Across-arc variation of the Famatinian magmatic arc (NW Argentina) exemplified by I-, S- and transitional I/S-type Early Ordovician granitoids of the Sierra de Velasco

2011 ◽  
Vol 32 (1) ◽  
pp. 110-126 ◽  
Author(s):  
Pablo Grosse ◽  
Laura I. Bellos ◽  
Camilo R. de los Hoyos ◽  
Mariano A. Larrovere ◽  
Juana N. Rossi ◽  
...  
Keyword(s):  
Magmatic Arc ◽  
Early Ordovician ◽  
Ordovician Granitoids

scholarly journals An Early Ordovician tonalitic–granodioritic belt along the Schistose-Greywacke Domain of the Central Iberian Zone (Iberian Massif, Variscan Belt)

2012 ◽  
Vol 149 (5) ◽  
pp. 927-939 ◽  
Author(s):  
A. RUBIO-ORDÓÑEZ ◽  
P. VALVERDE-VAQUERO ◽  
L. G. CORRETGÉ ◽  
A. CUESTA-FERNÁNDEZ ◽  
G. GALLASTEGUI ◽  
...  
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Variscan Belt ◽  
Iberian Massif ◽  
Calc Alkaline ◽  
Central Iberian Zone ◽  
Magmatic Arc ◽  
Early Ordovician ◽  
Icp Ms ◽  
Continental Magmatic Arc

AbstractThe Zarza la Mayor and Zarza de Montánchez tonalites and Arroyo de la Luz granodiorite are part of a tonalitic–granodioritic belt located along the Schistose-Greywacke Domain of the Central Iberian Zone. These intrusions are also part of the Central Extremadura Batholith, a set of plutons ranging from tonalite to leucogranite that have been considered a prime example of Variscan syn-kinematic plutonism. New LA-ICP-MS and CA-ID-TIMS U–Pb dating reveals that the Zarza la Mayor tonalite–granodiorite is an Early Ordovician intrusion. The LA-ICP-MS data show that there is an absence of inherited cores, despite some complex internal zoning with obvious resorption features in some of the zircon crystals. Dating of monazite and zircon by CA-ID-TIMS provides a concordant age of 478.1 ± 0.8 Ma. This age coincides with electron microprobe analysis (EMPA) monazite chemical ages for the Zarza de Montánchez (482 ± 10 Ma) and Arroyo de la Luz (470 ± 15 Ma) intrusions. These new data indicate the presence of an Early Ordovician belt of calc-alkaline tonalite–granodiorite in the Schistose-Greywacke Domain – the Beira Baixa–Central Extremadura tonalite–granodiorite belt – which resembles a continental magmatic arc. This belt is contemporaneous with the Ollo de Sapo magmatic event further north in the Central Iberian Zone.

Melt-enhanced deformation during emplacement of gabbro and granodiorite in the Sunnhordland Batholith, west Norway

1991 ◽  
Vol 128 (3) ◽  
pp. 207-226 ◽  
Author(s):  
Torgeir B. Andersen ◽  
Peter Nielsen ◽  
Erling Rykkelid ◽  
Hanne Sølna
Keyword(s):  
Internal Structure ◽  
Shear Zones ◽  
Island Arc ◽  
Upper Crust ◽  
Calc Alkaline ◽  
Magmatic Arc ◽  
Plate Convergence ◽  
Relative Age ◽  
Early Ordovician ◽  
Partial Melts

AbstractThe Caledonian Sunnhordland Batholith comprises calc-alkaline plutons that have been assigned to three units according to their relative age and composition: a gabbro-diorite unit, a granodiorite unit and a later granodiorite-granite unit. The batholith was emplaced into an envelope including ophiolite and island-arc complexes, sediments and volcanites of early Ordovician age that were developed in a zone of plate convergence. Continued convergence resulted in the formation of a mature magmatic arc and a thickened crust; the late granitoids (unit 3), which commenced their crystallization at pressures around 6 to 7 kb, rose as permitted diapiric intrusions. The ingress and ascent of the magmas in this setting is considered to have been facilitated by the presence of major shear zones developed in relation to plate convergence. In this model, plastic instabilities were formed in an otherwise elastic middle and upper crust. Non-coaxial deformation was accelerated by the emplacement of magmas and the formation of abundant partial melts in water-rich sediments of the envelope. The deformation, which was accelerated by magma and melt lubrication in aureoles, controlled both the shape and internal structure in the gabbro and granodiorite plutons.

