Ice-confined construction of a large basaltic volcano—Austurfjöll massif, Askja, Iceland

Austurfjöll is the largest basaltic glaciovolcanic massif at Askja volcano (Central Iceland), and through detailed studies of its volcanological and geochemical characteristics, we provide a detailed account of the sequence and structure of the ice-confined construction of a large Icelandic basaltic volcano. In particular, Austurfjöll represents a geometry of vents, and resulting glaciovolcanic morphology, not previously documented in ice-confined basaltic volcanoes. Austurfjöll was constructed during two major phases of basaltic volcanism, via seven eruptive episodes through disperse fissure-dominated eruptions. The earliest episode involved a rare and poorly exposed example of subaerial activity, and this was succeeded by six episodes involving the eruption of ice-confined pillow lavas and numerous overlapping fissure eruptions of phreatomagmatic tephra. Evidence of local subaerial lavas and tephras indicates the local growth of eruptive centers above englacial lake levels, and subsequent flooding, but no prolonged subaerial activity. Localized ice-contact facies, paleowater levels, and diamictons indicate the position and thickness of the ice was variable during the construction of Austurfjöll, and eruptive activity likely occurred in multiple and variable level meltwater lakes during the last glacial period. Lithofacies evidence including gradational transitions from effusive to explosive deposits, superposition of fragmental facies above coherent facies, and drainage channels suggest that changes in eruptive style were driven largely by external factors such as drainage and the increasing elevation of the massif. This study emphasizes the unique character of Austurfjöll, being composed of large pillow lava sheets, numerous (> 40) overlapping glaciovolcanic tindars, and only localized emergent deposits, as a product of its prolonged ice-confined eruptive history, contrasts with previous descriptions of tuyas and tindars

Seamounts off the West Antarctic margin: A case for non-hotspot driven intraplate volcanism

Highlights: • Marie Byrd Seamounts (MBS) formed off Antarctica at 65-56 Ma in an extensional regime • MBS originate from HIMU-type mantle attached at the base of the Antarctic lithosphere • Continental insulation flow transferred HIMU mantle into the oceanic mantle New radiometric age and geochemical data of volcanic rocks from the guyot-type Marie Byrd Seamounts (MBS) and the De Gerlache Seamounts and Peter I Island (Amundsen Sea) are presented. 40Ar/39Ar ages of the shield phase of three MBS are Early Cenozoic (65 to 56 Ma) and indicate formation well after creation of the Pacific-Antarctic Ridge. A Pliocene age (3.0 Ma) documents a younger phase of volcanism at one MBS and a Pleistocene age (1.8 Ma) for the submarine base of Peter I Island. Together with published data, the new age data imply that Cenozoic intraplate magmatism occurred at distinct time intervals in spatially confined areas of the Amundsen Sea, excluding an origin through a fixed mantle plume. Peter I Island appears strongly influenced by an EMII type mantle component that may reflect shallow mantle recycling of a continental raft during the final breakup of Gondwana. By contrast the Sr-Nd-Pb-Hf isotopic compositions of the MBS display a strong affinity to a HIMU type mantle source. On a regional scale the isotopic signatures overlap with those from volcanics related to the West Antarctic Rift System, and Cretaceous intraplate volcanics in and off New Zealand. We propose reactivation of the HIMU material, initially accreted to the base of continental lithosphere during the pre-rifting stage of Marie Byrd Land/Zealandia to explain intraplate volcanism in the Amundsen Sea in the absence of a long-lived hotspot. We propose continental insulation flow as the most plausible mechanism to transfer the sub-continental accreted plume material into the shallow oceanic mantle. Crustal extension at the southern boundary of the Bellingshausen Plate from about 74 to 62 Ma may have triggered adiabatic rise of the HIMU material from the base of Marie Byrd Land to form the MBS. The De Gerlache Seamounts are most likely related to a preserved zone of lithospheric weakness underneath the De Gerlache Gravity Anomaly

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Sheet hyaloclastite: density-current deposits of quench and bubble-burst fragments from thin, glassy sheet lava flows, Seamount Six, Eastern Pacific Ocean

