Lithostratigraphy of the Vuurdood Subsuite, an early mafic-ultramafic phase of the Palaeoproterozoic Vioolsdrif Intrusive Suite, Richtersveld Magmatic Arc, Northern Cape Province

2021 ◽  
Vol 124 (3) ◽  
pp. 805-814
Author(s):  
D.L. Reid ◽  
H. Minnaar
Keyword(s):  
Central Type ◽  
Magmatic Arc ◽  
Rock Types ◽  
Granitic Terrain ◽  
Border Town ◽  
Northern Cape ◽  
Group Form ◽  
Intrusive Suite ◽  
Lithologic Character ◽  
Desert Landscape

Abstract Mafic-ultramafic plutonic intrusions form an early phase in the emplacement of the predominantly granitic Vioolsdrif Suite, which together with its extrusive carapace, the Orange River Group, form the Richtersveld Magmatic Arc, a Palaeoproterozoic crustal segment formed between 1910 and 1865 Ma. Their lithologic character and distinctive dark weathering features in the mountain desert landscape of the Richtersveld, neighbouring regions of the Northern Cape Province and southern Namibia, make them a separate mappable unit in what is a predominantly granitic terrain. The name of the subsuite is taken from a spectacular twin peak massif near Goodhouse (Vuurdoodberg), while the type locality is one of the best preserved central-type intrusive bodies at Swartkop, situated 2 km off the N7 highway about 20 km south of the border town of Vioolsdrif, where the rock types present include gabbro, metagabbro, quartz-metagabbro, peridotite and troctolite.

Explanatory notes to the Geological Map of Greenland, 1:100 000, Ussuit 67 V.2 Nord

2007 ◽  
pp. 1-40
Author(s):  
Jeroen A.M. Van Gool ◽  
Mogens Marker
Keyword(s):  
Shear Zones ◽  
Hydrothermal Activity ◽  
Geological Survey ◽  
Easy Access ◽  
Dimension Stone ◽  
Magmatic Arc ◽  
The North ◽  
Rock Types ◽  
Geological Map ◽  
Intrusive Suite

NOTE: This Map Description was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: van Gool, J. A., & Marker, M. (2007). Explanatory notes to the Geological Map of Greenland, 1:100 000, Ussuit 67 V.2 Nord. Geological Survey of Denmark and Greenland Map Series 3, 1-40. https://doi.org/10.34194/geusm.v3.4596 _______________ The Ussuit map area is situated around the inner Nassuttooq (Nordre Strømfjord) in central West Greenland, in the core of the Palaeoproterozoic Nagssugtoqidian orogen. The orogen largely consists of reworked Archaean gneisses, as well as Palaeoproterozoic ortho- and paragneisses in its central part. Easy access through the branched fjord system and good exposures along its coastlines, combined with less intense reworking compared to neighbouring areas to the west and south, have made the Ussuit map area the most intensely studied and best known part of the orogen. The most recent research and mapping projects were organised by the Danish Lithosphere Centre (1994–1999) and the Geological Survey of Denmark and Greenland (2000–2001). The predominant rocks are late Archaean tonalitic and granodioritic orthogneisses, intruded by postkinematic granites. Archaean supracrustal rocks are predominantly of mafic composition, but only few have been recognised. Palaeoproterozoic rocks occur as tectonic sheets (the Ussuit unit) which are always in tectonic contact with the Archaean orthogneisses. The most abundant Palaeoproterozoic rock types are biotite schist and biotite-bearing paragneiss, besides orthogneiss of the Arfersiorfik intrusive suite. The latter rocks are mainly deformed quartz diorites intrusive into the metasedimentary rocks and interpreted as remnants of a magmatic arc above a subduction zone. The Ussuit unit also includes amphibolite, marble and calc-silicate rocks, and lenses of ultrabasic rocks. Small bodies of younger syn- and post-tectonic granites occur throughout the map area. The interleaved Palaeoproterozoic and Archaean rocks form a major anticlinal fold structure between two crustal-scale shear zones, the Nordre Strømfjord shear zone in the north and the Nordre Isortoq steep belt in the south. These shear zones formed during the latest ductiledeformation event (D4), following ductile thrusting (D1) and kilometre-scale folding (D2 and D3). The deformation and high grade metamorphism are the result of collision of two Archaean blocks at c. 1850 Ma, with a presumed strongly deformed suture rooted in the southern Ussuit area. No economically feasible mineral occurrences have been discovered to date within the Ussuit map area. Minor sulphide mineralisation related to hydrothermal activity occurs in faults and shear zones, and minor stratabound iron formations have been observed. The most promising industrial mineral deposits are minor diopside occurrences and potential dimension stone in migmatised orthogneiss.

