Phonon dispersion and electron-phonon interaction in peanut-shaped fullerene polymers

We reveal that the periodic radius modulation peculiar to one-dimensional (1D) peanut-shaped fullerene (C$_{60}$) polymers exerts a strong influence on their low-frequency phonon states and their interactions with mobile electrons. The continuum approximation is employed to show the zone-folding of phonon dispersion curves, which leads to fast relaxation of a radial breathing mode in the 1D C$_{60}$ polymers. We also formulate the electron-phonon interaction along the deformation potential theory, demonstrating that only a few set of electron and phonon modes yields a significant magnitude of the interaction relevant to the low-temperature physics of the system. The latter finding gives an important implication for the possible Peierls instability of the C$_{60}$ polymers suggested in the earlier experiment.Comment: 9 pages, 8 figure

Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand

The middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand

Pliocene Te Aute limestones, New Zealand: Expanding concepts for cool-water shelf carbonates

Acceptance of a spectrum of warm- through cold-water shallow-marine carbonate facies has become of fundamental importance for correctly interpreting the origin and significance of all ancient platform limestones. Among other attributes, properties that have become a hallmark for characterising many Cenozoic non-tropical occurrences include: (1) the presence of common bryozoan and epifaunal bivalve skeletons; (2) a calcite-dominated mineralogy; (3) relatively thin deposits exhibiting low rates of sediment accumulation; (4) an overall destructive early diagenetic regime; and (5) that major porosity destruction and lithification occur mainly in response to chemical compaction of calcitic skeletons during moderate to deep burial. The Pliocene Te Aute limestones are non-tropical skeletal carbonates formed at paleolatitudes near 40-42°S under the influence of commonly strong tidal flows along the margins of an actively deforming and differentially uplifting forearc basin seaway, immediately inboard of the convergent Pacific-Australian plate boundary off eastern North Island, New Zealand. This dynamic depositional and tectonic setting strongly influenced both the style and subsequent diagenetic evolution of the limestones. Some of the Te Aute limestones exhibit the above kinds of "normal" non-tropical characteristics, but others do not. For example, many are barnacle and/or bivalve dominated, and several include attributes that at least superficially resemble properties of certain tropical carbonates. In this regard, a number of the limestones are infaunal bivalve rich and dominated by an aragonite over a calcite primary mineralogy, with consequently relatively high diagenetic potential. Individual limestone units are also often rather thick (e.g., up to 50-300 m), with accumulation rates from 0.2 to 0.5 m/ka, and locally as high as 1 m/ka. Moreover, there can be a remarkable array of diagenetic features in the limestones, involving grain alteration and/or cementation to widely varying extents within any, or some combination of, the marine phreatic, burial, and meteoric diagenetic environments, including locally widespread development of meteoric cement sourced from aragonite dissolution. The message is that non-tropical shelf carbonates include a more diverse array of geological settings, of skeletal and mineralogical facies, and of diagenetic features than current sedimentary models mainly advocate. While several attributes positively distinguish tropical from non-tropical limestones, continued detailed documentation of the wide spectrum of shallow-marine carbonate deposits formed outside tropical regions remains an important challenge in carbonate sedimentology

Late Miocene to early Pliocene biofacies of Wanganui and Taranaki Basins, New Zealand: Applications to paleoenvironmental and sequence stratigraphic analysis

The Matemateaonga Formation is late Miocene to early Pliocene (upper Tongaporutuan to lower Opoitian New Zealand Stages) in age. The formation comprises chiefly shellbeds, siliciclastic sandstone, and siltstone units and to a lesser extent non-marine and shallow marine conglomerate and rare paralic facies. The Matemateaonga Formation accumulated chiefly in shelf paleoenvironments during basement onlap and progradation of a late Miocene to early Pliocene continental margin wedge in the Wanganui and Taranaki Basins. The formation is strongly cyclothemic, being characterised by recurrent vertically stacked facies successions, bounded by sequence boundaries. These facies accumulated in a range of shoreface to mid-outer shelf paleoenvironments during conditions of successively oscillating sea level. This sequential repetition of facies and the biofacies they enclose are the result of sixth-order glacio-eustatic cyclicity. Macrofaunal associations have been identified from statistical analysis of macrofossil occurrences collected from multiple sequences. Each association is restricted to particular lithofacies and stratal positions and shows a consistent order and/or position within the sequences. This pattern of temporal paleoecologic change appears to be the result of lateral, facies-related shifting of broad biofacies belts, or habitat-tracking, in response to fluctuations of relative sea level, sediment flux, and other associated paleoenvironmental variables. The associations also show strong similarity in terms of their generic composition to biofacies identified in younger sedimentary strata and the modern marine benthic environment in New Zealand

