Late Neogene changes in North America and Antarctica absolute plate motions inferred from the Mid‐Atlantic and Southwest Indian Ridges spreading histories. Issue 16 (25th August 2016)

• Record Type: Journal Article
• Authors: Iaffaldano, G.; DeMets, C.
• Is Part Of: Geophysical research letters. Volume 43:Issue 16(2016)
• Page Start: 8466
• Page End: 8472
• Publication Date: 2016-08-25
• Subjects: plate motion changes; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL070276
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Reconstructions of absolute plate motions underpin our understanding of the plate torque balance, but are challenging due to difficulties in inferring well‐dated rates and directions of plate movements from hot spot tracks. Useful information about plate dynamics can be inferred from rapid absolute plate motion changes, as these are linked only to the torque(s) that changed. Here we infer late Neogene changes in the absolute motions of North America and possibly Antarctica from changes in the easier‐to‐determine relative plate motions recorded along the Arctic, northern Mid‐Atlantic and Southwest Indian Ridges. We show that Eurasia/North America and Nubia/North America motions changed by the same amount between 8 and 5 Ma, as may have Nubia/Antarctica and Somalia/Antarctica plate motions. By considering additional, independent constraints on Somalia/India plate motion, we argue that a scenario in which North America and Antarctica absolute motions changed is the simplest one that explains the observed changes in relative motions. We speculate that these changes are linked to the late Neogene dynamics of the Pacific plate. Key Points: Spreading in the Mid‐Atlantic and Southwest Indian Ridges changed coevally between 8 and 5 Ma Relative motions of Nubia/North America and Nubia‐Eurasia changed by the same amount, as may have Nubia/Antarctica and Somalia/Antarctica The simplest scenario explaining these records is one where North America and Antarctica changed their absolute motions between 8 and 5 Ma