Date of this Version
Richardson, C. 2018 Integrated Geophysical Analysis of the New Caledonia Trough with Implications for the Geologic History and Continental Status of Zealandia. Undergraduate Honors Thesis. University of Nebraska-Lincoln.
The Southwest Pacific Ocean is a complex region which has been characterized by the creation and consumption of marginal oceanic basins through back-arc spreading and slab rollback processes. Zealandia, a 4,900,000 km2 landmass within the region, has been suggested to be Earth’s previously unidentified seventh geologic continent based on its elevation relative to surrounding oceanic crust, diverse geology, crustal structure, and extent. Arguments against this classification cite the boundary between the Australian and Pacific tectonic plates, which divides Zealandia into a northern and southern portion, as well as a feature known as the New Caledonia Trough (NCT) which lies in the northern portion and may be characteristic of oceanic crust. The geophysical analysis presented in this study serves as an investigation into the crustal nature of the NCT through a spatial analysis of the gravity and magnetic fields in the region, as well as a 2D subsurface model that integrates bathymetry, gravity, magnetic, seismic reflection, seismic refraction, and well data. This analysis suggests that the crust within the NCT is oceanic in nature, and explores the implications that this conclusion has for the continental status of Zealandia.