 | | Journal (article/letter/editorial) | | Montpellier, France Abstract It has been proposed that deep, high-T (up to 1000°C) hydrothermal alteration occurred...the paleo-ridge axis in the Oman ophiolite. In the deep, hot gabbros, the main water channels are submillimetric...close to the ridge axis. Since the first record of deep and high temperature hydrothermal alteration in...strontium and oxygen isotope tracing, the possibility of deep penetration of seawater close to the axis of fast...One reason was the difficulty of integrating such deep circulation in the framework of the wing-shaped |  | | Report (chapter) | | harzburgites at Hess Deep and Garrett Deep: implications for mantle processes beneath segments of the East Pacific...Pacific Rise STEPHEN J. E D W A R D S 1, T R E V O R J. F A L L O O N 2, J O H N B. P E D E R S E N ...fastspreading East Pacific Rise (EPR): a 'normal' spreading segment (represented by samples from Hess Deep) and...transform fault (represented by samples from Garrett Deep). A review of the petrology of harzburgites from...were impregnated by reactive and crystallizing mid-ocean ridge basaltic (MORB) melts. Despite this similar |  | | Journal (article/letter/editorial) | | in lower oceanic crustal troctolites from the Hess Deep Rift Toshio Nozaka1 · Romain Meyer2,4 · Robert...troctolites recovered from IODP Site U1415 at the Hess Deep Rift. The spinel is green-colored, has an irregular...of knowledge, Expedition 345 of the Integrated Ocean Drilling Program (IODP) was designed to drill and...level oceanic crustal rocks formed at the East Pacific Rise (EPR) with the principal objectives to understand...for their formation. Geological setting At the Hess Deep Rift, young plutonic crust formed at the fast-spreading |  | | Journal (article/letter/editorial) | | chromian spine1 can be also formed under the mid-ocean ridge condition [2,3]. The inclusion was found in...micropod within dunite drilled from Hess Deep, equatorial Pacific (see plate l-5 of Ref. [2]). The minerals...phlogopites (Na- and K-), pargasite, diopside, enstatite, jadeite, nepheline and albite; they are characterized...slab [3]. I think from the evidence from both Hess Deep and Mid-Cayman Trough [3] that the concentration...this case). The melt trapped by the spine1 from Hess Deep is supposed to be also alkalic but its chemical |  | | Journal (article/letter/editorial) | | Plagioclase-wehrlites and peridotites on the East Pacific Rise (Hess Deep) and the Mid-Atlantic Ridge (DSDP Site...The samples studied come from the East Pacific Rise (EPR) (Hess Deep) and the Mid-Atlantic Ridge (MAR)...for olivine suggest a magmatic origin for the Hess Deep wehrlite. Its phase chemistry is comparable to...mush. It differs drastically from the associated Hess Deep diopside-bearing harzburgites and dunites, which...plagioclase-wehrlites studied came from the Hess Deep in the Equatorial Pacific [31], and they are presented together |  | | Journal (article/letter/editorial) | | nepheline as inclusions in spinel of chromitite from Hess Deep, equatorial Paci®c: their genesis and implications...inclusions which consist of a few grains of diopside, enstatite, jadeite, nepheline, albite, pargasite, phlogopites...spinel in a chromitite pod and in troctolite from Hess Deep, equatorial Paci®c. The inclusion mineral suite...coexist with enstatite, and tend to occur as interstitial grains between subhedral enstatite (or other minerals)...minerals) and host spinel. Albite, diopside and enstatite occur as equant inclusions. The ma®c minerals |  | | Journal (article/letter/editorial) | | shallow mantle at the East Pacific Rise: evidence from ODP Site 895 (Hess Deep) STEPHEN J. EDWARDS Department... Abstract Ocean Drilling Program (ODP) Leg 147 recently drilled at Site 895 in Hess Deep (eastern Equatorial...Equatorial Pacific), where a structurally dissected section of the East Pacific Rise (EPR) is preserved...mantle melting than normally expected below mid-ocean ridges. Subsequently, basaltic