Late Cambrian – Early Ordovician magmatism in the Sierra de Pie de Palo, Sierras Pampeanas (Argentina): implications for the early evolution of the proto-Andean margin of Gondwana

2019 ◽  
Vol 157 (2) ◽  
pp. 321-339 ◽  
Author(s):  
Carlos D. Ramacciotti ◽  
César Casquet ◽  
Edgardo G. Baldo ◽  
Pablo H. Alasino ◽  
Carmen Galindo ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Regional Metamorphism ◽  
Shear Zones ◽  
Magmatic Activity ◽  
Sierras Pampeanas ◽  
Mafic Magmatism ◽  
Magmatic Arc ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Depleted Mantle

AbstractThe Sierra de Pie de Palo, in the Argentinean Sierras Pampeanas (Andean foreland), consists of a Mesoproterozoic basement and an Ediacaran – upper Cambrian sedimentary cover that underwent folding, thrusting and metamorphism during the Ordovician Famatinian orogeny. Mafic rocks and granitoids of the easternmost Sierra de Pie de Palo provide information about the magmatic activity at the proto-Andean margin of Gondwana during late Cambrian – Early Ordovician time. Magmatic activity began in the Sierra de Pie de Palo as dykes, sills and small intrusions of tholeiitic gabbros between 490 and 470 Ma, before shortening and regional metamorphism. Variable mantle sources (Nd depleted mantle age, TDM between 1.7 and 1.3 Ga) were involved in the mafic magmatism. Nd-isotope signatures were probably inherited from a Mesoproterozoic subcontinental mantle. Mafic magmatism was coincident with collapse of a Cambrian carbonate-siliciclastic platform that extended along SW Gondwana, and was probably coeval with the beginning of subduction. After mafic magmatism, peraluminous granitoids were emplaced in the Sierra de Pie de Palo along ductile shear zones during a contractional tectonic phase, coeval with moderate to high P/T metamorphism, and with the Cordilleran-type magmatic arc that resulted from a flare-up at c. 470 Ma. Granitoids resulted mainly from partial melting of metasedimentary rocks, although some hybridization with juvenile magmas and/or rocks cannot be ruled out. The evidence shown here further implies that the Pie de Palo block was part of the continental upper plate during the Famatinian subduction, and not an exotic block that collided with the Gondwana margin.

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

Early Ordovician alkali-ultramafic Zhilandy complex (Central Kazakhstan): structure and age of formation

2019 ◽  
Vol 484 (1) ◽  
pp. 61-65
Author(s):  
R. M. Antonuk ◽  
A. A. Tretyakov ◽  
K. E. Degtyarev ◽  
A. B. Kotov
Keyword(s):  
Complex Formation ◽  
Central Asian Orogenic Belt ◽  
Early Cambrian ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Central Asian ◽  
Geochronological Study ◽  
Three Stages ◽  
Late Neoproterozoic ◽  
Quartz Monzodiorites

U–Pb geochronological study of amphibole-bearing quartz monzodiorites of the alkali-ultramafic Zhilandy complex in Central Kazakhstan, whose formation is deduced at the Early Ordovician era (479 ± 3 Ma). The obtained data indicate three stages of intra-plate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic stage of alkali syenites of the Karsakpay complex intrusion, Early Cambrian stage of ultramafic-gabbroid plutons of the Ulutau complex formation, and Late Cambrian–Early Ordovician stage of formation of the Zhilandy complex and Krasnomay complex intrusions.

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