Papers by Francesco Salvini
Intraplate strike-slip deformation belts are typically steeply-dipping structures that develop in... more Intraplate strike-slip deformation belts are typically steeply-dipping structures that develop in both oceanic and continental lithosphere where they form some of the largest and most spectacular discontinuities found on Earth. In both modern and ancient continental settings, intraplate strike slip deformation belts are of major importance in accommodating horizontal displacements where they additionally form very persistent zones of weakness that substantially influence the rheological behaviour of the lithosphere over very long time periods (up to 1 Ga or more). These deformation zones provide a fundamental geometric, kinematic and dynamic link between the more rigid plate-dominated tectonics of the oceans and the non-rigid, complex behaviour of the continents. During convergence, they help to transfer major displacements deep into the plate interiors. During divergence, they act as transfer zones that segment rifts, passive continental margins and, ultimately, oceanic spreading ridges. Such belts are also of great economic importance, controlling the location of many destructive earthquakes, offshore and onshore hydrocarbon deposits and metalliferous ore deposits. In the oceans, intraplate strike-slip movements are relatively minor along transform-related fracture zones, but there are an increasing number of documented examples that may reflect spatial and temporal variations in spreading rate along individual active ridge segments.
Remote Sensing
In Antarctica, the severe climatic conditions and the thick ice sheet that covers the largest and... more In Antarctica, the severe climatic conditions and the thick ice sheet that covers the largest and most internal part of the continent make it particularly difficult to systematically carry out geophysical and geodetic observations on a continental scale. It prevents the comprehensive understanding of both the onshore and offshore geology as well as the relationship between the inner part of East Antarctica (EA) and the coastal sector of Victoria Land (VL). With the aim to reduce this gap, in this paper multiple geophysical dataset collected since the 1980s in Antarctica by Programma Nazionale di Ricerche in Antartide (PNRA) were integrated with geodetic observations. In particular, the analyzed data includes: (i) Geodetic time series from Trans Antarctic Mountains DEFormation (TAMDEF), and Victoria Land Network for DEFormation control (VLNDEF) GNSS stations installed in Victoria Land; (ii) the integration of on-shore (ground points data and airborne) gravity measurements in Victoria...
Remote Sensing
In order to make inferences on the geodynamics of Antarctica, geodetic and gravimetric maps deriv... more In order to make inferences on the geodynamics of Antarctica, geodetic and gravimetric maps derived from past and new observations can be used. This paper provides new insights into the geodynamics of Antarctica by integrating data at regional and continental scales. In particular, signatures of geodynamic activity at a regional extent have been investigated in Victoria Land (VL, Antarctica) by means of Global Navigation Satellite System (GNSS) permanent station observations, data from the VLNDEF (Victoria Land Network for Deformation control) discontinuous network, and gravity station measurements. At the continental scale, episodic GNSS observations on VLNDEF sites collected for 20 years, together with continuous data from the International GNSS Service (IGS) and Polar Earth Observing Network (POLENET) sites, were processed, and the Euler pole position assessed with the angular velocity of the Antarctic plate. Both the Bouguer and the free-air gravity anomaly maps were obtained by...
Journal of Geophysical Research: Planets
<p>The spiral troughs of the North Polar Layered deposits on Mars are deep depressi... more <p>The spiral troughs of the North Polar Layered deposits on Mars are deep depressions that dissect the Planum Boreum ice cap. These are enigmatic structures whose puzzling origin is still under debate. Advanced hypotheses on their genesis and evolution range between erosional to structural scenario. In this work, a double approach was followed to explore the structural/tectonic origin of the spiral troughs by means of Hybrid Cellular Automata (HCA) numerical modelling and lineament domain analysis. The SHARAD profile data were used to replicate the ice internal layering architecture associated to buried troughs in Gemina Lingula. Analysis of the lineament domains automatically detected at the ice surface from satellite images of the Mars Orbiter Camera strengthened the structural/tectonic interpretation of their origin and evolution. Similar, twofold approach was used for the investigation of a terrestrial analog identified in the Antarctic ice sheet. It presents at depth blind structures recognized as fractures/faults produced by ice sheet dynamics. Radargrams of Operation IceBridge mission and images from Sentinel-2 were used to produce a tectonic model that was in turn compared with the Planum Boreum one. Obtained results, and their comparison, show that the troughs of Gemina Lingula result from the activity of low-angle normal faults with listric geometry. The activity of listric faults is modelled and compared with the antarctic analog. At the surface the detected lineament domains confirm the tectonic setting by tracing the buried trough/fault orientations. The proposed tectonic model refers to extensional regime characterized by the presence of a deep detachment connecting the troughs at depth. This represents an internal ductile layer placed at depth greater than 1000 m whose kinematics induces the troughs/faults deformation. The extensional tectonics developed in Planum Boreum is possibly related to the ice cap collapse that induces internal dynamics. In this way, katabatic winds play a secondary role by maintaining at the surface the troughs nearly orthogonal to their directions.</p>
