Magnetic lineations in marginal basins of the western Pacific

1981 ◽  
Vol 300 (1454) ◽  
pp. 223-247 ◽  
Keyword(s):  
Small Time ◽  
Crustal Accretion ◽  
Magnetic Lineation ◽  
The Pacific ◽  
Oceanic Spreading ◽  
The Pacific Ocean ◽  
Magnetic Lineations ◽  
Back Arc ◽  
The Western Pacific ◽  
Plate Kinematics

This paper separates the small oceanic basins around the western perimeter of the Pacific Ocean into marginal basins that have formed through back-arc extension and those that apparently have not, and reviews our knowledge of magnetic lineation patterns observed in possible and probable back-arc basins. Magnetic lineations in these basins resemble lineations commonly associated with the world’s mid-oceanic spreading systems, indicating that similar processes of crustal accretion occur in both tectonic environments. In some back-arc basins of the southwestern Pacific, magnetic lineation and other evidence suggest that back-arc basins can evolve through the interaction and growth of ‘multi-plate’ systems. Because of the small time and space characteristics of back-arc basins compared with the world’s major oceanic spreading systems, tectonic conditions favourable for the generation of back-arc basins are either relaxed rapidly or easily interrupted. Models proposed to account for back-arc basin development include (a) ‘local’ models, where back-arc extension is mechanically driven by the downgoing slab, and (b) global plate kinematics models, where conditions favourable for back-arc extension are governed by the motion of the overriding plate relative to the trench axis.

Redescription of Mugil setosus Gilbert 1892 with comments on the occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean (Teleostei: Perciformes: Mugilidae)

Zootaxa ◽  
2019 ◽  
Vol 4671 (3) ◽  
pp. 396-406
Author(s):  
RICARDO BRITZKE ◽  
NAÉRCIO A. MENEZES ◽  
MAURO NIRCHIO
Keyword(s):  
Pacific Ocean ◽  
Pacific Coast ◽  
The Third ◽  
Dorsal Fin ◽  
The Pacific ◽  
Fin Rays ◽  
The Pacific Ocean ◽  
The Western Pacific ◽  
Pectoral Fin Rays ◽  
Pelvic Fin

Mugil setosus Gilbert 1892 was originally described by Gilbert based on specimens from Clarion Island, in the western and most remote of the Revillagigedo Islands, about 1,000 km off the western Pacific coast of Mexico. Examination of the type of material and recently collected specimens from Ecuador and Peru, resulted in the redescription provided herein. Diagnostic characters of the species were mainly: tip of the pelvic fin reaching beyond the vertical through the base of the third dorsal-fin spine, the pectoral-fin rays with ii+13–14 rays, the anterodorsal tip of second (soft) dorsal fin uniformly dark, and an external row of larger teeth, and more internally a patch of scattered smaller teeth, visible mainly in adults 150 mm SL. The expansion of geographic distribution of Mugil setosus and occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean are discussed. 

scholarly journals A subduction influence on ocean ridge basalts outside the Pacific subduction shield

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Y. Yang ◽  
C. H. Langmuir ◽  
Y. Cai ◽  
P. Michael ◽  
S. L. Goldstein ◽  
...  
Keyword(s):  
Upper Mantle ◽  
The Arctic ◽  
Mantle Flow ◽  
Mantle Heterogeneity ◽  
Gakkel Ridge ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
The Pacific Ocean ◽  
Back Arc ◽  
Ocean Ridge

AbstractThe plate tectonic cycle produces chemically distinct mid-ocean ridge basalts and arc volcanics, with the latter enriched in elements such as Ba, Rb, Th, Sr and Pb and depleted in Nb owing to the water-rich flux from the subducted slab. Basalts from back-arc basins, with intermediate compositions, show that such a slab flux can be transported behind the volcanic front of the arc and incorporated into mantle flow. Hence it is puzzling why melts of subduction-modified mantle have rarely been recognized in mid-ocean ridge basalts. Here we report the first mid-ocean ridge basalt samples with distinct arc signatures, akin to back-arc basin basalts, from the Arctic Gakkel Ridge. A new high precision dataset for 576 Gakkel samples suggests a pervasive subduction influence in this region. This influence can also be identified in Atlantic and Indian mid-ocean ridge basalts but is nearly absent in Pacific mid-ocean ridge basalts. Such a hemispheric-scale upper mantle heterogeneity reflects subduction modification of the asthenospheric mantle which is incorporated into mantle flow, and whose geographical distribution is controlled dominantly by a “subduction shield” that has surrounded the Pacific Ocean for 180 Myr. Simple modeling suggests that a slab flux equivalent to ~13% of the output at arcs is incorporated into the convecting upper mantle.