scholarly journals Explanatory notes to the Geological Map of Greenland, 1:100 000, Ussuit 67 V.2 Nord

2007 ◽  
pp. 1-40 ◽  
Author(s):  
Jeroen A.M. Van Gool ◽  
Mogens Marker
Keyword(s):  
Shear Zones ◽  
Hydrothermal Activity ◽  
Easy Access ◽  
Dimension Stone ◽  
Magmatic Arc ◽  
Metasedimentary Rocks ◽  
The North ◽  
Rock Types ◽  
Tectonic Contact ◽  
Intrusive Suite

The Ussuit map area is situated around the inner Nassuttooq (Nordre Strømfjord) in central West Greenland, in the core of the Palaeoproterozoic Nagssugtoqidian orogen. The orogen largely consists of reworked Archaean gneisses, as well as Palaeoproterozoic ortho- and paragneisses in its central part. Easy access through the branched fjord system and good exposures along its coastlines, combined with less intense reworking compared to neighbouring areas to the west and south, have made the Ussuit map area the most intensely studied and best known part of the orogen. The most recent research and mapping projects were organised by the Danish Lithosphere Centre (1994–1999) and the Geological Survey of Denmark and Greenland (2000–2001). The predominant rocks are late Archaean tonalitic and granodioritic orthogneisses, intruded by postkinematic granites. Archaean supracrustal rocks are predominantly of mafic composition, but only few have been recognised. Palaeoproterozoic rocks occur as tectonic sheets (the Ussuit unit) which are always in tectonic contact with the Archaean orthogneisses. The most abundant Palaeoproterozoic rock types are biotite schist and biotite-bearing paragneiss, besides orthogneiss of the Arfersiorfik intrusive suite. The latter rocks are mainly deformed quartz diorites intrusive into the metasedimentary rocks and interpreted as remnants of a magmatic arc above a subduction zone. The Ussuit unit also includes amphibolite, marble and calc-silicate rocks, and lenses of ultrabasic rocks. Small bodies of younger syn- and post-tectonic granites occur throughout the map area. The interleaved Palaeoproterozoic and Archaean rocks form a major anticlinal fold structure between two crustal-scale shear zones, the Nordre Strømfjord shear zone in the north and the Nordre Isortoq steep belt in the south. These shear zones formed during the latest ductiledeformation event (D4), following ductile thrusting (D1) and kilometre-scale folding (D2 and D3). The deformation and high grade metamorphism are the result of collision of two Archaean blocks at c. 1850 Ma, with a presumed strongly deformed suture rooted in the southern Ussuit area. No economically feasible mineral occurrences have been discovered to date within the Ussuit map area. Minor sulphide mineralisation related to hydrothermal activity occurs in faults and shear zones, and minor stratabound iron formations have been observed. The most promising industrial mineral deposits are minor diopside occurrences and potential dimension stone in migmatised orthogneiss.

scholarly journals Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

2015 ◽  
Vol 45 (3) ◽  
pp. 431-451 ◽  
Author(s):  
Letícia Alexandre Redes ◽  
Maria Zélia Aguiar de Sousa ◽  
Amarildo Salina Ruiz ◽  
Jean-Michel Lafon
Keyword(s):  
Geochemical Data ◽  
Alkaline Magmatism ◽  
Alluvial Deposits ◽  
Mato Grosso ◽  
Microgranular Enclave ◽  
Magmatic Arc ◽  
Rock Types ◽  
High K ◽  
Continental Magmatic Arc ◽  
Shrimp Zircon

