This page has only limited features, please log in for full access.
Ophiolites of the Alpine belt derive from the closure of the Mesozoic Tethys Ocean that was interposed between the palaeo-Europe and palaeo-Adria continental plates. The Alpine orogeny has intensely reworked the oceanic rocks into metaophiolites with various metamorphic imprints. In the Western Alps, metaophiolites and continental-derived units are distributed within two paired bands: An inner band where Alpine subduction-related high-pressure (HP) metamorphism is preserved, and an outer band where blueschist to greenschist facies recrystallisation due to the decompression path prevails. The metaophiolites of the inner band are hugely important not just because they provide records of the prograde tectonic and metamorphic evolution of the Western Alps, but also because they retain the signature of the intra-oceanic tectono-sedimentary evolution. Lithostratigraphic and petrographic criteria applied to metasediments associated with HP metaophiolites reveal the occurrence of distinct tectono-stratigraphic successions including quartzites with marbles, chaotic rock units, and layered calc schists. These successions, although sliced, deformed, and superposed in complex ways during the orogenic stage, preserve remnants of their primary depositional setting constraining the pre-orogenic evolution of the Jurassic Tethys Ocean.
Paola Tartarotti; Silvana Martin; Andrea Festa; Gianni Balestro. Metasediments Covering Ophiolites in the HP Internal Belt of the Western Alps: Review of Tectono-Stratigraphic Successions and Constraints for the Alpine Evolution. Minerals 2021, 11, 411 .
AMA StylePaola Tartarotti, Silvana Martin, Andrea Festa, Gianni Balestro. Metasediments Covering Ophiolites in the HP Internal Belt of the Western Alps: Review of Tectono-Stratigraphic Successions and Constraints for the Alpine Evolution. Minerals. 2021; 11 (4):411.
Chicago/Turabian StylePaola Tartarotti; Silvana Martin; Andrea Festa; Gianni Balestro. 2021. "Metasediments Covering Ophiolites in the HP Internal Belt of the Western Alps: Review of Tectono-Stratigraphic Successions and Constraints for the Alpine Evolution." Minerals 11, no. 4: 411.
Holes BA1B and BA3A were drilled into the Wadi Tayin Massif, southern ophiolite complex of Oman, a fragment of the Tethyan oceanic lithosphere obducted onto the Arabian continent. Within the sequence, we have studied a portion of the shallow mantle, composed mainly of strongly serpentinised harzburgite that embeds dunitic levels, the biggest being over 150 m thick. The formation of thick dunitic channels, already approached via published structural and mathematical models, is here investigated with a mineral chemistry approach. We focused on Cr-spinel, the only widespread phase preserved during serpentinization, whose TiO2 content displays a wide variability from low in harzburgite, (TiO2 < 0.25 wt. %), typical of non-metasomatised ophiolite mantle, to moderately high in dunite (TiO2 < 1.10 wt. %) characterizing a rock/melt interactions. The high variability of TiO2, accompanied by similar patterns of Cr# and Mg# is observed, in a fractal pattern, at all scales of investigation, from the whole channel scale to the single thin section, where it affects even single grain zonings. Our results suggest that the over 150 m thick dunite channel here investigated was formed by coalescence of different scale melt channels and reaction zones with different sizes, confirming the published structural model.
Giuseppe Cocomazzi; Giovanni Grieco; Paola Tartarotti; Micol Bussolesi; Federica Zaccarini; Laura Crispini; Oman Drilling Project Science Team. The Formation of Dunite Channels within Harzburgite in the Wadi Tayin Massif, Oman Ophiolite: Insights from Compositional Variability of Cr-Spinel and Olivine in Holes BA1B and BA3A, Oman Drilling Project. Minerals 2020, 10, 167 .
AMA StyleGiuseppe Cocomazzi, Giovanni Grieco, Paola Tartarotti, Micol Bussolesi, Federica Zaccarini, Laura Crispini, Oman Drilling Project Science Team. The Formation of Dunite Channels within Harzburgite in the Wadi Tayin Massif, Oman Ophiolite: Insights from Compositional Variability of Cr-Spinel and Olivine in Holes BA1B and BA3A, Oman Drilling Project. Minerals. 2020; 10 (2):167.
Chicago/Turabian StyleGiuseppe Cocomazzi; Giovanni Grieco; Paola Tartarotti; Micol Bussolesi; Federica Zaccarini; Laura Crispini; Oman Drilling Project Science Team. 2020. "The Formation of Dunite Channels within Harzburgite in the Wadi Tayin Massif, Oman Ophiolite: Insights from Compositional Variability of Cr-Spinel and Olivine in Holes BA1B and BA3A, Oman Drilling Project." Minerals 10, no. 2: 167.
