Regional geology and tectonic framework of the Southern Indian domain, Trans-Hudson Orogen, Manitoba

2021 ◽  
Author(s):  
Tania Martins ◽  
Nicole Rayner ◽  
David Corrigan ◽  
Paul Kremer
Keyword(s):  
Regional Scale ◽  
Foreland Basin ◽  
Geological Mapping ◽  
Metasedimentary Rocks ◽  
Mafic Intrusions ◽  
Plume Magmatism ◽  
Tectonic Framework ◽  
Lynn Lake ◽  
Clastic Sedimentary ◽  
Polymictic Conglomerate

The collaborative federal-provincial Southern Indian Lake project in north-central Manitoba covered an area of more than 3500 km2 of the Trans-Hudson orogen. Regional-scale geological mapping, sampling, and lithogeochemical, isotopic and geochronological studies resulted in the identification of distinct assemblages of supracrustal rocks and varied episodes of plutonism. A granodiorite gneiss dated at ca. 2520 Ma is interpreted to represent the basement of the Southern Indian domain and is considered a separate crustal domain, named the Partridge Breast block. The Churchill River assemblage is composed of juvenile pillow basalt with intervening clastic sedimentary rocks, possibly a reflection of plume magmatism related to initial rifting of the Hearne craton margin. The Pukatawakan Bay assemblage consists mainly of massive to pillowed, juvenile metabasaltic rocks and associated basinal metasedimentary rocks. The Partridge Breast Lake assemblage is dominated by continental-arc volcanic and volcaniclastic rocks associated with basinal metasedimentary rocks. The Strawberry Island assemblage, consisting of arenite and polymictic conglomerate, is interpreted to have been deposited in a foreland-basin basin or intra-orogen pull-apart basin environment. The Whyme Bay assemblage is characterized by fluvial-alluvial orogenic sediments and is temporally linked to the Sickle Group rocks in the Lynn Lake greenstone belt. Granitoid rocks, dominantly monzogranite and granodiorite, range in age from ca. 1890 to 1830 Ma and occur throughout the Southern Indian domain, and intermediate and mafic intrusions of similar ages are also present. In this paper we integrate these new data into a tectonic framework for the Southern Indian domain of the Trans-Hudson orogen in Manitoba.

Chapter 19 Regional context and tectonostratigraphic framework of the early–middle Paleozoic Caledonide orogen, northwestern Sweden

2020 ◽  
Vol 50 (1) ◽  
pp. 481-494 ◽  
Author(s):  
David G. Gee ◽  
Michael B. Stephens
Keyword(s):  
Foreland Basin ◽  
Metasedimentary Rocks ◽  
Mafic Intrusions ◽  
Late Cambrian ◽  
Iapetus Ocean ◽  
Nappe Complex ◽  
Middle Paleozoic ◽  
Thrust Sheets ◽  
Seve Nappe Complex ◽  
Augen Gneiss

AbstractThe Scandian mountains in northwestern Sweden are dominated by the eastern part of the Scandinavian Caledonides, an orogen that terminated during the middle Paleozoic with Himalayan-style collision of the ancient continents of Baltica and Laurentia. In this foreland region, far-transported higher allochthons from an exotic continental margin (Rödingsfjället Nappe Complex) and underlying mostly oceanic-arc basin character (Köli Nappe Complex) were emplaced at least 700 km onto the Baltoscandian margin of Baltica. The thrust sheets below the Iapetus Ocean terranes were derived from the transition zone to Baltica (Seve Nappe Complex), comprising mainly siliciclastic metasedimentary rocks, hosting abundant metamorphosed c. 600 Ma mafic intrusions. They preserve evidence of subduction (eclogites, garnet peridotites and microdiamonds in host paragneisses), starting in the late Cambrian; exhumation continued through the Ordovician. Underlying allochthons derived from the outer margin of Baltica are less-metamorphosed Neoproterozoic sandstone-dominated successions, also intruded by Ediacaran dolerite dykes (Särv Nappes); they are located tectonically above similar-aged metasandstone and basement slices, devoid of dykes (Offerdal and Tännäs Augen Gneiss nappes and equivalents). Lowermost allochthons (Jämtlandian Nappes and equivalents), from the inner Baltoscandian margin, provide evidence of Cryogenian rifting, Ediacaran–Cambrian drifting and platformal sedimentation, followed by foreland basin development in the Ordovician and Silurian.

