ABSTRACT In the following paper, we apply digital mapping techniques and tephrostratigraphy to correlate marker horizons across the Whanganui Basin, culminating in a new 1:25,000 geological map of the central Rangitikei. This is achieved by (1) compilation of existing research, (2) correlation of major element glass shard datasets to known eruptive products and (3) completion of a three-year field survey. We update and refine existing stratigraphic correlations, focusing on two critical units within the basin succession; namely the Makirikiri Tuff (1.6 Ma) and Kaimatira Pumice Sand (1 Ma) formations. Okehu Group is proposed to cover all strata from Pakihikura to Potaka pumice. Rewa Pumice is placed within its own formation bridging the Makirikiri Tuff and Kaimatira Pumice Sand formations. Mapping and analysis facilitate placement of Coutts Creek Horizon within Rewa Formation. Sub-aerial surfaces and influxes of greywacke and volcaniclastic detritus from c. 1.6 Ma onward provide evidence for an alluvial plain developing at the foot of the uplifting, paleo-axial range. We suggest uplift in the paleo-axial range occurred contemporaneously with the onset of rhyolitic activity at Mangakino caldera (c. 1.6 Ma) so that the first influxes of fluvial conglomerate and volcaniclastics occur in close proximity within the eastern basin succession.

中文翻译：

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新西兰旺格努伊盆地沉积和构造作用的地层限制

摘要在下面的论文中，我们应用数字绘图技术和火山地层学来关联 Whanganui 盆地的标记层，最终绘制了一张新的 1:25,000 中部 Rangitikei 地质图。这是通过 (1) 现有研究的汇编，(2) 主要元素玻璃碎片数据集与已知喷发产品的相关性和 (3) 完成为期三年的实地调查来实现的。我们更新和完善现有地层相关性，重点关注盆地序列中的两个关键单元；即 Makirikiri Tuff (1.6 Ma) 和 Kaimatira Pumice Sand (1 Ma) 地层。Okehu Group 拟覆盖从 Pakihikura 到 Potaka 浮石的所有地层。Rewa Pumice 位于它自己的地层内，连接着 Makirikiri Tuff 和 Kaimatira Pumice Sand 地层。绘图和分析有助于在 Rewa 组内放置 Coutts Creek Horizo​​n。亚空中表面和来自 c. 的灰岩和火山碎屑的流入。1.6 Ma 以后提供了在抬升的古轴系脚下发育冲积平原的证据。我们认为古轴范围的隆起与 Mangakino 破火山口（约 1.6 Ma）流纹岩活动的开始同时发生，因此河流砾岩和火山碎屑岩的第一次流入发生在东部盆地序列中的附近。