Autopsy on a dead spreading center: The Phoenix Ridge, Drake Passage, Antarctica

• Main Authors: Livermore, Roy, Balanyá, Juan Carlos, Maldonado, Andrés, Martínez-Martínez, José Miguel, Rodríguez-Fernández, José, Sanz de Galdeano, Carlos, Galindo Zaldívar, Jesús, Jabaloy, Antonio, Barnolas, Antonio, Somoza, Luis, Hernández-Molina, Francisco J., Suriñach, Emma, Viseras, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of America 2000
• Subjects: Drake passage; Phoenix ridge; Antarctic plate; Spreading centers; Antarctic; Drake Passage; Hero Fracture Zone; Shackleton; Shackleton Fracture Zone; West Scotia Ridge; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10261/29195; https://doi.org/10.1130/0091-7613(2000)28<607:AOADSC>2.0.CO;2

4 páginas, 4 figuras. New bathymetric and magnetic anomaly data from the Phoenix Ridge, Antarctica, show that extinction of all three remaining segments occurred at the time of magnetic chron C2A (3.3 ± 0.2 Ma), synchronous with a ridge-trench collision south of the Hero Fracture Zone. This implies that the ultimate cause of extinction was a change in plate boundary forces occasioned by this collision. Spreading rates slowed abruptly at the time of chron C4 (7.8 ± 0.3 Ma), probably as a result of extinction of the West Scotia Ridge, which would have led to an increase in slip rate and transpressional stress across the Shackleton Fracture Zone. Spectacular, high-relief ridges flanking the extinct spreading center, mapped for the first time using multibeam swath bathymetry, are interpreted as a consequence of a reduction in spreading rate, involving a temporary magma oversupply immediately prior to extinction. We thank the captain and crew of BIO Hesperides for their support during ANTPAC97. The Comisión Interministerial de Ciencia y Tecnología of Spain provided support for the work through the research project ANT96-1001. Peer reviewed