Southernmost nappes in the Scandinavian Caledonides: correlations, evidence for a Tonian marine volcanic-sedimentary terrane and paleogeographic implications

2020 ◽  
Author(s):  
Bernard Bingen ◽  
Espen Torgersen ◽  
Morgan Ganerød ◽  
Nick M W Roberts
Keyword(s):  
Regional Scale ◽  
White Mica ◽  
Geological Mapping ◽  
Detrital Zircons ◽  
Mica Schist ◽  
Metasedimentary Rocks ◽  
Scandinavian Caledonides ◽  
Metavolcanic Rocks ◽  
The Baltic ◽  
Augen Gneiss

<p>Nappes of the Scandinavian Caledonides are the repository of information on both Caledonian orogenic evolution and pre-Caledonian geologic evolution of the Baltica and Laurentia margins and the Iapetus ocean. We report geological mapping, zircon U–Pb geochronological data on 33 samples, and mica 40Ar/39Ar data on 4 samples, along five profiles in the southernmost Caledonides in the Stavanger-Ryfylke region (Stavanger, Suldal, Nedstrand, Randøy, Røldal). <br>In Stavanger, the lowermost phyllite nappe –Buadalen nappe– is overlain by the Madla and Sola nappes (former Jæren Nappe). The Madla nappe comprises c. 1510–1495 Ma orthogneiss with Sveconorwegian metamorphism (c. 1025 Ma). The overlying Sola nappe comprises a sequence of mica schist, metasandstone, marble, amphibolite and felsic metavolcanic rocks. The metavolcanic rocks – Snøda metadacite-rhyolite – are fine-grained, frequently porphyritic, mica gneisses, with calc-alkaline, peraluminous, composition and negative Nb-Ta anomaly. Their extrusion ages of c. 941 and 934 Ma date deposition of the whole sequence. Detrital zircons in a metasandstone sample (n=138) yield main age modes at c. 1050 and 1150 Ma, significant Proterozoic and Archaean modes, and a maximum deposition age of c.990 Ma. The Sola nappe was affected by Taconian metamorphism peaking in eclogite-facies conditions at c.470 Ma (Smit et al., 2010), followed by regional cooling between c.446 Ma (white-mica) and 438 Ma (biotite). Trondhjemite dykes intruded at c.429 Ma, cutting the pre-Scandian fabric. <br>At regional scale, the lower nappes correlate over long distances. The lowest phyllite nappes –Buadalen, Holmasjø, Lower Finse and Synnfjell– represent the Cambro-Ordovician sediment cover of the Baltic margin, containing thin tectonic slivers of the underlying c. 1521 to 1225 Ma orthogneiss. The overlying nappes –Madla, Storheia, Dyrskard, Hallingskarvet, Espedalen– consist of felsic metavolcanic or metaplutonic rocks with a consistent age between c. 1525 and 1493 Ma with c. 1040 Ma intrusive, corresponding to the Telemarkian crystalline basement in S Norway. The Kvitenut nappe hosts metaplutonic rocks ranging from c. 1625 to 1039 Ma and metasedimentary rocks. It requires additional characterization. The overlying far-travelled nappes do not correlate well. The metasedimentary Revseggi nappe in Røldal is affected by a Taconian metamorphism (470–450 Ma) and hosts c. 434–428 Ma felsic intrusives (Roffeis & Corfu, 2014). Detrital zircons (n=33) in a kyanite-mica-gneiss sample constrain deposition of the sequence after c. 890 Ma. The Revseggi nappe may correlate with the Sola nappe. In Nedstrand, a c. 932 Ma augen gneiss is overlain by amphibolite and mica schist, tentatively attributed to the Boknafjord nappe. Detrital zircon data (n=11) imply an Ordovician (<459 Ma) deposition, therefore refuting a correlation of this transect with the Sola nappe.<br>The Sola nappe exposes a far-travelled Tonian marine volcanic-sedimentary sequence. The Taconian metamorphism suggests an evolution in the Iapetus ocenic realm. The Sola sequence may represent the microcontinent onto which the Karmøy ophiolite complex (c. 493–470 Ma) was obducted. By analogy to several other Tonian sequences preserved in far-travelled allochthons in the Scandinavian and Greenland Caledonides, the Sola sequence may originate from the active Neoproterozoic Renlandian margin of Laurentia and Rodinia before opening of Iapetus.</p>

