scholarly journals Seismic imaging across fault systems in the Abitibi greenstone belt – An analysis of pre- and post-stack migration approaches in the Chibougamau area, Quebec, Canada

2020 ◽  
Author(s):  
Saeid Cheraghi ◽  
Alireza Malehmir ◽  
Mostafa Naghizadeh ◽  
David Snyder ◽  
Lucie Mathieu ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Seismic Imaging ◽  
Massive Sulfide ◽  
Geological Structure ◽  
The South ◽  
Element Analysis ◽  
Fault Systems ◽  
The North ◽  
Relative Contribution ◽  
Abitibi Subprovince

Abstract. Two high-resolution seismic reflection profiles acquired north and south of Chibougamau, located in the northeast of the Abitibi subprovince of Canada help understand historic volcanic-hosted massive sulfide (VMS) deposits and hydrothermal Cu-Au mineralization found there. Major faults crossed by the profiles include the Barlow fault in the north and the Doda fault and the Guercheville fault in the south, all targets of this study that seeks to determine spatial relationships with known metal endowment in the area. Common-offset DMO corrections and common-offset pre-stack time migrations (PSTM) were considered. Irregularities of the trace midpoint distribution resulting from the crooked geometry of both profiles and their relative contribution to DMO and PSTM method and seismic illumination were assessed in the context of the complex subsurface architecture of the area. To scrutinize this contribution, seismic images were generated for offset ranges of 0–9 km using increments of 3 km. Migration of out-of-plane reflections used cross-dip element analysis to accurately estimate the fault dip. The seismic imaging shows the thickening of the upper crustal rocks near the fault zones along both profiles. In the north seismic reflection section, key geological structure identified include the Barlow fault and two diffraction sets imaged within the fault zone that represent potential targets for future exploration. The south seismic reflection section shows rather a complicated geometry of two fault systems. The Guercheville fault observed as a subhorizontal reflector connects to a steeply dipping reflector. The Doda fault dips subvertical in the shallow crust but as a steeply dipping reflection set at depth. Nearby gold showings suggest that these faults may help channel and concentrate mineralizing fluids.

scholarly journals Seismic imaging across fault systems in the Abitibi greenstone belt – an analysis of pre- and post-stack migration approaches in the Chibougamau area, Quebec, Canada

Solid Earth ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 1143-1164
Author(s):  
Saeid Cheraghi ◽  
Alireza Malehmir ◽  
Mostafa Naghizadeh ◽  
David Snyder ◽  
Lucie Mathieu ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Seismic Imaging ◽  
Massive Sulfide ◽  
The South ◽  
Element Analysis ◽  
Fault Systems ◽  
The North ◽  
Relative Contribution ◽  
Abitibi Subprovince ◽  
Seismic Reflection Profiles

Abstract. Two high-resolution seismic reflection profiles acquired north and south of Chibougamau, located in the northeast of the Abitibi subprovince of Canada, help understand historic volcanically hosted massive sulfide (VMS) deposits and hydrothermal Cu–Au mineralization found there. Major faults crossed by the profiles include the Barlow fault in the north and the Doda fault and the Guercheville fault in the south, all targets of this study that seeks to determine spatial relationships with a known metal endowment in the area. Common-offset DMO corrections and common-offset pre-stack time migrations (PSTMs) were considered. Irregularities of the trace midpoint distribution resulting from the crooked geometry of both profiles and their relative contribution to the DMO and PSTM methods and seismic illumination were assessed in the context of the complex subsurface architecture of the area. To scrutinize this contribution, seismic images were generated for offset ranges of 0–9 km using increments of 3 km. Migration of out-of-plane reflections used cross-dip element analysis to accurately estimate the fault dip. The seismic imaging shows the thickening of the upper-crustal rocks near the fault zones along both profiles. In the northern seismic reflection section, the key geological structures identified include the Barlow fault and two diffraction sets imaged within the fault zone that represent potential targets for future exploration. The south seismic reflection section shows rather a complicated geometry of two fault systems. The Guercheville fault observed as a subhorizontal reflector connects to a steeply dipping reflector. The Doda fault dips subvertical in the shallow crust but as a steeply dipping reflection set at depth. Nearby gold showings suggest that these faults may help channel and concentrate mineralizing fluids.

