--> --> Abstract: Middle and Late Cretaceous Basins of Northeastern New Zealand, by M. G. Laird, J. S. Crampton, and C. Mazengarb; #91015 (1992).

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ABSTRACT: Middle and Late Cretaceous Basins of Northeastern New Zealand

LAIRD, M. G., J. S. CRAMPTON, and C. MAZENGARB, DSIR Geology and Geophysics, Lower Hutt, New Zealand.

In late Albian times, most of the New Zealand microcontinent suffered a change in tectonic regime from one of convergent margin tectonics to one of regional extension, with the creation of new basins. In northeastern New Zealand, however, compressional tectonics persisted in the northern half of a largely marine Cretaceous basin which developed between Kaikoura and East Cape, while extension occurred in its southern part.

In the southern portion of the basin half grabens, infilled with up to 2000 m of late Albian marine sediments of mainly sediment gravity flow origin, formed in the late Albian. Extrusion of intra-plate volcanics accompanied a new Cenomanian-Santonian depositional cycle which was dominated by non-marine to shallow marine transgressive clastics. The Campanian ushered in a period of tectonic subsidence, associated with spreading in the Tasman Sea, which caused continued deepening throughout the remainder of the Cretaceous.

In the north, the Cretaceous strata are inferred to have been emplaced in an accretionary forearc basin and trench which persisted until at least Campanian times. The forearc basin is dominated by transgressive sequences each with basal unconformities, while in the trench sedimentation, dominated by submarine fan sequences, was continuous throughout the entire Cretaceous.

Oil and gas seeps are relatively common throughout the basin. In its northern part, where the only published studies have been carried out, the hydrocarbons are likely to be derived from Cretaceous shales originating in a neritic environment.

 

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)