Structural analysis and 3D geological modelling of the Santerno transect in the Northern Apennines (Italy)

2020 ◽  
Author(s):  
Griso Lorenzo ◽  
Bistacchi Andrea ◽  
Storti Fabrizio
Keyword(s):  
Structural Analysis ◽  
Structural Model ◽  
Regional Scale ◽  
Structural Data ◽  
Northern Apennines ◽  
Geological Mapping ◽  
External Part ◽  
Recent Earthquakes ◽  
3D Framework ◽  
Combine Surface

<p>We present preliminary results of a structural analysis and 3D modelling project carried out along a transect in the Santerno Valley, between Firenzuola (Tuscany) and the outskirts of Imola. The aim of the project is to combine surface geological and structural data (available thanks to the national geological mapping CARG project and original surveys), with the available subsurface data (2D seismics and a few wells), and obtain a comprehensive 3D framework for deformation in this key area of the Northern Apennines. In addition, by combining geodetic, seismicity and interferometric data with the 3D structural model, we are able to obtain a better picture of the active structures in the area.</p><p>Our analysis shows that the studied transect is at the northern periclinal hinge of a regional anticline/window where the Marnoso-Arenacea Formation crops out and is crosscut by several regional-scale thrusts. Subsurface data suggest that these relatively shallow thrusts are rooted at the top of Mesozoic carbonates, that do not crop out in the area. Different balancing algorithms confirm a relevant along-strike variation of slip along these thrusts, that reduce their offset towards the periclinal hinge to the west.</p><p>In the more external part of the transect, towards the lower hills and the plain around Imola, a regional-scale pop-up, evidenced by the late-Messinian unconformity, is the main feature in subsurface datasets. This structure is rooted at the base of Mesozoic carbonates and is characterized by large and continuous ramps that can be considered candidates for recent earthquakes in the area.</p>

scholarly journals Geology of Shantipur-Wami Taksar Areas of Gulmi-Baglung Districts, Western Nepal

2020 ◽  
Vol 22 ◽  
pp. 29-32
Author(s):  
Sushant Sapkota ◽  
Pashupati Gaire ◽  
Kabi Raj Paudyal
Keyword(s):  
Regional Scale ◽  
Mineral Resources ◽  
Geological Structure ◽  
Geological Mapping ◽  
The North ◽  
Copper Mineralization ◽  
Metallic Mineral ◽  
Geological Map ◽  
Map Scale ◽  
Geological Units

