽  
Rafael Benites ◽  
Hector Aleman
Keyword(s):  
New Zealand ◽  
Active Faults ◽  
Strong Motion ◽  
Maximum Size ◽  
Southeastern Part ◽  
Ground Acceleration ◽  
Epicentral Area ◽  
Southern Peru ◽  
The One ◽  
2001 Southern Peru Earthquake

We present a precis of our reconnaissance trip to the area of the magnitude 8.3 June 23 2001 southern Peru earthquake and tsunami. The trip was undertaken because of the relevance of the event to hazard assessment in New Zealand. It is the best example in nearly 40 years of the maximum-size earthquake that might occur on the Hikurangi subduction zone, an event that is absent from the historical record of New Zealand (since 1840) and therefore of unknown potential in terms of hazard. Despite the great magnitude of this subduction interface earthquake, it produced only "moderately strong" levels of earthquake shaking (peak ground acceleration of 0.3g on alluvium from the one strong motion accelerograph in the earthquake area, and Modified Mercalli Intensity 8 in the epicentral area), and relatively minor ground damage (liquefaction and landslides). It did however produce a large and devastating tsunami. Our comparison of the one accelerograph record and attenuation curves for subduction interface earthquakes shows that the strength of shaking was typical for subduction interface earthquakes. If we apply our observations to New Zealand, they imply that a Hikurangi subduction interface earthquake may be less damaging to built-up areas in the southeastern part of the North Island (e.g. Wellington and Napier/Hastings) than earthquakes on major active faults in the shallow crust. However, the lateral extent of the strongest shaking in a subduction earthquake (300 km for the southern Peru event) and the associated tsunami generation will make the earthquake very significant in the national context.

HYDROCARBON GENERATION, MIGRATION AND ENTRAPMENT IN THE JACKSON-NACCOWLAH AREA, ATP 259P, SOUTHWESTERN QUEENSLAND

1985 ◽  
Vol 25 (1) ◽  
pp. 62 ◽  
Author(s):  
P.W. Vincent I.R. Mortimore ◽  
D.M. McKirdy
Keyword(s):  
Oil And Gas ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Structural Development ◽  
Southeastern Part ◽  
Gas Field ◽  
Early Tertiary ◽  
Oil Generation ◽  
Oil Source ◽  
Eromanga Basin

The northern part of the Naccowlah Block, situated in the southeastern part of the Authority to Prospect 259P in southwestern Queensland, is a major Eromanga Basin hydrocarbon province. The Hutton Sandstone is the main reservoir but hydrocarbons have been encountered at several levels within the Jurassic-Cretaceous sequence. In contrast, the underlying Cooper Basin sequence is generally unproductive in the Naccowlah Block although gas was discovered in the Permian at Naccowlah South 1. Oil and gas discoveries within the Eromanga Basin sequence are confined to the Naccowlah-Jackson Trend. This trend forms a prominent high separating the deep Nappamerri Trough from the shallower, more stable northern part of the Cooper Basin.The Murta Member is mature for initial oil generation along the Naccowlah-Jackson Trend and has sourced the small oil accumulations within this unit and the underlying Namur Sandstone Member. The Birkhead Formation is a good source unit in this area with lesser oil source potential also evident in the Westbourne Formation and 'basal Jurassic'. Source quality and maturation considerations imply that much of the oil discovered in Jurassic reservoirs along the Naccowlah-Jackson Trend was generated from more mature Jurassic source beds in the Nappamerri Trough area to the southwest. Maturation modelling of this deeper section suggests that hydrocarbon generation from Jurassic source units commenced in the Early Tertiary. Significant oil generation and migration has therefore occurred since the period of major structural development of the Naccowlah-Jackson Trend in the Early Tertiary. This trend, however, has long been a major focus for hydrocarbon migration paths out of the Nappamerri Trough as a result of intermittent structuring during the Mesozoic. Gas reservoired in Jurassic sandstones at Chookoo has been generated from more mature Jurassic source rocks in the deeper parts of the Nappamerri Trough.Permian sediments in the Nappamerri Trough area are overmature for oil generation and are gas prone. Gas generated in this area has charged the lean Permian gas Field at Naccowlah South, along the Wackett-Naccowlah- Jackson Trend. North of this trend Permian source rocks are mainly gas prone but more favourable levels of maturity allow the accumulation of some gas liquids and oil. However, geological and geochemical evidence suggests that Permian sediments did not source the oil found in Jurassic-Cretaceous reservoirs in the Jackson- Naccowlah area.