melt(s) interacted...harzburgite, mid-ocean ridge basalt, melt-peridotite interaction, mantle refertilization, Hess Deep, East Pacific |  | | Journal (article/letter/editorial) | | Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology R6jean H6bert 1, Daniel...the Garret Transform Fault near 13°S on the East Pacific Rise. Two dredge hauls taken on the northern wall...ilmenite-gabbros). The harzburgites are likely to represent deep-seated peridotites left after extraction of basaltic...Metallogenesis East Pacific) of the R.V. "Sonne" (Preussag, F.R.G.), along the East Pacific Rise (EPR), a survey...mafic rocks were previously reported from the Hess Deep near 101°W [3-5] and the Ecuador Fracture Zone |  | Gillis, Kathryn M., Muehlenbachs, Karlis, Stewart, Michael, Gleeson, Thomas, Karson, Jeffrey (2001) Fluid flow patterns in fast spreading East Pacific Rise crust exposed at Hess Deep. Journal of Geophysical Research: Solid Earth, 106. 26311-26329 doi:10.1029/2000jb000038 | Journal (article/letter/editorial) | | 2001 Fluid flow patterns in fast spreading East Pacific Rise crust exposedat HessDeep Kathryn M. Gillis...complexover a 4-km- wideregionat HessDeep(equatorial Pacific)revealsignificant spatialheterogeneity (10-103m)...hydrothermalalterationin young,fast spreadingEastPacific Rise crust.The volcanicsequenceis fairly uniformlyaltered...EPR CRUST AT HESS DEEP either buriedby lava or changesin the hydrologicaland thermal east-westtrendingscarpsthatboundthe...sheeteddikesthatformedat the fast youngingfrom west to east(Figure 2a). Volcanicrocksform the spreadingEPR. |  | | Journal (article/letter/editorial) | | Podiform chromitites do form beneath mid-ocean ridges Shoji Arai, Makoto Miura PII: DOI: Reference:...Makoto, Podiform chromitites do form beneath mid-ocean ridges, LITHOS (2015), doi: 10.1016/j.lithos.2015...MANUSCRIPT Podiform chromitites do form beneath mid-ocean ridges PT Shoji Arai* and Makoto Miura SC RI...have AC rarely been observed in the present-day ocean floor, even though some ophiolites are considered...apparent rarity of chromitites in the present-day ocean floor is SC RI simply a reflection of the under-sampling |  | Tseng, C.-Y., Yang, H.-Y., Wu, H.-Q., Zuo, G.-C. (2007) THE SILICATE MINERAL INCLUSIONS IN THE CHROMIAN SPINEL FROM THE DONGCAOHE OPHIOLITE, NORTH QILIAN MOUNTAINS, NORTHWESTERN CHINA: RECORD OF SYNTEXIS OF LOWER OCEANIC CRUST. The Canadian Mineralogist, 45 (4) 793-808 doi:10.2113/gscanmin.45.4.793 | Journal (article/letter/editorial) | | People’s Republic of China Abstract Diopside, enstatite, pargasite, aspidolite, analcime, chlorite, serpentine...enclosed by the growing crystals of chromian spinel. Enstatite, pargasite and aspidolite were products of the...Sommaire On décrit les inclusions de diopside, enstatite, pargasite, aspidolite, analcime, chlorite, serpentine...The Dongcaohe ophiolite, a typical Caledonian mid-ocean-ridge type of ophiolite with an age of 497 ± 7 Ma... It is interpreted to have originated in a mid-ocean ridge or mature back-arc environment on the basis |  | | Book | | Spreading Centers of the Easter Micropiate (South East Pacific) M. Constantin, R. Hekinian, D. Ackermand and...magmatic and tectonic processes which affected these deep zones of the ridge. Obviously, magmatic and tectonic...no manifestly cyclic activ- 2 ity. Exposure of deep rocks in such cases is much more limited as in the...probably a predecessor of the fast-spreading East Pacific Rise. Eventually, the volume closes with a numerical...the building of the lower crust at magma-starved ocean ridges, This model involves successive stages of |  | Morishita, Tomoaki, Maeda, Jinichiro, Miyashita, Sumio, Kumagai, Hidenori, Matsumoto, Takeshi, Dick, Henry J.B. (2007) Petrology of local concentration of chromian spinel in dunite from the slow-spreading Southwest Indian Ridge. European Journal of Mineralogy, 19 (6) 871-882 doi:10.1127/0935-1221/2007/0019-1773 | Journal (article/letter/editorial) | | lithological boundary