The RRR triple junction at the southern end of the Pacific-Cocos East Pacific Rise

Five species of the hippolytid shrimp genus Lebbeus White, 1847 are reported from various deep-water hydrothermal ventsites in the Pacific Ocean: L. laurentae Wicksten, 2010 from the East Pacific Rise 13°N; L. wera Ahyong, 2009 from theBrothers Seamount, Kermadec Ridge, New Zealand; L. pacmanus sp. nov. from the Manus Basin, Bismarck Sea; L.shinkaiae sp. nov. from the Okinawa Trough, Japan; and L. thermophilus sp. nov. from the Manus and Lau basins, south-western Pacific. Lebbeus laurentae is fully redescribed because the original and subsequent descriptions are not totallydetailed. Differentiating characters among the three new species and close allies are discussed. Previous records of Lebbeus species from hydrothermal vents are reviewed.

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A three-dimensional gravity study of the Pacific-Antarctic East Pacific Rise/Menard transform intersection

Journal of Geophysical Research Atmospheres ◽

10.1029/95jb01056 ◽

1995 ◽

Vol 100 (B9) ◽

pp. 17813-17822 ◽

Cited By ~ 5

Author(s):

Kelly D. Enriquez ◽

Y. John Chen

Keyword(s):

East Pacific Rise ◽

Three Dimensional ◽

East Pacific ◽

The Pacific ◽

Dimensional Gravity

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Phylogeny of hydrothermal vent Iphionidae, with the description of a new species (Aphroditiformia, Annelida)

ZooKeys ◽

10.3897/zookeys.779.24781 ◽

2018 ◽

Vol 779 ◽

pp. 89-107

Author(s):

Marina F. McCowin ◽

Greg W. Rouse

Keyword(s):

Pacific Ocean ◽

Hydrothermal Vent ◽

Hydrothermal Vents ◽

East Pacific Rise ◽

Rrna Genes ◽

28S Rrna ◽

West Pacific ◽

East Pacific ◽

The Pacific ◽

The Pacific Ocean

The scale-worm family Iphionidae consists of four genera. Of these, Thermiphione has two accepted species, both native to hydrothermal vents in the Pacific Ocean; T.fijiensis Miura, 1994 (West Pacific) and T.tufari Hartmann-Schröder, 1992 (East Pacific Rise). Iphionella is also known from the Pacific, and has two recognized species; Iphionellarisensis Pettibone, 1986 (East Pacific Rise, hydrothermal vents) and I.philippinensis Pettibone, 1986 (West Pacific, deep sea). In this study, phylogenetic analyses of Iphionidae from various hydrothermal vent systems of the Pacific Ocean were conducted utilizing morphology and mitochondrial (COI and 16S rRNA) and nuclear (18S and 28S rRNA) genes. The results revealed a new iphionid species, described here as Thermiphionerapanuisp. n. The analyses also demonstrated the paraphyly of Thermiphione, requiring Iphionellarisensis to be referred to the genus, as Thermiphionerisensis (Pettibone, 1986).

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A new species ofExrima,synonymy of four species ofAphotopontius, StygiopontiusandRhogobius, and record of first copepodid stage of Dirivultidae (Copepoda: Siphonostomatoida) from deep-sea hydrothermal vents of the East Pacific Rise (13°N)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315411000178 ◽

2011 ◽

Vol 91 (7) ◽

pp. 1547-1559 ◽

Cited By ~ 5

Author(s):

Viatcheslav N. Ivanenko ◽

Danielle Defaye ◽

Michel Segonzac ◽

Alexis Khripounoff ◽

Jozée Sarrazin ◽

...

Keyword(s):

