Cretaceous-Cenozoic lithostratigraphy of the Chatham Islands

Abstract

New mapping on the Chatham Islands, coupled with many new fossil determinations, has significantly refined our understanding of stratigraphic relationships of the Cretaceous-Cenozoic rocks exposed there. The following units are recognisable: Waihere Bay Group (emended), Tupuangi Formation (redefined; 240-400 m; Late Albian-Santonian), Pitt Island Group (emended), Kahuitara Tuff « 225 m; Campanian-Maastrichtian), Southern Volcanics (>300 m; Campanian-Maastrichtian), unnamed Cretaceous sandstone (>0.3 m; Late (?) Cretaceous), unnamed Haumurian limestone (fissure fills; Late Maastrichtian), Tioriori Group (emended), Takatika Grit (c. 6 m;

Phylogeny and Character Evolution in the New Zealand Endemic Genus Plagianthus (Malveae, Malvaceae)

“…regius 8.42. This prior corresponds to the emergence of the Chatham Islands between 1 and 3 million years ago ( Campbell et al 1994 ;Trewick et al 2007 ;Landis et al 2008 ;Wallis and Trewick 2009 ). We applied Bayesian and maximum likelihood approaches to estimate divergence times at three well-supported nodes.…”

Pushing the limits of neutron tomography in palaeontology: Three-dimensional modelling of in situ resin within fossil plants

“…The Tupuangi Formation has been recorded only from Pitt Island (Māori: Rangiauria; Moriori: Rangiaotea), the second largest island of the archipelago (Figure 1.2). The unit comprises >400 m of siliciclastic strata deposited in a fluviodeltaic system (Campbell et al, 1993;Mays and Stilwell, 2013) during tectonic extension prior to Cretaceous seafloor spreading between Zealandia and Antarctica (Laird and Bradshaw, 2004). The most complete outcrop succession of this unit occurs at Waihere Bay, on the northwestern portion of Pitt Island, and includes the fossil locality recorded herein (Figure 1.3).…”

“…The outcrop succession at Waihere Bay is dominated by interbedded carbonaceous siltstone and quartzofeldspathic fine to medium sandstone (Hay et al, 1970;Campbell et al, 1993;Mays and Stilwell, 2013, figure 4). Dozens of these siltstone horizons have yielded compression fossils of macroflora (Mays et al, 2015a(Mays et al, , 2015b(Mays et al, , 2017 and insects (Stilwell et al, 2016).…”

“…Neutrons were converted to pho- Figure 1.3. 3) Geological map of the Waihere Bay area, northwest Pitt Island, fossil locality recorded in this study is indicated, age estimates from the following sources: Tupuangi Formation (Mildenhall, 1994;Mays and Stilwell, 2013), Kahuitara Tuff (Mildenhall, 1994;Stilwell, 1998), other estimates (Campbell et al, 1993;Panter et al, 2006). Modified from figures 1 and 3 of Mays et al (2015b) with permission.…”

Early Paleocene marine vertebrates from the Wangaloa Formation, South Island, New Zealand

“…indet), represented by plastron and carapace fragments from the Maungataniwha Sandstone of Hawke's Bay (Wiffen 1981). Marine turtles persisted through the Cenozoic with a possible turtle humérus recorded from the Amuri Limestone (Paleocene) of Marlborough (Fordyce 1979) and possible late Paleocene to early Eocene turtle remains in the Red Bluff Tuff of the Chatham Islands (Campbell et al 1988); the lattermost specimen has been re-identified as a probable sponge (E. Fordyce pers. comm.…”