Northern margin of the Limpopo mobile belt, southern Africa

1976 ◽  
Vol 87 (4) ◽  
pp. 601 ◽  
Author(s):  
M. P. COWARD ◽  
P. R. JAMES ◽  
L. WRIGHT
Keyword(s):  
Southern Africa ◽  
Mobile Belt ◽  
Northern Margin

scholarly journals Petrogenesis and geochronology of the Arkasani Granophyre and felsic Dalma volcanic rocks: implications for the evolution of the Proterozoic North Singhbhum Mobile Belt, east India

2014 ◽  
Vol 152 (3) ◽  
pp. 492-503 ◽  
Author(s):  
H.N. BHATTACHARYA ◽  
D.R. NELSON ◽  
E.R. THERN ◽  
W. ALTERMANN
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Tectonic Activity ◽  
Mobile Belt ◽  
Northern Margin ◽  
The North ◽  
Ne India ◽  
New Findings ◽  
Minimum Age ◽  
Felsic Volcanic

AbstractThe North Singhbhum Mobile Belt (NSMB) is a 200 km long, curved Proterozoic fold–thrust belt that skirts the northern margin of the Archean Singhbhum Craton of NE India. The Singhbhum Shear Zone (SSZ) developed between the Dhanjori and Chaibasa formations near the southern margin of the NSMB and represents an important Cu-U-P metallotect. A SHRIMP U–Pb zircon date of 1861±6 Ma, obtained for the syn- to post-kinematic Arkasani Granophyre that has intruded the SSZ, provides a minimum age for the prolonged tectonic activity and mineralization along the SSZ and for the time of closure of the Chaibasa and Dhanjori sub-basins. The Dalma Volcanic Belt, a submarine rift-related bimodal mafic-felsic volcanic suite, forms the spine of the NSMB. A SHRIMP U–Pb zircon igneous crystallization date of 1631±6 Ma was obtained for an unfoliated felsic volcanic rock from the base of the Dalma volcanic sequence. These new findings suggest that the different sub-basins in the NSMB evolved diachronously under contrasting tectonic environments and were juxtaposed during a later orogenic movement.

Contribution of an Eastern Indochina-derived fragment to the formation of island arc systems in the Philippine Mobile Belt

2021 ◽  
Author(s):  
Lin Gong ◽  
Pete Hollings ◽  
Yu Zhang ◽  
Jing Tian ◽  
Dengfeng Li ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Plate Boundary ◽  
Philippine Sea Plate ◽  
Geochemical Data ◽  
Mobile Belt ◽  
Potential Contribution ◽  
Northern Margin ◽  
Early Oligocene ◽  
Arc Setting ◽  
T Values

The Philippine Mobile Belt is a complex plate boundary with multiple terranes in Southeast Asia, yet its early tectonic evolution is still not fully understood due to a scarcity of solid evidence. Here we report new whole rock geochemical, Sr-Nd isotopic, and zircon U-Pb-Hf isotopic data for Cretaceous-Miocene arc magmatic rocks from the Cebu and Bohol Islands, Philippine Mobile Belt. Bulk geochemical data display arc affinities with enriched large ion lithophile elements (e.g., Sr and Ba) and depleted high field strength elements (e.g., Nb, Ta, and Ti). The high positive εNd(t) (+4.6 to +9.1) values and low initial 87Sr/86Sr ratios (0.7032−0.7048) suggest that these igneous rocks were generated by partial melting of mantle wedge in an arc setting. U-Pb dating of zircons revealed Cretaceous (ca. 120−90 Ma), middle Eocene to early Oligocene (ca. 43−30 Ma), and middle Miocene (ca. 14 Ma) crystallization ages for the arc magmatism with abundant Permian-Triassic zircon xenocrysts clustering at ca. 250 Ma. The Permian-Triassic grains show dominantly negative εHf(t) values ranging from −16.2 to −6.6, which are similar to those of coeval rocks in Eastern Indochina. Combined with previous paleomagnetic studies, we propose that an Eastern Indochina-derived continental fragment was involved during the formation of arcs in the Cebu and Bohol Islands, which highlights the potential contribution of ancient continental materials in the formation of intra-oceanic arcs. This scenario does not support the previously proposed model that the Cretaceous arc in the Philippine Mobile Belt formed in the northern margin of the proto-Philippine Sea Plate and Australian margin.

A Discussion on the evolution of the Precambrian crust - The Limpopo mobile belt — Southern Africa

1973 ◽  
Vol 273 (1235) ◽  
pp. 463-485 ◽  
Keyword(s):  
Shear Deformation ◽  
Southern Africa ◽  
Central Zone ◽  
Kaapvaal Craton ◽  
Mobile Belt ◽  
High Grade ◽  
The South ◽  
Geological Time ◽  
The North ◽  
Limpopo Belt

The Limpopo belt is an extensive ENE-trending linear zone of high-grade metamorphic tectonites which separates the Archaean nucleii of the Rhodesian craton to the north from the Kaapvaal craton to the south. The belt consists of reworked Archaean granite-greenstone terrain with an early Proterozoic cover sequence, the Messina Formation, infolded and metamorphosed with the basement. Two major zones of shearing and transcurrent dislocation separate marginal granulite zones from a central zone which consists of complexly infolded cover rocks and reworked basement. The northern granulite zone appears to grade transitionally into the Rhodesian craton to the north, whereas there is some evidence that the southern granulite zone is faulted against the Kaapvaal craton to the south. The whole belt has behaved as a zone of crustal weakness throughout geological time, and is characterized by repeated shear deformation, igneous intrusion and extrusion, despite the cessation of major regional tectono-thermal reactivation about 1900 Ma ago.

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