A subduction complex of the Northwestern Alps consists of serpentinites, eclogitic metagabbros, flysch‐like metasediments, meta‐ophicarbonates, and gneissic slices. Unlike other subduction complexes, it contains unusual hybridized rocks described here for the first time in the Northwestern Alps. They are preserved as patches interstitial in the metagabbro and as layers within metagabbros and serpentinites. The hybridized rocks are made of high modal zoisite/clinozoisite+white mica pseudomorphs of lawsonite, garnet, and amphibole associated with an Alpine eclogite‐facies fabric. While these eclogitic metagabbros are chemically comparable to oceanic oxide gabbros from the ultraslow Southwest Indian Ridge, the layers are extremely enriched in Al2O3 and CaO and depleted in TiO2, MgO, and SiO2 relative to metagabbros. Patches have a geochemical signature that is intermediate between that of layers and metagabbros. Trace element compositions of hybridized rocks suggest a contribution from a fluid derived from a mixed source made of sediments and serpentinites. Except for Ba, Rb and K, layers are comparable to the Global Subducting Sediments, indicating a sedimentary contribution, whereas the enrichment in Cr indicates a serpentinite contribution. Metasediment dehydration and chemical exchange of Ca and Sr have resulted in significant lawsonite crystallization in the subduction zone, as reflected by the ubiquitous presence of lawsonite pseudomorphs. In light of the unique textures and geochemical signature of the lawsonite pseudomorph‐bearing hybridized rocks, an origin by fluid‐rock interaction and Ca‐metasomatism in the subduction environment is inferred and considered in the Western Alps context.
P. Tartarotti; S. Martin; C. M. Meyzen; L. Benciolini; L. Toffolo. Structural Evolution and Metasomatism of Subducted Metaophiolites in the Northwestern Alps. Tectonics 2019, 38, 4185 -4206.
AMA StyleP. Tartarotti, S. Martin, C. M. Meyzen, L. Benciolini, L. Toffolo. Structural Evolution and Metasomatism of Subducted Metaophiolites in the Northwestern Alps. Tectonics. 2019; 38 (12):4185-4206.
Chicago/Turabian StyleP. Tartarotti; S. Martin; C. M. Meyzen; L. Benciolini; L. Toffolo. 2019. "Structural Evolution and Metasomatism of Subducted Metaophiolites in the Northwestern Alps." Tectonics 38, no. 12: 4185-4206.
The primary stratigraphic fabric of a chaotic rock unit in the Zermatt Saas ophiolite of the Western Alps was reworked by a polyphase Alpine tectonic deformation. Multiscalar structural criteria demonstrate that this unit was deformed by two ductile subduction-related phases followed by brittle-ductile then brittle deformation. Deformation partitioning operated at various scales, leaving relatively unstrained rock domains preserving internal texture, organization, and composition. During subduction, ductile deformation involved stretching, boudinage, and simultaneous folding of the primary stratigraphic succession. This deformation is particularly well-documented in alternating layers showing contrasting deformation style, such as carbonate-rich rocks and turbiditic serpentinite metasandstones. During collision and exhumation, deformation enhanced the boudinaged horizons and blocks, giving rise to spherical to lozenge-shaped blocks embedded in a carbonate-rich matrix. Structural criteria allow the recognition of two main domains within the chaotic rock unit, one attributable to original broken formations reflecting turbiditic sedimentation, the other ascribable to an original sedimentary mélange. The envisaged geodynamic setting for the formation of the protoliths is the Jurassic Ligurian-Piedmont ocean basin floored by mostly serpentinized peridotites, intensely tectonized by extensional faults that triggered mass transport processes and turbiditic sedimentation.
Paola Tartarotti; Sara Guerini; Francesca Rotondo; Andrea Festa; Gianni Balestro; Gray E. Bebout; Enrico Cannaò; Gabe S. Epstein; Marco Scambelluri. Superposed Sedimentary and Tectonic Block-In-Matrix Fabrics in a Subducted Serpentinite Mélange (High-Pressure Zermatt Saas Ophiolite, Western Alps). Geosciences 2019, 9, 358 .
AMA StylePaola Tartarotti, Sara Guerini, Francesca Rotondo, Andrea Festa, Gianni Balestro, Gray E. Bebout, Enrico Cannaò, Gabe S. Epstein, Marco Scambelluri. Superposed Sedimentary and Tectonic Block-In-Matrix Fabrics in a Subducted Serpentinite Mélange (High-Pressure Zermatt Saas Ophiolite, Western Alps). Geosciences. 2019; 9 (8):358.
