We are excited to invite you to the 14th seminar of the 2025 Geology and Geophysics Seminar Series, featuring Nick Mortimer, a petrologist who has spent most of his career with GNS Science. Nick will be presenting on “Metamorphic core complexes, from Nevada to New Zealand“. In this engaging talk, he will present on the evolution of metamorphic core complexes, highlight recent findings from the Dunstan Range in Otago, New Zealand, and discuss their significance for understanding the tectonic history of Zealandia.
Date: July 30, 2025
Time: 11:00 a.m. – 12:00 p.m. AEST, Sydney Time
Location: Room 449 (Conference Room), Madsen Building (F09), School of Geosciences
or Online (Join via zoom)
We look forward to seeing you there in person or joining us online!
https://uni-sydney.zoom.us/j/84796471781?from=addon
Metamorphic core complexes, from Nevada to New Zealand
Abstract
Metamorphic core complexes (MCCs) were first identified as enigmatic arch-like geological features in the western U.S.A. comprising a ductilely-deformed, lower plate metamorphic core, separated from brittlely-deformed unmetamorphosed upper plate by a gently-dipping detachment fault and/or mylonite zone.
By the 1990s MCCs were seemingly everywhere, including mid-ocean ridges and New Zealand, and interpreted as being geological records of hyperextension. One of my more recent published papers has confirmed the presence of a Late Cretaceous MCC in the Otago Schist of New Zealand, a schist belt usually interpreted as a Jurassic-Early Cretaceous convergent accretionary wedge.
This talk will review the development of ideas on metamorphic core complexes, show how the Dunstan Range, near Cromwell, Otago, New Zealand, came to be identified as New Zealand’s fourth Late Cretaceous MCC, and reveal how MCCs fit into the broader tectonic development of Zealandia.
Graphical Abstract