between dunite and enstatite-poor harzburgite. The enstatite-poor harzburgite has relatively...chemical compositions of clinopyroxene in the enstatite-poor harzburgite suggest that some clinopyroxenes...spinel, chromitite, dunite, slow-spreading ocean-ridge, ocean floor, melt-mantle interaction. Introduction...flow likely occurs in the shallow mantle beneath ocean ridges (Dick, 1989). The average abyssal peridotite...peridotite sampled from an ultraslow spreading ocean ridge representing a key end-member for seafloor |  | | Journal (article/letter/editorial) | | came from supra-subduction settings instead of mid-ocean ridge settings (e.g., Miyashiro 1973, and see reviews...Thus, there is a stratigraphic progression from east to west from greenschist facies metavolcanics to...approximately 1.5 km thick. Another remnant arc lies to the East of the Josephine Contrib Mineral Petrol (2014)...coeval arc to the West, and an older arc to the East. To the West, the Josephine ophiolite is in fault...Basin in the Western Pacific. However, there are several examples in the Western Pacific of boninites erupting |  | | Journal (article/letter/editorial) | | of the Franciscan subduction complex, and on the east, across the steep Stony Creek fault, by the JuraCretaceous...radiolarian chert and thin argillite (deep-sea clay?). An open-ocean setting, far from a continent margin...oceanic lithosphere that records only Jurassic open-ocean depositional and tectonic history. It escaped latest...across the CRO and adjacent TCSM/Franciscan Jurassic ocean floor; (3) resumption of eastward subduction in...AND PESSAGNO progressed behind the ridge on the east. The Stony Creek–Beehive Flat composite fault sytem |  | Payot, Betchaida D., Arai, Shoji, Dick, Henry J. B., Abe, Natsue, Ichiyama, Yuji (2014) Podiform chromitite formation in a low-Cr/high-Al system: An example from the Southwest Indian Ridge (SWIR) Mineralogy and Petrology, 108 (4) 533-549 doi:10.1007/s00710-013-0317-z | Journal (article/letter/editorial) | | was from the ODP Leg 147 drilling in Hess Deep, equatorial Pacific, wherein a chromitite micropod about...because of the limited sampling of the current ocean floor (Arai 1997). Recent reassessment of abyssal...southern Atlantic Ocean to the Rodrigues Triple Junction (26°S, 70°E) in the Indian Ocean, it separates the...spreading segments oblique to the direction of ocean floor spreading and shorter near-orthogonal magmatic...m) compared to the oblique supersegment. Further east, the fourth subsection includes the 150 km long |  | | Journal (article/letter/editorial) | | com/locate/epsl Genesis of andesitic–boninitic magmas at mid-ocean ridges by melting of hydrated peridotites: Geochemical...nor from any MORB composition documented along ocean ridges. Their parent melts are richer in SiO2 than...of these lithologies whose occurrence in a mid-ocean ridge setting is rather puzzling, we performed a...residual peridotite at shallow depth beneath mid-ocean ridges can lead mantle rocks and their melts to...magma; mid-ocean ridges; Atlantic Ocean 1. Introduction Gabbroic cumulates sampled along mid-ocean ridges |  | Morishita, Tomoaki, Tani, Ken-Ichiro, Soda, Yusuke, Tamura, Akihiro, Mizukami, Tomoyuki, Ghosh, Biswajit (2018) The uppermost mantle section below a remnant proto-Philippine Sea island arc: Insights from the peridotite fragments from the Daito Ridge. American Mineralogist, 103 (7) 1151-1160 doi:10.2138/am-2018-6030 | Journal (article/letter/editorial) | | event including melt extraction expected for mid-ocean ridge mantle. Instead, the peridotite source must...following the initiation of subduction of the Pacific Plate under the Philippine Sea Plate at ~52 Ma...proto-Philippine Sea Plate that existed along the Pacific Plate margin. Cretaceous rocks have been reported...manned-submersible (SHINKAI 6500) coupled with a deep-tow camera survey, and the second expedition (KR13-15)...metamorphic rocks were discovered in an exposed deep-crustal section, along with volcanic rocks ranging |  | | Journal (article/letter/editorial) | | the subduction-related arc-type and/or MORB (mid-ocean ridge basalt)-like magmas are mainly responsible...found from the Pacific Ocean also contains subduction-related arc-type and/or MORB (mid-ocean ridge basalt)-like...is varied but mainto minerals are pyroxenes (enstatite and (~0.5) chromite, were possibly formed inthe...