Chicago/Turabian StylePaola Tartarotti; Sara Guerini; Francesca Rotondo; Andrea Festa; Gianni Balestro; Gray E. Bebout; Enrico Cannaò; Gabe S. Epstein; Marco Scambelluri. 2019. "Superposed Sedimentary and Tectonic Block-In-Matrix Fabrics in a Subducted Serpentinite Mélange (High-Pressure Zermatt Saas Ophiolite, Western Alps)." Geosciences 9, no. 8: 358.
We compare three poorly known, historical Ni–Co-bearing hydrothermal deposits in different geological settings in Italy: The Ni–Co–As–Sb–Au-bearing Arburese vein system (SW Sardinia), the Co–Ni–As-rich Usseglio vein system (Piedmont), and the small Cu–Ag–Co–Ni–Pb–Te–Se stockwork at Piazza (Liguria). These deposits share various (mineralogical, chemical, thermal, and stable isotopic) similarities to the Five Element Vein-type ores but only the first two were economic for Co–Ni. The Sardinian Ni-rich veins occur in Paleozoic basement near two Variscan plutons. Like the Co-rich Usseglio vein system, the uneconomic Piazza deposit is hosted in an ophiolite setting anomalous for Co. The Sardinian and Usseglio deposits share a polyphasic assemblage with Ni–Co–As–Sb–Bi followed by Ag-base metal sulfides, in siderite-rich gangue, whereas Piazza shows As-free, Ag–Pb–Te–Se-bearing Co–Ni–Cu sulfides, in prehnite–chlorite gangue. Fluid inclusions indicated Co–Ni arsenide precipitation at ≈170 °C for Usseglio, whereas for the Sardinian system late sulfide deposition occurred within the 52–126 °C range. Ore fluids in both systems are NaCl-CaCl2-bearing basinal brines. The chlorite geothermometer at Piazza provides the range of 200–280 °C for ore deposition from CO2-poor fluids. Enrichments in Se and negative δ13C in carbonates suggest interaction with carbonaceous shales. These deposits involve issues about source rocks, controls on Co/Ni and possible role of arsenic and carbonate components towards economic mineralization.
Marilena Moroni; Piergiorgio Rossetti; Stefano Naitza; Lorenzo Magnani; Giovanni Ruggieri; Andrea Aquino; Paola Tartarotti; Andrea Franklin; Elena Ferrari; Daniele Castelli; Giacomo Oggiano; Francesco Secchi. Factors Controlling Hydrothermal Nickel and Cobalt Mineralization—Some Suggestions from Historical Ore Deposits in Italy. Minerals 2019, 9, 429 .
AMA StyleMarilena Moroni, Piergiorgio Rossetti, Stefano Naitza, Lorenzo Magnani, Giovanni Ruggieri, Andrea Aquino, Paola Tartarotti, Andrea Franklin, Elena Ferrari, Daniele Castelli, Giacomo Oggiano, Francesco Secchi. Factors Controlling Hydrothermal Nickel and Cobalt Mineralization—Some Suggestions from Historical Ore Deposits in Italy. Minerals. 2019; 9 (7):429.
Chicago/Turabian StyleMarilena Moroni; Piergiorgio Rossetti; Stefano Naitza; Lorenzo Magnani; Giovanni Ruggieri; Andrea Aquino; Paola Tartarotti; Andrea Franklin; Elena Ferrari; Daniele Castelli; Giacomo Oggiano; Francesco Secchi. 2019. "Factors Controlling Hydrothermal Nickel and Cobalt Mineralization—Some Suggestions from Historical Ore Deposits in Italy." Minerals 9, no. 7: 429.
The permeability structure of oceanic crust controls both the spatial and temporal extent of hydrothermal circulation, but the detailed geometry of fractures in seafloor rocks is not well known. We apply an equivalent channel model to veins, joints, faults, and breccias preserved in recovered cores from ODP‐IODP Hole 1256D to calculate paleo‐permeability. In the ~250‐m transition between dikes and lavas, paleo‐permeability is 10−13~10−14 m2 with narrow zones of >10−9 m2 that presumably act as conduits for the largest volume of fluids. Most of these high‐permeability zones are oriented vertically as a result of diking events into a significant thickness of lavas outside of the neovolcanic zone. After an increase in permeability due to off‐axis diking events, fluid temperatures drop, pathways are sealed, and the permeability of the upper oceanic crust drops significantly.
L. A. Gilbert; Laura Crispini; P. Tartarotti; M. L. Bona. Permeability Structure of the Lava-Dike Transition of 15-Myr-Old Oceanic Crust Formed at the East Pacific Rise. Geochemistry, Geophysics, Geosystems 2018, 19, 3555 -3569.
