A geochemical and biostratigraphic approach has been applied to investigate the spatial and stratigraphic variability of Palaeogene sandstones from key wells in Taranaki Basin, New Zealand. Chronostratigraphic control is predominantly based on miospore zonation, while differences in the composition of Paleocene and Eocene sandstones are supported by geochemical evidence. Stratigraphic changes are manifested by a significant decrease in Na2O across the New Zealand miospore PM3b/MH1 early Eocene zonal boundary, at approximately 53.5 Ma. The change in Na2O is associated with a decrease in baseline concentrations of many other major (MnO, CaO, TiO2) and trace elements, and is interpreted to reflect a significant change in sandstone maturity. Paleocene sandstones are characterized by abundant plagioclase (albite and locally Na–Ca plagioclase), significant biotite and a range of heavy minerals, while Eocene sandstones are typically quartzose, with K-feldspar dominant over plagioclase, low mica contents and rare heavy minerals comprising a resistant suite. This change could reflect a change in provenance from local plutonic basement during the Paleocene Epoch to relatively quartz- and K-feldspar-rich granitic sources during Eocene time. However, significant quartz enrichment of Eocene sediment was also likely due to transportation reworking/winnowing along the palaeoshoreface and enhanced chemical weathering, driven in part by long-term global warming associated with the Early Eocene Climatic Optimum. The broad-ranging changes in major-element composition overprint local variations in sediment provenance, which are only detectable from the immobile trace-element geochemistry.

中文翻译：

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研究砂岩成分随时间的区域变化的地球化学和生物地层学方法；新西兰塔拉纳基盆地古新世-始新世地层的一个例子

已应用地球化学和生物地层学方法研究新西兰塔拉纳基盆地关键井古近系砂岩的空间和地层变异性。年代地层控制主要基于微孢子带，而古新世和始新世砂岩成分的差异得到地球化学证据的支持。地层变化表现为 Na 显着减少2O 穿过新西兰微孢子 PM3b/MH1 早始新世纬向边界，约 53.5 Ma。Na的变化2O 与许多其他主要物质（MnO、CaO、TiO2) 和微量元素，并被解释为反映砂岩成熟度的显着变化。古新世砂岩的特征是大量斜长石（钠长石和局部 Na-Ca 斜长石）、大量黑云母和一系列重矿物，而始新世砂岩通常为石英质，钾长石占优势，超过斜长石，云母含量低，稀有重矿物包括抗性套件。这种变化可能反映了从古新世时期的局部深成岩基底到始新世时期相对富含石英和钾长石的花岗岩来源的物源变化。然而，始新世沉积物的显着石英富集也可能是由于沿古海岸面的运输改造/风选和增强的化学风化作用，部分原因是与早始新世气候最佳期相关的长期全球变暖。主要元素组成的广泛变化覆盖了沉积物来源的局部变化，这些变化只能从固定的微量元素地球化学中检测到。