 | | Journal (article/letter/editorial) | | magmatism prior to continental break-up in the North Atlantic and geodynamic implications Urs Scha«rer a; *...and Gorringe banks and in the Iberia Abyssal Plain of the North Atlantic, unroofed subcontinental mantle...Based on the new results, a structural model for Iberia^America rifting is discussed putting forward the...magmatism; U/Pb; absolute age; hafnium; isotopes; North Atlantic * Corresponding author. Tel.: +33-1-44-27-28-20;...documented, in particular for cases such as the Iberia margin, where riftrelated volcanism is absent on |  | | Journal (article/letter/editorial) | | consequences for the evolution of the southern North Atlantic Othmar Müntener a,⁎, Gianreto Manatschal b a ...mineral compositions similar to the most depleted abyssal peridotites worldwide and different from those...peridotite basement resemble normal to transitional mid-ocean ridge basalt. This, together with the unusually...was exhumed close to the ocean floor during the rifting evolution of the Atlantic. Compared to the spinel...inherited, primary, Ca-richer composition of the Iberia peridotite, or, alternatively, by local melt impregnation |  | | Journal (article/letter/editorial) | | margins (e.g., the Western Iberia margin, [1] and references therein) and at Mid-Ocean Ridges (MORs; e.g., [2...an environment favoring microbial development (Ocean Drilling Program (ODP) Leg 149 Site 897; [25])....hydrothermal systems exist at MORs such as the Mid-Atlantic Ridge (MAR; Kane Fracture Zone [26]; 15◦ N [27])...[27]) and in passive margins (e.g., Western Iberia margin; [25]). Fossil systems are also found in mountain...lead to crystallization of Si-rich phases, like talc [10,29] or quartz [30]. The composition of carbonates |  | | Report (chapter) | | serpentinized peridotites occur within a wide continent-ocean transition (COT) and beneath the edge of the thinned...thickness of serpentinites at the SW Greenland and West Iberia margins, and the Rockall Trough. They also explain...break-up. Larger melt production than in the West Iberia type margins and concentration of the lithospheric...Well-known examples of such margins include the West Iberia-Newfoundland conjugate margins (Boillot & Winterer...within a broad continent-ocean transition (COT; Fig. 2). Of these, the West Iberia margin has become the |  | Pinto, Victor Hugo G., Manatschal, Gianreto, Karpoff, Anne Marie, Ulrich, Marc, Viana, Adriano R. (2017) Seawater storage and element transfer associated with mantle serpentinization in magma-poor rifted margins: A quantitative approach. Earth and Planetary Science Letters, 459. 227-237 doi:10.1016/j.epsl.2016.11.023 | Journal (article/letter/editorial) | | transfer water storage magma-poor rifted margins ocean continent transitions a b s t r a c t Continental...process of serpentinization within the evolving ocean may have the potential to change: (i) seawater chemistry;...exhumed continental mantle, slow spreading mid-ocean ridges as well as sampled in ophiolites have allowed...complexes located at slow to ultraslow spreading mid-ocean ridges, have also showed that serpentinization is...drill hole data following the Ocean Drilling Program (ODP) along the Iberia margin (e.g. Gibson et al., |  | | Report (chapter) | | magma-poor rifted margins: an example from the West Iberia –Newfoundland conjugate margins MARTA PÉREZ-GUSSINYÉ...margins are characterized by a wide continent –ocean transition and anomalously small fractions of magmatism...on the West Iberia Margin (WIM)–Newfoundland (NF) conjugates in the North Atlantic Ocean. The architectural...Hyperextended margins are characterized by a wide continent–ocean transition and anomalously small fractions of magmatism...Porcupine, Rockall, More, Vøring and West Orphan North Atlantic basins, once interpreted as magmatic underplating |  | | Journal (article/letter/editorial) | | Serpentinite Occurrences in the Oceans: Mantle-Ocean Interactions in the Plate Tectonic Cycle Patricia...Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of...regional scales as continental rifts open and new ocean basins form. The process of seawater incursion deep...into faulted oceanic crust at slow-spreading mid-ocean ridges during periodic amagmatic phases produces...supposed. Serpentinite may form at the ends of mid-ocean rift segments as a consequence of low-angle faulting |  | | Journal (article/letter/editorial) | | thriving in Ophicalcites (lizardite, chrysotile) and talc, diopside and chromite accompanying these minerals...ultramafic rocks, serpen tine + magnesite, magnesite + talc and finally magnesite + quartz formations show the...many rock series thriving in metaperidotites, midocean ridges, subduction zone ophiolites and the fronts...in the north and south tributary of neotethyan ocean. anic areas in MiddleUpper Trias, which is formed...belonging to the northern tribu tary of the neotethyan ocean also known as the Izmir– Ankara–Erzincan Zone and |  | Cooperdock, Emily H.G., Raia, Natalie H., Barnes, Jaime D., Stockli, Daniel F., Schwarzenbach, Esther M. (2018) Tectonic origin of serpentinites on Syros, Greece: Geochemical signatures of abyssal origin preserved in a HP/LT subduction complex. Lithos, 296. 352-364 doi:10.1016/j.lithos.2017.10.020 | Journal (article/letter/editorial) | | serpentinites on Syros, Greece: Geochemical signatures of abyssal origin preserved in a HP/LT subduction complex...that consist of variable amounts of serpentine, talc, chlorite, and magnetite. δD and δ18O values of...derivation from abyssal peridotites in a hyper-extended margin setting or mid-ocean ridge and fracture...associated with the Cretaceous opening of the Pindos Ocean and not a subduction-related derivation from the...originating from seafloor-altered peridotite (i.e., mid-ocean ridges and fracture zones or hyper-extended margins) |  | Barnes, Jaime D., Beltrando, Marco, Lee, Cin-Ty A., Cisneros, Miguel, Loewy, Staci, Chin, Emily (2014) Geochemistry of Alpine serpentinites from rifting to subduction: A view across paleogeographic domains and metamorphic grade. Chemical Geology, 389. 29-47 doi:10.1016/j.chemgeo.2014.09.012 | Journal (article/letter/editorial) | | serpentinites from the Western Alps is consistent with an abyssal origin in a hyper-extended rifted margin •Relict...REE RI concentrations, compared to typical mid-ocean ridge serpentinites, with nearly flat REE patterns...these NU observations are consistent with an abyssal origin in a hyper-extended rifted margin with minimal...margins of the kind presently found in the Northern Atlantic are exposed SC (e.g., Afilhado et al., 2008;...serpentinites are notably enriched in FME, compared to abyssal peridotites, (Deschamps et al., NU 2010; Hattori |  | Marchesi, Claudio, Garrido, Carlos J., Padrón-Navarta, José Alberto, López Sánchez-Vizcaíno, Vicente, Gómez-Pugnaire, María Teresa (2013) Element mobility from seafloor serpentinization to high-pressure dehydration of antigorite in subducted serpentinite: Insights from the Cerro del Almirez ultramafic massif (southern Spain) Lithos, 178. 128-142 doi:10.1016/j.lithos.2012.11.025 | Journal (article/letter/editorial) | | special volume “Serpentine and serpentinites from ocean floor to subduction” [*] Address of the corresponding...Ba, U and Pb and locally the crystallization of talc by silica fluid addition. Transformation to antigorite...orthopyroxene (partially or completely retrograded to talc and associated with tremolite and olivine) are common...types of antigorite partially replaced by RI P talc: 1) large (up to 3 mm) and variably oriented grains... Orthopyroxene is occasionally replaced by late talc, and olivine forms coarse (up to 3 mm) subhedral |  | Alt, Jeffrey C., Schwarzenbach, Esther M., Früh-Green, Gretchen L., Shanks, Wayne C., Bernasconi, Stefano M., Garrido, Carlos J., Crispini, Laura, Gaggero, Laura, Padrón-Navarta, José A., Marchesi, Claudio (2013) The role of serpentinites in cycling of carbon and sulfur: Seafloor serpentinization and subduction metamorphism. Lithos, 178. 40-54 doi:10.1016/j.lithos.2012.12.006 | Journal (article/letter/editorial) | | serpentinite. We estimate that serpentinization at mid ocean ridges is a sink for 0.35–0.64×1011 mol C y−1 and...as the Logatchev and Rainbow sites on the mid-Atlantic Ridge (Charlou et al., 2002; Douville et al.,...opening of the Atlantic Ocean basin in the early Cretaceous, and several drill holes of the Ocean Drilling...temperature processes. For example, amphibole and talc replacing orthopyroxene or 18O-depletion of serpentinites...complexes exposed by detachment faulting at mid ocean ridges. Uplifted mantle peridotites were intruded |  | Schwarzenbach, Esther M., Früh-Green, Gretchen L., Bernasconi, Stefano M., Alt, Jeffrey C., Plas, Alessio (2013) Serpentinization and carbon sequestration: A study of two ancient peridotite-hosted hydrothermal systems. Chemical Geology, 351. 