AMA StyleL. A. Gilbert, Laura Crispini, P. Tartarotti, M. L. Bona. Permeability Structure of the Lava-Dike Transition of 15-Myr-Old Oceanic Crust Formed at the East Pacific Rise. Geochemistry, Geophysics, Geosystems. 2018; 19 (9):3555-3569.
Chicago/Turabian StyleL. A. Gilbert; Laura Crispini; P. Tartarotti; M. L. Bona. 2018. "Permeability Structure of the Lava-Dike Transition of 15-Myr-Old Oceanic Crust Formed at the East Pacific Rise." Geochemistry, Geophysics, Geosystems 19, no. 9: 3555-3569.
The geological map of the Saint-Marcel valley at the scale of 1:20,000 illustrates the tectonic setting of metaophiolites from the southern Aosta Valley, in the Italian side of the Western Alpine belt. The map highlights the sharp contact between the metaophiolitic basement and its metasedimentary cover, which mainly consists of quartzites, marbles, and calcschists. In spite of the Alpine tectonics, this contact is regarded as deriving from the original oceanic crust/sediments interface. Metaophiolites mostly consist of metabasalts hosting Fe–Cu sulphide mineralisations, characterised by high-pressure metamorphic imprint. These rocks likely represent the shallowest portion of the Tethyan oceanic lithosphere created near the axis of the slow-spreading ridge where hydrothermal fluid circulation was active. Selected key-sections through metasediments reveal a consistent internal lithostratigraphy, in spite of the pervasive metamorphic and tectonic reworking acting during the Alpine evolution. Metasediments reflect various sedimentation episodes starting from pelagic and proximal settings to the onset of the orogenic stage. The Saint-Marcel valley metasediments thus reflect a changing in the sedimentation environments through time and space during the overall geologic evolution.
Paola Tartarotti; Silvana Martin; Bruno Monopoli; Luca Benciolini; Alessio Schiavo; Riccardo Campana; Irene Vigni. Geology of the Saint-Marcel valley metaophiolites (Northwestern Alps, Italy). Journal of Maps 2017, 13, 707 -717.
AMA StylePaola Tartarotti, Silvana Martin, Bruno Monopoli, Luca Benciolini, Alessio Schiavo, Riccardo Campana, Irene Vigni. Geology of the Saint-Marcel valley metaophiolites (Northwestern Alps, Italy). Journal of Maps. 2017; 13 (2):707-717.
Chicago/Turabian StylePaola Tartarotti; Silvana Martin; Bruno Monopoli; Luca Benciolini; Alessio Schiavo; Riccardo Campana; Irene Vigni. 2017. "Geology of the Saint-Marcel valley metaophiolites (Northwestern Alps, Italy)." Journal of Maps 13, no. 2: 707-717.
The eclogite facies Zermatt-Saas ophiolite in the Western Alps includes a composite chaotic unit exposed in the Lake Miserin area, in the southern Aosta Valley region. The chaotic unit is characterized by a block-in-matrix texture consisting of ultramafic clasts and blocks embedded within a carbonate matrix. This unit overlies massive serpentinite and ophicarbonate rocks and is unconformably overlain by layered calcschist. Despite the effects of subduction and collision-related deformation and metamorphism, the internal stratigraphy and architecture of the chaotic unit are recognizable and are attributed to different types of mass transport processes in the Jurassic Ligurian-Piedmont Ocean. This finding represents an exceptional record of the preorogenic history of the Alpine ophiolites, marked by different pulses of extensional tectonics responsible for the rough seafloor topography characterized by structural highs exposed to submarine erosion. The Jurassic tectonostratigraphic setting envisioned is comparable to that observed in present-day magma-poor slow- and ultraslow-spreading ridges, characterized by mantle exposure along fault scarps that trigger mass transport deposits and turbiditic sedimentation. Our preorogenic reconstruction is significant in an eclogitized collisional orogenic belt in which chaotic rock units may be confused with the exclusive product of subduction-related tectonics, thus obscuring the record of an important preorogenic history. © 2017 Geological Society of America
Paola Tartarotti; Andrea Festa; Luca Benciolini; Gianni Balestro. Record of Jurassic mass transport processes through the orogenic cycle: Understanding chaotic rock units in the high-pressure Zermatt-Saas ophiolite (Western Alps). Lithosphere 2017, 9, 399 -407.
AMA StylePaola Tartarotti, Andrea Festa, Luca Benciolini, Gianni Balestro. Record of Jurassic mass transport processes through the orogenic cycle: Understanding chaotic rock units in the high-pressure Zermatt-Saas ophiolite (Western Alps). Lithosphere. 2017; 9 (3):399-407.
