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Hamilton, Bermuda

Thirty-one widespread visible Holocene tephras in Hokkaido, northern Japan, were identified and their stratigraphic relationships were examined. Among these, three tephras from Komagatake volcano (Ko-c1, Ko-c2, and Ko-g), three from Tarumae volcano (Ta-a, Ta-b, and Ta-c), Us-1663 from Usu volcano, Ma-b from Mashu volcano, and B-Tm from Baegdusan volcano (on the boundary between North Korea and China) cover a large area of southern and eastern Hokkaido and are thus useful tephras for correlating sedimentary records and Holocene phenomena. All tephras were identified on the basis of their mineral composition and the refractive indices and major elements of their glass shards. The volcanic glass samples were dehydrated before refractive index measurement by heating at 400°C for 12h. Most Holocene tephras in Hokkaido can be easily identified on the basis of the refractive indices and major element compositions of volcanic glass. © 2015 Elsevier Ltd and INQUA.

Many fossil footprints of mammals and birds have been described in Pleistocene-age eolianite formations from SW Alentejo, constituting an interesting record hitherto completely unknown. Here is reported the occurrence of rare footprints from a medium-sized felid probably attributed to the Iberian lynx, which was recently considered close to extinction in Portugal. © 2014 LNEG – Laboratório Nacional de Geologia e Energia IP.

Reich M.,geopark
Echinoderms: Durham - Proceedings of the 12th International Echinoderm Conference | Year: 2010

The early evolution and diversification of the sea cucumbers have shortly been reviewed and reinterpreted, including new records of Ordovician, Silurian, and Devonian material. Holothuroids have a Phanerozoic history extending back more than 464 Ma, ranging from the early Middle Ordovician to the present time. The maximum level of morphological diversification was apparently reached in the Mesozoic, in all likelihood due to a lack of research in other strata. A revised hypothesis of Early Palaeozoic higher-level relationships within the Holothuroidea is presented. © 2010 Taylor & Francis Group.

Baucon A.,University of Milan | Baucon A.,geopark | Felletti F.,University of Milan
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

Barrier-islands are common landforms and biodiverse habitats, yet they received scarce neoichnological attention. This gap is tackled by studying the Mula di Muggia barrier-island system (Grado lagoon, Italy), focusing on morphology, ecology and ethology of individual traces. The following incipient ichnotaxa are identified: Archaeonassa, Arenicolites, Bergaueria, 'diverging shafts', Helminthoidichnites, Lockeia, Macanopsis, Monocraterion, Nereites, Parmaichnus, Polykladichnus, Skolithos, Thalassinoides and 'squat burrows'. Vertebrate (Avipeda-/Ardeipeda-like, Canipeda) and invertebrate tracks ('parallel furrows') are also described.For each ichnotaxon, tracemaker and behavior are discussed, together with their position with respect to sediment barriers. Results suggest that sediment barriers impose a sharp contrast in terms of ichnological composition. Back-barrier is dominated by branched burrows (i.e. Thalassinoides, Parmaichnus), while the fore-barrier presents vertical and U-shaped burrows (Arenicolites, Skolithos). The environmental conditions of the back-barrier show that low-oxygen substrates favor intense bioturbation, provided that the water column is sufficiently oxygenated. © 2013 Elsevier B.V.

Baucon A.,University of Milan | Baucon A.,geopark | Felletti F.,University of Milan
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

A new method is proposed for capturing, managing, analyzing, and displaying geographically referenced ichnological data: IchnoGIS. This approach is based on the integration of spatial, geostatistical techniques with network theory, aiming to characterize the environmental significance of recent traces. The efficiency of the IchnoGIS method is tested against a case-study: the Grado lagoon (Italy). The studied site, located within the epeiric Northern Adriatic Sea, consists of a complex mosaic of peritidal environments in a barrier-island context. Here, a diverse ichnofauna includes the following incipient ichnotaxa: Arenicolites, Helminthoidichnites, Lockeia, Macanopsis, Monocraterion, Parmaichnus, Polykladichnus, Skolithos, Thalassinoides and 'squat burrows'. Ichnofaunal distribution is described by the spatial and geostatistical tools proper of the IchnoGIS approach. Additionally, the application of network theory documents the emergence of organized structures (ichnoassociations) from interactions driven by environmental factors. Our results elucidate the role that environmental processes play in producing the complex ichnological patterns of the Grado site. In particular, emersion time, hydrodynamics, substrate firmness and microbial binding are the major control factors determining the structure and distribution of trace associations. These structuring factors are used to define a predictive model of ichnoassociation composition, providing an immediate tool for future palaeoenvironmental reconstitutions. © 2013 Elsevier B.V.

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