Sedimentation of the alternation greywacke and argillite strata in the Porirua district Journal Paper
- Author
- Webby, B.D.
- Year
- 1959
- Journal / Source
- New Zealand Journal of Geology and Geophysics
- Volume
- 2
- Pages
- 461-478
- Summary
- The Lower Mesozoic alternating greywackes and argillites in the Porirua district exhibit graded bedding, lamination, convolute lamination, cross lamination, mud flakes, and current markings. The sediments, rapidly derived from a plutonic terrain, were rapidly transported and deposited by turbidity currents in the New Zealand Geosyncline. The orientation of cross lamination and current markings suggests that the turbidity currents flowed north-north-east, sub-parallel to the present regional tectonic trend. At Porirua, sedimentation was in deep water, a considerable distance from the supplying land mass, and not far from the axis of the geosyncline.