Chicago/Turabian StylePaola Tartarotti; Andrea Festa; Luca Benciolini; Gianni Balestro. 2017. "Record of Jurassic mass transport processes through the orogenic cycle: Understanding chaotic rock units in the high-pressure Zermatt-Saas ophiolite (Western Alps)." Lithosphere 9, no. 3: 399-407.
Gianni Balestro; Andrea Festa; Yildirim Dilek; Paola Tartarotti. Pre-Alpine extensional tectonics of a peridotitelocalized oceanic core complex in the Late Jurassic, high-pressure Monviso ophiolite (Western Alps). Episodes 2015, 38, 266 -282.
AMA StyleGianni Balestro, Andrea Festa, Yildirim Dilek, Paola Tartarotti. Pre-Alpine extensional tectonics of a peridotitelocalized oceanic core complex in the Late Jurassic, high-pressure Monviso ophiolite (Western Alps). Episodes. 2015; 38 (4):266-282.
Chicago/Turabian StyleGianni Balestro; Andrea Festa; Yildirim Dilek; Paola Tartarotti. 2015. "Pre-Alpine extensional tectonics of a peridotitelocalized oceanic core complex in the Late Jurassic, high-pressure Monviso ophiolite (Western Alps)." Episodes 38, no. 4: 266-282.
Paola Tartarotti; Andrea Festa; Luca Benciolini; Gianni Balestro. Fossil mantle-sediments interface recognized in the Western Alps metaophiolites: a key to unravel the accretion mechanism of the Jurassic Tethys ocean. Rendiconti Online della Società Geologica Italiana 2015, 37, 68 -71.
AMA StylePaola Tartarotti, Andrea Festa, Luca Benciolini, Gianni Balestro. Fossil mantle-sediments interface recognized in the Western Alps metaophiolites: a key to unravel the accretion mechanism of the Jurassic Tethys ocean. Rendiconti Online della Società Geologica Italiana. 2015; 37 ():68-71.
Chicago/Turabian StylePaola Tartarotti; Andrea Festa; Luca Benciolini; Gianni Balestro. 2015. "Fossil mantle-sediments interface recognized in the Western Alps metaophiolites: a key to unravel the accretion mechanism of the Jurassic Tethys ocean." Rendiconti Online della Società Geologica Italiana 37, no. : 68-71.
Andrea Festa; Gianni Balestro; Yildirim Dilek; Paola Tartarotti. A Jurassic oceanic core complex in the high-pressure Monviso ophiolite (western Alps, NW Italy). Lithosphere 2015, L458.1 .
AMA StyleAndrea Festa, Gianni Balestro, Yildirim Dilek, Paola Tartarotti. A Jurassic oceanic core complex in the high-pressure Monviso ophiolite (western Alps, NW Italy). Lithosphere. 2015; ():L458.1.
Chicago/Turabian StyleAndrea Festa; Gianni Balestro; Yildirim Dilek; Paola Tartarotti. 2015. "A Jurassic oceanic core complex in the high-pressure Monviso ophiolite (western Alps, NW Italy)." Lithosphere , no. : L458.1.
Giovanni Muttoni; Paola Tartarotti; Marco Chiari; Chiara Marieni; Daniel Rodelli; Edoardo Dallanave; Uwe Kirscher. Paleolatitudes of Late Triassic radiolarian cherts from Argolis, Greece: Insights on the paleogeography of the western Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology 2015, 417, 476 -490.
AMA StyleGiovanni Muttoni, Paola Tartarotti, Marco Chiari, Chiara Marieni, Daniel Rodelli, Edoardo Dallanave, Uwe Kirscher. Paleolatitudes of Late Triassic radiolarian cherts from Argolis, Greece: Insights on the paleogeography of the western Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology. 2015; 417 ():476-490.
Chicago/Turabian StyleGiovanni Muttoni; Paola Tartarotti; Marco Chiari; Chiara Marieni; Daniel Rodelli; Edoardo Dallanave; Uwe Kirscher. 2015. "Paleolatitudes of Late Triassic radiolarian cherts from Argolis, Greece: Insights on the paleogeography of the western Tethys." Palaeogeography, Palaeoclimatology, Palaeoecology 417, no. : 476-490.
The Mount Avic massif consists of serpentinized peridotite exposed in the southern Aosta valley (Northwestern Alps), covering an area of ca. 180 km2. The 1:10,000 scale geological map is located in the southern portion of the massif, where serpentinite is in contact with ophiolitic rocks pertaining to the Piemonte Zone, which represents the fossil Mesozoic Tethyan ocean. Southwards, ophiolites are overthrusted by the continental-derived Austroalpine Mont Glacier unit. Serpentinite consists of antigorite, magnetite, and coarse grained Ti-clinohumite, olivine, and diopside, which are reminiscent of the original mantle texture. Rodingitic mafic dykes are intruded within serpentinite; other mafic rocks, consisting of (not rodingitized) metagabbro and metabasalt with relict eclogitic minerals, occur as tectonic slices associated with serpentinite, calcschist and sulphide-rich epidosite. The map gives detailed and updated information on the structure and lithostratigraphy of the Mount Avic ophiolites, providing an insight to the mantle-crust transition of the Tethyan oceanic lithosphere.
