Zircon U–Pb–Hf isotopic and whole-rock geochemical studies of Paleoproterozoic metasedimentary rocks in the northern segment of the Jiao–Liao–Ji Belt, China: Implications for provenance and regional tectonic evolution

2017 ◽  
Vol 298 ◽  
pp. 472-489 ◽  
Author(s):  
En Meng ◽  
Chao-Yang Wang ◽  
Yan-Guang Li ◽  
Zhuang Li ◽  
Hong Yang ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Metasedimentary Rocks ◽  
Regional Tectonic ◽  
Geochemical Studies ◽  
Northern Segment

Geochronological and petrogenetic constraints on the regional tectonic evolution of the Guanghua Group in northeastern Jiao-Liao-Ji Belt, China

2018 ◽  
Vol 305 ◽  
pp. 427-443 ◽  
Author(s):  
Chao-Yang Wang ◽  
En Meng ◽  
Hong Yang ◽  
Chao-Hui Liu ◽  
Jia Cai ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Regional Tectonic

Silurian provenance variation in the Southern Uplands terrane, Scotland, assessed using neodymium isotopes and linked with regional tectonic evolution

2000 ◽  
Vol 91 (3-4) ◽  
pp. 447-455 ◽  
Author(s):  
P. Stone ◽  
J. A. Evans
Keyword(s):  
Continental Margin ◽  
Tectonic Evolution ◽  
Abrupt Change ◽  
Regional Variations ◽  
Red Sandstone ◽  
Neodymium Isotopes ◽  
Compact Range ◽  
Iapetus Ocean ◽  
Regional Tectonic ◽  
Proterozoic Basement

ABSTRACTThe progressive changes in the provenance of Silurian greywacke turbidites in the Southern Uplands terrane reflect geotectonic events at the Laurentian continental margin during closure of the Iapetus Ocean. In the northern Gala Group, juvenile andesitic detritus in some beds gives εNd values no lower than −4·2; more commonly, quartzo-feldspathic greywackes have εNd values in the −5·5 to −6·7 range, produced by the mixing of juvenile plutonic and Proterozoic basement detritus during arc unroofing. In the southern (younger) Gala Group, Proterozoic εNd values range down from −7·7 to −11·2 with only sporadic evidence for a juvenile component. An abrupt change is seen between the Gala Group and its tectonostratigraphical successor, the Hawick Group. In the latter, εNd values have a compact range between −4·7 and −6·6, indicating the renewed dominance of a more juvenile, plutonic provenance. Regional variations in the Sr/Rb ratio suggest that this was more evolved than the source of the Gala Group plutonic material. The Wenlock greywackes of the Riccarton Group have εNd values in the range −5·1 to −7·8, overlapping with the Hawick Group and with coeval greywackes from both the Midland Valley and Lakesman terranes. Overall, the data support proposals that the Iapetus Ocean had effectively closed by mid-Silurian times. Conversely, data from greywacke boulders in the basal Old Red Sandstone conglomerate of the Midland Valley terrane militate against its Wenlock juxtaposition with the Southern Uplands.

Paleozoic subduction of the Mongol-Okhotsk oceanic plate: insight from the petrogenesis of Ordovician to Devonian granitic plutons in the Hangay Range, central Mongolia

2021 ◽  
Author(s):  
jiaqi Ling ◽  
pengfei Li
Keyword(s):  
Tectonic Evolution ◽  
Magma Source ◽  
Oceanic Plate ◽  
Early Devonian ◽  
Central Mongolia ◽  
Middle Ordovician ◽  
Basaltic Rocks ◽  
History Of ◽  
Geochemical Studies ◽  
T Values

<p>Email: [email protected]; [email protected]</p><p> </p><p>The pre-Mesozoic subduction history of the Mongol-Okhotsk oceanic plate has been poorly understood. Here we conducted geochronological and geochemical studies on four granitic plutons in the westernmost Mongol-Okhotsk Orogen (Hangay Range), with an aim to understand their petrogenesis and role in the Paleozoic tectonic evolution of the Mongol-Okhotsk Orogen. Our geochronological results constrain four granitic plutons to be emplaced from middle Ordovician to early Devonian. Geochemically, the Ordovician pluton belongs to A2-type granites, and three Silurian to Devonian plutons show the characteristics of I-type granites. These granitic plutons were probably generated by partial melting of basaltic rocks in the lower crust given the high contents of Na<sub>2</sub>O and K<sub>2</sub>O. The negative ε<sub>Nd</sub>(t) values (-4.7 to -0.9) and variable ε<sub>Hf</sub>(t) values (-2.6 to +6.1) for the four granitic plutons suggest that ancient basement materials were possibly involved in the magma source. We further investigate the geodynamic origin of these plutons in the context of the Paleozoic tectonics of the Mongol-Okhotsk Orogen, and we conclude that they were probably formed in response to the Ordovician to Devonian subduction of the Mongol-Okhotsk oceanic plate.</p>

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