History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic--a synthesis

The New Zealand sector of the Southern Ocean (NZSSO) has opened about the Indian-Pacific spreading ridge throughout the Cenozoic. Today the NZSSO is characterised by broad zonal belts of antarctic (cold), subantarctic (cool), and subtropical (warm) surface-water masses separated by prominent oceanic fronts: the Subtropical Front (STF) c. 43deg.S, Subantarctic Front (SAF) c. 50deg.S, and Antarctic Polar Front (AAPF) c. 60deg.S. Despite a meagre database, the broad pattern of Cenozoic evolution of these fronts is reviewed from the results of Deep Sea Drilling Project-based studies of sediment facies, microfossil assemblages and diversity, and stable isotope records, as well as from evidence in onland New Zealand Cenozoic sequences. Results are depicted schematically on seven paleogeographic maps covering the NZSSO at 10 m.y. intervals through the Cenozoic. During the Paleocene and most of the Eocene (65-35 Ma), the entire NZSSO was under the influence of warm to cool subtropical waters, with no detectable oceanic fronts. In the latest Eocene (c. 35 Ma), a proto-STF is shown separating subantarctic and subtropical waters offshore from Antarctica, near 65deg.S paleolatitude. During the earliest Oligocene, this front was displaced northwards by development of an AAPF following major global cooling and biotic turnover associated with ice sheet expansion to sea level on East Antarctica. Early Oligocene full opening (c. 31 Ma) of the Tasmanian gateway initiated vigorous proto-circum-Antarctic flow of cold/cool waters, possibly through a West Antarctic seaway linking the southern Pacific and Atlantic Oceans, including detached northwards "jetting" onto the New Zealand plateau where condensation and unconformity development was widespread in cool-water carbonate facies. Since this time, a broad tripartite division of antarctic, subantarctic, and subtropical waters has existed in the NZSSO, including possible development of a proto-SAF within the subantarctic belt. In the Early-early Middle Miocene (25-15 Ma), warm subtropical waters expanded southwards into the northern NZSSO, possibly associated with reduced ice volume on East Antarctica but particularly with restriction of the Indonesian gateway and redirection of intensified warm surface flows southwards into the Tasman Sea, as well as complete opening of the Drake gateway by 23 Ma allowing more complete decoupling of cool circum-Antarctic flow from the subtropical waters. During the late Middle-Late Miocene (15-5 Ma), both the STF and SAF proper were established in their present relative positions across and about the Campbell Plateau, respectively, accompanying renewed ice buildup on East Antarctica and formation of a permanent ice sheet on West Antarctica, as well as generally more expansive and intensified circum-Antarctic flow. The ultimate control on the history of oceanic front development in the NZSSO has been plate tectonics through its influence on the paleogeographic changes of the Australian-New Zealand-Antarctic continents and their intervening oceanic basins, the timing of opening and closing of critical seaways, the potential for submarine ridges and plateaus to exert some bathymetric control on the location of fronts, and the evolving ice budget on the Antarctic continent. The broad trends of the Cenozoic climate curve for New Zealand deduced from fossil evidence in the uplifted marine sedimentary record correspond well to the principal paleoceanographic events controlling the evolution and migration of the oceanic fronts in the NZSSO

Differential Extinction and the Contrasting Structure of Polar Marine Faunas

Background: The low taxonomic diversity of polar marine faunas today reflects both the failure of clades to colonize or diversify in high latitudes and regional extinctions of once-present clades. However, simple models of polar evolution are made difficult by the strikingly different faunal compositions and community structures of the two poles. Methodology/Principal Findings: A comparison of early Cenozoic Arctic and Antarctic bivalve faunas with modern ones, within the framework of a molecular phylogeny, shows that while Arctic losses were randomly distributed across the tree, Antarctic losses were significantly concentrated in more derived families, resulting in communities dominated by basal lineages. Potential mechanisms for the phylogenetic structure to Antarctic extinctions include continental isolation, changes in primary productivity leading to turnover of both predators and prey, and the effect of glaciation on shelf habitats. Conclusions/Significance: These results show that phylogenetic consequences of past extinctions can vary substantially among regions and thus shape regional faunal structures, even when due to similar drivers, here global cooling, and provide the first phylogenetic support for the ‘‘retrograde’ ’ hypothesis of Antarctic faunal evolution

Macrofossil evidence for a rapid and severe Cretaceous–Paleogene mass extinction in Antarctica

Debate continues about the nature of the Cretaceous–Paleogene (K–Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K–Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous–Paleogene succession: the López de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian