Late Paleocene to middle Eocene foraminiferal biostratigraphy of the Hampden Beach section, eastern South Island, New Zealand

Abstract

The Hampden Beach section is a well-exposed and near-complete 256.5 m thick Paleogene succession of moderately to well-exposed claystone, siltstone, and glauconitic sandstone of Moeraki, Kurinui, and Hampden Formations that spans over 20 m.y. from Teurian to Kaiatan Stages (Paleocene to late Eocene). The sequence was deposited on a passive margin at shelf (Moeraki Formation) to deep upper bathyal (Kurinui Formation) and outermost shelf to upper bathyal paleodepths (Hampden Formation). Paleocirculation was restricted to the north, placing the site under a marginally neritic watermass.The lowest 30 m of the section consists of non-calcareous mudstone of upper Moeraki Formation which is dated as Teurian (Paleocene) by an assemblage of long-ranging, agglutinated foraminifers. Kurinui Formation (30-134.8 m) comprises non-calcareous basal greensand overlain by a fining-upwards succession of slightly calcareous siltstone and claystone. The formation spans the Waipawan, Mangaorapan, and Heretaungan Stages (early to early middle Eocene). The first occurrence of Elphidium hampdenense at 59.7 m marks the base of the Heretaungan Stage. Hampden Formation (134.8-256.5 m) consists of a moderately calcareous basal greensand, grading up into a calcareous siltstone. Hampden Formation contains the Bortonian boundary stratotype which overlies an incomplete or very condensed Porangan interval within the basal greensand, as defined by the presence of the key index species Elphidium saginatum. Bortonian strata are identified by the first appearance of Globigerinatheka index 0.7 m above the base of the formation. The Bortonian/Kaiatan boundary is identified 5.5 m below the top of the section (at 251.0 m) by the highest occurrence of Acarinina primitiva. Revised age control on Acarinina primitiva implies that the top of the Bortonian Stage may be lowered by 2 m.y. to 39 Ma, which represents a significant reduction in the duration of the Bortonian and a tripling in the duration of the Kaiatan Stage-from 1 to 3 m.y. Other abundant microfossils in the section provide scope for further integrated biostratigraphy.

Sequence stratigraphy and controls on reservoir sandstone distribution in an Eocene marginal marine-coastal plain fairway, Taranaki Basin, New Zealand

“…A re-evaluation of the New Zealand Paleogene stages was initiated as part of this study in order to recalibrate the New Zealand timescale against more recently determined absolute ages of the global timescale (Gradstein et al, 2004;Ogg et al, 2008), and to accommodate a redefinition of the base of the Kaiatan Stage by Morgans (2009). Figure 7 illustrates our recalibrated timescale with geomagnetic polarity and miospore zones, with more details presented in Hollis et al (2010).…”

Early Paleogene evolution of terrestrial climate in the SW Pacific, Southern New Zealand

“…[7] The Hampden Beach section is located in the southern part of the Canterbury Basin ( Figure 1). We use the same sample suite reported by Hollis et al [2012] with the stratigraphy described by Morgans [2009]. The sample suite comprises two samples from the Lower to Middle Eocene Kurinui Formation and 10 samples from an interval spanning four climate cycles in the Middle Eocene Hampden Formation [Burgess et al, 2008].…”

Surface-circulation change in the southwest Pacific Ocean across the Middle Eocene Climatic Optimum: inferences from dinoflagellate cysts and biomarker paleothermometry

“…Along with the indirect inferences from modeling and heat distribution based on SST reconstructions, biogeographic patterns of surface-water plankton may be used as a tool to reconstruct surface-ocean circulation. In the Paleogene SO, high levels of endemism characterize a diverse range of fossil groups, including mollusks (Zinsmeister, 1979), radiolarians and diatoms (Harwood, 1991;Lazarus et al, 2008;Pascher et al, 2015), calcareous nannoplankton and planktonic foraminifera (Nelson and Cooke, 2001;Villa et al, 2008), and organic-walled dinoflagellate cysts (dinocysts) (Wrenn and Beckman, 1982;Wrenn and Hart, 1988;Bijl et al, 2011Bijl et al, , 2013a. The endemic dinocyst assemblage from the SO is traditionally referred to as "Transantarctic Flora" (Wrenn and Beckman, 1982).…”