scholarly journals Geological structure and petroleum potential of the Kara Sea shelf

2019 ◽  
Vol 489 (3) ◽  
pp. 272-276
Author(s):  
V. A. Kontorovich ◽  
A. E. Kontorovich
Keyword(s):  
Oil And Gas ◽  
Sedimentary Basins ◽  
Geological Structure ◽  
Water Area ◽  
Kara Sea ◽  
Gas Content ◽  
Liquid Hydrocarbons ◽  
The South ◽  
Petroleum Potential ◽  
The North

On the Kara Sea shelf, there are two sedimentary basins separated by the North-Siberian sill. Tectonically the southern part of the Kara Sea covers the South Kara regional depression, which is the northern end of the West Siberian geosyncline. This part of the water area is identified as part of the South Kara oil and gas region, within which the Aptian-Albian-Senomanian sedimentary complex is of greatest interest in terms of gas content, in terms of liquid hydrocarbons - Neocomian and Jurassic deposits. The northern part of the Kara Sea is an independent North Kara province, for the most part of which the prospects of petroleum potential are associated with Paleozoic sedimentary complexes. Oil and gas perspective objects of this basin may be associated with anticlinal, non-structural traps and reef structures.

Constraints on Reelfoot Rift Evolution from a Reflection Seismic Profile in the Northern Rift

1992 ◽  
Vol 63 (3) ◽  
pp. 233-241 ◽  
Author(s):  
M.B. Goldhaber ◽  
C.J. Potter ◽  
C.D. Taylor
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Seismic Profile ◽  
Fault System ◽  
Seismic Reflection Profile ◽  
The South ◽  
Dome A ◽  
Reflection Seismic ◽  
The North ◽  
Northwestern Margin

Abstract An 82.8 km segment of a northwest-southeast trending seismic-reflection profile across the northernmost part of the Reelfoot rift shows that the Cambrian rift geometry there is quite distinct from that of the main part of Reelfoot rift to the south, and that of the Rough Creek graben to the east. The profile is within the area of intersection of the Reelfoot rift and Rough Creek graben and shows a systematic southeastward thickening of the Cambrian synrift clastic sequence with as much as 1940 meters of section present against the Pennyrile fault system as compared to 970 meters near the Lusk Creek and Shawneetown fault systems, towards the northwestern margin of the rift. This contrasts with the more symmetric rift pattern in the seismically active zone to the south, where the maximum thickness of synrift sediments is along the rift axis, and with an opposite sense of rift asymmetry in the Rough Creek graben, where the synrift sequence thickens to the north against the Rough Creek - Shawneetown fault. Reflection patterns in the vicinity of Hicks dome, a “cryptovolcano”, are consistent with the hypothesis that the dome originated by explosive release of mantle-derived gases associated with alkali volcanism. The seismic data also reveal that the fluorine mineralization in the area is associated with faults that offset basement; this is further evidence that deeply-derived fluids are significant in the geologic evolution of the area.

Crustal geometry of the Abitibi Subprovince, in light of three-dimensional seismic reflector orientations

1998 ◽  
Vol 35 (5) ◽  
pp. 569-582 ◽  
Author(s):  
G Bellefleur ◽  
A J Calvert ◽  
M C Chouteau
Keyword(s):  
Seismic Reflection ◽  
Three Dimensional ◽  
Seismic Reflection Data ◽  
Volcanic Arc ◽  
The North ◽  
Reflection Data ◽  
Abitibi Subprovince ◽  
Seismic Reflection Profiles ◽  
Lower Crustal ◽  
Seismic Reflector