The Taquaral Granite is located on southern Amazon Craton in the region of Corumbá, westernmost part of the Brazilian state of Mato Grosso do Sul (MS), near Brazil-Bolivia frontier. This intrusion of batholitic dimensions is partially covered by sedimentary rocks of the Urucum, Tamengo Bocaina and Pantanal formations and Alluvial Deposits. The rock types are classified as quartz-monzodiorites, granodiorites, quartz-monzonites, monzo and syenogranites. There are two groups of enclaves genetically and compositionally different: one corresponds to mafic xenoliths and the second is identified as felsic microgranular enclave. Two deformation phases are observed: one ductile (F1) and the other brittle (F2). Geochemical data indicate intermediate to acidic composition for these rocks and a medium to high-K, metaluminous to peraluminous calk-alkaline magmatism, suggesting also their emplacement into magmatic arc settings. SHRIMP zircon U-Pb geochronological data of these granites reveals a crystallization age of 1861 ± 5.3 Ma. Whole rock Sm-Nd analyses provided εNd(1,86 Ga) values of -1.48 and -1.28 and TDM model ages of 2.32 and 2.25 Ga, likely indicating a Ryacian crustal source. Here we conclude that Taquaral Granite represents a magmatic episode generated at the end of the Orosirian, as a part of the Amoguija Magmatic Arc.

Superimposed Quesnel (late Paleozoic–Jurassic) and Yukon–Tanana (Devonian–Mississippian) arc assemblages, Cassiar Mountains, northern British Columbia: field, U–Pb, and igneous petrochemical evidence

2004 ◽  
Vol 41 (10) ◽  
pp. 1201-1235 ◽  
Author(s):  
JoAnne Nelson ◽  
Richard Friedman
Keyword(s):  
British Columbia ◽  
Early Jurassic ◽  
Late Paleozoic ◽  
Time Interval ◽  
Magmatic Arc ◽  
The North ◽  
Mid Ocean Ridge ◽  
Plutonic Belt ◽  
Intrusive Suite ◽  
Ocean Ridge

Allochthons in the Cassiar Mountains of northern British Columbia contain assemblages belonging to two distinct Canadian Cordilleran terranes, Yukon–Tanana (YTT) and Quesnellia. These assemblages, of pre-Late Devonian, Devonian–Mississippian, Pennsylvanian–Permian, and Early Jurassic age, occur in intrusive and depositional, as well as structural, contact with each other. The allochthons are gently dipping thrust panels, interrupted by the mid-Cretaceous Cassiar Batholith. A key element for correlation across the batholith is the Mississippian and older pericratonic Dorsey Complex. New Devonian–Mississippian U–Pb ages for deformed plutons within it document an igneous suite like those in type Yukon–Tanana exposures farther north. Other characteristics of the Dorsey Complex that ally it with YTT are orthoquartzites and grits, and amphibolite bodies with transitional mid-ocean ridge basalt (MORB) to ocean-island basalt (OIB) petrochemical signatures. Unconformities, deformed clasts in the late Paleozoic sequences, and a shared mid-Permian intrusive suite show that later arcs onlapped the mid-Paleozoic and older YTT assemblage. The Early Jurassic intrusive suite cuts all major contacts and fabrics except the terrane-bounding fault between the Slide Mountain and combined YTT–Quesnel terranes. It represents a northern continuation of a plutonic belt that extends the length of the Mesozoic Quesnel magmatic arc. These relationships carry important implications for Cordilleran terrane history and the tectonic evolution of the North American margin. At least some of the major terranes were not unrelated entities prior to their accretion to the continent, but a system of superimposed and interconnected arcs that developed over a protracted time interval, with complex and evolving paleogeographic configurations much like the modern western Pacific province.

Terrane accretion in the internal zone of the Ungava orogen, northern Quebec. Part 1: Tectonostratigraphic assemblages and their tectonic implications

1992 ◽  
Vol 29 (4) ◽  
pp. 746-764 ◽  
Author(s):  
M. R. St-Onge ◽  
S. B. Lucas ◽  
R. R. Parrish
Keyword(s):  
Oceanic Crust ◽  
Sedimentary Rocks ◽  
Plate Boundary ◽  
Plate Boundaries ◽  
Magmatic Arc ◽  
Thrust Sheets ◽  
Domain 3 ◽  
Mafic Lavas ◽  
Intrusive Suite ◽  
Terrane Accretion

