The Late Tertiary and Quaternary Geological History of the Hutt Valley

Abstract

Study of the geology of the Wellington area is complicated by the total absence of covering strata, complexity of structure, homogeneity of the rocks and paucity, or lack, of fossils. Formerly, the Wellington district was thought of as an area of undermass rocks that had remained emergent throughout the Tertiary. However, in 1946, C.O. Hutton discovered an infaulted strip of lower Oligocene (Whaingaroan) rocks near Paraparaumu [described by Macpherson, 1948], being a remnant of a formerly extensive development of cover beds, deformed in the "Kaikoura Orogeny". An indication of the area studied in this report is given in fig.1. As the study progressed, it became increasingly apparent that the elucidation of the geologic history of the Lower Hutt - Port Nicholson depression was dependent on study of critical areas outside the Lower Hutt area. Thus the original scope of the work was extended and detailed examination has been made of the Korokoro - Belmont - Haywards - Trentham - Lower Hutt - Eastbourne area and reconnaissance examination of peripheral areas. As most of these examinations are of a geomorphological nature, extensive use has been made of photographic illustrations.