The study area represents a small part of the Lesser Himalaya in western Nepal and lies about 346 km west from Kathmandu. It covers 250 km area representing some parts of Gulmi and Baglung districts. The area was selected for the present study on the impression from the previous geological map that has showed some metallic mineral resources like iron, copper and lead in the region. Similarly, studies reveal that there is very complicated geological structure which raised the interest for the study. Main objective of the study was to prepare a geological map of the area in a scale of 1:25,000 and study the possible mineral deposits. An extensive geological mapping was carried out in the field covering at one data within one centimetre of the map scale and large number of samples was collected for the petrographic as well as ore genesis studies. The rocks of the region were mapped under two geological units as the Nourpul Formation (older) and the Dhading Dolomite (younger).  There are a series of folds in the area. From regional to micro-scale all folds are trending towards east-west. The Badi Gad Fault and the Harewa Khola Thrust are the regional scale thrust mapped in the area. The Badi Gad is considered as a strike-slip in nature. The Harewa Khola Thrust is probably an imbricate fault. It has propagated to the north which is out of sequence in nature. Some metallic minerals like copper and iron along with old working mines were observed during the study. Occurrences of copper and iron mineralization has been mapped and described. Present study revealed that copper mineralization is limited within the veins and boudinage forms as hydrothermal deposit while the iron is tabular and syngenetic in nature.

scholarly journals Revised Timing of Cenozoic Atlantic Incursions and Changing Hinterland Sediment Sources during Southern Patagonian Orogenesis

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Julie C. Fosdick ◽  
R. A. VanderLeest ◽  
J. E. Bostelmann ◽  
J. S. Leonard ◽  
R. Ugalde ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Atlantic Coast ◽  
Foreland Basin ◽  
Late Eocene ◽  
Coarse Grained ◽  
Plate Convergence ◽  
Metasedimentary Rocks ◽  
Sediment Routing ◽  
Thrust Sheets ◽  
Major Shift

Abstract New detrital zircon U-Pb geochronology data from the Cenozoic Magallanes-Austral Basin in Argentina and Chile ~51° S establish a revised chronostratigraphy of Paleocene-Miocene foreland synorogenic strata and document the rise and subsequent isolation of hinterland sources in the Patagonian Andes from the continental margin. The upsection loss of zircons derived from the hinterland Paleozoic and Late Jurassic sources between ca. 60 and 44 Ma documents a major shift in sediment routing due to Paleogene orogenesis in the greater Patagonian-Fuegian Andes. Changes in the proportion of grains from hinterland thrust sheets, comprised of Jurassic volcanics and Paleozoic metasedimentary rocks, provide a trackable signal of long-term shifts in orogenic drainage divide and topographic isolation due to widening of the retroarc fold-thrust belt. The youngest detrital zircon U-Pb ages confirm timing of Maastrichtian-Eocene strata but require substantial age revisions for part of the overlying Cenozoic basinfill during the late Eocene and Oligocene. The upper Río Turbio Formation, previously mapped as middle to late Eocene in the published literature, records a newly recognized latest Eocene-Oligocene (37-27 Ma) marine incursion along the basin margin. We suggest that these deposits could be genetically linked to the distally placed units along the Atlantic coast, including the El Huemul Formation and the younger San Julián Formation, via an eastward deepening within the foreland basin system that culminated in a basin-wide Oligocene marine incursion in the Southern Andes. The overlying Río Guillermo Formation records onset of tectonically generated coarse-grained detritus ca. 24.3 Ma and a transition to the first fully nonmarine conditions on the proximal Patagonian platform since Late Cretaceous time, perhaps signaling a Cordilleran-scale upper plate response to increased plate convergence and tectonic plate reorganization.

Cross-border megasequence stratigraphy of the Northern, Central and Southern North Sea: a comparative tectono-stratigraphic synthesis

2021 ◽  
pp. SP494-2020-228
Author(s):  
Stefano Patruno ◽  
Henk Kombrink ◽  
Stuart G. Archer
Keyword(s):  
North Sea ◽  
Regional Scale ◽  
Foreland Basin ◽  
First Order ◽  
Cross Border ◽  
Southern North Sea ◽  
The North ◽  
Lithostratigraphic Units ◽  
The North Sea ◽  
Basin Fill