Geophysical Journal International
Tectonics
The Cenozoic deformation history of Central Iran has been dominantly accommodated by the activati... more The Cenozoic deformation history of Central Iran has been dominantly accommodated by the activation of major intracontinental strike-slip fault zones, developed in the hinterland domain of the Arabia-Eurasia convergent margin. Few quantitative temporal and kinematic constraints are available from these strike-slip deformation zones, hampering a full assessment of the style and timing of intraplate deformation in Iran and the understanding of the possible linkage to the tectonic reorganization of the Zagros collisional zone. This study focuses on the region to the north of the active trace of the sinistral Doruneh Fault. By combing structural and low-temperature apatite fission track (AFT) and (U-Th)/He (AHe) thermochronology investigations, we provide new kinematic and temporal constraints to the deformation history of Central Iran. Our results document a post-Eocene polyphase tectonic evolution dominated by dextral strike-slip tectonics, whose activity is constrained since the early Miocene in response to an early, NW-SE oriented paleo-σ1 direction. A major phase of enhanced cooling/exhumation is constrained at the Miocene/Pliocene boundary, caused by a switch of the maximum paleo-σ1 direction to N-S. When integrated into the regional scenario, these data are framed into a new tectonic reconstruction for the Miocene-Quaternary time lapse, where strike-slip deformation in the intracontinental domain of Central Iran is interpreted as guided by the reorganization of the Zagros collisional zone in the transition from an immature to a mature stage of continental collision.
Egs Agu Eug Joint Assembly, Apr 1, 2003
ABSTRACT
Annals of Geophysics, Nov 25, 1993
Journal of Geophysical Research Solid Earth, 2008
The Pliocene-Holocene Newer Volcanic Province in Victoria, southeast Australia, is a wide volcani... more The Pliocene-Holocene Newer Volcanic Province in Victoria, southeast Australia, is a wide volcanic field site of the most recent volcanic activity of Australia. The intraplate signature and the localization on the northern side of the Southern Ocean have been used in the past to ascribe the volcanic activity either to the presence of a mantle hot spot or to thermal anomalies inherited from the seafloor spreading that separated Australia from Antarctica during the Gondwana breakup. The spacing and distribution of groups of eruption points suggests the presence of a 32 km deep mantle thermal anomaly. Alignments of eruption points indicate a strong tectonic control on magma emplacement mainly along NW-SE Mesozoic-Cenozoic structures and along N-S Palaeozoic and E-W Late Cretaceous structures. This volcano tectonic setting relates to the interference of the left-lateral kinematics of the major N-S trending faults associated with the Tasman Fracture Zone and the extensional structures of the Otway basin. This interpretation is also coherent with stress in situ data and focal mechanisms of earthquakes (S Hmax oriented N150°). This interpretation enhances the role of the Tasman Fracture Zone, a major sinistral transform, on the reactivation of transtensional structures, and on triggering the magmatism of the Newer Volcanic Province.
The Ethiopian Rift is a Plio-Quaternary continental rift characterized by two interact- ing NE-SW... more The Ethiopian Rift is a Plio-Quaternary continental rift characterized by two interact- ing NE-SW trending segments. Remote sensing and field data show that the axial part of the Rift is made up of extensional fractures and open normal faults. These show a mean N50W opening direction along a distance of 400 km, indicating an overall NW- SE spreading direction between
Earth and Planetary Science Letters, 2016
Permeability in carbonates is strongly influenced by the presence of brittle deformation patterns... more Permeability in carbonates is strongly influenced by the presence of brittle deformation patterns, i.e pressure-solution surfaces, extensional fractures, and faults. Carbonate rocks achieve fracturing both during diagenesis and tectonic processes. Attitude, spatial distribution and connectivity of brittle deformation features rule the secondary permeability of carbonatic rocks and therefore the accumulation and the pathway of deep fluids (ground-water, hydrocarbon). This is particularly true in fault zones, where the damage zone and the fault core show different hydraulic properties from the pristine rock as well as between them. To improve the knowledge of fault architecture and faults hydraulic properties we study the brittle deformation patterns related to fault kinematics in carbonate successions. In particular we focussed on the damage-zone fracturing evolution. Fieldwork was performed in Meso-Cenozoic carbonate units of the Latium-Abruzzi Platform, Central Apennines, Italy. Th...