First record of Hyalascus (Hexactinellida: Rossellidae) from the Indian Ocean, with description of a new species from a volcanic seamount in the Andaman Sea

Zootaxa ◽  
2010 ◽  
Vol 2667 (1) ◽  
pp. 64 ◽  
Author(s):  
SABYASACHI SAUTYA ◽  
KONSTANTIN R. TABACHNICK ◽  
BABAN INGOLE
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Indian Ocean ◽  
First Record ◽  
Andaman Sea ◽  
The Pacific ◽  
The Indian Ocean ◽  
The Pacific Ocean ◽  
Back Arc ◽  
A New Species

A new species of Hyalascus is described from the submarine volcanic crater seamount of Andaman Back-arc Basin, Indian Ocean. The genus was previously known in the Pacific Ocean only.

scholarly journals Genetic structure of the crown-of-thorns seastar in the Pacific Ocean, with focus on Guam

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1970 ◽  
Author(s):  
Sergio Tusso ◽  
Kerstin Morcinek ◽  
Catherine Vogler ◽  
Peter J. Schupp ◽  
Ciemon F. Caballes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Pacific Ocean ◽  
Long Distance ◽  
The Past ◽  
The Pacific ◽  
Tropical Coral ◽  
Population Outbreaks ◽  
Geographical Regions ◽  
The Pacific Ocean ◽  
The Western Pacific

Population outbreaks of the corallivorous crown-of-thorns seastar (COTS),Acanthaster ‘planci’ L., are among the most important biological disturbances of tropical coral reefs. Over the past 50 years, several devastating outbreaks have been documented around Guam, an island in the western Pacific Ocean. Previous analyses have shown that in the Pacific Ocean, COTS larval dispersal may be geographically restricted to certain regions. Here, we assess the genetic structure of Pacific COTS populations and compared samples from around Guam with a number of distant localities in the Pacific Ocean, and focused on determining the degree of genetic structure among populations previously considered to be isolated. Using microsatellites, we document substantial genetic structure between 14 localities from different geographical regions in the Pacific Ocean. Populations from the 14 locations sampled were found to be structured in three significantly differentiated groups: (1) all locations immediately around Guam, as well as Kingman Reef and Swains Island; (2) Japan, Philippines, GBR and Vanuatu; and (3) Johnston Atoll, which was significantly different from all other localities. The lack of genetic differentiation between Guam and extremely distant populations from Kingman Reef and Swains Island suggests potential long-distance dispersal of COTS in the Pacific.

scholarly journals An Analysis of Secular Change in Tides at Open-Ocean Sites in the Pacific

2014 ◽  
Vol 44 (7) ◽  
pp. 1704-1726 ◽  
Author(s):  
Edward D. Zaron ◽  
David A. Jay
Keyword(s):  
Sea Level ◽  
Open Ocean ◽  
Secular Change ◽  
Semidiurnal Tide ◽  
Equatorial Station ◽  
Timing Errors ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Western Pacific ◽  
Site History

Abstract Hourly sea level is examined at 25 open-ocean stations in the Pacific Ocean with records longer than 30 yr. A search for trends finds that the amplitude of the dominant semidiurnal tide M2 is increasing at 12 of the 13 sites where a statistically significant trend can be identified. It is also found that nontidal variance in the neighborhood of M2 is decreasing at all 12 of the sites where a significant increase in M2 tide is occurring. The trend in amplitude of the dominant diurnal tide K1 is significant at six stations, and it is both increasing (four stations) and decreasing (two stations). The trend in semidiurnal-band variance suggests the hypothesis that increases in M2 could be caused by improvements in time keeping or data processing that would reduce the apparent phase variability of the tide. This possibility is examined and found to be the likely explanation for tidal trends at four stations. Local changes are found to explain the trend at two stations, Johnston Island and Mokuoloe, as diagnosed from correlated changes in nonlinear overtides and site history. Changes in M2 at the equatorial station of Kanton are significant and unexplained by either timing errors or local morphodynamics; although, strong nonlinear overtides are present. Changing tides at five stations in the western Pacific, Malakal, Yap, Saipan, Kapingamarangi, and Pohnpei cannot be explained by the above and suggest a region where a connection between climate and tides may yet be identified.