AbstractThe Devonian-Recent tectono-stratigraphic history of the Northern, Central and Southern North Sea is here reviewed at a regional scale and four novel cross-border pseudo-Wheeler diagrams are presented to summarize the stratigraphic evolution of the cycles of basin fill and uplift/erosion. In this scheme, six first-order megasequence boundaries have been defined, characterized by extensive and long-lasting erosional hiatuses and major coastal regressions: (1) Caledonian (or Base Devonian) Unconformity; (2) Variscan-Saalian (or Base Permian) Unconformity; (3) Mid Cimmerian (or Intra-Aalenian) Unconformity; (4) Late Cimmerian (or Base Cretaceous) Unconformity; (5) Atlantean (or Near-Base Tertiary) Unconformity; (6) Eridanos (or Mid-Miocene) Unconformity. These surfaces have been linked to regional causal factors ranging from: orogenesis-related compressional uplifts, in either active plate margin settings (1) or foreland basin settings (2); intra-plate dynamically supported uplifts associated with the development of mantle plumes (3, 5 and 6); the end-of-rifting and associated widespread erosion of tilted fault block crests (4).The aforementioned megasequence boundaries punctuate the geodynamic evolution of the North Sea area and facilitate the sub-division of the entire the North Sea sedimentary basin fill into six megasequences, named here from A to F. All the lithostratigraphic units of the North Sea (formations and members) have been described within the context of this first-order tectono-stratigraphic framework. The correlation power of certain stratigraphic markers are also compared and contrasted, together with the potential cross-border equivalence of sedimentary units on different sides of the political median lines.

Petrology of the Fort Smith - Great Slave Lake radiometric high near Pilot Lake, N.W.T.

1981 ◽  
Vol 18 (5) ◽  
pp. 842-851 ◽  
Author(s):  
R. A. Burwash ◽  
D. F. Cape
Keyword(s):  
Granulite Facies ◽  
Mica Schist ◽  
Biotite Gneiss ◽  
Black Sand ◽  
Metasedimentary Rocks ◽  
Great Slave Lake ◽  
Fort Smith ◽  
High Concentrations ◽  
Orogenic Cycle ◽  
Clastic Sedimentary

Near Pilot Lake, the east boundary of the Fort Smith – Great Slave Lake radiometric high coincides with the contact of a well-foliated, porphyroblastic microcline–plagioclase–quartz-garnet–biotite gneiss1 (Pilot Lake Gneiss) with a hybrid assemblage of quartzite, mica schist, garnet–cordierite gneiss, and minor amphibolite (Variable Paragneiss). Anomalously high concentrations of uranium and thorium are associated with mafic-rich, lenticular bodies with a mineral assemblage biotite + monazite + zircon + ilmenite + hematite ± apatite ± plagioclase ± quartz. The mafic pods occur within both the Variable Paragneiss and the Pilot Lake Gneiss. Corundum and spinel occur in the mafic lenses and sillimanite, kyanite, and hypersthene in other inclusions in the Pilot Lake Gneiss.The ilmenite–magnetite–monazite–zircon–apatite assemblage is interpreted as a "black sand" concentration in a clastic sedimentary sequence subsequently metamorphosed by a regional granulite facies event. A granitic pluton intruded during the same orogenic cycle assimilated the clastic metasedimentary rocks containing black sand interlayers, becoming enriched in thorium from the monazite. A second metamorphic event at lower P–T conditions, accompanied by strong cataclasis, developed the texture of the Pilot Lake Gneiss as now observed. Shearing within the gneiss locally concentrated hematite + quartz + uranium.Regional tectonic extrapolations suggest that the pyroxene granulite event was Kenoran and the later amphibolite event Hudsonian.

scholarly journals Short Note: On the age and relation between metamorphic gneisses and the Trinity Peninsula Group, Bowman Coast, Graham Land, Antarctica

2008 ◽  
Vol 20 (5) ◽  
pp. 511-512 ◽  
Author(s):  
Michael J. Flowerdew
Keyword(s):  
Short Note ◽  
Geological Mapping ◽  
High Grade ◽  
Metasedimentary Rocks ◽  
Local Geology ◽  
Relationship Of ◽  
The Relationship ◽  
The Trinity