Topographic contour maps of the East Antarctic Plateau show a prominent but apparently unrecogniz... more Topographic contour maps of the East Antarctic Plateau show a prominent but apparently unrecognized basin of ~700,000 km2 that lies ~200 m below surrounding surfaces. The basin's defining hallmark is a remarkably straight, 900 km-long headwall or headslope, passing almost under the pole and linking upper reaches of the Recovery and Foundation ice streams, the two separated by a central platform (CP). Throughout the basin a distinctive regional snow and firn unit, identifiable on satellite images by ~2km wavelength, zebra-striped megadunes, forms the basal horizon for a new type of geologic map for the Plateau. This unit underlies all other features, probably as an inactive paleo-climatic relic of diachronous Holocene age. Most deposits covering it consist of several generations of successively overprinted longitudinal dunes commonly intermingling with wind eroded channels, ice deformational features, and regionally curving snow streamers. Above this complex, a widespread but dis...
The East Antarctic craton (EAC) is a fragment of the Gondwanaland Precambrian shield as confirmed... more The East Antarctic craton (EAC) is a fragment of the Gondwanaland Precambrian shield as confirmed from the sea floor geophysical reconstruction. Despite the progress achieved in the last decades for the understanding of the tectonic evolution of the EAC, our knowledge of the subglacial geology mainly derives from geophysical data because the ice sheet (3500m average thickness) prevents from direct investigations. Since the onset of the East Antarctic Ice Sheet (EAIS) (34 Ma), the tectonic activity represents the major modelling agent of the subglacial landscape, due to the dry ice cap-bedrock contact preventing any erosional or sedimentary episodes. Radio echo-sounding (RES) data evidence the existence of an articulated bedrock physiography characterised by elongated valleys. From W to E there are: the Vostok Subglacial Depression, the Aurora Trench, the Concordia Trench and the Adventure Trench. All these valleys have asymmetric shape with the eastern steeper side and the western g...
Gamburtsev Subglacial Mts (GSM) are by far one of the most puzzling physiographic feature of the ... more Gamburtsev Subglacial Mts (GSM) are by far one of the most puzzling physiographic feature of the East Antactic craton. Located at the centre of the Antarctic continent and beneath the highest point of East Antarctic Ice Sheet (Dome A) they were discovered during the 1957-58 International Geophysical Year by a Soviet expedition using seismic instruments to measure the thickness of the ice sheet. This intracratonic mountain range is characterised by peaks with elevation exceeding 3500 m and covers an area bigger than the European Alps. The GSM were the target of a huge international geophysical expedition during the 2008-2009 summer season with the aim of revealing the geologic nature and origin of this mountain range, as well as to further understand the tectonic setting of two of the largest Antarctic subglacial lakes bounding to the East and to the West the GSM, namely the Vostok and Recovery lakes. Preliminary results of this international scientific campaign have been presented t...
Published models of snow deposits of the East Antarctic Plateau visualize km-scale snow stripes i... more Published models of snow deposits of the East Antarctic Plateau visualize km-scale snow stripes in scattered megadune fields as actively-forming stratigraphic zones growing through later Holocene time in parallel with other patches and zones of more normal snow and ice, in effect a stratigraphy of lumps scattered like fruit-cake ``goodies.'' An alternate four-unit layer-cake model seems more appropriate based on superposition relationships in satellite images. In this model the oldest unit (#1) contains upslope-climbing, relic megadune sets and cosets of pseudo-beds beneath the striped surfaces. This unit is transitional upward into unit #2, divisible into several facies: a) abandoned megadune plains or wind-swept snow regs to use a sand desert term, b) sudden appearance of high topographic relief ``Duke of York'' dunes from the children's song of the Grand Old Duke's soldiers abandoned ``neither up nor down,'' c) extensions of megadune snow stripes g...
Recent satellite mosaics of East Antarctica (EA) contradict current megadune origin models based ... more Recent satellite mosaics of East Antarctica (EA) contradict current megadune origin models based on modern wind patterns, sastrugi, and slow, snow/firn accumulation rates. The images invariably show older megadune fields buried by younger snow/firn or cut by younger structures with sastrugi as surface decorations. An alternative model proposes these enigmatic, 2-4 km spaced, zebra-striped, snow ripple marks are relics of a past climate wherein summer glaze preserved winter antidunes that grew at rates 10 to 50 times present values. This requires an earlier Holocene, warm climatic excursion with extremely rapid snow accumulation from moisture- rich air off more open winter seas. Following this, present-day snow/firn has slowly accumulated over about 2/3 of EA. This, plus limited apparent erosion / ablation of megadune areas, implies relatively minor, net accumulation over the post-megadune surface, now collapsing from deeper, bedrock-controlled outflow. A new type of snow/firn geolog...
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Papers by Francesco Salvini