scholarly journals A root for massive crown-of-thorns starfish outbreaks in the Pacific Ocean

2021 ◽  
Author(s):  
Nina Yasuda ◽  
June Inoue ◽  
Michael R. Hall ◽  
Manoj R. Nair ◽  
Mehdi Adjeroud ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Environmental Changes ◽  
French Polynesia ◽  
The Philippines ◽  
Marshall Islands ◽  
Western Pacific ◽  
Central Pacific ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Western Pacific

AbstractRecurring outbreaks of crown-of-thorns starfish (COTS) severely damage healthy corals in the Western Pacific Ocean. To determine the source of outbreaking COTS larvae and their dispersal routes across the Western Pacific, complete mitochondrial genomes were sequenced from 243 individuals collected in 11 reef regions. Our results indicate that Pacific COTS comprise two major clades, an East-Central Pacific clade (ECP-C) and a Pan-Pacific clade (PP-C). The ECP-C consists of COTS from French Polynesia (FP), Fiji, Vanuatu and the Great Barrier Reef (GBR), and does not appear prone to outbreaks. In contrast, the PP-C, which repeatedly spawns outbreaks, is a large clade comprising COTS from FP, Fiji, Vanuatu, GBR, Papua New Guinea, Vietnam, the Philippines, Japan, Micronesia, and the Marshall Islands. Given the nature of Pacific Ocean currents, the vast area encompassing FP, Fiji, Vanuatu, and the GBR likely supplies larvae for repeated outbreaks, exacerbated by anthropogenic environmental changes, such as eutrophication.

scholarly journals The Regional Hadley Cells Response to the Sea Surface Temperature Distribution Across the Indo-Pacific Ocean

2021 ◽  
Vol 893 (1) ◽  
pp. 012008
Author(s):  
D Fatmasari
Keyword(s):  
Pacific Ocean ◽  
Enso Event ◽  
Western Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Meridional Temperature Gradient ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Hadley Cells ◽  
The Western Pacific

Abstract Hadley Cells are thermally driven cell in the tropics. On its occurrence, these cells are strongly influenced by the sea surface temperature (SST) distribution across the tropical ocean or the Pacific Ocean as the investigated location in this study. The SST shifting in the Pacific Ocean is mainly due to the ENSO. An opposite SST polarity between the western and eastern Pacific Ocean are captured during ENSO events. This means that ENSO could trigger an anomalous regional Hadley Cells that behave oppositely between Indonesia or the western Pacific and the eastern Pacific. This study examines the strength of the regional Hadley Cells related to the ENSO event across the Indonesian region and the Pacific Ocean. A significant correlation between the Hadley Cells and ENSO as the tropical climate variability in the Pacific Oceans are found. The strength of the Hadley Cells associated with ENSO event is examined by using the zonally average vertical velocity across the Pacific Ocean. During La Nina, the regional Hadley Cells over Indonesia or the western Pacific strengthened, whereas the regional cells over the eastern Pacific weakened. In contrast, during El Nino where the warm pool shifted to the eastern Pacific, the regional cell in the eastern Pacific strengthened, while the cell over the western Pacific weakened. These anomalous conditions clearly show that the meridional temperature gradient is strongly affecting the regional Hadley Cells strength. The stronger the meridional temperature gradient, the stronger the regional Hadley Cells.

Copepods of the family Dirivultidae (Siphonostomatoida) from deep-sea hydrothermal vent fields on the Mid-Atlantic Ridge at 14ºN and 5ºS

Zootaxa ◽  
2006 ◽  
Vol 1277 (1) ◽  
pp. 1 ◽  
Author(s):  
VIATCHESLAV N. IVANENKO ◽  
PEDRO MARTÍNEZ ARBIZU ◽  
JENS STECHER
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
First Record ◽  
Remotely Operated Vehicle ◽  
The Pacific ◽  
The Family ◽  
Mid Atlantic Ridge ◽  
The Pacific Ocean ◽  
Menez Gwen ◽  
Back Arc

