A GIS-BASED GLACIER INVENTORY FOR THE ANTARCTIC PENINSULA AND THE SOUTH SHETLAND ISLANDS——A FIRST CASE STUDY ON KING GEORGE ISLAND

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＷｏｒｋｉｎｇＧｒｏｕｐｏｎＧｅｏｄｅｓｙａｎｄＧｅｏｇｒａｐｈｉｃＩｎｆｏｒｍａｔｉｏｎ (ＷＧ＿ＧＧＩ)ｏｆｔｈｅＳｃｉｅｎｔｉｆｉｃＣｏｍｍｉｔ ｔｅｅｏｎＡｎｔａｒｃｔｉｃＲｅｓｅａｒｃｈ (ＳＣＡＲ )ｌａｕｎｃｈｅｄｔｈｅｐｒｏｊｅｃｔＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄＧＩＳ (ＫＧＩＳ) .Ｉｎｏｒｄｅｒｔｏｐｒｏｖｉｄｅａｎｏｐｅｒａｔｉｏｎａｌｓｙｓｔｅｍ ,ａｄａｔａｍｏｄｅｌ,ｄａｔａａｃｃｕｒａｃｙｓｔａｎｄａｒｄｓａｎｄａｄａｔａｉｎｖｅｎｔｏｒｙｈａｖ…     

Reconstructing the development of sampled sites on fluvial island surfaces of the Tagliamento River,Italy, from historical sources

In parallel with research on surface sediment characteristics of evolving island features (patches) along an island‐braided reach of the Tagliamento River, Italy, the present research reconstructed the development of the sampled sites using historical information coupled with field measurements. Since any field sediment sampling programme inevitably focuses on small areas (of the order of a few metres), the historical sources were assessed bearing in mind their spatial resolution and geographical accuracy in relation to the size of the sampled sites, and the information they could provide regarding the historical evolution of those sites. The analysis combined four sources of information: (i) river stage records revealed flood events that had the potential to reset bar surfaces and float in wood and seeds to initiate vegetation colonization; (ii) oblique ground photographs identified areas of the river's active corridor where riparian vegetation colonization appeared to have been initiated by specific flood events; (iii) dendrochronology was used to estimate the age of sampled sites; (iv) field‐measured geographical locations of the sampled sites were combined with historical vertical areal imagery to further establish sampling site age and changes in vegetation cover from 1944 to 2012. A chronosequence of sampled sites (0, 2, 8, 12, 40 years) was established. Vegetation colonization and island development showed a statistically significant development trajectory among sites of each age across the 40 year period following formative floods in 1965–1966, 2000, 2004 and a flow pulse in 2010. The trajectory progressed through pioneer and building island stages until vegetated areas became part of established islands. Evidence from the younger sites indicates that the pioneer island phase lasts up to eight years. Evidence from the oldest site indicates a building island phase lasting a maximum of 30 years, but probably a lot less. Copyright © 2014 John Wiley & Sons, Ltd.     

Optically stimulated luminescence dating of fluvioglacial (sandur) sediments from north-eastern Germany

This study presents first results of a project which aims to develop an absolute chronology of the Weichselian ice marginal positions in north-eastern Germany using Optically Stimulated Luminescence (OSL) dating. Owing to the special geomorphological and stratigraphical setting, many of the sampling sites were situated close to the former ice margin. At some sections the sediments showed an incomplete resetting of the OSL signal. For this study the representative sandur sediment section from the Beelitz outwash cone was chosen to elaborate a strategy to reliably detect insufficient bleaching and to choose an appropriate age model for the calculation of the true burial dose of each sample. The age determined for the formation of the Beelitz outwash cone is 34.1 ± 3.0 ka. Although this age might still be a maximum age, this study shows that by applying the proposed methodological strategy, plausible ages can be derived from insufficiently bleached, ice proximal sandur sediments.     

