Blind magmatism abets nonvolcanic continental rifting
Abstract Tectonic forces alone cannot drive rifting in old and thick continental lithosphere. Geodynamic models suggest that thermal weakening is critical for lithospheric extension, yet many active rifts lack volcanism, seeming to preclude this process. We focus on one such rift, the Tanganyika-Ruk...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2024-02-01
|
| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-024-01244-7 |
| _version_ | 1797273131720638464 |
|---|---|
| author | Rasheed Ajala Folarin Kolawole William Menke |
| author_facet | Rasheed Ajala Folarin Kolawole William Menke |
| author_sort | Rasheed Ajala |
| collection | DOAJ |
| description | Abstract Tectonic forces alone cannot drive rifting in old and thick continental lithosphere. Geodynamic models suggest that thermal weakening is critical for lithospheric extension, yet many active rifts lack volcanism, seeming to preclude this process. We focus on one such rift, the Tanganyika-Rukwa segment of the East African Rift System, where we analyze local seismicity for shear wave anisotropy and couple the results with numerical modeling. The strongest splitting measurements are from earthquakes with paths sampling lower crustal regions of high compressional-to-shear wave velocity ratios and have fast polarization directions parallel to the local mantle flow, implying the existence of oriented melt lenses. This lower crustal magmatism and observed high surface heat flow are consistent with substantial lithospheric weakening and explain the enigmatic relief and increasing strain accommodation along the rift axis. We conclude that progressive nonvolcanic rifting is assisted by deep crustal melts yet to breach the surface. |
| first_indexed | 2024-03-07T14:39:13Z |
| format | Article |
| id | doaj.art-dd4a4b3e10534ee58ce87e730ec077be |
| institution | Directory Open Access Journal |
| issn | 2662-4435 |
| language | English |
| last_indexed | 2024-03-07T14:39:13Z |
| publishDate | 2024-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Earth & Environment |
| spelling | doaj.art-dd4a4b3e10534ee58ce87e730ec077be2024-03-05T20:27:45ZengNature PortfolioCommunications Earth & Environment2662-44352024-02-01511810.1038/s43247-024-01244-7Blind magmatism abets nonvolcanic continental riftingRasheed Ajala0Folarin Kolawole1William Menke2Lamont-Doherty Earth Observatory, Columbia UniversityLamont-Doherty Earth Observatory, Columbia UniversityLamont-Doherty Earth Observatory, Columbia UniversityAbstract Tectonic forces alone cannot drive rifting in old and thick continental lithosphere. Geodynamic models suggest that thermal weakening is critical for lithospheric extension, yet many active rifts lack volcanism, seeming to preclude this process. We focus on one such rift, the Tanganyika-Rukwa segment of the East African Rift System, where we analyze local seismicity for shear wave anisotropy and couple the results with numerical modeling. The strongest splitting measurements are from earthquakes with paths sampling lower crustal regions of high compressional-to-shear wave velocity ratios and have fast polarization directions parallel to the local mantle flow, implying the existence of oriented melt lenses. This lower crustal magmatism and observed high surface heat flow are consistent with substantial lithospheric weakening and explain the enigmatic relief and increasing strain accommodation along the rift axis. We conclude that progressive nonvolcanic rifting is assisted by deep crustal melts yet to breach the surface.https://doi.org/10.1038/s43247-024-01244-7 |
| spellingShingle | Rasheed Ajala Folarin Kolawole William Menke Blind magmatism abets nonvolcanic continental rifting Communications Earth & Environment |
| title | Blind magmatism abets nonvolcanic continental rifting |
| title_full | Blind magmatism abets nonvolcanic continental rifting |
| title_fullStr | Blind magmatism abets nonvolcanic continental rifting |
| title_full_unstemmed | Blind magmatism abets nonvolcanic continental rifting |
| title_short | Blind magmatism abets nonvolcanic continental rifting |
| title_sort | blind magmatism abets nonvolcanic continental rifting |
| url | https://doi.org/10.1038/s43247-024-01244-7 |
| work_keys_str_mv | AT rasheedajala blindmagmatismabetsnonvolcaniccontinentalrifting AT folarinkolawole blindmagmatismabetsnonvolcaniccontinentalrifting AT williammenke blindmagmatismabetsnonvolcaniccontinentalrifting |