• journal_title：Geology
• Contributor：Peter A. Rivizzigno ; Jeffrey A. Karson
• Publisher：Geological Society of America
• Date：2004-
• Format：text/html
• Language：en
• Identifier：10.1130/G19906.1
• journal_abbrev：Geology
• issn：0091-7613
• volume：32
• issue：2
• firstpage：125

The Macquarie Island ophiolite is an uplifted block of oceanic crust formed at the Australia-Pacific spreading center between 12 and 9 Ma. The sense of motion and geological processes across this plate boundary reflect an evolution from orthogonal spreading through progressively more oblique spreading to the present-day transpressional regime. The crust that makes up the island was formed during an interval of oblique spreading along east-trending spreading segments punctuated by a series of northwest-trending discontinuities. The discontinuities are accommodation zones marked by oblique-slip dextral-normal faults, localized dikes and lava flows, and extensive hydrothermal alteration, indicating that these zones were active near the spreading axis. These features provide a window into the internal structure of oceanic crust generated by oblique spreading.