The tectonostratigraphic record of the Ungava orogen contains evidence for the interaction of divergent, transform, and convergent plate boundaries over a > 0.2 Ga period in the Early Proterozoic. Three principal tectonic domains are recognized: (1) autochthonous basement plutonic and supracrustal rocks of Archean age; (2) autochthonous and allochthonous sedimentary and volcanic units associated with a ca. 1.99–1.92 Ga rift-to-drift margin; and (3) "suspect' ' crustal components of a ca. 2.00 Ga ophiolite and ca. 1.90–1.83 Ga island-arc terrane. Domain 1 is the stratigraphic or structural basement to domains 2 and 3. Field relationships indicate that domain 2 units were accumulated on or near domain 1, whereas no tectonostratigraphic linkages are known between domain 3 and the others. Accumulation of continent-derived sedimentary rocks, continental tholeiites, komatiitic basalts, and mafic lavas equivalent to modern normal mid-oceanic ridge basalts (n-MORB's) in domain 2 is interpreted as recording continental rifting leading to the possible formation of oceanic crust. Pillowed basalts, sheeted dykes, and cumulate rocks suggest that the crustal portion of an ophiolite is preserved within domain 3. The ophiolite is interpreted as a "suspect" fragment of oceanic crust, which may represent an earlier rifted portion of domain 2, possibly juxtaposed by transform plate boundary motions. Within domain 3, calc-alkaline volcanic and plutonic units and sequences of volcanogenic and siliciclastic sedimentary rocks are thought to indicate the development of a magmatic arc and fore-arc basin and thus the establishment of a convergent plate boundary. The most internal lithotectonic packages in domain 3 are predominantly crystalline thrust sheets containing (i) an older intrusive suite, interpreted as the plutonic foundation of the magmatic arc, and (ii) younger plutons, interpreted as the result of a reversal in subduction polarity. The reversal may have followed attempted subduction of domains 1 and 2 beneath the upper-plate arc assemblage of domain 3.

scholarly journals LAJINHA, UMA INTRUSÃO TARDI-OROGÊNICA E PÓSCOLISIONAL NO EXTREMO OESTE DO COMPLEXO PARAÍBA DO SUL, MINAS GERAIS, ESPÍRITO SANTO, BRASIL

1998 ◽  
Author(s):  
Adolf Heinrich Horn
Keyword(s):  
Chemical Interaction ◽  
Contact Region ◽  
The Other ◽  
Coarse Grained ◽  
Geochemical Data ◽  
Espírito Santo ◽  
Magmatic Arc ◽  
Body Distribution ◽  
Intrusive Suite ◽  
Espirito Santo

This is an interpretation of geological, petrological and geochemical data of the Lajinha intrusion,which belongs to the Alto Capim Subsuite of the Espírito Santo Magmatic Suite. The Lajinhaintrusion is a plutonic body of medium extensions (48km2) with diapiric structure and magmaticzoning. Two magmatic groups build up this body, one of granitic affinity and the other group ofdioritic affinity. Between this two groups do not exist “commingling” but a chemical interaction (e.g.: “mixing” in the contact region). The acid rocks, that crop out in a ringlike form, can be observedin two distinct litological groups. The main group is coarse-grained, has a great number of big potassicfeldspar-phenocrysts (up to 15cm), small part of matrix and it do not have a preferencial orientation.In some parts exist a flux orientation of the phenocrystals and at the contact with the host rockapears weak intrusive foliation. The other subordinate group is formed by a middle to coarse grainedmatrix, with isotropic apearence and with a very low content of K-feldspar phenocrystals. Theseparation of the two groups may be a result of “filter-pressing” and/or “gravity separation”. Thegranites are constituted principally of quartz, K-feldspar, plagioclase, biotite, accessory and opaqueminerals. Their chemical composition ranges from alkaligranite to granodiorite. The basic rockgroup,which crops out in an oval formed elonged central nuclei, has a middle to coarse granulometry,homogeneous and isotropic apearence over all of the visited outcrops. This rock is built up byamphibole, biotite, plagioclase, small percentage of pyroxene, accessory and opaque minerals. Thechemical composition vary between syeno-diorite, diorite and gabbrodiorite. The contact betweenthe granitc rockgroup and the basic rockgroup is very well defined and shows only metasomatismeffects and not “commingling”. The host of the intrusion are para-rocks like migmatites, bandedgneisses, quartzites, and ortho-rocks like an homogeneous gneisse (Galileia Intrusive Suite; PocraneComplex) and amphibolitic. They are very strong foliated. The contact between the host and theintrusive rocks is normally formed by gradational evolution (transformation) and in some parts ofthe north western contact by faults. From the host towards the intrusion growth up the number ofblasts and the distribuion of fusion effects. Pegmatitic veins cut the mainbody in the same directionas distension fractures (NE-SW). In the northeastern part this fractures are invaded by a fine grainedalkaline basalt of probably cretaceous age. This veins cut the host and the granites of the intrusion,too. The observations make possible the idea of an intrusive process under late-orogeneous to postcollisionalregime. The differentiation trends of the two rock groups are calco-alkaline (trondhjemiticto monzonitic), with peraluminous to metaluminous and alkaline to subalkaline tendency. Thisintrusion make part of the symetric body distribution within the Espírito Santo Magmatic Arc,beginning with late to post-collisional intrusion in the west and east and early to syn-collisionalintrusions in the central region, the later influenced by compressional and transcorrent movements.