New Species ◽

Hydrothermal Vents ◽

East Pacific Rise ◽

Posterior Part ◽

First Record ◽

Sediment Traps ◽

Additional Material ◽

East Pacific ◽

The Pacific ◽

Ocean Study

Females of the new speciesExrima walterisp. nov. were found in sediment trap samples deployed over different sites of the East Pacific Rise (13°N) at 2600 m depth. Four traps were deposited during the HOPE99 cruise (1999) and recovered during the AMISTAD (1999) cruise on the research vessel ‘L'Atalante’. The new species is distinguished from congeners,E. singulaHumes, 1987 andE. dolichopusHumes, 1987, by the following derived characters: first somite of the urosome with 3 (one dorsal and two lateral) stout conical extensions; distal endopodal segment on the swimming leg 4 broad. In addition, many specimens of copepodids I and lecithotrophic nauplii, identified as belonging to Dirivultidae gen. sp., were found in the samples of all sediment traps. This is the first record of copepodids I and of a nauplius of dirivultids from the Pacific Ocean. Study of type and additional material collected during different Ifremer cruises at different vent sites (HERO91, EXOMAR, PHARE and MoMARETO) required synonymy of four species ofAphotopontiusHumes, 1987,StygiopontiusHumes, 1987 andRhogobiusHumes, 1987.Aphotopontius rapunculusHumes and Segonzac, 1998 is transferred to the genusRhogobiusbecause it possesses all presumed derived attributes of this genus: last abdominal somite with lobes at sides of anal operculum; second segment of antennal endopod elongate and slender. A new study of the type material suggests that:Aphotopontius temperatusHumes, 1997 is a synonym ofA. atlanteusHumes, 1996;Stygiopontius lumigerHumes, 1989 is a synonym ofS. sentiferHumes, 1987 whileS. bulbisetigerHumes, 1996 is a synonym ofS. pectinatusHumes, 1987. Females of the three synonymized species were found to be sub-adult females at copepodid V. Leg 6 on these specimens is one seta located dorsolaterally on the posterior part of the genital somite. This position for leg 6 is unknown for copepodid V of other siphonostomatoids whose leg 6 is located ventrally at copepodid V; the dorsolateral position is presumed derived and shared by the dirivultid generaAphotopontiusHumes, 1987 andStygiopontiusHumes, 1987. A new key to the Dirivultidae genera is presented.

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Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling

Science Advances ◽

10.1126/sciadv.1601107 ◽

2016 ◽

Vol 2 (12) ◽

pp. e1601107 ◽

Cited By ~ 11

Author(s):

David B. Rowley ◽

Alessandro M. Forte ◽

Christopher J. Rowan ◽

Petar Glišović ◽

Robert Moucha ◽

...

Keyword(s):

East Pacific Rise ◽

Oceanic Lithosphere ◽

Plate Motion ◽

Mantle Flow ◽

Plate Boundaries ◽

Tectonic Plates ◽

Ocean Ridges ◽

East Pacific ◽

The Pacific ◽

Negative Buoyancy

Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pull should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. The mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.

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Pb, Sr, and Nd isotopic systematics of rocks from the Galapagos Microplate

Canadian Journal of Earth Sciences ◽

10.1139/e95-043 ◽

1995 ◽

Vol 32 (4) ◽

pp. 508-515

Author(s):

G. L. Cumming ◽

D. Krstic ◽

H. Puchelt

Keyword(s):

East Pacific Rise ◽

Sedimentary Cover ◽

Specific Area ◽

Nd Isotope ◽

Isotopic Variation ◽

East Pacific ◽

The Pacific ◽

Isotopic Analyses ◽

Galapagos Microplate ◽

Rift Valleys

Pb, Sr, and Nd isotopic analyses were performed on a suite of compositionally variable rock samples representing an approximately 2500 m thickness of oceanic crustal lithologies from the deep rift valleys and spreading centers along the periphery of the Galapagos Microplate at the junction of the Pacific, Cocos, and Nazca plates. Samples were obtained from lower peridotite and gabbro layers, Fe–Ti basalts, very recent neovolcanic flows, and the thin sedimentary cover. The samples were dredged, cored, or video-grabbed during the research cruise Sonne 60. For unaltered igneous rocks, 206Pb/204Pb ratios range from 17.70 to 18.90, 87Sr/86Sr ratios from 0.7024 to 0.7035, clustering around 0.7027, while 143Nd/144Nd ratios range from 0.51307 to 0.51324. Based on these data, little systematic isotopic variation can be associated with any specific area or lithology of the microplate. One exception is a series of very thin volcanic flows from the Summit Graben area, where Pb and Nd isotope ratios change gradually, with each successive flow. The extent of the observed Pb isotopic variation covers almost the entire range of ratios for the East Pacific Rise mid-oceanic ridge basalts published to date, suggesting that the part of the mantle responsible for formation of the Galapagos Microplate rocks is no more isotopically homogeneous than the East Pacific Rise mantle as a whole, taken over a length of several thousands of kilometres.

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