A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus
Abstract Extension within a continental back‐arc basin initiates within continental rather than oceanic lithosphere, and the geochemical characteristics of magmatic rocks within continental back‐arcs are poorly understood relative to their intraoceanic counterparts. Here, we compile published geoche...
Published in: | Geochemistry, Geophysics, Geosystems |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2021
|
Subjects: | |
Online Access: | https://doi.org/10.1029/2020GC009490 https://doaj.org/article/0db263d61857433cb47ee11d4174325f |
id |
ftdoajarticles:oai:doaj.org/article:0db263d61857433cb47ee11d4174325f |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:0db263d61857433cb47ee11d4174325f 2023-12-03T10:20:29+01:00 A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus Dylan A. Vasey Eric Cowgill Kari M. Cooper 2021-06-01T00:00:00Z https://doi.org/10.1029/2020GC009490 https://doaj.org/article/0db263d61857433cb47ee11d4174325f EN eng Wiley https://doi.org/10.1029/2020GC009490 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2020GC009490 https://doaj.org/article/0db263d61857433cb47ee11d4174325f Geochemistry, Geophysics, Geosystems, Vol 22, Iss 6, Pp n/a-n/a (2021) Caucasus Basin collision‐induced trench retreat continental back‐arc spreading subduction zone magmatism Tethyan realm trace‐element geochemistry Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.1029/2020GC009490 2023-11-05T01:35:55Z Abstract Extension within a continental back‐arc basin initiates within continental rather than oceanic lithosphere, and the geochemical characteristics of magmatic rocks within continental back‐arcs are poorly understood relative to their intraoceanic counterparts. Here, we compile published geochemical data from five exemplar modern continental back‐arc basins—the Okinawa Trough, Bransfield Strait, Tyrrhenian Sea, Patagonia plateau, and Aegean Sea/Western Anatolia—to establish a geochemical framework for continental back‐arc magmatism. This analysis shows that continental back‐arcs yield geochemical signatures more similar to arc magmatism than intraoceanic back‐arcs do. We apply this framework to published data for Triassic‐Jurassic magmatic rocks from the Caucasus arc system, which includes a relict continental back‐arc, the Caucasus Basin, that opened during the Jurassic and for which the causal mechanism of formation remains debated. Our analysis of 40Ar/39Ar and U‐Pb ages indicates Permian‐Triassic arc magmatism from ∼260 to 220 Ma due to subduction beneath the Greater Caucasus and Scythian Platform. Late Triassic (∼220–210 Ma) collision of the Iranian block with Laurasia likely induced trench retreat in the Caucasus region and led to migration of the Caucasus arc and opening of the Caucasus Basin. This activity was followed by Jurassic arc magmatism in the Lesser Caucasus from ∼180 to 140 Ma and back‐arc spreading in the Caucasus Basin from ∼180 to 160 Ma. Trace element and Sr‐Nd isotopic data for magmatic rocks indicate that Caucasus Basin magmatism is comparable to modern continental back‐arcs and that the source to the Lesser Caucasus arc became more enriched at ∼160 Ma, likely from the cessation of back‐arc spreading. Article in Journal/Newspaper Bransfield Strait Directory of Open Access Journals: DOAJ Articles Bransfield Strait Patagonia Geochemistry, Geophysics, Geosystems 22 6 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Caucasus Basin collision‐induced trench retreat continental back‐arc spreading subduction zone magmatism Tethyan realm trace‐element geochemistry Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
Caucasus Basin collision‐induced trench retreat continental back‐arc spreading subduction zone magmatism Tethyan realm trace‐element geochemistry Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 Dylan A. Vasey Eric Cowgill Kari M. Cooper A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
topic_facet |
Caucasus Basin collision‐induced trench retreat continental back‐arc spreading subduction zone magmatism Tethyan realm trace‐element geochemistry Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
Abstract Extension within a continental back‐arc basin initiates within continental rather than oceanic lithosphere, and the geochemical characteristics of magmatic rocks within continental back‐arcs are poorly understood relative to their intraoceanic counterparts. Here, we compile published geochemical data from five exemplar modern continental back‐arc basins—the Okinawa Trough, Bransfield Strait, Tyrrhenian Sea, Patagonia plateau, and Aegean Sea/Western Anatolia—to establish a geochemical framework for continental back‐arc magmatism. This analysis shows that continental back‐arcs yield geochemical signatures more similar to arc magmatism than intraoceanic back‐arcs do. We apply this framework to published data for Triassic‐Jurassic magmatic rocks from the Caucasus arc system, which includes a relict continental back‐arc, the Caucasus Basin, that opened during the Jurassic and for which the causal mechanism of formation remains debated. Our analysis of 40Ar/39Ar and U‐Pb ages indicates Permian‐Triassic arc magmatism from ∼260 to 220 Ma due to subduction beneath the Greater Caucasus and Scythian Platform. Late Triassic (∼220–210 Ma) collision of the Iranian block with Laurasia likely induced trench retreat in the Caucasus region and led to migration of the Caucasus arc and opening of the Caucasus Basin. This activity was followed by Jurassic arc magmatism in the Lesser Caucasus from ∼180 to 140 Ma and back‐arc spreading in the Caucasus Basin from ∼180 to 160 Ma. Trace element and Sr‐Nd isotopic data for magmatic rocks indicate that Caucasus Basin magmatism is comparable to modern continental back‐arcs and that the source to the Lesser Caucasus arc became more enriched at ∼160 Ma, likely from the cessation of back‐arc spreading. |
format |
Article in Journal/Newspaper |
author |
Dylan A. Vasey Eric Cowgill Kari M. Cooper |
author_facet |
Dylan A. Vasey Eric Cowgill Kari M. Cooper |
author_sort |
Dylan A. Vasey |
title |
A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
title_short |
A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
title_full |
A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
title_fullStr |
A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
title_full_unstemmed |
A Preliminary Framework for Magmatism in Modern Continental Back‐Arc Basins and Its Application to the Triassic‐Jurassic Tectonic Evolution of the Caucasus |
title_sort |
preliminary framework for magmatism in modern continental back‐arc basins and its application to the triassic‐jurassic tectonic evolution of the caucasus |
publisher |
Wiley |
publishDate |
2021 |
url |
https://doi.org/10.1029/2020GC009490 https://doaj.org/article/0db263d61857433cb47ee11d4174325f |
geographic |
Bransfield Strait Patagonia |
geographic_facet |
Bransfield Strait Patagonia |
genre |
Bransfield Strait |
genre_facet |
Bransfield Strait |
op_source |
Geochemistry, Geophysics, Geosystems, Vol 22, Iss 6, Pp n/a-n/a (2021) |
op_relation |
https://doi.org/10.1029/2020GC009490 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2020GC009490 https://doaj.org/article/0db263d61857433cb47ee11d4174325f |
op_doi |
https://doi.org/10.1029/2020GC009490 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
22 |
container_issue |
6 |
_version_ |
1784267918133952512 |