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Terrestrial methane (CH 4) emissions may have increased during the Paleocene-Eocene Thermal Maximum (PETM; ca. 56 Ma) and promoted additional warming, especially in the high latitudes. Although there is evidence for increased CH 4 cycling in a single Northern Hemisphere site, whether enhanced methane cycling was globally widespread is unknown because there have been no subsequent investigations. The mechanism of CH4 release is also unknown because a direct comparison between temperature and CH 4 cycling has so far not been possible. Here we use biomarkers to reconstruct temperature change and CH 4 cycling in a new PETM-aged succession in New Zealand. Our results indicate that the stable carbon isotopic composition (δ 13C) of bacterial hopanoids decreased to very low values (−60‰) during the onset of the PETM, indicating enhanced consumption of CH 4. These values are much lower than found in modern wetlands and suggest a major perturbation of the CH 4 cycle during the onset of the PETM. Low hopanoid δ 13C values do not persist into the early Eocene, despite evidence for elevated temperatures. This indicates that the terrestrial CH 4 cycle operates differently during transient compared to gradual warming events. Enhanced CH 4 cycling during the PETM may help to resolve the temperature data-model mismatch in the high latitudes and could yield higher estimates of Earth system sensitivity than expected from CO 2alone.

A reconstruction of terrestrial temperature and precipitation for the New Zealand landmass over the past ∼30 million years is produced using pollen data from >2000 samples lodged in the New Zealand Fossil Record Electronic Database and modern climate data of nearest living relatives. The reconstruction reveals a warming trend through the late Oligocene to early Miocene, peak warmth in the middle Miocene, and stepwise cooling through the late Neogene. Whereas the regional signal in our reconstruction includes a ∼5–10° northward tectonic drift, as well as an increase in high altitude biomes due to late Neogene and Pliocene uplift of the Southern Alps, the pattern mimics inferred changes in global ice extent, which suggests that global drivers played a major role in shaping local vegetation. Importantly, seasonal temperature estimates indicate low seasonality during the middle Miocene, and that subsequent Neogene cooling was largely due to cooler winters. We suggest that this may reflect increased Subantarctic influence on New Zealand vegetation as the climate cooled.

Although significant angiosperm diversification occurred during the Cretaceous, the timing of subsequent expansion of flowering plants across austral landscapes is poorly understood due to a lack of continuous records. Our new 100 million year composite pollen record from New Zealand shows a striking temporal separation between diversification and ecological dominance in this group. While Cretaceous diversification was closely followed by an increase in angiosperm frequency, maximum frequency did not occur for another 40 million years, during the Eocene. The two most consistent intervals of floral change over the 100 Myr record occur within the middle Eocene and the middle Miocene. Notable floral changes also occur around the Cretaceous-Paleogene, Paleocene-Eocene, and Pliocene-Pleistocene transitions. These major changes occur in the context of the northward drift of Zealandia across the Antarctic circle, global warming in the early Paleogene, and middle Miocene, and onset of Southern Ocean circumpolar circulation and cooling in the late Paleogene.

Stratigraphic drilling from the McMurdo Ice Shelf in the 2006/2007 austral summer recovered a 1284.87 m sedimentary succession from beneath the sea floor. Key age data for the core include magnetic polarity stratigraphy for the entire succession, diatom biostratigraphy for the upper 600 m and 40Ar/39Ar ages for in-situ volcanic deposits as well as reworked volcanic clasts. A vertical seismic profile for the drill hole allows correlation between the drill hole and a regional seismic network and inference of age constraint by correlation with well‐dated regional volcanic events through direct recognition of interlayered volcanic deposits as well as by inference from flexural loading of pre‐existing strata. The combined age model implies relatively rapid (1 m/2–5 ky) accumulation of sediment punctuated by hiatuses, which account for approximately 50% of the record. Three of the longer hiatuses coincide with basin‐wide seismic reflectors and, along with two thick volcanic intervals, they subdivide the succession into seven chronostratigraphic intervals with characteristic facies: 1. The base of the cored succession (1275–1220 mbsf) comprises middle Miocene volcaniclastic sandstone dated at approx 13.5 Ma by several reworked volcanic clasts; 2. A late-Miocene sub-polar orbitally controlled glacial–interglacial succession (1220–760 mbsf) bounded by two unconformities correlated with basin‐wide reflectors associated with early development of the terror rift; 3. A late Miocene volcanigenic succession (760–596 mbsf) terminating with a ~1 my hiatus at 596.35 mbsf which spans the Miocene–Pliocene boundary and is not recognised in regional seismic data; 4. An early Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession (590–440 mbsf), separated from; 5. A late Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession (440–150 mbsf) by a 750 ky unconformity interpreted to represent a major sequence boundary at other locations; 6. An early Pleistocene interbedded volcanic, diamictite and diatomite succession (150–80 mbsf), and; 7. A late Pleistocene glacigene succession (80–0 mbsf) comprising diamictite dominated sedimentary cycles deposited in a polar environment.