115-133 doi:10.1016/j.chemgeo.2013.05.016 | Journal (article/letter/editorial) | | Keywords: Carbon sequestration Serpentinization Ocean Drilling Program Northern Apennine Iberian Margin...calcite-veined serpentinites from the Iberian Margin (Ocean Drilling Program (ODP) Legs 149 and 173), and compare...field (LCHF) on the Atlantis Massif near the Mid-Atlantic Ridge (MAR). Our results show that large amounts...of seawater with ultramafic rocks exposed at the ocean floor results in serpentinization reactions and the...Lost City hydrothermal field (LCHF), along the Mid-Atlantic Ridge (MAR), low-temperature (b 40 to ~90 °C) |  | | Journal (article/letter/editorial) | | mineralogical variability within rodingites from the ocean floor is mainly driven by steep activity gradients...Seyfried et al., 2007). Such fluids are known from mid-ocean ridge settings (Kelley et al., 2001; Kelley et al...situation is less complicated in rodingites from mid-ocean ridge settings, because the composition and state...those of depleted upper mantle and depleted mid-ocean ridge basalt (MORB) from the mid- 104 W. Bach...crossed polars and field of view is 2.75 mm wide. Atlantic ridge (MAR). Oceanic rodingites from the MAR (Honnorez |  | Hodel, F., Trindade, R.I.F., Macouin, M., Meira, V.T., Dantas, E.L., Paixão, M.A.P., Rospabé, M., Castro, M.P., Queiroga, G.N., Alkmim, A.R., Lana, C.C. (2019) A Neoproterozoic hyper-extended margin associated with Rodinia's demise and Gondwana's build-up: The Araguaia Belt, central Brazil. Gondwana Research, 66. 43-62 doi:10.1016/j.gr.2018.08.010 | Journal (article/letter/editorial) | | propose that the Araguaia Belt comprises a fossil ocean-continent MA transition (OCT) accreted on the...and chlorite schist with intercalations of talc schist, talc-actinolite schist, serpentinite, metabasite...transition is characterized by an extensively deformed talc- ACCEPTED MANUSCRIPT rich zone produced by interactions...1994), and serpentinized peridotites from MA mid-ocean ridges (Rouméjon and Cannat, 2014) (Fig. 3a, b)...RI the three units plot in the spinel field of abyssal and OCT peridotites (Fig. 6a, b). Cr# is slightly |  | Schwarzenbach, Esther M., Früh-Green, Gretchen L., Bernasconi, Stefano M., Alt, Jeffrey C., Shanks III, Wayne C., Gaggero, Laura, Crispini, Laura (2012) Sulfur geochemistry of peridotite-hosted hydrothermal systems: Comparing the Ligurian ophiolites with oceanic serpentinites. Geochimica et Cosmochimica Acta, 91. 283-305 doi:10.1016/j.gca.2012.05.021 | Journal (article/letter/editorial) | | Margin formed during the opening of the North Atlantic, and with serpentinites sampled at the active...hydrothermal field on the Atlantis Massif near the Mid-Atlantic Ridge. The sulfide and oxide mineral assemblage...serpentinization and tectonic activity along a mid-ocean ridge. Additionally, local enrichment in 34S in...serpentinization of ultramafic rocks exposed to seawater on the ocean floor. We suggest that the thermal structure of the...processes observed today in systems along the Mid-Atlantic Ridge. Ó 2012 Elsevier Ltd. All rights reserved |  | Halama, Ralf, Savov, Ivan P., Garbe-Schönberg, Dieter, Schenk, Volker, Toulkeridis, Theofilos (2013) Vesuvianite in high-pressure-metamorphosed oceanic lithosphere (Raspas Complex, Ecuador) and its role for transport of water and trace elements in subduction zones. European Journal of Mineralogy, 25 (2) 193-219 doi:10.1127/0935-1221/2013/0025-2281 | Journal (article/letter/editorial) | | large sections in the oceans is difficult and abyssal peridotites sampled by dredging only represent...the per mil deviation from Vienna Standard Mean Ocean Water (V-SMOW) in the standard d-notation. Mineral...Massif, mid-Atlantic ridge; Godard et al., 2009) and serpentinites (ODP hole 1268A, mid-Atlantic ridge; Paulick...average composition of oceanic gabbro from the Iberia abyssal plane (ODP hole 900A, Seifert et al., 1996)...serpentinites comprise 13 samples from ODP hole 1268A (mid-Atlantic ridge) that are characterized by U-shaped REE |  | | Journal (article/letter/editorial) | | 73-83 Talc-rich hydrothermal rocks from the St. Paul and Conrad fracture zones in the Atlantic Ocean MASSIMO...R., I-40129 Bologna, Italy 2Istituto Abstract: Talc-rich rocks covered by Fe-Mn coatings were recovered...the St. Paul F.Z. (00°37’S-25°34’W, equatorial Atlantic) and Conrad F.Z. (55°29’S-02°05’W, American-Antarctic...American-Antarctic Ridge). In both occurrences, the talc-rich rocks are associated with serpentinized peridotites...consisting of angular clasts of botryoidal/colloform talc in a subordinate foraminiferal ooze sediment. These |  | | Journal (article/letter/editorial) | | Rifting Hyperextended rifted margins Alpine Tethys Iberia–Newfoundland Numerical modeling a b s t r a c...are the Alpine Tethys, Pyrenean–Bay of Biscay and Iberia–Newfoundland rift systems. However, as all these...the development of the magma-poor southern North Atlantic and Alpine Tethys rift systems and that the role...hyperextended rift systems of the southern North Atlantic and Alpine Tethys can be translated to other less...Manatschal and Bernoulli, 1998). In the North Atlantic (Lundin and Doré, 2011) and the NW Shelf of Australia |  | | Report (chapter) | | revisited: mantle exhumation and magmatism along an ocean-continent transition: the Platta nappe, eastern...by eNd values typical for an asthenospheric mid-ocean ridge-type source of the melts. They may be the...the axial part of the 'geosyncline' and the deep ocean floor. Although Steinmann considered diabase, spilite...onto the serpentinites previously exposed on the ocean floor (Fig. 1; Decandia & Elter 1972; Lagabrielle...Generalized stratigraphy of transitional crust (ocean-continent transition) in the Platta nappe, eastern |  | | Journal (article/letter/editorial) | | ultramafic clasts from the South Chamorro Seamount (Ocean Drilling Program Leg 195, Site 1200): inferences...K EY WORDS : serpentinization, forearc mantle, Ocean Drilling Program, serpentine mud volcano, mineral...the décollement between the subducting Pacific Ocean lithosphere and the overlying forearc mantle wedge...carboncoated, polished thin sections provided by the Ocean Drilling Program (West Coast Repository, Scripps...that Fe may partition into serpentine, brucite and talc only to a limited extent (e.g. Hyndman and Peacock |  | | Report (chapter) | | Mesozoic passive continental margin and of the Tethyan ocean floor are preserved in the Austroalpine and Upper...northern Italy. Reconstructions of the continent-ocean transition indicate that large areas of subcontinental...upper-mantle rocks from both present-day (e.g. West Iberia) and ancient (e.g. Alps) margins thus place important...and upper-mantle rocks from the Alps and the West Iberia margin, emphasizing similarities and also major...early Cretaceous time. LP, Ligurian-Piemontese ocean. The sedimentary and upper-crustal tectonic evolution |  | | Journal (article/letter/editorial) | | DOI 10.1007/s00410-017-1381-x ORIGINAL PAPER Abyssal and hydrated mantle wedge serpentinised peridotites:...subducted serpentinised mantle is serpentinised on the ocean floor settings. Yet this material is poorly represented...from different geodynamic settings as a proxy for abyssal serpentinites from spreading settings must be undertaken...undertaken with caution. Keywords Serpentinite · Abyssal · Subduction · Redox Introduction Serpentinised...comparable in magnitude to that of subducted altered ocean crust Evans (2012), and dehydration of serpentinised |  | Spandler, Carl, Hermann, Jörg, Faure, Kevin, Mavrogenes, John A., Arculus, Richard J. (2008) The importance of talc and chlorite “hybrid” rocks for volatile recycling through subduction zones; evidence from the high-pressure subduction mélange of New Caledonia. Contributions to Mineralogy and Petrology, 155 (2) 181-198 doi:10.1007/s00410-007-0236-2 | Journal (article/letter/editorial) | | 1007/s00410-007-0236-2 ORIGINAL PAPER The importance of talc and chlorite ‘‘hybrid’’ rocks for volatile recycling...oceanic crust and contains a significant proportion of talc and chlorite schists associated with serpentinite...The bulk-rock and stable isotope compositions of talc and chlorite schist and serpentinite indicate that...oceanic lithosphere prior to subduction, whereas the talc and chlorite schists were formed by fluid-induced...University, Canberra 0200, Australia dehydration of talc and chlorite schists should occur at subarc depths |  | | Journal (article/letter/editorial) | | serpentinites from the Rainbow and Saldanha sites (Mid-Atlantic Ridge) Isabel RIBEIRO DA COSTA1 *, Fernando J...*Corresponding author, e-mail: isabelrc@fc.ul.pt 2 School of Ocean and Earth Sciences, Southampton Oceanographic Centre...the Saldanha seamount (36˚14’N and 36˚34’N, Mid-Atlantic Ridge) often exhibit late-stage carbonatization...low-T carbonates, aragonite, serpentinites, Mid-Atlantic Ridge. Introduction Serpentinized harzburgites...carbonate-rich serpentinites were collected from the deep ocean-floor, where measured seawater temperatures are |
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