scholarly journals Geochronology, whole-rock geochemistry, Sr Nd isotopes, and biotite chemistry of the Deh-Bala intrusive rocks, Central Urumieh-Dokhtar Magmatic Arc (Iran): Implications for magmatic processes and copper mineralization

Lithos ◽  
2021 ◽  
pp. 106544
Author(s):  
Kazem Kazemi ◽  
Soroush Modabberi ◽  
Yilin Xiao ◽  
Fatemeh Sarjoughian ◽  
Ali Kananian
Keyword(s):  
Nd Isotopes ◽  
Magmatic Arc ◽  
Copper Mineralization ◽  
Intrusive Rocks ◽  
Magmatic Processes

Subduction erosion and crustal material recycling indicated by adakites in central Tibet

Geology ◽  
2021 ◽  
Author(s):  
Zong-Yong Yang ◽  
Qiang Wang ◽  
Lu-Lu Hao ◽  
Derek A. Wyman ◽  
Lin Ma ◽  
...  
Keyword(s):  
Crustal Material ◽  
Convergent Margins ◽  
Nd Isotopes ◽  
Magmatic Arc ◽  
Material Recycling ◽  
Intrusive Rocks ◽  
Subducted Oceanic Crust ◽  
Subduction Erosion ◽  
Central Tibet ◽  
Qiangtang Terrane

Subduction erosion is important for crustal material recycling and is widespread in modern active convergent margins. However, such a process is rarely identified in fossil convergent systems, which casts doubt on the importance of subduction erosion through the geological record. We report on ca. 155 Ma Kangqiong (pluton) intrusive rocks of a Mesozoic magmatic arc in the southern Qiangtang terrane, central Tibet. These rocks mainly consist of trondhjemites and tonalites and are similar to slab-derived adakites with mantle-like zircon oxygen isotope compositions (δ18O = 5.2‰–5.6‰), they display more evolved Sr-Nd isotopes and higher Th/La relative to mid-oceanic ridge basalts from the Bangong-Nujiang suture, and they contain abundant amphibole and biotite. These characteristics indicate magma generation via H2O-fluxed melting of eroded forearc crust debris with subducted oceanic crust at 1.5–2.5 GPa and 700–800 °C. In addition, the intrusions are exposed <20 km north of the Bangong-Nujiang suture. Given the formation of adakites, narrow arc-suture distance, migration of the Jurassic frontal arc toward the continent interior, and other independent geological archives, we suggest that the hydrated forearc crust materials were removed from the overlying plate and carried into the mantle by subduction erosion. Our study provides the first direct magmatic evidence for a subduction erosion process in pre-Cenozoic convergent systems, which confirms an important role for such processes in subduction-zone material recycling.

Structure of the Deep Freeze Range–Eisenhower Range of the Wilson Terrane (North Victoria Land, Antarctica): emplacement of magmatic intrusions in the Early Palaeozoic deformed margin of the East Antarctic Craton

2000 ◽  
Vol 12 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Giovanni Musumeci ◽  
Piero Pertusati
Keyword(s):  
Thermal State ◽  
Structural Data ◽  
Shear Zones ◽  
Magmatic Arc ◽  
Victoria Land ◽  
Intrusive Rocks ◽  
Magmatic Processes ◽  
Early Palaeozoic ◽  
Terrane Accretion ◽  
Host Rocks

In North Victoria Land (Antarctica), the Wilson Terrane is a portion of the palaeomargin of the East Antarctic Craton, deformed during the Late Cambrian–Early Ordovician Ross Orogeny. Crustal deformation, from westward subduction of the palaeo Pacific plate and terrane accretion on this palaeomargin, gave rise to the development of a transpressive fold belt and a wide magmatic arc. In the inner portion of the Wilson Terrane, (Deep Freeze Range–Eisenhower Range) a large portion of this magmatic arc is made up of intrusions and dyke systems. Intrusive rocks range from large unfoliated plutons to well foliated sheet intrusions emplaced in low and medium–high grade metamorphic rocks respectively. Field and structural data on intrusive rocks and metamorphic host rocks, coupled with parameters relative to deformation mechanism and magmatic processes (crystallization and cooling) rates, make it possible to outline an episode of diffuse synkinematic magmatism in the Wilson Terrane. The emplacement of intrusions in both the middle and upper crust was coeval and related to the development of transpressional and transtensional structures along dextral strike-slip shear zones. Furthermore the development of foliated or unfoliated fabrics is related to competition between rates of deformation and magmatic processes, which is a function of the thermal state of the host rocks.

Stable (C, O) and radiogenic (Sr, Nd) isotopes of carbonates as indicators of magmatic and post-magmatic processes of phoscorite-series rocks and carbonatites from Catalão I, central Brazil

2010 ◽  
Vol 161 (3) ◽  
pp. 451-464 ◽  
Author(s):  
Pedro Filipe de Oliveira Cordeiro ◽  
José Affonso Brod ◽  
Roberto Ventura Santos ◽  
Elton Luiz Dantas ◽  
Claudinei Gouveia de Oliveira ◽  
...  
Keyword(s):  
Nd Isotopes ◽  
Central Brazil ◽  
Magmatic Processes

Mafic magmatism associated with the Goiás magmatic arc in the Anicuns region, Goiás, central Brazil: Sm–Nd isotopes and new ID-TIMS and SHIMP U–Pb data

2004 ◽  
Vol 16 (7) ◽  
pp. 599-614 ◽  
Author(s):  
Jorge Henrique Laux ◽  
Márcio Martins Pimentel ◽  
Elton Luiz Dantas ◽  
Richard Armstrong ◽  
Alan Armele ◽  
...  
Keyword(s):  
Nd Isotopes ◽  
Mafic Magmatism ◽  
Magmatic Arc ◽  
Central Brazil