[16,44–48]. The chromitite pod found from the Pacific Ocean also contains chromite with abundant solid inclusions...is varied but the main minerals are pyroxenes (enstatite and diopside), micas (aspidolite and phlogopite) |  | | 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...continental rifts open and new ocean basins form. The process of seawater incursion deep into faulted oceanic crust...crust at slow-spreading mid-ocean ridges during periodic amagmatic phases produces bands of serpentinized...supposed. Serpentinite may form at the ends of mid-ocean rift segments as a consequence of low-angle faulting |  | | Journal (article/letter/editorial) | | abyssal spinel peridotites of the East Pacific Rise (ODP Leg 147: Hess Deep) Kirsten T. Hesse a,⁎, Jürgen...2015 Available online 30 June 2015 Keywords: East Pacific Rise Geothermometry Infrared spectroscopy Nominally...c t Abyssal spinel peridotites from Hess Deep, East Pacific Rise (ODP Leg 147) were investigated concerning...after melt extraction and before exhumation to the ocean floor, the rocks experienced significant cooling in...Compared to Mid-Atlantic Ridge peridotites, the East Pacific Rise samples of Leg 147 contain somewhat lower |  | | Report (volume) | | Hydrothermal and Biological Segmentation of Mid-Ocean Ridges Geological Society Special Publications...Hydrothermal and Biological Segmentation of Mid-Ocean Ridges EDITED BY C. J. M A C L E O D University...(08) 379-0444 Fax (08) 379-4634) India Affiliated East-West Press PVT Ltd G-1/16 Ansari Road New Delhi...transform 61 BATIZA, R. Magmatic segmentation of mid-ocean ridges: a review 103 ROBINSON, C. J., WHITE, R...harzburgites at Hess Deep and Garrett Deep: implications for mantle processes beneath segments of the East Pacific |  | | Journal (article/letter/editorial) | | processes, including the peridotite-magma reaction, deep-seated magmatic evolution, and mantle dynamics....some are of the mid-ocean ridge type; ED chromitites may be common beneath the ocean floor, although it...associated with chemical alteration, which gives rise to even more complicated modes of AC occurrence...aspidolite (the Na analogue of phlogopite), diopside, enstatite, NU phlogopite, and sulfides (e.g., Talkington...that chromite in a micropod of chromitite from Hess Deep, EPR, contains similar inclusions of hydrous minerals |  | | Journal (article/letter/editorial) | | Saunders b, R.N. Wilson b a b School of Earth and Ocean Sciences, Bob Wright Building, University of Victoria...constraints (e.g. from the volume of melt produced at mid-ocean ridges). Substantially higher crystallization temperatures...picrites from Baffin Island (up to 1408 °C; Fo91.3) and East Greenland (up to 1354 °C; Fo90.1), Cretaceous (86...http://dx.doi.org/10.1016/j.chemgeo.2014.01.004 mid-ocean ridge (MOR) system due to plate spreading and nearadiabatic...to contain forsterite + spinel + cordierite + enstatite + glass at 1340 °C (i.e. relatively high aSiO2; |  | | Journal (article/letter/editorial) | | was possibly incomplete in the very incipient mid ocean ridge as in the short lived Nain back arc basin...of Iran). It is located on the margin of Central East Iranian Microcontinent, northeast of Isfahan province...by the Neotethys subducting slab. The Nain Baft Ocean has been widely described as a short lived (45 Ma)...depleted melt) from the Mid Atlantic ridge and East Pacific Rise (Sobolev and Shimizu, 1993; Arai and Takemoto...the Central East Iranian Microcontinent (CEIM) to form the Nain basin as initiation of ocean floor spreading |
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