1:1 000 000 Geological Map

The 1:1 000 000 Geological Map of New Zealand covers Aotearoa New Zealand and includes geology of the Kermadec, Bounty, Snares, Antipodes, Auckland and Campbell islands. The generalised 1:1 000 000 scale has dictated a chronostratigraphic emphasis where geological units are primarily distinguished by age of deposition or emplacement, using international time scale units. Sedimentary units are differentiated and coloured according to their depositional age. Late Cretaceous and younger intrusive and volcanic rock units, including widespread ignimbrite deposits in the North Island, are coloured shades of red to pink rather than the colours assigned to sedimentary units of comparable ages.

Metamorphic rock units are portrayed according to their known or inferred protolith age. Major allochthonous units (Northland and East Coast allochthons) are distinguished by having a diagonal white stripe overprint on the underlying protolith body colour. Where deformation has sufficiently disassociated and mixed protoliths, the allochthon “matrix” is coloured grey, rather than by emplacement age. Basement sedimentary rocks are portrayed according to age and tectonostratigraphic terrane affinity.

The uppermost deposit or rock unit more than about 10 m thick has been depicted and thinner veneers of soils, tephra, loess and scree are commonly omitted. Geological units are represented as polygons with associated attributes that include stratigraphic affiliation, rock type and deposition or emplacement age.

Faults are mapped, including most of the known active faults, but out of necessity there has been significant “thinning” where there are dense clusters of faults. Faults are represented by line features with attributes describing accuracy, type, orientation, name and age, magnitude and sense of movement.

In 2009, GNS Science began the compilation of new 1:1 000 000 geological maps covering New Zealand. The two maps were created by generalising and simplifying the 1:250 000 Geological Map of New Zealand.

Each of the 21 1:250 000 geological maps was simplified for reproduction at 1:1 000 000. This involved redrawing and smoothing complicated geological boundaries, removing small or very thin polygons and reducing dense clusters of fault and other data.
Digital versions of the 1:1 000 000 maps will be updated periodically as new data and interpretation become available.

The 1:1 000 000 geological map is available in several formats (maps only – either flat or folded, maps and text, and digital data) from the GNS Science Online Shop(external link).

The map is also viewable through the New Zealand geology webmap application(external link). GIS users can purchase the digital data which comes packaged with a choice of free GIS viewers or can access the data as Web Map Services and Web Feature Services from ArcGIS Server. GIS layerfiles that reference the web services are available for use in ArcGIS (ArcMap and ArcGIS Pro) and QGIS.  Metadata that describes the GIS data and provides access to services and layerfiles is available from the GNS Science Dataset Catalogue (link(external link)).