Origin of the Caroline mantle plume and its interaction with the Caroline basin

2020 ◽  
Author(s):  
Guoliang Zhang ◽  
Ji Zhang ◽  
Shuai Wang
Keyword(s):  
Trace Element ◽  
Major And Trace Elements ◽  
Age Dating ◽  
Large Igneous Province ◽  
Spreading Center ◽  
Main Stage ◽  
Ontong Java Plateau ◽  
The Pacific ◽  
Caroline Islands ◽  
The Western Pacific

<p>The Caroline Rise has played an important role in the tectonic frame of the western Pacific, however, the nature and origin of the Caroline Rise has long been unclear. The boundary between the Pacific plate and the Caroline plate has long been unclear, thus, it unclear which plate is underneath the Caroline Rise. In this study, we confirmed that the Caroline Rise represents an oceanic plateau formed as a large igneous province based on seafloor sampling. In this study, we have age-dated and analyzed the whole-rock major and trace elements and Sr-Nd-Pb-Hf isotopes of the basalt samples from the Caroline Plateau. The basalt samples are classified into two groups, the alkali group and the tholeiite group. The results of age-dating indicate older ages for the tholeiite group than the alkali group. The tholeiite group basalts are apparently older than the Caroline Islands and are close to the basalts of Ontong Java Plateau in trace element compositions. We suggest that the tholeiite group basalts represent the main stage volcanism and the alkali group basalts represent the late stage volcanism of the Caroline Plateau. The alkali group basalts show trace element and isotope compositions similar to those of the Caroline Islands to the east. The tholeiitie group basalts have involved significant amount of depleted asthenosphere components, which suggests interactions of the Caroline plume with the Caroline basin spreading center. The MORB-like depleted geochemical nature of the Caroline tholeiite group basalts indicates formation of the Caroline Plateau under the young and thin Caroline plate lithosphere. Our results of age and geochemistry of the Caroline Plateau/Seamount system could be explained by the activities of the Caroline hotspot. This work was financially supported by the National Natural Science Foundation of China (91858206, 41876040).</p>

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 Annonaceae in the Western Pacific: geographic patterns and four new species

2017 ◽  
Author(s):  
Ian M. Turner ◽  
Timothy M.A. Utteridge
Keyword(s):  
New Species ◽  
Solomon Islands ◽  
New Guinea ◽  
Western Pacific ◽  
New Combinations ◽  
Geographic Patterns ◽  
The Pacific ◽  
Two New Species ◽  
The Western Pacific ◽  
A New Species

The taxonomy and distribution of Pacific Annonaceae are reviewed in light of recent changes in generic delimitations. A new species of the genus Monoon from the Solomon Archipelago is described, Monoon salomonicum I.M.Turner & Utteridge sp. nov., together with an apparently related new species from New Guinea, Monoon pachypetalum I.M.Turner & Utteridge sp. nov. The confirmed presence of the genus in the Solomon Islands extends the generic range eastward beyond New Guinea. Two new species of Huberantha are described, Huberantha asymmetrica I.M.Turner & Utteridge sp. nov. and Huberantha whistleri I.M.Turner & Utteridge sp. nov., from the Solomon Islands and Samoa respectively. New combinations are proposed: Drepananthus novoguineensis (Baker f.) I.M.Turner & Utteridge comb. nov., Meiogyne punctulata (Baill.) I.M.Turner & Utteridge comb. nov. and Monoon merrillii (Kaneh.) I.M.Turner & Utteridge comb. nov. One neotype and four lectotypes are designated. The geographic patterns exhibited by nine native Annonaceae genera, that range in the Pacific beyond New Guinea, are discussed.

scholarly journals Supplemental Material: Forearc magmatic evolution during subduction initiation: Insights from an Early Cretaceous Tibetan ophiolite and comparison with the Izu-Bonin-Mariana forearc

2020 ◽  
Author(s):  
Jin-Gen Dai ◽  
et al.
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Early Cretaceous ◽  
Analytical Methods ◽  
Major And Trace Elements ◽  
Magmatic Evolution ◽  
Isotopic Data ◽  
Subduction Initiation ◽  
Mariana Forearc

Detailed analytical methods in Text S1, major- and trace-element compositions of clinopyroxene, orthopyroxene, and amphibole, whole-rock major and trace elements, Sr-Nd isotopic data, and zircon U-Pb and Lu-Hf data in Tables S1–S7; Figures S1–S5.

scholarly journals Identification of a Kulshan caldera correlative tephra in the Palouse loess of Washington State, northwest USA

2016 ◽  
Vol 86 (2) ◽  
pp. 232-241 ◽  
Author(s):  
Georgina E. King ◽  
Nicholas J.G. Pearce ◽  
Helen M. Roberts ◽  
Victoria C. Smith ◽  
John A. Westgate ◽  
...  
Keyword(s):  
Trace Element ◽  
Pacific Northwest ◽  
Washington State ◽  
Fractional Crystallisation ◽  
Early Pleistocene ◽  
East Central ◽  
Trace Element Chemistry ◽  
The Pacific ◽  
Eruptive Volume ◽  
Reversed Polarity