We provide precise estimates of reflector orientations beneath the Archean Abitibi Subprovince, using two distinct approaches based on Lithoprobe seismic reflection data. In the first, we use the dip of reflections observed on intersecting profiles to establish the three-dimensional orientation of reflective structures. In the second, the strikes and dips of reflectors are estimated in the crooked parts of seismic reflection profiles by calculating a measure of coherency along the traveltime trajectories defined by a particular azimuth, dip, depth, and medium velocity. Mid-crustal reflectors define two areas with distinctive geometry: reflectors beneath the southern Abitibi belt are oppositely dipping, and convergent at depth, providing a V-shape aspect to the greenstone rocks; other reflectors beneath the northern Abitibi belt are, in general, subparallel, dipping at an average of 30° toward the north. These north-dipping reflectors are partly disrupted by a low-reflectivity zone, which is attributed to rocks of the Opatica Subprovince, located underneath the northern Abitibi belt. Lower-crustal reflectors have a similar, shallowly north-dipping orientation throughout the Abitibi Subprovince. The geometry of the reflectors recovered is consistent with the different tectonic histories proposed for the southern and northern Abitibi assemblages, until common deformation during a north-south shortening event. Attitudes recovered in the northern Abitibi belt are consistent with tectonic scenarios involving underthrusting of Abitibi middle and lower crustal terranes beneath the Opatica belt, whereas the oppositely dipping reflectors recovered in the middle crust beneath the southern Abitibi belt could be representative of a rifted volcanic arc environment.

Geological Studies in the Dublin District. I. The Heavy Minerals of the Granite and the Contiguous Rocks in the Ballycorus District

1928 ◽  
Vol 65 (1) ◽  
pp. 12-25 ◽  
Author(s):  
F. Smithson
Keyword(s):  
Geological Structure ◽  
Heavy Minerals ◽  
East Side ◽  
The South ◽  
Large Area ◽  
Lower Carboniferous ◽  
North West ◽  
The North ◽  
South West ◽  
The Hill

From the southern shores of Dublin Bay there stretches to the south-west a broad granite intrusion with rocks of supposed Ordovician age on both sides of it. These rocks are metamorphosed near the granite, and the belt of metamorphism is wider on the south-east than on the north-west side, indicating, no doubt, that the plane of junction dips more steeply on the latter side. Near Dublin the Lower Carboniferous rocks rest unaltered upon the granite. On the south-east side, in the northern part of the county of Wicklow, the belt of Ordovician rocks is only some 2 miles wide, and a large area of supposed Cambrian rocks lies between it and the sea. Around the hill of Carrickgollogan a. patch of similar rocks appears incongruously in the middle of the Ordovician belt. After a study of the region to the south of Dublin one seems to be naturally drawn towards this small area around Carrickgollogan, for it presents a problem, the key to which may explain the geological structure of a much wider area.

scholarly journals GROUNDWATERS OF NIKOLSKOHO REGION (DONBASS): GEOLOGY, STRATIGRAPHY, HYDROGEOLOGY, TOPOGRAPHIC AND GEODESIC WORKS

2020 ◽  
Author(s):  
Liudmyla Datsenko ◽  
◽  
Serhii Kolomiiets
Keyword(s):  
Arid Regions ◽  
Geological Structure ◽  
Crystalline Rocks ◽  
Geological Mapping ◽  
Clear Understanding ◽  
The South ◽  
Supply Source ◽  
The North ◽  
The World ◽  
North Western

