Geoelectric structure of the northeastern Williston basin and underlying Precambrian lithosphereEarth Science Sector (ESS) Contribution 20080509.

2009 ◽  
Vol 46 (6) ◽  
pp. 441-464 ◽  
Author(s):  
Evan J. Gowan ◽  
Ian J. Ferguson ◽  
Alan G. Jones ◽  
James A. Craven
Keyword(s):  
Tensor Decomposition ◽  
Williston Basin ◽  
Boundary Zone ◽  
Lower Paleozoic ◽  
The North ◽  
Upper Paleozoic ◽  
Paleozoic Rocks ◽  
Superior Craton ◽  
East West ◽  
Made In

Magnetotelluric (MT) measurements were made in southern Manitoba, Canada, as part of the Portable Observatories for Lithosphere Analysis and Research Investigating Seismicity (POLARIS) project, to image the northeastern part of the Williston basin and underlying Precambrian lithosphere. Data collected at 21 sites along a 400 km east–west profile at 49.5°N and a 300 km north–south profile at 100°W were analyzed using robust spectral analysis, tensor decomposition, and two-dimensional inversion. The resulting resistivity models allow subdivision of the Williston basin into three layers: an upper layer of 1–5 Ω·m corresponding to Mesozoic and upper Paleozoic rocks, a 20–50 Ω·m layer corresponding to lower Paleozoic carbonate rocks, and a 2–3 Ω·m layer corresponding to the Ordovician Winnipeg Formation. Deeper penetrating MT responses, interpreted with other MT data, reveal a region in the westernmost Superior craton with a southwest–northeast geoelectric fabric that is oblique to subprovince boundaries. The observations can be explained by Proterozoic deformation extending several hundred kilometres east of the Superior boundary zone or by a separate Archean terrane adjacent to the boundary. The Thompson belt (TOBE) conductor in the south of the study area has previously been interpreted as part of the Superior boundary zone (SBZ). However, MT results show that the conductor does not extend continuously along the margin of the zone and MT studies to the north define conductors on the margin of the Sask craton. The results suggest the TOBE conductor is associated with the Sask craton margin. The MT results indicate significant along-strike variation of the SBZ in southern Manitoba.

The mineralogical composition of some Scottish soils

1925 ◽  
Vol 15 (3) ◽  
pp. 257-271 ◽  
Author(s):  
James Hendrick ◽  
George Newlands
Keyword(s):  
Mineralogical Composition ◽  
Fine Sand ◽  
Plant Food ◽  
Sand Fraction ◽  
Extensive Survey ◽  
North East ◽  
The North ◽  
Local Origin ◽  
East West ◽  
Made In

1. Previous investigations showed that certain Scottish soils were of glacial drift origin, that they were comparatively rich in unweathered silicates and therefore in reserves of plant-food, that they showed considerable variation in such silicates and were capable of classification accordingly. Some indication was also shown that the glacial drift, and hence the resulting soil, was sometimes of local origin, its character being determined by the underlying rock. In the present investigation a more extensive survey of Scottish soils has been made in order to discover to what extent these preliminary findings might be applicable generally.2. For this purpose soils have been collected from various localities in the north, north-east, west and south of Scotland, and have been analysed mechanically and the “fine sand” fraction examined mineralogically.

scholarly journals A missing link in the peri-Gondwanan terrane collage: the Precambrian basement of the Moroccan Meseta and its lower Paleozoic cover

2018 ◽  
Vol 55 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dominik Letsch ◽  
Mohamed El Houicha ◽  
Albrecht von Quadt ◽  
Wilfried Winkler
Keyword(s):  
Carbonate Platform ◽  
Source Area ◽  
Source Rocks ◽  
Lower Paleozoic ◽  
Northern Margin ◽  
Precambrian Geology ◽  
The North ◽  
Late Cambrian ◽  
Paleozoic Rocks ◽  
Rifted Margin

This article provides stratigraphic and geochronological data from a central part of Gondwana’s northern margin — the Moroccan Meseta Domain. This region, located to the north of the Anti-Atlas area with extensive outcrops of Precambrian and lower Paleozoic rocks, has hitherto not received much attention with regard to its Precambrian geology. Detrital and volcanic zircon ages have been used to constrain sedimentary depositional ages and crustal affinities of sedimentary source rocks in stratigraphic key sections. Based on this, a four-step paleotectonic evolution of the Meseta Domain from the Ediacaran until the Early Ordovician is proposed. This evolution documents the transition from a terrestrial volcanic setting during the Ediacaran to a short-lived carbonate platform setting during the early Cambrian. The latter then evolved into a rifted margin with deposition of thick siliciclastic successions in graben structures during the middle to late Cambrian. The detritus in these basins was of local origin, and a contribution from a broader source area (encompassing parts of the West African Craton) can only be demonstrated for postrifting, i.e., laterally extensive sandstone bodies that seal the former graben. In a broader paleotectonic context, it is suggested that this Cambrian rifting is linked to the opening of the Rheic Ocean, and that several peri-Gondwanan terranes (Meguma and Cadomia–Iberia) may have been close to the Meseta Domain before drifting, albeit some of them seem to have been constituted by a distinctly different basement.

