Hales Discontinuity in the Southern Indian Continental Lithosphere: Seismological and Petrological Models

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
Jashodhara Chaudhury ◽  
Supriyo Mitra ◽  
Tapabrato Sarkar
Keyword(s):  
Continental Lithosphere ◽  
Hales Discontinuity

scholarly journals Helium in diamonds unravels over a billion years of craton metasomatism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yaakov Weiss ◽  
Yael Kiro ◽  
Cornelia Class ◽  
Gisela Winckler ◽  
Jeff W. Harris ◽  
...  
Keyword(s):  
Continental Lithosphere ◽  
Late Mesozoic ◽  
Tectonic Events ◽  
Upper Limit ◽  
Age Limits ◽  
Fluid Bearing ◽  
Major Surface ◽  
Chemical Events

AbstractChemical events involving deep carbon- and water-rich fluids impact the continental lithosphere over its history. Diamonds are a by-product of such episodic fluid infiltrations, and entrapment of these fluids as microinclusions in lithospheric diamonds provide unique opportunities to investigate their nature. However, until now, direct constraints on the timing of such events have not been available. Here we report three alteration events in the southwest Kaapvaal lithosphere using U-Th-He geochronology of fluid-bearing diamonds, and constrain the upper limit of He diffusivity (to D ≈ 1.8 × 10−19 cm2 s−1), thus providing a means to directly place both upper and lower age limits on these alteration episodes. The youngest, during the Cretaceous, involved highly saline fluids, indicating a relationship with late-Mesozoic kimberlite eruptions. Remnants of two preceding events, by a Paleozoic silicic fluid and a Proterozoic carbonatitic fluid, are also encapsulated in Kaapvaal diamonds and are likely coeval with major surface tectonic events (e.g. the Damara and Namaqua–Natal orogenies).

scholarly journals Episodic construction of the early Andean Cordillera unravelled by zircon petrochronology

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
José Joaquín Jara ◽  
Fernando Barra ◽  
Martin Reich ◽  
Mathieu Leisen ◽  
Rurik Romero ◽  
...  
Keyword(s):  
Continental Lithosphere ◽  
Complex Interplay ◽  
Continental Arcs ◽  
The Andes ◽  
Andean Cordillera ◽  
Continental Arc ◽  
The World ◽  
Oceanic Plates ◽  
Orogenic Belts ◽  
Continental Growth

AbstractThe subduction of oceanic plates beneath continental lithosphere is responsible for continental growth and recycling of oceanic crust, promoting the formation of Cordilleran arcs. However, the processes that control the evolution of these Cordilleran orogenic belts, particularly during their early stages of formation, have not been fully investigated. Here we use a multi-proxy geochemical approach, based on zircon petrochronology and whole-rock analyses, to assess the early evolution of the Andes, one of the most remarkable continental arcs in the world. Our results show that magmatism in the early Andean Cordillera occurred over a period of ~120 million years with six distinct plutonic episodes between 215 and 94 Ma. Each episode is the result of a complex interplay between mantle, crust, slab and sediment contributions that can be traced using zircon chemistry. Overall, the magmatism evolved in response to changes in the tectonic configuration, from transtensional/extensional conditions (215–145 Ma) to a transtensional regime (138–94 Ma). We conclude that an external (tectonic) forcing model with mantle-derived inputs is responsible for the episodic plutonism in this extensional continental arc. This study highlights the use of zircon petrochronology in assessing the multimillion-year crustal scale evolution of Cordilleran arcs.

scholarly journals Earthquake cycle deformation and the Moho: Implications for the rheology of continental lithosphere

2013 ◽  
Vol 609 ◽  
pp. 504-523 ◽  
Author(s):  
Tim J. Wright ◽  
John R. Elliott ◽  
Hua Wang ◽  
Isabelle Ryder
Keyword(s):  
Continental Lithosphere ◽  
Earthquake Cycle

The influence of second-scale convection on the thickness of continental lithosphere and crust

1991 ◽  
Vol 189 (1-4) ◽  
pp. 281-306 ◽  
Author(s):  
Harro Schmeling ◽  
Gabriele Marquart
Keyword(s):  
Continental Lithosphere
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