Geology Of The Auckland Area

Edbrooke, S.W. 2001
Geology of the Auckland area. Lower Hutt: Institute of Geological & Nuclear Sciences Limited.
Institute of Geological & Nuclear Sciences 1:250,000 geological map 3
74 p. + 1 fold. map

Abstract

The Auckland 1:250,000 geological map covers an impressive 11,800 km² of the greater Auckland area, including:

• Parts of southern Northland and northern Waikato
• Coromandel Peninsula
• Adjacent offshore areas and islands of the Hauraki Gulf, such as Great Barrier Island

This region, located in the north of the North Island, New Zealand, is shaped primarily by late Cenozoic block faulting and volcanicity. The landscape is characterized by four major geomorphic elements:

1. Mesozoic and Cenozoic Highlands

   • Elevated blocks including the Hunua, Hapuakohe, and Taupiri ranges in South Auckland and North Waikato
   • Rolling hill country in North Auckland and West Waikato
   • Rugged, well-dissected volcanic landscapes of the Coromandel Range, Great Barrier Island, and Waitakere Ranges

2. Pliocene and Quaternary Barrier Dune Complexes

   • Found along much of the west coast
   • Also present in the western Bay of Plenty

3. Extensive Lowland Areas

   • Infills of Pliocene and Quaternary sediments
   • Includes the Lower Waikato and Manukau lowlands, as well as the Hauraki Plains

4. Quaternary Basalt Fields

   • Located in Auckland and South Auckland
   • Feature gently rolling surfaces with volcanic cones rising above them

Offshore Features:

• The seafloor west of Auckland slopes gently westward for 20-40 km to the shelf edge
• Water depth transitions from approximately 150 m at the shelf edge to over 1000 m in deeper areas