Arid regions of the south of Ukraine (Donetsk, Zaporizhia, Kherson regions) are facing an acute shortage of drinking and technical water, which consumption increases from year to year. A clear understanding of the shortage not only drinking water but also water for fish breeding, cultural and recreational needs is worrying the world scientific community. Understanding of hydrogeological, hydrogeochemical processes is important for groundwater protection, especially in arid regions of the world. The study area is located within the central part of the Priazovsk highland. Administratively, it belongs to Nikolsk Region (formerly Volodarsky Region) in Donetsk Region. There are four research periods in geological mapping and study of the Eastern and North-Western Priazovia region. The most important researches of the late last century include medium-size deep geological mapping of the North-Western and Eastern Priazovia, generalization of all geological materials of the previous researchers, obtaining data from stratigraphy, magmatism, tectonics and metallogeny, hydrogeology, which allowed to significantly clarify the geological structure of the region. The only possible centralized water supply source on the most part of the territory may be an aquifer of Proterozoic crystalline rocks. In the south-eastern part of the territory can be used Sarmatian sands, sandstones and limestone horizon, for the aquifer of crystalline rocks, the most water-rich is the tectonic disturbance zone with open fracturing.

The Prehistory of the Isle of Man

1935 ◽  
Vol 1 ◽  
pp. 70-92 ◽  
Author(s):  
Grahame Clark
Keyword(s):  
Geological Structure ◽  
Irish Sea ◽  
The South ◽  
Isle Of Man ◽  
The North ◽  
Equal Distance ◽  
Geographical Position ◽  
The Irish Sea ◽  
Carboniferous Limestone ◽  
Flat Ground

‘Rising from the middle of the Irish Sea, within sight of each of the three Kingdoms, with a history and associations so distinct, yet so intimately linked with those of the rest of Britain, this interesting Island presents in its geological structure features which connect it alike with England, Scotland, and Ireland, while at the same time it retains a marked individuality in regard to some of the rocks that form its framework.’—Sir Archibald Geikie.The prehistory no less than the geology of the Isle of Man is of absorbing interest from its geographical position in relation to the larger units of the British Isles. The island is placed (fig. 1) at an equal distance (31 miles) between the coasts of Ireland and of Cumberland; its northern tip, the Point of Ayre, reaches to within 16 miles of Wigtonshire, and Anglesey lies 45 miles to the south of Langness Point. An observer on Snaefell (2034 feet) can view England, Scotland, Ireland and Wales in one sweep. Since the first settlement of the island, cultural and ethnic influences have approached from all directions, but its size (227 sq. miles) and the distance of sea which isolates it from the coasts of the mainlands have been sufficient to ensure vigorous local developments. The interaction of British and Irish influences and the occasional insular developments are the chief features of the prehistory of the island.Apart from a triangle of flat ground to the north, broken only by the Bride Hills (200–300 feet), and so far as its drift deposits are concerned, relatively recent in origin, the island consists almost entirely of slate diversified by local intrusions of igneous rocks (granite and diabase), by the sandstone of the Peel area, and by the carboniferous limestone of the Castletown district in the south. Most of the area of older rocks lies above the 400 foot contour and quite large areas are more than 1000 feet above sea level. The mountainous mass of the island, divided by the valley between Douglas and Peel, remained almost uninhabited throughout prehistoric and historic times.

New constraints on the geometry of the Lac Bouchette gabbro – anorthosite from magnetotellurics and magnetics

1995 ◽  
Vol 32 (9) ◽  
pp. 1365-1377 ◽  
Author(s):  
R. L. Kellett
Keyword(s):  
High Frequency ◽  
Seismic Reflection ◽  
Fault Zones ◽  
The South ◽  
Grenville Province ◽  
Magnetotelluric Soundings ◽  
The North ◽  
Geophysical Study ◽  
Magnetic Modelling ◽  
Tectonic Boundaries