Five species of three genera of Dirivultidae Humes and Dojiri, 1980 were found at deep-sea hydrothermal vent fields on the Mid-Atlantic Ridge, at the Logachev-1 field at 14ºN and at two new sites (Turtle Pits and Red Lion) explored at 5ºS. The copepods were collected with a Remotely Operated Vehicle (ROV Quest 4000) and Video Controlled Grab, operated from the R/V Meteor during two cruises (M60/3 and M64/1) conducted in 2004 and 2005 at depths 2992–3048 m. The male of Stygiopontius lomonosovi n. sp. from the Logachev field shares a medioventrally prolonged syncoxa of the maxilliped with S. mirus Humes, 1996 and S. latulus Humes, 1996 from the Snake Pit at 23ºN of the Mid-Atlantic Ridge, but differs from them in having two, instead of three, outer spines on the distal exopodal segment of leg 4. Aphotopontius atlanteus Humes, 1996 previously known from the Lucky Strike and the Menez Gwen sites at 37°N and Rimipontius mediospinifer Humes, 1996 known from three sites (Logachev, Snake Pit, and Broken Spur at 29°N) are recorded from the Logachev field. Stygiopontius pectinatus Humes, 1987 previously recorded from the Mid-Atlantic Ridge hydrothermal vent fields TAG (26°N), Snake Pit, Broken Spur (29°N), and from the Mariana Back-Arc Basin of the Pacific Ocean and Stygiopontius cladarus Humes, 1996 previously known only from Snake Pit and Broken Spur, were found associated with alvinocaridid shrimps (Rimicaris sp.) from the hydrothermal vent field at 5ºS. The discovery of dirivultids at 5ºS represents the first record of copepods from a deep-sea hydrothermal vent southward of the Logachev field in the Atlantic Ocean.

The subduction influence on ocean ridge basalts and its significance

2021 ◽  
Author(s):  
Alexandra Yang Yang ◽  
Charles Langmuir ◽  
Yue Cai ◽  
Steven Goldstein ◽  
Peter Michael ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Upper Mantle ◽  
The Arctic ◽  
Plate Tectonic ◽  
Gakkel Ridge ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
The Pacific Ocean ◽  
Back Arc ◽  
Ocean Ridge

Abstract The plate tectonic cycle produces chemically distinct mid-ocean ridge basalts (MORB) and arc volcanics, with the latter enriched in fluid-mobile elements and depleted in Nb owing to fluxes from the subducted slab. Basalts from back-arc basins (BABB), with intermediate compositions, show that the subduction flux can escape the arc. Hence it is puzzling why arc signatures have rarely been recognized in MORB. Here we report the first MORB samples with distinct arc signatures, akin to BABB, from the Arctic Gakkel Ridge. A new high precision dataset for 576 Gakkel samples suggests a pervasive subduction influence. This influence can also be identified in Atlantic and Indian MORB with a “BABB filter”, but is nearly absent in Pacific MORB. This global distribution reflects the control of a “subduction shield” that has surrounded the Pacific Ocean for 180Myr. Statistics suggest that a flux equivalent to ~ 13% of output at arcs is incorporated into the convecting upper mantle.

scholarly journals Genetic structure of the Crown-of-Thorns seastar in the Pacific Ocean, with focus on Guam

2016 ◽  
Author(s):  
Sergio Tusso ◽  
Kerstin Morcinek ◽  
Catherine Vogler ◽  
Peter J Schupp ◽  
Ciemon F Caballes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Pacific Ocean ◽  
Larval Dispersal ◽  
The Past ◽  
The Pacific ◽  
Tropical Coral ◽  
Population Outbreaks ◽  
Geographical Regions ◽  
The Pacific Ocean ◽  
The Western Pacific

Population outbreaks of the corallivorous crown-of-thorns seastar (COTS), Acanthaster ‘planci’ L., are among the most important biological disturbances of tropical coral reefs. Over the past 50 years, several devastating outbreaks have been documented around Guam, an island in the western Pacific Ocean. Previous analyses have shown that in the Pacific Ocean, COTS larval dispersal may be geographically restricted to certain regions. Here, we assess the genetic structure of Pacific COTS populations and compared samples from around Guam with a number of distant localities in the Pacific Ocean, and focused on determining the degree of genetic structure among populations previously considered to be isolated. Using microsatellites, we document substantial genetic structure between 14 localities from different geographical regions in the Pacific Ocean. Populations from the 14 locations sampled were found to be structured in three significantly differentiated groups: (1) all locations immediately around Guam, as well as Kingman Reef and Swains Island; (2) Japan, Philippines, GBR and Vanuatu; and (3) Johnston Atoll, which was significantly different from all other localities. The most stark divergence of these groupings from previous studies is the lack of genetic differentiation between Guam and extremely distant populations from Kingman Reef and Swains Island. These findings suggest potential long-range dispersal of COTS in the Pacific, and highlight the importance of ecological determinants in shaping genetic structure.

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