Emanuele Fontana; Paola Tartarotti; Matteo Panseri; Salvatore Buscemi. Geological map of the Mount Avic massif (Western Alps Ophiolites). Journal of Maps 2014, 11, 126 -135.
AMA StyleEmanuele Fontana, Paola Tartarotti, Matteo Panseri, Salvatore Buscemi. Geological map of the Mount Avic massif (Western Alps Ophiolites). Journal of Maps. 2014; 11 (1):126-135.
Chicago/Turabian StyleEmanuele Fontana; Paola Tartarotti; Matteo Panseri; Salvatore Buscemi. 2014. "Geological map of the Mount Avic massif (Western Alps Ophiolites)." Journal of Maps 11, no. 1: 126-135.
In the Inner Western Alps, three different types of block-in-matrix structures (BIMs) formed sequentially through time at a convergent plate margin. These show the superposition of progressive deformation from (i) subduction to eclogite-facies depths, (ii) collision, accretion, and exhumation of oceanic crust, represented by the Monviso Meta-ophiolite Complex, to (iii) collision, accretion, and exhumation of the continental Dora Maira units. The Type 1 occurs in the metasedimentary cover of the Dora Maira Unit and consists of a map-scale broken formation with boudinaged ‘native’ blocks of marble (Early Jurassic) in a calcschist matrix. It results from the tectonic overprinting of exhumation-related folding (D2-stage) on an earlier subduction-related dismembered succession (D1-stage). Type 1 also includes ‘non-mappable’ BIMs with ‘exotic’ blocks, resulting from the gravitational collapse of the Triassic carbonate platform of European Continental Margin, triggered by the Early Jurassic rifting. In the Monviso Meta-ophiolite Complex, Types 2 and 3 represent tectonically induced broken and dismembered formations, respectively. They differ from each other in the degree of stratal disruption of primary interbedded horizons of mafic metabreccia (Type 3) and mafic metasandstone (Types 2 and 3) sourced by the Late Jurassic–Early Cretaceous denudation of an oceanic core complex. Dismembered interbeds (Type 2) and isolated blocks were mixed together (Type 3) by the overlap of D2 tectonics and late- to post-exhumation extensional shearing (D3-stage). Development of these types of BIMs may be common in many exhumed convergent plate margins, where severe tectonics and metamorphic recrystallization under high-pressure conditions normally prevent the reconstruction of BIMs or mélange-forming processes. Our findings show that documenting the mode and time of the processes forming BIMs is highly relevant in order to reconstruct the oceanic seafloor morphology and composition of associated stratigraphic successions, and their control in the evolution of those convergent plate margins.
Gianni Balestro; Andrea Festa; Paola Tartarotti. Tectonic significance of different block-in-matrix structures in exhumed convergent plate margins: examples from oceanic and continental HP rocks in Inner Western Alps (northwest Italy). International Geology Review 2014, 57, 581 -605.
AMA StyleGianni Balestro, Andrea Festa, Paola Tartarotti. Tectonic significance of different block-in-matrix structures in exhumed convergent plate margins: examples from oceanic and continental HP rocks in Inner Western Alps (northwest Italy). International Geology Review. 2014; 57 (5):581-605.
Chicago/Turabian StyleGianni Balestro; Andrea Festa; Paola Tartarotti. 2014. "Tectonic significance of different block-in-matrix structures in exhumed convergent plate margins: examples from oceanic and continental HP rocks in Inner Western Alps (northwest Italy)." International Geology Review 57, no. 5: 581-605.
The ocean crust is formed by the rising of magma from mid‐ocean ridges and voluminous (1–30 km3) flows of lava away from ridge axes. However, our understanding of the emplacement kinematics of submarine lava is often limited to plan view geometries of near‐axis lava. Drilled cores provide in situ access to the intact internal structure of submarine lavas. We used neutron diffraction to study off‐axis lava flows drilled into the uppermost crust of ODP/IODP‐Site 1256 (Cocos Plate). We provide quantitative insights into submarine lava microstructures and strong evidence for a secondary lava injection into the interior of a solidifying flow of lava along the NW‐SE direction parallel to the paleo‐ridge axis of the East Pacific Rise. The dynamics of lava inflow are controlled by crystal abundance and the temperature of the lava‐crystal mixture rather than by local seafloor topography. We provide a description of an in situ shear within submarine lavas revealed by composite shape and lattice preferred orientations, accounting for a dominant laminar nonuniform‐type flow.
