The kinematic evolution of the Macquarie Plate: A case study for the fragmentation of oceanic lithosphere

• Published in: Earth and Planetary Science Letters
• Main Authors: Choi, Hakkyum, Kim, Seung-Sep, Dyment, Jérôme, Granot, Roi, Park, Sung-Hyun, Hong, Jong Kuk
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: marine magnetics; tectonics; plate reconstruction; Macquarie Plate; [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarctic; Indian; Southeast Indian Ridge; Hjort Trench; Antarc*
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-03748832; https://doi.org/10.1016/j.epsl.2017.08.035

International audience The tectonic evolution of the Southeast Indian Ridge (SEIR), and in particular of its easternmost edge, has not been constrained by high-resolution shipboard data and therefore the kinematic details of its behavior are uncertain. Using new shipboard magnetic data obtained by R/VIB Araon and M/V L'Astrolabe along the easternmost SEIR and available archived magnetic data, we estimated the finite rotation parameters of the Macquarie-Antarctic and Australian-Antarctic motions for eight anomalies (1o, 2, 2Ay, 2Ao, 3y, 3o, 3Ay, and 3Ao). These new finite rotations indicate that the Macquarie Plate since its creation ∼6.24 million years ago behaved as an independent and rigid plate, confirming previous estimates. The change in the Australian-Antarctic spreading direction from N-S to NW-SE appears to coincide with the formation of the Macquarie Plate at ∼6.24 Ma. Analysis of the estimated plate motions indicates that the initiation and growth stages of the Macquarie Plate resemble the kinematic evolution of other microplates and continental breakup, whereby a rapid acceleration in angular velocity took place after its initial formation, followed by a slow decay, suggesting that a decrease in the resistive strength force might have played a significant role in the kinematic evolution of the microplate. The motions of the Macquarie Plate during its growth stages may have been further enhanced by the increased subducting rates along the Hjort Trench, while the Macquarie Plate has exhibited constant growth by seafloor spreading.