scholarly journals COMMENTS ON THE ARTICLE AUTHORED BY M.V. MINTS AND K.A. DOKUKINA – THE BELOMORIAN ECLOGITE PROVINCE (EASTERN FENNOSCANDIAN SHIELD, RUSSIA): MESO-NEOARCHEAN OR LATE PALEOPROTEROZOIC?

2021 ◽  
Vol 12 (3) ◽  
pp. 652-661
Author(s):  
S. G. Skublov ◽  
A. V. Berezin ◽  
L. I. Salimgaraeva
Keyword(s):  
White Sea ◽  
Distribution Patterns ◽  
Fennoscandian Shield ◽  
Mobile Belt ◽  
Chemical Compositions ◽  
The White Sea ◽  
Tectonic Model ◽  
Precambrian Geology ◽  
Dating Methods ◽  
The One

The comments are given on the article authored by M.V. Mints and K.A. Dokukina – The Belomorian Eclogite Province (Eastern Fennoscandian Shield, Russia): Meso-Neoarchean or Late Paleoproterozoic? (Geodynamics & Tectonophysics 2020, 11 (1), 151–200). The Belomorian (White Sea) province of the Fennoscandia Shield is a key site for studying the tectonics of the early periods because numerous Precambrian eclogites have been found there. It was not anticipated, but the problem of age determinations of the eclogite metamorphism of gabbroids in the White Sea mobile belt has turned out to be extremely relevant not only for this region, but also for the Precambrian geology in general. The reason is that a number of authors determine the age of eclogites as Archean (2.7–2.8 Ga), which makes the White Sea mobile belt the only example of the Archean eclogite metamorphism in the world and, therefore, the only dated evidence in support of the plate tectonic model of the evolution of the Earth’s crust at the earliest stage of its formation. The article consistently provides a critical analysis of the arguments put forward by the supporters of the Archean age of the eclogites of the White Sea mobile belt. Special emphasis is made on the isotope geochronological and geochemical features of the composition of zircons from eclogite samples, as well as on the phase and chemical compositions and distribution patterns of mineral inclusions. Considering the age of eclogite metamorphism that led to the formation of eclogites in the White Sea mobile belt, we propose our interpretation based on a set of independent isotope geochemical dating methods, including the local U- Pb method for heterogeneous zircons with magmatic cores and eclogite rims, the Lu-Hf and Sm-Nd methods for the minerals of eclogite paragenesis (garnet and omphacite). And this age interpretation is fundamentally different from the one described in the commented article: all the three methods independently determine the eclogite metamorphism as Paleoproterozoic and yield the same age of circa 1.9 Ga. According to our data, the eclogites of the White Sea mobile belt are among the most ancient high-pressure rocks, their reliably established age of metamorphism is circa 1.9 Ga, and the age of the magmatic protolith is the range of 2.2–2.9 Ga.

scholarly journals LOCAL SUPERSYMMETRY IN ONE-LOOP QUANTUM COSMOLOGY

1994 ◽  
Vol 03 (03) ◽  
pp. 593-607 ◽  
Author(s):  
GIAMPIERO ESPOSITO
Keyword(s):  
Boundary Conditions ◽  
Quantum Cosmology ◽  
Degrees Of Freedom ◽  
Gauge Condition ◽  
Function Technique ◽  
Local Boundary ◽  
Three Sphere ◽  
Spin Fields ◽  
Eigenvalue Condition ◽  
The One