Cooperative seismic surveys across the Superior–Churchill boundary zone in southern Canada

1980 ◽  
Vol 17 (5) ◽  
pp. 617-632 ◽  
Author(s):  
A. G. Green ◽  
O. G. Stephenson ◽  
G. D. Mann ◽  
E. R. Kanasewich ◽  
G. L. Cumming ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Small Region ◽  
Superior Province ◽  
Boundary Zone ◽  
Reflection Point ◽  
Preliminary Results ◽  
The North ◽  
Seismic Surveying ◽  
Point Data ◽  
East West

Three seismic surveying techniques have been employed in a study of the Superior–Churchill boundary zone in southwestern Manitoba and southeastern Saskatchewan. Two reversed refraction – wide angle reflection profiles, one north–south within the Superior tectonic province and one east–west traversing part of the Superior tectonic province, the boundary zone, and part of the Churchill tectonic province, were used to obtain information on the gross velocity structure of the crust over a large region. Preliminary results from these surveys suggest that the crust beneath the north–south profile is typical of previously published crustal models of the western Superior Province, while the crust beneath the east–west profile is similar to that reported for the Churchill Province in eastern Alberta and western Saskatchewan. Generally, the upper and middle crustal sections in the two tectonic provinces are quite similar, while the lower crust in the Churchill Province has a distinct ~7 km/s layer that is not observed in this part of the Superior Province. In addition, there is a marked thickening of the crust within the boundary zone from ~41 km in the Superior Province to ~46 km in the Churchill Province.A 72 km length of fourfold common reflection point coverage was collected in order to determine the fine structure of the crust over a relatively small region. Reliable stacking velocities that may be used for future processing of the common reflection point data were obtained from an expanding spread reflection survey. Various data processing techniques, including common reflection point stacking, linear and nonlinear velocity filtering, and velocity spectral analysis, have been successful in enhancing reflections from the middle and lower parts of the crust. From the preliminary results of the two reflection surveys, it may be concluded that those parts of the crust which are shown as relatively simple layers in the refraction derived models, may be quite complex when viewed on a smaller scale.

The Soil Geochemical Abnormal Characteristics in Eastern of Luonan County in Shanxi Province

2013 ◽  
Vol 662 ◽  
pp. 459-462
Author(s):  
Wan Wan Zhang ◽  
Hua Ming Peng ◽  
Jia Yong Peng ◽  
Fu Sheng Guo ◽  
Fei Xia
Keyword(s):  
Shanxi Province ◽  
Lower Paleozoic ◽  
Clastic Rocks ◽  
The North ◽  
Upper Paleozoic

The study area is located in the north belt of Qingling latitudinal structural belt and contains well developed folds and faults directed EW and the iliceous carbonate sedimentary formations mainly in Lower Paleozoic Group and the sedimentary clastic rocks in Middle-upper Paleozoic Group. Tuyaowa anomaly belt, mainly with Au, As, Sb anomalies, is the favorable target for Au, As, Sb. Zhaizigou-Jianggou-Yujiagou anomaly belt, with Au, Ag, Cu, Zn, Mo anomalie, is the favorable target for Au, Ag, Cu, Zn, Mo. Miaowa-Houling abnomal belt, with Pb, Hg anomalies and Au, Ag, Zn, Mo weak anomalies, is the favorable target looking for Au, Ag, Zn, Mo and Pb. The abnomal belt of Shuigou-Hugou, with Au, Cu, Mo, Pb, V anomalie, is a favorable target for Au, Cu, Mo, Pb and V.

Chronology of transpression, magmatism, and sedimentation in the Thompson Nickel Belt (Manitoba, Canada) and timing of Trans-Hudson Orogen – Superior Province collisionThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh.

2011 ◽  
Vol 48 (2) ◽  
pp. 295-324 ◽  
Author(s):  
Nuno Machado ◽  
Denis Gapais ◽  
Alain Potrel ◽  
Gilles Gauthier ◽  
Erwan Hallot
Keyword(s):  
Crustal Thickening ◽  
Superior Province ◽  
Mafic Intrusions ◽  
The North ◽  
Continental Block ◽  
Diffuse Zone ◽  
Detrital Zircon Ages ◽  
Superior Craton ◽  
East West ◽  
Group Part

The Thompson Nickel Belt marks the boundary between the Archean Superior Province and the Trans-Hudson Orogen in Canada. It comprises Archean gneisses, and Paleoproterozoic rocks with metasediments and metavolcanites (Ospwagan Group) and intrusions. The gneisses are frequently migmatitic and host numerous pegmatites. The western belt boundary is a fault contact with the Kisseynew Domain of the Reindeer Zone. In the south, the transition zone between the belt and the Kisseynew Domain comprises granitoids and a detrital sequence (Grass River Group), part of which grades into turbidites in the Kisseynew Domain. The eastern belt boundary is a diffuse zone where the Archean east–west (E–W) structural trend changes into the north-northeast (NNE) trend of the belt. This paper presents U–Pb ages for granitoids and 207Pb/206Pb detrital zircon ages from the Ospwagan and Grass River groups. Ages and a comparison of events in the belt and in the eastern Reindeer Zone have major implications. The change from stable platform deposits to syn-tectonic filling and emplacement of mafic intrusions in the Ospwagan Group are attributed to the convergence between the Reindeer Zone and the Superior Province at 1891–1885 Ma. At ca. 1850 Ma, continuing convergence led to drowning of marginal basins of the Superior craton and to the development of a transpressive regime in the belt, the onset of which could be as old as ca. 1885 Ma. Metamorphic ages of 1818–1785 record closure of the Kisseynew basin and crustal thickening. Collision of the new continental block with the Superior Province was accommodated by transpression until 1750–1720 Ma.

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.

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.

On the role of the Hercynian and Alpine thrusts in the Upper Paleozoic rocks of the Central and Eastern Pyrenees

1989 ◽  
Vol 3 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Josep M. Casas ◽  
Francese Domingo ◽  
Josep Poblet ◽  
Albert Soler
Keyword(s):  
Eastern Pyrenees ◽  
Upper Paleozoic ◽  
Paleozoic Rocks
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