Lower Palaeozoic and Precambrian igneous rocks from eastern England, and their bearing on late Ordovician closure of the Tornquist Sea: constraints from U-Pb and Nd isotopes

1993 ◽  
Vol 130 (6) ◽  
pp. 835-846 ◽  
Author(s):  
S. R. Noble ◽  
R. D. Tucker ◽  
T. C. Pharaoh
Keyword(s):  
Volcanic Rocks ◽  
Igneous Rocks ◽  
Calc Alkaline ◽  
Nd Isotopes ◽  
Nd Isotope ◽  
Magmatic Arc ◽  
The North ◽  
Basement Rocks ◽  
Continental Arc ◽  
Lower Palaeozoic

AbstractThe U-Pb isotope ages and Nd isotope characteristics of asuite of igneous rocks from the basement of eastern England show that Ordovician calc-alkaline igneous rocks are tectonically interleaved with late Precambrian volcanic rocks distinct from Precambrian rocks exposed in southern Britain. New U-Pb ages for the North Creake tuff (zircon, 449±13 Ma), Moorby Microgranite (zircon, 457 ± 20 Ma), and the Nuneaton lamprophyre (zircon and baddeleyite, 442 ± 3 Ma) confirm the presence ofan Ordovician magmatic arc. Tectonically interleaved Precambrian volcanic rocks within this arc are verified by new U-Pb zircon ages for tuffs at Glinton (612 ± 21 Ma) and Orton (616 ± 6 Ma). Initial εNd values for these basement rocks range from +4 to - 6, consistent with generation of both c. 615 Ma and c. 450 Ma groups of rocksin continental arc settings. The U-Pb and Sm-Nd isotope data support arguments for an Ordovician fold/thrust belt extending from England to Belgium, and that the Ordovician calc-alkaline rocks formed in response to subductionof Tornquist Sea oceanic crust beneath Avalonia.

scholarly journals The 1590-1520 Ma Cachoeirinha magmatic arc and its tectonic implications for the Mesoproterozoic SW Amazonian craton crustal evolution

2004 ◽  
Vol 76 (4) ◽  
pp. 807-824 ◽  
Author(s):  
Amarildo S. Ruiz ◽  
Mauro C. Geraldes ◽  
João B. Matos ◽  
Wilson Teixeira ◽  
William R. Van Schumus ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Major And Trace Elements ◽  
Magmatic Arc ◽  
Rio Negro ◽  
Intrusive Rocks ◽  
Amazonian Craton ◽  
Granitoid Rocks ◽  
Geologic Setting ◽  
Fractional Crystallization Process ◽  
Tectonic Relationship

Isotopic and chemical data of rocks from the Cachoeirinha suite provide new insights on the Proterozoic evolution of the Rio Negro/Juruena Province in SW Amazonian craton. Six U-Pb and Sm-Nd analyses in granitoid rocks of the Cachoeirinha suite yielded ages of 1587-1522 Ma and T DM model ages of 1.88-1.75 Ga (EpsilonNd values of -0.8 to +1.0). In addition, three post-tectonic plutonic rocks yielded U-Pb ages from 1485-1389 Ma (T DM of 1.77-1.74 Ga and EpsilonNd values from -1.3 to +1.7). Variations in major and trace elements of the Cachoeirinha suite rocks indicate fractional crystallization process and magmatic arc geologic setting. These results suggest the following interpretations: (1) The interval of 1590-1520 Ma represents an important magmatic activity in SW Amazonian craton. (2) T DM and arc-related chemical affinity supportthe hypothesis that the rocks are genetically associated with an east-dipping subduction zone under the older (1.79-1.74 Ga) continental margin. (3) The 1590-1520 Ma age of intrusive rocks adjacent to an older crust represents similar geological framework along the southern margin of Baltica, corroborating the hypothesis of tectonic relationship at that time.

The geology of central Isla Hoste, southern Chile: sedimentation, magmatism and tectonics in part of a Mesozoic back-arc basin

1980 ◽  
Vol 117 (4) ◽  
pp. 339-349 ◽  
Author(s):  
C. P. Andrews-Speed
Keyword(s):  
Sedimentary Rocks ◽  
Igneous Rocks ◽  
Ocean Floor ◽  
Turbidity Currents ◽  
Southern Chile ◽  
Magmatic Arc ◽  
The Pacific ◽  
Pacific Side ◽  
Intrusive Rocks ◽  
Back Arc

SummaryCentral Isla Hoste lies towards the Pacific side of a Mesozoic back-arc basin in southern Chile, behind a magmatic arc represented by the Patagonian batholith. The volcaniclastic sediments on Isla Hoste were derived from the magmatic arc and deposited in the back-arc basin by turbidity currents. These sediments may, in part, overlie mafic volcanic and intrusive rocks. Geochemical and lithologic data are used to suggest an ocean-floor origin for these mafic igneous rocks on central Isla Hoste. The sedimentary and mafic igneous rocks were deformed and uplifted during the middle Cretaceous Andean orogeny. However, the nature of the crust underlying most of the sedimentary rocks in the back-arc basin and the style of deformation in most of this basement are unknown. Therefore the role, if any, of subduction within the back-arc basin during the middle Cretaceous ‘closure’ of this basin is not certain. Post-kinematic intrusions within the back-arc basin are common. These intrusions will confuse attempts to determine by geophysical means the nature of the pre-kinematic basement of the back-arc basin and attempts to outline the present extent of the basin in offshore regions.

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