Twelve fossil species of Proteaceous pollen, predominantly attributable to Proteacidites and Beaupreaidites, were recovered from the Maastrichtian-Paleocene sedimentary succession of the Garden Cove Formation on Campbell Island, the southernmost landmass of the Zealandia continent. Among these are two new species, Proteacidites campbellensis and Proteacidites hortisinus. The high diversity of Proteaceae pollen in the sediments encompassing the Cretaceous-Paleogene boundary on Campbell Island is consistent with the fossil record from neighbouring landmasses but strongly contrasts with the impoverished record of the family in the extant New Zealand flora. Examples of Beauprea- and Knightia-like pollen in the Campbell Island assemblages confirm the presence of these lineages on Zealandia by the end of the Cretaceous and suggest that their present endemism in New Caledonia and New Zealand can be explained in terms of relictual vicariant distributions, perhaps modified by northward tracking of warmer climates on Zealandia through the Cenozoic. (C) 2011 Elsevier Ltd. All rights reserved. (Less)

An early Miocene (ca. 23 Ma) flora from the Foulden Maar diatomite deposit, Otago, southern New Zealand contains numerous organically-preserved fossil leaf compressions, flowers and fruits. A fossilised male partial lax inflorescence carrying in situ pollen of the type Nyssapollenites endobalteus (McIntyre) Kemp & Harris is assigned to Euphorbiaceae, subfamily Acalyphoideae, tribe Acalypheae. Leaves from the same site are referred to the Mallotus–Macaranga clade (Euphorbiaceae: Acalyphoideae) on the basis of leaf architecture and epidermal features and described as Malloranga fouldenensis gen. et sp. nov. In addition, euphorbiaceous trilobed capsular fruits are assigned to the form genus Euphorbiotheca as E. mallotoides sp. nov. and an immature infructescence is also described. The inflorescence, pollen, leaves and fruits blew or fell into a small enclosed maar lake and must have been derived from trees or shrubs growing around the lake margin.

High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from the Maungataniwha Sandstone Member of the Tahora Formation in Mangahouanga Stream, Hawkes Bay, New Zealand. A palynological investigation of strata exposed along Mangahouanga Stream and of transported boulders hosting vertebrate fossils reveals well-preserved assemblages dominated by terrestrial pollen and spores but also including marine dinoflagellate cysts in some samples. The palynofacies are strongly dominated by wood fragments including charcoal; one outcrop sample and the sample taken from a boulder hosting plesiosaur vertebrae contain entirely terrestrially derived palynoassemblages, suggesting a freshwater habitat for at least some of the plesiosaurs. The host unit spans the Santonian to lowermost Maastrichtian, while the key pollen taxa Nothofagidites senectus and Tricolpites lilliei, together with the dinocyst Isabelidinium pellucidum and the megaspore Grapnelispora evansii, indicate a late Campanian...

The Late Cretaceous Rakopi Formation (Pakawau Group) represents one of the most important petroleum source rock units and a potential reservoir unit in the highly prospective Taranaki Basin. This paper presents a predominantly outcrop‐based study of the sedimentology, petrography, stratigraphy, and depositional environment of the Rakopi Formation in the Paturau River and Pakawau areas of northwest Nelson, southern Taranaki Basin, together with some preliminary insights into the stratigraphie architecture of the Pakawau Group on a more basin‐wide scale. The Rakopi Formation is interpreted here as a terrestrial deposit, representing sedimentation in fluvial channels and their associated overbank and levee environments. However, the presence of dinoflagellates, glauconite, and elevated coal seam sulfur contents is evidence for periodic marine influence during deposition. This could be explained by a low‐gradient coastal plain paleogeography, crossed by a series of rivers and their associated floodpl...

RAINE, J.I., June, 2008. Zonate lycophyte spores from New Zealand Cretaceous to Paleogene strata. Alcheringa 32, 99–127. ISSN 0311-5518. The morphology, taxonomy, and stratigraphic occurrence of zonate lycophytic spores recovered from New Zealand Cretaceous to Paleogene strata are reviewed. Five species of Perotrilites include the new species Perotrilites otagoensis described from the Late Cretaceous, and Kraeuselisporites papillatus Harris now transferred to this genus. Kraeuselisporites is represented by a new Late Cretaceous species, Kraeuselisporites alexii. Evansispora, based on the new species Evansispora senonica from Late Cretaceous to Paleocene strata, is proposed for distally reticulate zonate spores of the type met with in modern Lycopodium volubile G. Forst.; Eocene and younger populations are distinguished as Evansispora cenozoica sp. nov. Kraeuselisporites laceratus Norris is transferred to Evansispora. Waiparaspora is established for reticulate zonate spores of different morphology, based o...

