1,721,045 research outputs found
High-resolution aeromagnetic mapping over a buried pipeline and a domestic waste site in Friuli (North-Eastern Italy)
No full textAeromagnetic and gravity anomaly constraints for an early Paleozoic subduction system of Victoria Land, Antarctica
No full textSerum antioxidant activity and related variables in rheumatoid arthritis. Behaviour during sulphydrylant treatment.
No full textAeromagnetic legacy for a diffuse intraplate boundary between northern Victoria Land and the Wilkes Subglacial Basin (East Antarctica)
No full textMajor terrane bounding faults and intra-terrane faults that were active during early Paleozoic subduction and accretion
stages of the Ross Orogen have been subject to intense research over the northern Victoria Land sector of
East Antarctica. However, the paucity of outcrop, coupled with incomplete geophysical data coverage, has limited
the ability to trace the inland extent and architecture of these basement fault systems and has hampered efforts
to assess their controls on later Cenozoic intraplate faulting within the Transantarctic Mountains and the eastern
margin of the Wilkes Subglacial Basin. Here we compile and analyse new enhanced aeromagnetic anomaly images
that help constrain regional-scale crustal architecture and tectonic evolution over northern Victoria Land and
the eastern margin of the Wilkes Subglacial Basin. Long-wavelength magnetic lows are modelled as reflecting
several-km thick sedimentary basins of inferred early Cambrian age that were inverted along major thrust faults
during the late stages of the Ross Orogen to form a major pop-up structure within the Wilson Terrane. A residual
Bouguer gravity high in the central Wilson Terrane corresponds to a broad magnetic low and images the 500
Ma old high-grade granulite-facies core of the pop-up. Arrays of NNW trending magnetic lineaments reveal thin
sheared sheets of mylonitic granitoids emplaced along the late Ross (480 Ma old) Exiles Thrust fault system
within the western Wilson Terrane, which is also marked by a prominent deep electrical conductivity anomaly.
In contrast, much thicker magmatic arc intrusions are modelled along the Prince Albert Fault System that fringes
the eastern margin of the Wilkes Subglacial Basin. Recent zircon U–Pb dating over exposures of gabbro-diorites
within the Prince Albert Mountains further south suggest that these intrusions may have been emplaced during
an earlier stage of subduction (520 Ma or older?), likely in a transtensional setting. Our magnetic models suggests
that these batholiths may have provided a back-stop for the late Ross-age thrust fault belt of the central and
western Wilson Terrane. Comparisons with California and other regions reveals striking similarities between the
complex patterns of fault strands imaged from our aeromagnetic compilation and those typically associated with
major strike-slip fault systems. When coupled with independent regional interpretations of Cenozoic brittle fault
arrays, our findings support the hypothesis of a diffuse Cenozoic intraplate strike-slip boundary between northern
Victoria Land and the Wilkes Subglacial Basin that reactivated the inherited Ross-age fault systems and provided
key kinematic connections with the West Antarctic Rift System
Exploring deep electrical conductivity from the Transantarctic Mountains to the Wilkes Subglacial Basin
No full textRevisiting Tectonic Models for an early Palaeozoic Subduction System from a Potential Field, Perspective over Victoria Land, Antarctica.
No full textNew geophysical views of Mt. Melbourne Volcano (East Antarctica)
No full textAB: Mt. Melbourne volcano is located along the transition between the Transantarctic Mountains and the West Antarctic Rift System. Recent volcanic activity is suggested by the occurrence of blankets of pyroclastic pumice and scoria fall around the eastern and southern flanks of Mt Melbourne and by pyroclastic layers interbedded with the summit snows. Geothermal activity in the crater area of Mount Melbourne may be linked to the intrusion of dykes within the last 200 years. Geophysical networks suggest that Mount Melbourne is a quiescent volcano, possibly characterised by slow internal dynamics. During the 2002-2003 Italian Antarctic campaign a high-resolution aeromagnetic survey was performed within the TIMM (Tectonics and Interior of Mt. Melbourne area) project. This helicopter-borne survey was flown at low-altitude and in drape-mode configuration (305 m above terrain) with a line separation less than 500 m. Our new high-resolution magnetic maps reveal the largely ice-covered magmatic and tectonic patters in the Mt. Melbourne volcano area. Additionally, in the frame of the UK-Italian ISODYN-WISE project (2005-06), an airborne ice-sounding radar survey was flown. We combine the sub-ice topography with images and models of the interior of Mt. Melbourne volcano, as derived from the high resolution aeromagnetic data and land gravity data. Our new geophysical maps and models also provide a new tool to study the regional setting of the volcano. In particular we re-assess whether there is geophysical evidence for coupling between strike-slip faulting, the Terror Rift, and Mount Melbourne volcano
Rifted margin of Rodinia revealed from airborne gravity in interior East Antarctica
No full textThe existence of the Rodinia supercontinent is widely accepted, although the distribution of its constituent cratons and mobile belts and the process and timing of its break-up remain hotly debated. Several models predict that Rodinia break-up involved Neoproterozoic rifting between formerly juxtaposed East Antarctica and Laurentia. However, the paucity of geophysical exploration has hampered tracing Neoproterozoic rifting in East Antarctica, adding uncertainty to Rodinia reconstructions. We interpret new airborne gravity data to reveal the crustal architecture of the Neoproterozoic rifted margin of Rodinia in East Antarctica. A linear, ~900 km long, positive Airy isostatic gravity anomaly is recognised along the western edge of the Wilkes Subglacial Basin. Gravity and magnetic models reveal a ~10 km thick mafic body emplaced along the leading edge of the Precambrian craton, beneath interpreted Neoproterozoic rift basins. We infer that voluminous mid-crustal(?) mafic magmatism accompanied Rodinia break-up in this part of East Antarctica, and was perhaps coeval with the more weakly magmatic Adelaide Rift Complex in Australia and with continental rifts and mantle-plume related magmatism in South China
Newly identified subglacial lakes along the eastern margin of the Wilkes Subglacial Basin, East Antarctica.
No full textAn aeromagnetic survey and gravity/GDS transect over the Admiralty Mountains region: field activities
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