Petrology, magnetostratigraphy and geochronology of the Miocene volcaniclastic Tepoztlán Formation: implications for the initiation of the Transmexican Volcanic Belt (Central Mexico)

The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones, conglomerates and breccias, originating from fluvial and mass flow processes, respectively. Within these sediments fall deposits and lavas are sparsely intercalated. The clastic material is almost exclusively of volcanic origin, ranging in composition from andesite to rhyolite. Thick gravity-driven deposits and large-scale alluvial fan environments document the buildup of steep volcanic edifices. K-Ar and Ar-Ar dates, in addition to eight magnetostratigraphic sections and lithological correlations served to construct a chronostratigraphy for the entire Tepoztlán Formation. Correlation of the 577 m composite magnetostratigraphic section with the Cande and Kent (1995) Geomagnetic Polarity Time Scale (GPTS) suggests that this section represents the time intervall 22.8–18.8 Ma (6Bn.1n-5Er; Aquitanian-Burdigalian, Lower Miocene). This correlation implies a deposition of the TF predating the extensive effusive activity in the TMVB at 12 Ma and is therefore interpreted to represent its initial phase with predominantly explosive activity. Additionally, three subdivisions of the TF were established, according to the dominant mode of deposition: (1) the fluvial dominated Malinalco Member (22.8–22.2 Ma), (2) the volcanic dominated San Andrés Member (22.2–21.3 Ma) and (3) the mass flow dominated Tepozteco Member (21.3–18.8 Ma).     

Determinants of corporate adaptation to climate change in winter tourism: An econometric analysis

While corporate adaptation strategies in response to climate change have been characterized, the determinants of adaptation have not been comprehensively analyzed. Knowledge of these determinants is particularly useful for policy makers to provide favorable conditions in support of corporate adaptation measures. Based on unique data from a survey of Swiss ski lift operators, this paper empirically examines such determinants at the business level. Our econometric analysis with linear regression and count data models finds a positive influence of the awareness of possible climate change effects on the scope of corporate adaptation. Surprisingly, no significant influence of the vulnerability to climate change effects on the scope of adaptation could be found. Finally, the dependency on the affected business and the ability to adapt influence the specific strategic directions of corporate adaptation.     

Coastal upwelling systems and Eastern boundary currents: A review of terminology

The use of terms such as Benguela Current or Peru Current System for different features of the oceanic circulation in the eastern parts of the oceans is reviewed. During 50 years of upwelling research these terms have been used for different oceanographic phenomena. It is argued that one reason for inconsistent use has been that names of currents were chosen on geographic rather than hydrodynamic principles, and that although knowledge of the dynamics of current systems expanded, it became increasingly difficult to modify the existing nomenclature accordingly. In order to provide a basis for a unified terminology, the dynamics of ocean currents in the eastern pans of the oceans are reviewed. It is argued that the coastal upwelling current system is a modification of the inshore part of the eastern boundary current and consequently should not be named as opposed to it but as part of it. It is suggested that the traditional geographic names be used for the eastern boundary currents and new names be assigned by international agreement to the coastal upwelling currents.     

Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales

We present a model for earthquake failure at intermediate scales (space: 100 m–100 km, time: 100 m/v _shear- 1000’s of years). The model consists of a segmented strike–slip fault embedded in a 3-D elastic solid as in the framework of Ben-Zion and Rice (1993). The model dynamics is governed by realistic boundary conditions consisting of constant velocity motion of the regions around the fault, static/kinetic friction laws with possible gradual healing, and stress transfer based on the solution of Chinnery (1963) for static dislocations in an elastic half-space. As a new ingredient, we approximate the dynamic rupture on a continuous time scale using a finite stress propagation velocity (quasi–dynamic model) instead of instantaneous stress transfer (quasi–static model). We compare the quasi–dynamic model with the quasi–static version and its mean field approximation, and discuss the conditions for the occurrence of frequency-size statistics of the Gutenberg–Richter type, the characteristic earthquake type, and the possibility of a spontaneous mode switching from one distribution to the other. We find that the ability of the system to undergo a spontaneous mode switching depends on the range of stress transfer interaction, the cell size, and the level of strength heterogeneities. We also introduce time-dependent log (t) healing and show that the results can be interpreted in the phase diagram framework. To have a flexible computational environment, we have implemented the model in a modular C++ class library.