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  • Articles  (3)
  • 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods  (1)
  • 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics  (1)
  • 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous  (1)
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  • Articles  (3)
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  • 1
    Publication Date: 2017-04-04
    Description: The Frontier Mountain blue ice field is an important Antarctic meteorite trap which has yielded 472 meteorite specimens since its discovery in 1984. Remote sensing analyses and field campaigns from 1993 to 1999 have furnished new glaciological data on ice flow, ice thickness, bedrock topography, ice ablation and surface mass transport by wind, along with detailed descriptions of the field situation at the trap. This solid set of data combined with an updated meteorite distribution map and terrestrial ages available from literature allows us to better describe the nature of the concentration mechanism. In particular, we observe that the meteorite trap forms in a blue ice field (1) located upstream of an absolute and a shallow sub-ice barriers; (2) characterized by compressive ice flow with horizontal velocities decreasing from 100 to 〈10 cm/year on approaching the obstacle; (3) undergoing mean ablation rates of 6.5 cm/year; (4) nourished by a limited snow accumulation zone extending ∼20 km upstream of the blue ice area. We also draw the following conclusions: (1) the origin of the meteorite trap can be explained according to the present-day glaciological situation; (2) the meteorite concentration develops according to the general principles of the "ice flow model"; (3) the accumulation model can be described as "stagnant ice or slow-moving ice against an absolute and submerged barriers", according to the descriptive schemes present in literature; (4) the Frontier Mountain ice field is an effective trap for meteorites weighing more than ∼200 g; for smaller masses, the combination of wind and glacial drift may remove meteorites in less than a few tens of thousands of years; (5) although the activation age of the Frontier Mountain trap is not yet constrained, we infer that one of the most important findsites may be as old as 50 ka, predating the last glacial maximum.
    Description: Published
    Description: 209-228
    Description: JCR Journal
    Description: reserved
    Keywords: Frontier Mountain ; Antarctic meteorite trap ; remote sensing ; glaciological data ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2017-04-04
    Description: Molto è noto delle particolarissime condizioni che rendono l'Antartide un laboratorio veramente speciale per tante discipline. Tuttavia, per le Scienze della Terra il continente antartico ha un doppio interesse. Oltre ad essere un luogo poco conosciuto dove avvengono processi straordinari ed unici per il nostro pianeta, esso occupa anche una posizione privilegiata per la registrazione di dati geofisici. Questi dati sono essenziali per la comprensione globale di molti processi fisici e ci aiutano dunque a capire come la Terra "funziona" nel suo insieme. L'Antartide è, quindi, un luogo di osservazione cruciale per la conoscenza del pianeta in cui viviamo. I processi geofisici presentano variazioni su lunghi periodi. Di conseguenza, la registrazione di lunghe e ininterrotte serie temporali è un impegno basilare per gli osservatori geofisici. Come noi traiamo vantaggio dalle registrazioni della declinazione del campo magnetico fatte dai marinai del XVIII secolo, dalle cronologie degli effetti dei terremoti trovate in archivi storici e dalle informazioni sul tempo e sulle temperature dell'aria scritte negli antichi almanacchi, così dobbiamo impegnarci per acquisire ed allo stesso tempo conservare le registrazioni strumentali secondo i migliori livelli consentiti dalla tecnologia odierna. Seguendo queste considerazioni, il programma antartico Italiano - in modo simile ai programmi di altre nazioni - si sta prodigando in uno sforzo continuo nel mantenimento e nel miglioramento degli osservatori geofisici permanenti. Forse alcune di queste attività non forniscono dati con forte impatto immediato, ma la loro vera importanza si evidenzierà certamente in futuro. Il funzionamento degli osservatori geofisici antartici è anche un obbligo verso le prossime generazioni, per metterle in condizione di comprendere quello che a noi sfugge ancora.
    Description: PNRA
    Description: Published
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: open
    Keywords: Antartide ; Osservatori permanenti ; PNRA ; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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  • 3
    Publication Date: 2017-04-04
    Description: A Global Positioning System (GPS) network of 30 semi-permanent vertices known as the Victoria Land Network for Deformation Control (VLNDEF) was set up in the Austral summer of 1998 in Northern Victoria Land (NVL), including the permanent GPS station of Terra Nova Bay (TNB1), Antarctica. The locations were selected according to the known Cenozoic fault framework, which is characterized by a system of NW[U+2010]SE regional faults with right[U+2010]lateral, strike[U+2010]slip kinematics. The TNB1 permanent GPS station is included within the VLNDEF, and was installed on a bedrock monument in October 1998, it has been recording almost continuously up to the present. The GPS network has been surveyed routinely every two summers, using high[U+2010]quality, dual[U+2010]frequency GPS receivers like Trimble 5700, TopCon GB100, and Ashtech Z-XII. In this study we present the results of a distributed session approach based on Gamit/Globk 10.4 software package applied to the processing of the GPS data of the VLNDEF aimed to obtain the preliminary framework of the active tectonics of this region of Antarctica. An improved reference frame definition was implemented, including a new Euler rotation pole, to compute the Antarctic intra-plate residual velocities. The projection of the residual velocities on the main faults in NVL show present[U+2010]day activities for some faults, including the Tucker, Leap Year, Lanterman, Aviator, and David faults, with right[U+2010]lateral strike[U+2010]slip kinematics and local extensional and compressional components. This active fault pattern divides NVL into eight rigid blocks, each characterized by its relative movements and rigid rotations. These show velocities of up to several millimeters per year, which are comparable to those predicted by plate tectonic theory at active plate margins. During the austral summer 2010, in the framework of the Italian Antarctic campaign, field investigations at 25 geodetic stations were performed both for survey of the instruments and measurements as well as for the geological study necessary to evaluate the geological stability of the sites. Preliminary analysis of the collected structural data showed the stability of most of the investigated stations, thus confirming the proposed active tectonic framework of the NVL at the regional scale.
    Description: Published
    Description: Vienna, Austria 3–8 April 2011
    Description: 3.2. Tettonica attiva
    Description: reserved
    Keywords: Antarctica ; Northern Victoria Land ; Active Tectonics ; GPS data ; Geologic Setting ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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