The Trinity Peninsula Group (TPG) of northern Graham Land, a weakly metamorphosed thick sequence of predominantly quartz- and feldspar-rich greywacke, has tentatively been correlated with metasedimentary rocks exposed along the Bowman Coast of Graham Land (Stubbs 1968). The base of the TPG is not observed but the Bowman Coast rocks, here newly defined as the Bowman Coast Succession (BCS), is proximal to high-grade gneisses, which may represent the local basement. Recent geological mapping along the Bowman Coast has allowed a revision of the local geology (Fig. 1) and this note focuses on the relationship of the BCS with the adjacent gneisses.

Oligocene-Miocene tectonics of the SW Alps and western Apennines coupled orogenic belts, as recorded by their internal and external syn-orogenic basins

2020 ◽  
Author(s):  
Luca Barale ◽  
Piana Fabrizio ◽  
Bertok Carlo ◽  
d'Atri Anna ◽  
Irace Andrea ◽  
...  
Keyword(s):  
Regional Scale ◽  
Foreland Basin ◽  
Mediterranean Area ◽  
Western Alps ◽  
Western Mediterranean ◽  
Northern Apennines ◽  
Kinematic Evolution ◽  
Ligurian Alps ◽  
Internal Side ◽  
Miocene Tectonics

<p>The Oligocene-Miocene evolution of the westernmost part of the Northern Apennines was constrained firstly by Oligocene E-W regional sinistral shearing and then by Early Miocene shortening and Middle to Late Miocene NW-SE dextral transpression affecting the southern termination of the Western Alps arc (Maritime and Ligurian Alps) and the substrate of the Tertiary Piemonte Basin (TPB), which started to be incorporated, in the same time span, in the Northern Apennines belt</p><p>In other words, the dynamics accommodating the different motion of the WNW-directed Adria and SW Alps with respect to the ENE-directed Ligurian-Corso-Sardinian block also controlled the evolution of TPB and its Ligurian substrate since at least the Aquitanian, when a regional conterclockwise rotation began and a deep reshaping of the basin occurred, due to predominant NE-SW shortening concomitant with the Northern Apennines thrust fronts propagation (Burdigalian). On the other side, the infilling of the SW Alps foreland basin was partially controlled also by the resedimentation of non-metamorphic Cretaceous-Paleocene Ligurian units previously deposited along the Briançonnais-Dauphinois continental margin. The subsequent Late Burdigalian to Serravallian extension in the internal side of the SW Alps allowed the creation of accomodation space and the deposition of relevant thickness of sediments in the TPB, during the coeval progressive uplifting of Alpine crystalline and metamorphic units (e.g. the Argentera Massif and Dora-Maira Unit). This Alpine process constrained the shape and evolution of the TPB syn-orogenic sub-basins and their subsequent tectonic paths within the NW Apennines belt, while it was being built. The steps of this Alps-Apennines evolution have been clearly recorded by a set of regional scale, Oligocene to Pleistocene unconformities that can be continuously traced at surface in the southern part of the Piemonte region and in the subsurface of the western Po plain.</p><p>We thus remark that the evolution of the westernmost part of the Apennines can be studied largely referring to the Alpine geodynamics, since, although the Alps and the Apennines are two distinct geomorphologic and geophysical entities at the scale of the Western Mediterranean area, they share common synorogenic basins and consistent kinematic evolution in their junction zone of NW Italy.</p>

scholarly journals The Southern Atlas Front in Tunisia and its foreland basin: Structural style and regional-scale deformation

2019 ◽  
Vol 764 ◽  
pp. 1-24 ◽  
Author(s):  
Amara Masrouhi ◽  
Mohamed Gharbi ◽  
Olivier Bellier ◽  
Mohamed Ben Youssef
Keyword(s):  
Regional Scale ◽  
Foreland Basin ◽  
Structural Style
Sign in / Sign up

Export Citation Format

Share Document