Michele Zucali; Emanuele Fontana; M. Panseri; Paola Tartarotti; S. Capelli; B. Ouladdiaf. Submarine lava flow direction revealed by neutron diffraction analysis in mineral lattice orientation. Geochemistry, Geophysics, Geosystems 2014, 15, 765 -780.
AMA StyleMichele Zucali, Emanuele Fontana, M. Panseri, Paola Tartarotti, S. Capelli, B. Ouladdiaf. Submarine lava flow direction revealed by neutron diffraction analysis in mineral lattice orientation. Geochemistry, Geophysics, Geosystems. 2014; 15 (3):765-780.
Chicago/Turabian StyleMichele Zucali; Emanuele Fontana; M. Panseri; Paola Tartarotti; S. Capelli; B. Ouladdiaf. 2014. "Submarine lava flow direction revealed by neutron diffraction analysis in mineral lattice orientation." Geochemistry, Geophysics, Geosystems 15, no. 3: 765-780.
[1] New ocean crust is constantly being formed from mid‐ocean ridge axis. Voluminous flows of lava are emplaced also away from the ridge axis, adding off‐axis crustal layers to the crustal pile. Research on deep sea is of great importance to better understand the mechanisms and the nature of the crust forming and evolution. In this work, we decipher the first stages of the postmagmatic evolution of an intact volcanic section from the upper oceanic crust at ocean drilling program/integrated ocean drilling program (ODP/IODP) Site 1256 (Eastern Pacific Ocean). Using for the first time an innovative core‐log integration technique to match direct (core‐related) and indirect (borehole‐related) data by depth shifting and reorienting individual core pieces recovered by drilling, we are able to identify the clusterization of structures and physical properties within distinct downdeep “strong” and “weak” lava zones, reflecting the cooling and tectonic evolution of lavas rather than lithological variations. We define the evolution of the structural zones that typically affect lava flows: colonnades and entablature zones, studying an off‐axis lava flow encountered in present‐day upper ocean crust. For the same off‐axis flow, we are also able to suggest the lava flow direction (NW‐SE) and its relationships with the paleoridge axis. Despite the environmental difficulties in the study of the subseafloor under deep water and using only one‐dimensional data deriving from ocean drilling, this work shows how an array of diverse data can be integrated into a coherent interpretation of lava flow history obtaining detailed information on the mechanism of submarine lava emplacement and flow.
Emanuele Fontana; Paola Tartarotti. Structural and petrophysical characterization of the upper basement crustal section at ODP/IODP Site 1256 (East Pacific Ocean). Geochemistry, Geophysics, Geosystems 2013, 14, 2399 -2431.
AMA StyleEmanuele Fontana, Paola Tartarotti. Structural and petrophysical characterization of the upper basement crustal section at ODP/IODP Site 1256 (East Pacific Ocean). Geochemistry, Geophysics, Geosystems. 2013; 14 (7):2399-2431.
Chicago/Turabian StyleEmanuele Fontana; Paola Tartarotti. 2013. "Structural and petrophysical characterization of the upper basement crustal section at ODP/IODP Site 1256 (East Pacific Ocean)." Geochemistry, Geophysics, Geosystems 14, no. 7: 2399-2431.
The ophiolitic rocks of the Frido Unit include serpentinites derived from a lherzolitic to cpx-rich harzburgitic mantle, as suggested by microstructural and petrographical features. The serpentinites are englobed in tectonic slices where they are associated with mafic dykes and medium to high-grade metamorphic rocks such as amphibolites, gneiss, granofels as well as gabbros and basalts with pillow structures. The matrix of tectonic slices is mainly composed of calchschists and phyllites. The serpentinites of the Frido Unit show pseudomorphic and vein textures. Primary mantle minerals are represented by olivine, orthopyroxene, clinopyroxene and spinel and are identifiable either for the occurrence of mineral relics or pseudomorphs maintaining the mineral shape. Pseudomorphic minerals are serpentine, magnetite, chlorite, and tremolite. Olivine is replaced by serpentine forming a mesh texture; orthopyroxene is mostly altered to bastite; in some cases it shows exsolution lamellae of clinopyroxene and kink bands; fresh orthopyroxene is preserved as exsolution inside clinopyroxene porphyroclasts. Clinopyroxene is armoured by tremolite rim. Spinel shows a holly-leaf habit and is often armoured by a corona of Cr-chlorite. The core of the analyzed spinel has a Cr-Al spinel composition corresponding to chromite (Al2O3=29-31 wt %; Cr2O3= 28-37 wt%), whereas the rim has a Fe-Cr spinel composition corresponding to ferrit-chromite (Al2O3= 1-2% wt; Cr2O3=28-30 wt %). The Cr-Al spinel/ferritchromite ratio may be various in different spinel porphyroclasts. Magnetite replaces spinel or occurs within the mesh textured serpentine. The metamorphic assemblages in the Frido Unit serpentinites allow to infer qualitatively the physical conditions operating during serpentinization. The metamorphic mineral assemblages are typical of the greenschist-amphibolite transition and greenschist facies conditions, as suggested by the occurrence of tremolite replacing clinopyroxene and of Cr-chlorite and ferrit-chromite after Al-rich chromite. These minerals were produced by interactions between hydrothermal fluids and mantle peridotites. Serpentinites are cut by veins filled with mineralogical assemblages typical of the prehnite-pumpellyite facies likely related to later orogenic Apennine evolution. HP/LT metamorphic conditions (blueschist facies) have been documented in mafic dykes enclosed in serpentinites, but similar conditions are not recorded in serpentinites. This suggests that P-T conditions during the orogenic event were not able to produce a HP/LT mineral assemblage in serpentinites.