Subduction-related magmatism of late Ordovician age in eastern England

1993 ◽  
Vol 130 (5) ◽  
pp. 647-656 ◽  
Author(s):  
T. C. Pharaoh ◽  
T. S. Brewer ◽  
P. C. Webb
Keyword(s):  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Late Ordovician ◽  
Igneous Rocks ◽  
Calc Alkaline ◽  
Geochemical Composition ◽  
Magmatic Arc ◽  
Hypabyssal Intrusions ◽  
Deep Boreholes ◽  
Intrusive Suite

AbstractDeep boreholes show that plutonic and volcanic igneous rocks comprise an important component of the Caledonian basement in eastern England. The isotopic compositions of these rocks reveal that many of them are of late Ordovician age (440–460 Ma), and their geochemical compositions suggest calc–alkaline affinities. The intermediate (diorite-tonalite) plutonic rocks are associated with a prominent northwest–southeast trending belt of aeromagnetic anomalies extending from Derby to St Ives, Hunts., which is interpreted to work the plutonic core of a calc-alkaline magmatic arc. It is inferred that this arc was generated by the subduction of oceanic lithosphere, possibly from the Tornquist Sea, in a south or southwest direction beneath the Midlands Microcraton in late Ordovician times. The age and geochemical composition of concealed Ordovician volcanic rocks in eastern England, and hypabyssal intrusions of the Midlands Minor Intrusive Suite in central England, is compatible with such a hypothesis.

Correlation of Pore Structure and Permeability by SEM-Image Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 428-429
Author(s):  
C. A. Callender ◽  
Wm. C. Dawson ◽  
J. J. Funk
Keyword(s):  
Image Analysis ◽  
Pore Structure ◽  
Imaging System ◽  
Pore Space ◽  
Simulation Models ◽  
Image Analyzer ◽  
Imaging Data ◽  
Sem Images ◽  
Thin Sections ◽  
Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

Studi Awal Geologi di Daerah Beruang Kanan Kabupaten Gunung Mas Propinsi Kalimantan Tengah

PROMINE ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 1-11
Author(s):  
Retno Anjarwati ◽  
Arifudin Idrus ◽  
Lucas Donny Setijadji
Keyword(s):  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Gold Deposits ◽  
Central Kalimantan ◽  
Magmatic Arc ◽  
Tertiary Sediment ◽  
Copper Gold ◽  
Regional Tectonic ◽  
Mineralization Processes ◽  
High Yields

The regional tectonic conditions of the KSK Contract of Work are located in the mid-Tertiary magmatic arc (Carlile and Mitchell, 1994) which host a number of epithermal gold deposits (eg, Kelian, Indon, Muro) and significant prospects such as Muyup, Masupa Ria, Gunung Mas and Mirah. Copper-gold mineralization in the KSK Contract of Work is associated with a number of intrusions that have occupied the shallow-scale crust at the Mesozoic metamorphic intercellular junction to the south and continuously into the Lower Tertiary sediment toward the water. This intrusion is interpreted to be part of the Oligocene arc of Central Kalimantan (in Carlile and Mitchell 1994) Volcanic rocks and associated volcanoes are older than intrusions, possibly aged Cretaceous and exposed together with all three contacts (Carlile and Mitchell, 1994) some researchers contribute details about the geological and mineralogical background, and some papers for that are published for the Beruang Kanan region and beyond but no one can confirm the genesis type of the Beruang Kanan region The mineralization of the Beruang Kanan area is generally composed by high yields of epithermal sulphide mineralization. with Cu-Au mineralization This high epithermal sulphide deposition coats the upper part of the Cu-Au porphyry precipitate associated with mineralization processes that are generally controlled by the structure

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