A new genus and species, Wairarapaia mildenhallii Cantrill et Raine, is established for two ovulate cones with helically inserted cone‐scale complexes and a centrally positioned inverted ovule from the Cretaceous (late Albian to Cenomanian) of New Zealand. The cones are up to 60 mm in diameter with wedge‐shaped cone‐scale complexes, at least 18 mm long by 8 mm wide and with narrow wings and a short apical spine. The ovules sit centrally in a distinct hollow on the cone‐scale complex surface but are attached only by a basal pad of tissue. Ovules are oriented with the micropyle facing the cone axis. They have short lateral wings and are interpreted to be dehiscent from the cone‐scale complex. The cone organization suggests affinities with the Araucariaceae. The seed has a narrow attachment point similar to that seen in Agathis and Wollemia and quite unlike that of Araucaria, where the ovule is embedded in the cone‐scale complex. Recent phylogenetic analyses suggest that features used to assign fossil taxa t...

The Pongaroa‐Akitio area, Northern Wairarapa, North Island, New Zealand, is part of the exposed East Coast Deformed Belt at the obliquely convergent plate boundary of the Hikurangi margin. The sedimentary succession includes an allochthonous unit of Early Cretaceous greywacke basement resting on latest Cretaceous rocks. Since the unit's basal contact is subparallel to the bedding of the strata it overlies, the allochthon is inferred to be an unrooted gliding nappe similar to allochthonous outliers described in Northland and the Raukumara Peninsula. The southward emplacement of this “Greywacke Nappe” is supported by structural markers in the body of the nappe and is well dated as earliest Miocene by the youngest rocks involved, which are earliest Miocene (Waitakian; c. Aquitanian), and because Otaian‐Altonian (c. Burdigalian) faults postdate nappe emplacement. This thin‐skinned tectonic phase immediately preceded inception of dextral strike‐slip faulting along northeast‐trending Otaian‐Altonian (B...

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40 Ar/ 39 Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition.

A quantitative biostratigraphic analysis of the Paleocene to lower Miocene of the Taranaki Basin has enabled high precision in correlation, zonation, and assessment of depositional history. Biostratigraphic range-end events, based on 493 taxa in cuttings samples from eight wells, representing foraminifera, nannofossils, dinoflagellates, and miospores, were culled to 87 range-top events that were then analyzed by deterministic (constrained optimization [CONOP]) and probabilistic (ranking and scaling [RASC]) techniques. All except 16 of the events are found to have relatively good biostratigraphic reliability. The RASC probable sequence and probabilistic zonation give the best estimate of the sequence of events and zones to be encountered in any new well in the basin and a precise biostratigraphic scale for future exploration. The CONOP composite section, which matches well with that derived by conventional graphic correlation (GRAPHCOR), is readily related to previous zonations based on maximum ranges of taxa but gives an order-of-magnitude greater precision. CONOP provides a precise correlation framework and reveals marked variation in thickness of stages across the basin. When the composite section is calibrated against the time scale, basinwide changes in depositional rate are revealed. The upper Eocene and Oligocene mark an interval of slow deposition, whereas the Miocene marks a sharp increase in deposition. The time-calibrated composite section enables unconformities and changes in depositional rate found in individual wells to be precisely estimated. Many new unconformities are indicated, particularly in the Paleocene and Eocene.

Three types of fossil fern fronds bearing sporangia with in situ spores are described from the late Eocene Pikopiko Fossil Forest, southern New Zealand. They are referable to the extant fern genus Thelypteris subgenus Cyclosorus (Thelypteridaceae) and an extinct fern of uncertain affinity. The matching of Thelypteris (Cyclosorus) macrofossils to the spore form taxon Laevigatosporites ovatus is recognised for the first time. Five additional fern taxa, including another probable Blechnum, are distinguished on the basis of sterile foliage. The Pikopiko site is one of the richest known Cenozoic fern floras globally and the diversity and abundance of ferns (eight fern macrofossil parataxa and 20 miospore types) implies that ferns dominated the evergreen, tall forest understorey as in modern New Zealand rainforests. At least 40% of modern New Zealand fern families are represented in this 35 Ma flora and the discovery of fronds with in situ spores of a type recorded throughout the Cenozoic in New Zealand supports a long history for some fern genera in the region. The abundance of ferns, epiphyllous fungi on many leaves and the presence of palms is evidence for warm humid conditions in Late Eocene New Zealand.