Maria T. Cristi Sansone; Giacomo Prosser; Giovanna Rizzo; Paola Tartarotti. Spinel-peridotites of the Frido Unit ophiolites (Southern Apennine-Italy): evidence for oceanic evolution. 2012, 81, 35 -59.
AMA StyleMaria T. Cristi Sansone, Giacomo Prosser, Giovanna Rizzo, Paola Tartarotti. Spinel-peridotites of the Frido Unit ophiolites (Southern Apennine-Italy): evidence for oceanic evolution. . 2012; 81 (1):35-59.
Chicago/Turabian StyleMaria T. Cristi Sansone; Giacomo Prosser; Giovanna Rizzo; Paola Tartarotti. 2012. "Spinel-peridotites of the Frido Unit ophiolites (Southern Apennine-Italy): evidence for oceanic evolution." 81, no. 1: 35-59.
Maria T. Cristi Sansone; Paola Tartarotti; Giacomo Prosser; Giovanna Rizzo. From ocean to subduction: the polyphase metamorphic evolution of the Frido Unit metadolerite dikes (Southern Apennine, Italy). Journal of the Virtual Explorer 2012, 41, 1 .
AMA StyleMaria T. Cristi Sansone, Paola Tartarotti, Giacomo Prosser, Giovanna Rizzo. From ocean to subduction: the polyphase metamorphic evolution of the Frido Unit metadolerite dikes (Southern Apennine, Italy). Journal of the Virtual Explorer. 2012; 41 ():1.
Chicago/Turabian StyleMaria T. Cristi Sansone; Paola Tartarotti; Giacomo Prosser; Giovanna Rizzo. 2012. "From ocean to subduction: the polyphase metamorphic evolution of the Frido Unit metadolerite dikes (Southern Apennine, Italy)." Journal of the Virtual Explorer 41, no. : 1.
Michele Zucali; Paola Tartarotti; Silvia Capelli; Bachir Ouladdiaf. Multiscalar structural study of the ultramafic rocks of the Antrona Ophiolite (Pennine Alps). Journal of the Virtual Explorer 2012, 41, 1 .
AMA StyleMichele Zucali, Paola Tartarotti, Silvia Capelli, Bachir Ouladdiaf. Multiscalar structural study of the ultramafic rocks of the Antrona Ophiolite (Pennine Alps). Journal of the Virtual Explorer. 2012; 41 ():1.
Chicago/Turabian StyleMichele Zucali; Paola Tartarotti; Silvia Capelli; Bachir Ouladdiaf. 2012. "Multiscalar structural study of the ultramafic rocks of the Antrona Ophiolite (Pennine Alps)." Journal of the Virtual Explorer 41, no. : 1.
Emanuele Fontana; Gerardo J. Iturrino; Paola Tartarotti. Depth-shifting and orientation of core data using a core–log integration approach: A case study from ODP–IODP Hole 1256D. Tectonophysics 2010, 494, 85 -100.
AMA StyleEmanuele Fontana, Gerardo J. Iturrino, Paola Tartarotti. Depth-shifting and orientation of core data using a core–log integration approach: A case study from ODP–IODP Hole 1256D. Tectonophysics. 2010; 494 (1):85-100.
Chicago/Turabian StyleEmanuele Fontana; Gerardo J. Iturrino; Paola Tartarotti. 2010. "Depth-shifting and orientation of core data using a core–log integration approach: A case study from ODP–IODP Hole 1256D." Tectonophysics 494, no. 1: 85-100.