Journal of Systemics, Cybernetics and Informatics (Aug 2020)
The Australian-Antarctic Discordance (Revisited) – Pressurized vs. Non-Pressurized Ridge System
Abstract
The axial morphology of the Southeast Indian Ridge (SEIR) between Australia and Antarctica changes dramatically along 120oE to 127oE (Fig. 1). At approximately 127oE the ridge changes character along with a difference in water depth of about 1 km. Eastward it changes from a Mid-Atlantic Ridge (MAR) type cross-section to an East-Pacific Rise (EPR) type cross-section (Fig. 2). The MAR profiles a bathymetric low (5- to 20-km wide, 500- to 1500-m-deep rift valley), while the EPR profiles a bathymetric high (10-km-wide, 500-m-high ridge). The MAR type extends westward to approximately 100oE and is called the Australian-Antarctic Discordance (AAD). This geomorphology is unique globally. The MAR is considered a slow-spreading center and like the AAD has similar segmentation characteristics of non-transform (small, oE, and westward propagating rifts are the only non-transform discontinuities.