The contribution of physical degrees of freedom to the one-loop amplitudes of Euclidean supergravity is here evaluated in the case of flat Euclidean backgrounds bounded by a three-sphere, recently considered in perturbative quantum cosmology. In Euclidean supergravity, the spin-[Formula: see text] potential has the pair of independent spatial components [Formula: see text]. Massless gravitinos are here subject to the following local boundary conditions on [Formula: see text], where [Formula: see text] is the Euclidean normal to the three-sphere boundary. The physical degrees of freedom (denoted by PDF) are picked out imposing the supersymmetry constraints and choosing the gauge condition [Formula: see text], [Formula: see text]. These local boundary conditions are then found to imply the eigenvalue condition [Jn + 2 (E)]2 - [Jn + 3(E)]2 = 0, ∀ n ≥ 0, with degeneracy (n+4)(n+1). One can thus apply again a zeta-function technique previously used for massless spin-½ fields. The PDF contribution to the full ζ(0) value is found to be [Formula: see text]. Remarkably, for the massless gravitino field the PDF method and local boundary conditions lead to a result for ζ(0) which is equal to the PDF value one obtains using spectral boundary conditions on S3.

Vulnerability of soils to degradation by wildfires in Torres del Paine National Park (Patagonia, Chile)

2021 ◽  
Author(s):  
Jorge Mataix-Solera ◽  
Jorge E. Jaña ◽  
Eduardo Arellano ◽  
Luis Olivares ◽  
José Guardiola ◽  
...  
Keyword(s):  
National Park ◽  
Soil Survey ◽  
Rainfall Simulation ◽  
Vegetation Coverage ◽  
Annual Rainfall ◽  
Forest Steppe ◽  
Structural Development ◽  
Erosion Processes ◽  
The One ◽  
Torres Del Paine

<p>Wildfires are a common phenomenon across the world, but some ecosystems are more adapted to this perturbation than others. In this work we show some results of a study conducted in the Torres del Paine National Park (Chile) that suffered a big forest fire in 2011 affecting 17,666 ha. Based on vegetation coverage, five areas of the park were sampled in 2019 following the transects where a vegetation recovery study has been monitored in order to know the status of the ecosystem and how fire and post-fire conditions affected.</p><p>The study area is in a temperate cold rainy climate zone without dry season. The park is located in the transitional forest-steppe zone whose annual rainfall varies between 1500 mm and 300 mm. Plant communities goes from Patagonian steppe, pre-Andean scrub to Magallanic forest. The soils of the region vary from Cryorthents and Udorthents to Haplocryolls (Soil Survey Staff, 2014), most of them with scarce development.</p><p>A total of 69 composite soil samples were taken, and the following parameters were analysed: texture, soil water repellency (WR), organic matter (OM), and aggregation, including total content of macroaggregates (TCA; % of sample that are forming macroaggregates) and their stability (AS; % of macroaggregates that resist the energy of a rainfall simulation of known energy).</p><p>The results showed high values of OM, with an average of 10.5%. Three of the five areas showed statistically lower values of OM in burned samples. WR (from slight to severe) was present in the 75% of the samples, and without differences between burned and unburned samples. The correlations analyses indicated that WR is more related with the OM quality than with quantity, since better correlations were obtained when only samples from same area -thus similar vegetation- were included in the analyses, and no correlation when all samples from different sites are pooled together. The results of aggregation indicated that these soils have a poor structural development. The TCA varies from 16 to 50%, and the AS is not very high (average of 66 %), being the higher in the area with lower TCA, and more affected by the fire and erosion processes. This suggests that the higher values of AS are consequence of the destruction and loss of the less resistant fraction after the fire.</p><p>WR is a natural property in these soils. The combination of the high sand content (low specific surface area) and high OM make them very susceptible to develop WR. Since these soils have a scarce development with a poor structure, the combination of these factors make them very vulnerable to erosion processes after the fire. This could be verified in three of the five study areas and specially the one with plant community in transition between steppe to scrub, which was the one more affected by the perturbation caused by the fire and post-fire erosion processes. Measures to protect the soils or accelerate the recovery are recommended in these areas when new human caused wildfires will occur.</p>

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