New observations with the submersible ALVIN and deep-tow camera show that bedded sheet-hyaloclastites are common deposits between 2024 and 1723 m depth on the upper flank of Seamount Six, located on the Cocos plate at 12°45′N, 102°35′W. The individual sheets are highly localized and of small areal extent (<200 m2), though no vent sites were found. Several facies associations of hyaloclastite, with pillow talus, knobbly fist-sized lava fragments and thin sheet lava (<10 cm) underlying hyaloclastite, are identified. Recovered samples consist of angular, polyhedral sand-sized sideromelane shards and thin, bent, plate-like sideromelane fragments called Limu O'Pelee. Limu are solidified fragments of burst magma bubbles, which formed by vapourization of water entrapped by lava. Analysis of lava and hyaloclastite shards including limu shows three geochemically distinct populations, depleted MORB (N1), more evolved NMORB (N2) and hawaiite (H) of diverse composition. In individual hyaloclastite samples, shards of two or three different types may occur in various proportions, though in samples of hyaloclastite associated with sheet lava the predominant shards are of the same geochemical type as the sheet lava. Deposition of hyaloclastites occurred from lateral density currents formed by transformation from convective suspension settling. Grain size distribution, settling behaviour of different co-deposited shard types and sedimentary structures, together with pelagic ooze in the matrix and geochemically mixed shard populations, indicate some erosion, traction reworking and turbulence during transport. Critical observations are that contorted sheet lava protrudes through hyaloclastite and that sheet lava flow vugs commonly contain pelagic ooze. Facies associations plus consideration of limu formation allow the establishment of a new, multi-component model of hyaloclastite formation. It is inferred that the formation of limu-bearing sheet hyaloclastite involves entrapment of pelagic sediment beneath or within lava. This leads to limu bubble formation and suppressed tephra jetting. Together with convectively rising water heated by the lava flow, these processes loft shards slightly into the water column, from which they settle singly or in vertical sediment gravity flows that are redirected to flow along the seafloor

A platform for onsite data gathering and online data amalgamation in collaborative research projects: Presentation held at Ecological Society of America, 97th Annual Meeting 2012, 5 - 10 Aug 2012, Portland, Oregon

Since Porters work on competitive strategies in the 1980s, the concept of competitive intelligence has become part of the management mainstream. Currently, two big shifts are challenging the state of the art. On the one hand there is the rise of the ubiquitous servicification in all industries which makes the existing methods for product-oriented industries outdated. On the other hand there is the rise of big data (volume, velocity, variety). Both shifts are driving the development towards interactive competitive intelligence systems. The authors introduced a framework for interactive competitive intelligence systems which overcome the sequential water-fall processes which are current CI practice. In the introduced framework they combine the concept of Key Intelligence Topics (KIT) with the concept of (boundary) objects from interaction theory. The authors demonstrated with examples within their IP Industry Base how interactive CI for service-oriented sectors can be implemented. The resulting vector-based representations of the companies service profiles allow the user to visualize, compare, retrieve and analyse companies in a constructive and scalable way. Der Begriff der Resilienz erfährt aktuell eine starke Resonanz in der Wirtschaftsgeographie. Das Platzen der Dotcom-Blase und die Finanz- und Wirtschaftskrise Ende der 2000er Jahre werfen Fragen dazu auf, wie ökonomische Krisen entstehen und wie sie vermieden oder gemeistert werden können. Auch Herausforderungen des Klimawandels, der Ressourcenverknappung oder des demographischen Wandels wirken sich auf ökonomische Systeme aus. Staaten und Regionen sind von Krisen nicht nur in unterschiedlichem Maße betroffen, auch ihre Reaktionen darauf unterscheiden sich erheblich. Einige gehen gestärkt aus Krisen hervor, andere werden in ihrer Entwicklung zurückgeworfen, und wieder andere scheinen kaum betroffen zu sein. Ist dieser Umstand begründet in einer unterschiedlich starken Resilienz? Und wenn j a, welche Prozesse bedingen oder beeinflussen eine mehr oder weniger starke Resilienz von räumlichen Einheiten

Harmonizing, annotating and sharing data in biodiversityecosystem functioning research

The integrative research field of biodiversityecosystem functioning (BEF) requires close collaboration between researchers from different disciplines working on different scales in time, space as well as taxon resolution. Data can describe anything from abiotic ecosystem components, to organisms, parts of organisms, genetic information or element stocks and flows. Researchers prefer the convenience of spreadsheets for data preparation, which can lead to isolated data sets that are diverse in structure and follow diverging naming conventions. BEFdata (https://github.com/befdata/befdata) is a new, open source web platform for the upload, validation and storage of data from a formatted Excel workbook. Metadata can be downloaded in Ecological Metadata Language (EML). BEFdata allows the harmonization of naming conventions by generating category lists from the primary data, which can be reviewed and managed via the Excel workbook or directly on the platform. BEFdata provides a secure environment during ongoing analysis; project members can only access primary data from other researchers after the acceptance of a data request. Due to its generic database schema, BEFdata platforms can be used for any research domain working with tabular data. It supports the compilation of coherent data sets at the level of the primary data, allowing researchers to explicitly model correlation structures across data sets for synthesis. The EML export enables efficient publishing of data in global repositories