AbstractThe Kulshan caldera formed at ∼1.15 Ma on the present-day site of Mt. Baker, Washington State, northwest USA and erupted a compositionally zoned (dacite-rhyolite) magma and a correlative eruptive, the Lake Tapps tephra. This tephra has previously been described, but only from the Puget Lowland of NW Washington. Here an occurrence of a Kulshan caldera correlative tephra is described from the Quaternary Palouse loess at the Washtucna site (WA-3). Site WA-3 is located in east-central Washington, ∼340 km southeast of the Kulshan caldera and ∼300 km east-southeast of the Lake Tapps occurrence in the Puget Lowland. Major- and trace element chemistry and location of the deposit at Washtucna within reversed polarity sediments indicates that it is not correlative with the Mesa Falls, Rockland, Bishop Ash, Lava Creek B or Huckleberry Ridge tephras. Instead the Washtucna deposit is related to the Lake Tapps tephra by fractional crystallisation, but is chemically distinct, a consequence of its eruption from a compositionally zoned magma chamber. The correlation of the Washtucna occurrence to the Kulshan caldera-forming eruption indicates that it had an eruptive volume exceeding 100 km3, and that its tephra could provide a valuable early-Pleistocene chronostratigraphic marker in the Pacific Northwest.

scholarly journals The eye-catching cicada Hamza ciliaris (Linnaeus, 1758) comb. n. in Indonesia and the Pacific: taxonomic status, synonymy, and distribution (Homoptera, Cicadoidea)

1991 ◽  
Vol 61 (2) ◽  
pp. 119-130 ◽  
Author(s):  
J.P. Duffels
Keyword(s):  
Taxonomic Status ◽  
The Philippines ◽  
New Combination ◽  
The Pacific ◽  
Caroline Islands

The new combination Hamza ciliaris (Linnaeus) is proposed for a cicada species widely distributed in Maluku ( = Moluccas), Timor, Banda, Kei and Banggai Islands, the Philippines, and the Palau group of the Caroline Islands.

scholarly journals Petrologic Insights into Rift Zone Magmatic Interactions from the 2011 Eruption of Kīlauea Volcano, Hawaiʻi

2019 ◽  
Vol 60 (11) ◽  
pp. 2051-2075
Author(s):  
Brett H Walker ◽  
Michael O Garcia ◽  
Tim R Orr
Keyword(s):  
Trace Element ◽  
Rift Zone ◽  
Magma Mixing ◽  
Major And Trace Elements ◽  
Kilauea Volcano ◽  
The Other ◽  
Least Squares Regression ◽  
Mixing Processes ◽  
Residual Magma ◽  
Kīlauea Volcano

Abstract The high frequency of historical eruptions at Kīlauea Volcano presents an exceptional opportunity to address fundamental questions related to the transport, storage, and interaction of magmas within rift zones. The Nāpau Crater area on Kīlauea’s East Rift Zone (ERZ) experienced nine fissure eruptions within 50 years (1961–2011). Most of the magma intruded during these frequent eruptions remained stored within the rift zone, creating a potential magma mixing depot within the ERZ. The superbly monitored and sampled 2011 eruption (Puʻu ʻŌʻō episode 59) presents an extraordinary opportunity to evaluate magma mixing processes within the ERZ. Whole-rock, glass, and olivine compositions were determined, not only for lava from the 2011 eruption, but also for a new suite of Nāpau Crater area samples from the 1963, 1965, 1968, 1983, and 1997 eruptions, as well as the previously undocumented 1922 eruption. Whole-rock XRF data revealed two geochemically distinct magma batches for episode 59: one less evolved (∼6·6 wt % MgO, 0·46 wt % K2O) than the other (∼6·2 wt % MgO, 0·58 wt % K2O). Episode 59 lava is remarkably aphyric (∼0·1 vol. % phenocrysts), making use of mineralogy to identify parent magma affinities problematic. Linear compositional trends of whole-rock major and trace elements, and reversely zoned olivine crystals indicate episode 59 lavas underwent magma mixing. Least squares regression calculations and plots of major and trace element data, were used to evaluate whether the episode 59 samples are products of mixing summit-derived magma with residual magma from previous Nāpau Crater area eruptions. The regression results and trace element ratios are inconsistent with previously proposed mixing scenarios, but they do support mixing between summit-derived magma and residual magma from the 1983 and 1997 Nāpau Crater area eruptions. These magmas were stored in physically and chemically distinct pods at depths of 1·6–3·0 km prior to mixing with new magma intruded from the summit to produce the episode 59 lava. One pod contained a fractionated equivalent of 1983 lava, and the other a hybrid of compositions similar to 1983 and 1997 lavas. The petrology of episode 59 lava demonstrates that magmas from two previous eruptions (1983 and 1997) were available to mix with magma intruded from the summit region. This study clarifies the pre-eruptive history of the mixed episode 59 lava, and elucidates the evolution of the volcano's magmatic system in a region of frequent eruptions.

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