A Geological Map of Te Kuiti Sheet BF33 at 1:50 000 scale, King Country Basin, New Zealand
Whiteman, B. D. (2017). A Geological Map of Te Kuiti Sheet BF33 at 1:50 000 scale, King Country Basin, New Zealand (Thesis, Master of Science (MSc)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/11633
Permanent Research Commons link: https://hdl.handle.net/10289/11633
The principal research objective of this thesis has been to produce a new 1:50 000 scale geological map of topographic map BF33 (Te Kuiti Sheet), one of the new Topo 50 topographic map sheets covering New Zealand. The geological map was produced through a conventional field mapping approach coupled with structure contouring using ArcGIS software. Hence the physical map printed at a 1:50 000 scale is backed-up by a database in ArcGIS, which is scaleless. The map illustrates the distribution and extent of Cenozoic stratigraphic units (Te Kuiti Group, Mahoenui Group, Mokau Group, Otunui Formation and Pakaumanu Group ignimbrites) and Jurassic basement in the field area. The map represents significant revision of the distribution of units and occurrence of faults compared with previous geological maps of the area, including the 1:50 000 field sheet prepared for the production of the new 1:250 000 Waikato QMAP sheet (Edbrooke, 2005). Several new normal faults east of Te Kuiti have been identified and mapped, as well as minor changes in the location of Waipa Fault. A west-east trending syncline has also been identified and mapped in the southern part of the field area. Stratigraphic columns through Te Kuiti, Mahoenui and Mokau groups, and Otunui Formation, have been drawn for numerous sites, appealing in some cases to previously produced columns. Facies descriptions of these successions have also been made and environments of deposition interpreted from them. The Oligocene to Earliest Miocene (Whaingaroan-Waitakian stages) Te Kuiti Group is comprised of basal coal measures, calcareous sandstone, calcareous siltstone and limestone facies, which accumulated in fluvial environments (coal measures) and mainly in shelf environments. The Early Miocene (Otaian Stage) Mahoenui Group is comprised mainly of mudstone facies (Taumatamaire Formation) with some interbedded occurrences of turbidites. Limestone facies (Cherry Tree Limestone Member), occurs near the base of Taumatamaire Formation in the close vicinity of Te Kuiti, comprising redeposited beds. The Mahoenui succession accumulated in upper bathyal environments as the basin rapidly subsided. Bexley Sandstone (Mokau Group) comprises mainly sandstone facies with interbedded mudstonesandstone within Mangarino Member, which occurs in the lower part of the formation north of Te Kuiti. Bexley Sandstone accumulated in shallow marine and marginal marine (Mangarino Member) environments within a transgressive systems tract. Otunui Formation comprises mainly silty sandstone facies. A shellbed at the base of the formation, known as Mangarara Formation, accumulated as a transgressive shoreface to innermost shelf deposit; it is conformably overlain by thick bioturbated silty fine sandstone facies that accumulated in shelf and upper bathyal environments. From its degree of induration, a 2 km thick succession accumulated above Otunui Formation (e.g. Mt Messenger Formation to Matemateaonga Formation), but it was eroded prior to emplacement of Early Pleistocene Pakaumanu Group ignimbrites sourced from Taupo Volcanic Zone. Individual ignimbrite eruptives have not been differentiated on the geological map. A landscape with considerable relief has developed upon the ignimbrite units and Holocene alluvium has accumulated in valley floors.
University of Waikato
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