Marine Source Rocks of New Zealand

Andrew P. Murray, C. Norgate, R. E. Summons, and Francis D. A.

Exploration in New Zealand is moving beyond the Taranaki Basin with its mainly terrestrial source rocks. Good to excellent quality marine source rocks exist and have generated oil in the Northland, East Coast and North Taranaki Basins. These high quality source rocks are widespread throughout the late Cretaceous - Paleocene passive margin sequence in these basins as well in offshore Canterbury and the Great South Basin.

This paper details the character, distribution, generative capacity and maturation behaviour of the two main source units and shows how they can be correlated to the numerous seeps and oil impregnations found in the East Coast and Northlands Basins. As well as being useful in basin modelling, kinetic maturation parameters for these two source rock facies help to explain differences in the biomarker and isotopic composition of seep oils and also explain trends in Rock Eval T[max] which are unrelated to maturity. In the East Coast Basin alone, the raw oil potential of the Waipawa Black Shale approaches 80 billion barrels. An understanding of the marine source rocks described here is crucial to evaluating the hydrocarbon prospectivity of New Zealand away from the Taranaki Basin.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California