Geology topics

Research about New Zealand

Source-linked reports with geographic coverage including New Zealand.

111 records · Page 7Linked to original sources

USGS1973

The Dun Mountain ultramafic belt Permian oceanic crust and upper mantle in New Zealand

Geologic evidence suggests that the Dun Mountain ultramafic belt in New Zealand is the basal part of a Lower Permian ophiolite suite. By analogy with other ophiolite suites, and as a result of marine geophysical studies of the present ocean basins, the ophiolite is believed to represent oceanic crust and upper mantle upon which the Upper Permian Maitai Group was deposited. After this, much of the ultramafic belt was extensively deformed to tectonic melange.

Journal of Research of the U.S. Geological Survey↗

USGS1971

Remanent magnetization and susceptibility of late Cenozoic rocks from New Zealand

Measurements of magnetic remanence and susceptibility were made on 176 samples of volcanic rocks from 22 late Cenozoic formations from the North Island. Intensities of remanence, susceptibilities, and Q ratios are highly variable in both the ignimbrites and andesites and their ranges overlap, indicating that the magnetic anomalies produced by ignimbrite bodies would be difficult to distinguish from those produced by andesite flows. An analysis of the directions of magnetization of the ignimbrites indicates that groups of petrologically distinct ignimbrites probably formed during the same volcanic episode.

North Island↗

USGS1969

A paleomagnetic study of secular variation in New Zealand

Ancient secular variation in New Zealand was determined from paleomagnetic measurements on 22 volcanic formations with ages of less than 0.68 m.y. The angular standard deviation from the field of an axial dipole is 13.2° with 95% confidence limits between 10.9° and 16.7°. The angular standard deviation of the corresponding virtual geomagnetic poles is 19.6° with confidence limits between 16.2° and 24.7°. These values are larger than those predicted by most models for secular variation. No difference was detected between the angular secular variation in New Zealand and that at the same latitude in North America.

Earth and Planetary Science Letters↗