Reciprocality between biology and geology: Reconstructing polar Gondwana     

B. Michaux   《Gondwana Research》2009,16(3-4):655-668

The reciprocal nature of the relationship between historical geology (reconstruction models) and biology (constructing phylogenies) is discussed and the conceptual basis of such a relationship is examined through its historical development. Examples to illustrate aspects of the relationship are drawn from the Cretaceous breakup of polar Gondwana and the Cenozoic history of some of the resultant microcontinental fragments. A new mid-Cretaceous (circa 100 Ma) rift zone, separating the west Gondwanan Campbell Plateau, southern New Zealand, from the east Gondwanan Melanesian Rift is proposed, and biological and geological evidence for it is presented and discussed. It is also suggested that the Bounty Trough, Chatham Rise, and Hikurangi Plateau unit is incorrectly placed in reconstruction models, and it should be fitted outboard of the Melanesian Rift until its mid-Cenozoic attachment to the Campbell Plateau. It is concluded that both reconstruction modelling and phylogenetic analyses have much to gain through ‘reciprocal illumination’.  相似文献   

REGIONAL DEVELOPMENT IN DENMARK     

ROLF GUTTESEN M.Sc.  FRANK HANSEN M.Sc.  BUE NIELSEN M.Sc. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):74-87

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The Problem of Double Longitudes on Glavač’s Map     

Marina Viličić  Miljenko Lapaine 《The Cartographic journal》2013,50(3):217-234

Abstract

Exploring large volumes of geospatial data is difficult. This paper presents an approach that combines visual and computational analysis to make this process easier. This approach is based on the effective application of computational algorithms, such as the Self-Organizing Map (SOM). These are used to uncover the structure, patterns, relationships and trends in the data, and for the creation of abstractions where conventional methods may be limited. In addition, graphical representations are applied to portray extracted patterns in a visual form that allows for better understanding of the derived structures and possible geographical processes, and should facilitate knowledge construction.  相似文献   

A GIS-based glacier inventory for the Antarctic Peninsula and the South Shetland Islands —A first case study on King George Island     

Matthias Braun  F. Rau  Jefferson Simões 《地球空间信息科学学报》2013,16(2):15-24

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)” headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery. This data set will form a first digital baseline study for future glacier monitoring. The presented GIS-based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula. In the database of the glacier inventory topographic information, specific glaciological parameters as well as metadata will be included. The topographic data consists of drainage basin limits, basin areas, altitudinal ranges, perimeters and mean lengths. Glaciological data sets should comprise information on glacier retreat in different periods, glacier velocities, ice thickness and bedrock topography as well as derived parameters. Modelled and measured mass balance parameters could be included as additional data layers. In particular, these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS). Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications, but also other environmental studies on the island will benefit from this standardised remote sensing data sets. Therefore, a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms. Finally, better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950's onward.  相似文献   

Recent macroids on the Kikai‐jima shelf,Central Ryukyu Islands,Japan     

DAVIDE BASSI  YASUFUMI IRYU  MARC HUMBLET  HIROKI MATSUDA  HIDEAKI MACHIYAMA  KEIICHI SASAKI  SHINYA MATSUDA  KOHSAKU ARAI  TAKAHIKO INOUE 《Sedimentology》2012,59(7):2024-2041

Sandy and gravelly carbonate sediments found off Kikai‐jima, southern Japan, a coral reef‐related island shelf, represent the northernmost sub‐tropical, carbonate deposits in the Central Ryukyu Islands (Ryukyus). On the Kikai‐jima shelf, at water depths of 61 to 105 m, these sediments are characterized by macroid pavements. Since the abundance of very small and of exceptionally large macroids may indicate specific hydrodynamic controls regarding constraints on growth and taphonomy, the detailed analysis of recent and fossil macroid pavements is meaningful ecologically and environmentally. Macroids, ranging in size from ca 25 to 130 mm in diameter, are spheroidal and sub‐spheroidal in shape and consist mainly of the encrusting foraminifer Acervulina inhaerens and subordinate thin encrusting and lumpy coralline algae. Accessory components include bryozoans, serpulids and, to a lesser extent, encrusting arborescent foraminifera (Homotrema and Miniacina). Low sedimentation rates and occasional movement due to current action are indicated by sizes, shapes and growth‐forms of the studied macroids, the Entobia–Gastrochaenolites–Trypanites–Maeandropolydora ichnocoenosis and the ‘Bioerosion Index’ for coated grains (introduced herein). The deep‐water tidally induced current energy was sufficient to maintain multi‐directional growth (spheroidal shapes) of the larger macroids and to initiate macroid growth using the diverse biogenic remnants as nuclei. The asymmetrical inner arrangement suggests possible periods of stability for the macroids. The residence time of the coated grain in its original environment determines the size and morphology of the macroid and the selection of coating organisms. The composition of the coating community is mainly a consequence of component growth rates in relation to turnover time and residence time. Long‐term studies are needed to assess the spatial and temporal resolution of present‐day encrusting communities across biogeographic provinces and shelf to slope regions.  相似文献   

U/Pb dating of detrital zircons from late Palaeozoic deposits of Bel’kovsky Island (New Siberian Islands): critical testing of Arctic tectonic models     