A cross section of the resistivity structure through the Lac Bouchette gabbro–anorthosite provides a new image of the thin-skinned geometry of an allochthonous terrane in the western Grenville Province of Canada. Two-dimensional inversion of high-frequency magnetotelluric soundings and magnetic modelling indicate that the gabbro–anorthosite is a 1.5 km thick slice bounded by conductive thrust faults. Graphite, which is present at the margins of the gabbro–anorthosite and in the metasedimentary Réservoir Cabonga terrane to the south, is the most likely source of the enhanced electrical conductivity in the fault zones. The southern margin of the gabbro–anorthosite dips at about 15° to the south beneath the Réservoir Cabonga terrane. The gabbro–anorthosite can be divided into a highly magnetic gabbroic body in the south, a less magnetic metagabbro in the north, and a thin anorthositic lense in the centre. The combination of closely spaced magnetotelluric soundings and magnetic modelling provides independent constraints for gravity and seismic reflection studies in progress. The geometry of the Lac Bouchette gabbro–anorthosite, revealed by this geophysical study, supports a hypothesis that some gabbro–anorthosites behave as competent blocks adjacent to the major tectonic boundaries of the Grenville Province.

Spatial distribution of denudation processes in Bhutan

2021 ◽  
Author(s):  
Małgorzata Mazurek ◽  
Zbigniew Zwoliński ◽  
Przemysław Niedzielski
Keyword(s):  
Water Samples ◽  
Geological Structure ◽  
Middle Part ◽  
Mountain Range ◽  
River Channels ◽  
The South ◽  
Monsoon Period ◽  
River Waters ◽  
The North ◽  
Belt System

<p>Bhutan, being a Himalayan mountain country, extends ca. 305 km from west to east and 145 km from south to north, covering an area of 47,000 km<sup>2</sup>. Bhutanese Himalaya mountains are divided into three latitudinal belts from south to north: the sub-Himalayas or Himalayan foothills (up to 1,500 m in altitude), the inner Himalayas or middle ranges with flat valleys (from 1,500 to 4,500 m), and the Great Himalayas of high mountains (about 4 500 m). The Black Mountain Range, stretching longitudinally, divides this country into the eastern and western parts. The belt system of landforms is closely related to the geological structure. In the north, metamorphic and crystalline rocks (mainly gneisses and granites) dominate, while in the south there are sedimentary rocks associated with the molasse-like sediments in the Siwalik range. The distribution of precipitation from approx. 500 mm in the north to 5000 mm in the south of the country relates to this geological and morphological belt system. The main rivers flow longitudinally and have perpendicular tributaries. The digital elevation model of Bhutan was analysed geomorphometrically and, on this basis, places with high potential mechanical denudation were identified. The most evident manifestation of this denudation are numerous landslides occurring on the valley slopes. These landslides, especially in the monsoons period, deliver enormous amounts of landslide material to the valley bottoms, and most often directly to the river channels. The landslide material in the form of fluvial material is further transported along the rivers and deposited in the foreland of the Himalayas. After the summer monsoon period, water samples were collected in selected rivers. The collected water samples were subjected to hydrochemical analyzes. The studied river waters in the middle part of the country are characterized by low mineralization. The obtained results allow for a preliminary characterization of the spatial diversification of the denudation potential of Bhutan's river waters. Referring to the physiographic division of Bhutan, it can be confirmed that the middle zones, meridional ridges and valleys of this country are characterized by low chemical denudation and high mechanical denudation, while the southern tips of the country Front Hills and Piedmont are dominated by accumulation processes due to a significant reduction in river gradient.</p>

scholarly journals XXXII.—The Canonbie Coalfield: its Geological Structure and Relations to the Carboniferous Rocks of the North of England and Central Scotland

1905 ◽  
Vol 40 (4) ◽  
pp. 835-877 ◽  
Author(s):  
B. N. Peach ◽  
J. Horne
Keyword(s):  
Geological Structure ◽  
Limited Extent ◽  
The South ◽  
East Part ◽  
The North

The Canonbie Coalfield occupies a small tract of ground between the Liddel Water and the river Esk in the south-east part of the county of Dumfries. Though of limited extent, the coalfield has aroused considerable interest, due partly to the important series of plants obtained from the beds, and partly to the questions bearing on the correlation of the Carboniferous rocks of the Scottish Border with those in the North of England and Central Scotland.

Sign in / Sign up

Export Citation Format

Share Document