《International Geology Review》2012,54(2):199-210

Detrital zircon U/Pb ages provide new insights into the provenance of Upper Devonian–Permian clastic rocks of Bel’kovsky Island, within the New Siberian Islands archipelago. Based on these new data, we demonstrate that Upper Devonian–Carboniferous turbidites of Bel’kovsky Island were derived from Grenvillian, Sveconorwegian, and Timanian sources similar to those that fed Devonian–Carboniferous deposits of the Severnaya Zemlya archipelago and Wrangel Island and were probably located within Laurentia–Baltica. Detrital zircon ages from the lower Permian deposits of Bel’kovsky Island suggest a drastic change in provenance and show a strong affinity with the Uralian Orogen. Two possible models to interpret this shift in provenance are proposed. The first involves movement of these continental blocks from the continental margin of Laurentia–Baltica towards the Uralian Orogen during the late Carboniferous to Permian, while the second argues for long sediment transport across the Barents shelf.  相似文献   

Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain)     

Sánchez-Rodríguez A  Sosa-Ferrera Z  Santana-del Pino A  Santana-Rodríguez JJ 《Marine pollution bulletin》2011,62(5):985-991

The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%.  相似文献   

Contemporary 14C radiocarbon levels of oxygenated polybrominated diphenyl ethers (O-PBDEs) isolated in sponge-cyanobacteria associations     

Guitart C  Slattery M  Ankisetty S  Radwan M  Ross SJ  Letcher RJ  Reddy CM 《Marine pollution bulletin》2011,62(3):631-636

Considerable debate surrounds the sources of oxygenated polybrominated diphenyl ethers (O-PBDEs) in wildlife as to whether they are naturally produced or result from anthropogenic industrial activities. Natural radiocarbon (¹⁴C) abundance has proven to be a powerful tool to address this problem as recently biosynthesized compounds contain contemporary (i.e. modern) amounts of atmospheric radiocarbon; whereas industrial chemicals, mostly produced from fossil fuels, contain no detectable ¹⁴C. However, few compounds isolated from organisms have been analyzed for their radiocarbon content. To provide a baseline, we analyzed the ¹⁴C content of four O-PBDEs. These compounds, 6-OH-BDE47, 2′-OH-BDE68, 2′,6-diOH-BDE159, and a recently identified compound, 2′-MeO-6-OH-BDE120, were isolated from the tropical marine sponges Dysidea granulosa and Lendenfeldia dendyi. The modern radiocarbon content of their chemical structures (i.e. diphenyl ethers, C₁₂H₂₂O) indicates that they are naturally produced. This adds to a growing baseline on, at least, the sources of these unusual compounds.  相似文献   

Cenozoic temperate and sub‐tropical carbonate sedimentation on an oceanic volcano – Chatham Islands,New Zealand     

NOEL P. JAMES  BRIAN JONES  CAMPBELL S. NELSON  HAMISH J. CAMPBELL  JEREMY TITJEN 《Sedimentology》2011,58(4):1007-1029

The Chatham Islands, at the eastern end of the Chatham Rise in the South‐west Pacific, are the emergent part of a Late Cretaceous to Cenozoic stratovolcano complex that is variably covered with limestones and fossiliferous tuffs. Most of these deposits accumulated in relatively shallow, high‐energy, tide‐influenced palaeoenvironments with deposition punctuated by periods of deeper‐water pelagic accumulation. Carbonate components in these neritic deposits are biogenic and dominated by molluscs and bryozoans – a heterozoan assemblage. The widespread Middle to Late Eocene Matanginui Limestone contains local photozoan elements such as large benthonic foraminifera (especially Asterocyclina) and calcareous green algae, reflecting the general Palaeogene sub‐tropical oceanographic setting. More localized Late Eocene to Oligocene deposits (Te One Limestone) as well as Pliocene carbonates (Onoua Limestone) are, however, wholly heterozoan and confirm a generally cooler‐water oceanographic setting, similar to today. Early sea floor diagenesis is interpreted to have removed most aragonite components (infaunal bivalves and epifaunal gastropods). Lack of aragonite resulted in the absence of intergranular calcite cementation during subaerial exposure, such that most carbonates are friable or unlithified. Cementation is, however, present at nodular hardground–firmground caps to metre‐scale cycles. Such cements are microcrystalline or micrometre‐thick isopachous circumgranular rinds with insufficient definitive attributes to pinpoint their environment of formation. The overall palaeoenvironment of deposition is interpreted as mesotrophic, resulting in part from upwelling about the Chatham volcanic massif and in part from nutrient element delivery from the adjacent volcanic terrane and coeval volcanism. Biotic diversity in tuffs is two to three times that in limestones, supporting the notion of especially high nutrient availability during periods of volcanism. These mid‐latitude deposits are strikingly different from their low‐latitude, tropical, photozoan counterparts in the volcanic island–coral reef ecosystem. Ground water seepage and fluvial runoff attenuate coral growth and promote microbial carbonate precipitation in these warm‐water settings. In contrast, nutrients from the same sources feed the system in the Chatham Islands cool‐water setting, promoting active heterozoan carbonate sedimentation.  相似文献   

Choppy waters ahead in “a sea of peace cooperation and friendship”?: Slow progress towards the application of maritime joint development to the East China Sea     

Clive H. Schofield  Ian Townsend-Gault 《Marine Policy》2011

China and Japan’s June 2008 agreement in principle on maritime cooperation in the East China Sea raised hopes of a significant breakthrough in the parties' complex and long-standing disputes in the area. Subsequent progress towards the realisation of a legally binding, formal treaty on, for example, offshore petroleum joint development has been slow to materialise. In fact, the area under dispute appears to have become more rather than less extensive. This paper examines competing maritime and sovereignty claims in the East China Sea together with progress towards maritime cooperation in the context of overlapping jurisdictional claims. The paper identifies some of the key challenges that need to be overcome in realizing a functioning joint resource management regime in the East China Sea.  相似文献