Geochemical and chronological constraints on the mantle plume origin of the Caroline Plateau

Zhang, Guoliang; Zhang, Ji; Wang, Shuai; Zhao, Jian‐xin

doi:10.1016/j.chemgeo.2020.119566

Cited by 28 publications

(31 citation statements)

References 63 publications

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“…The estimated lithosphere-asthenosphere boundary depth for these islands is ~96 km [17], thicker than those of the Caroline Plateau [13] and Hawaiian Islands (88-90 km) [17]. The 3 He/ 4 He ratios (7.6-12.8 Ra) of basalts from these islands indicate a deep mantle source [10,13,16], possibly related to recycled oceanic components [10]. However, Caroline lavas do not have the high 3 He/ 4 He compositions that are characteristic of Hawaii, Iceland, and Samoa lavas among others, possibly because they are more degassed, or higher U-Th concentrations were maintained in their mantle source over geologic time [10].…”

Section: Geological Backgroundmentioning

confidence: 85%

“…However, Caroline lavas do not have the high 3 He/ 4 He compositions that are characteristic of Hawaii, Iceland, and Samoa lavas among others, possibly because they are more degassed, or higher U-Th concentrations were maintained in their mantle source over geologic time [10]. The absence of newer volcanism near Kosrae, the youngest island, suggests the activity of the Caroline hotspot has decreased or, more likely, ceased [13,16]. The sampling locations on the Pohnpei Island.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The three volcanic islands, Pohnpei, Chuuk, and Kosrae, are associated with the Caroline Seamount Chain connected to the western Caroline Plateau (Figure 1), which developed at 23.9-8.13 Ma [13][14][15] after formation of the Caroline Plateau, and their ages decrease from west to east (since the middle Cenozoic): Chuuk, 14.8-4.3 Ma; Pohnpei, 8.7-0.92 Ma; and Kosrea, 2-1 Ma [16]. They are considered to be derived from a common mantle source related to the deep-rooted Caroline hotspot, which erupted through an old (162-153 Ma) portion of the Pacific Ocean crust with a relatively thick lithosphere [8][9][10][11].…”

Section: Geological Backgroundmentioning

confidence: 99%

“…They are considered to be derived from a common mantle source related to the deep-rooted Caroline hotspot, which erupted through an old (162-153 Ma) portion of the Pacific Ocean crust with a relatively thick lithosphere [8][9][10][11]. The estimated lithosphere-asthenosphere boundary depth for these islands is ~96 km [17], thicker than those of the Caroline Plateau [13] and Hawaiian Islands (88-90 km) [17]. The 3 He/ 4 He ratios (7.6-12.8 Ra) of basalts from these islands indicate a deep mantle source [10,13,16], possibly related to recycled oceanic components [10].…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The Caroline Islands in Micronesia were formed on a thick, ancient Pacific lithosphere at 162-153 Ma [8], and are associated with the Caroline hotspot [9][10][11][12][13]. Three of these volcanic to the Caroline Plateau [13]. Jackson et al [10] suggested that the Caroline Islands were formed by partial melting of a compositionally homogeneous mantle source, with a small contribution of recycled oceanic crust.…”

Section: Introductionmentioning

confidence: 99%

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Geochemical Constraints on Mantle Melting and Magma Genesis at Pohnpei Island, Micronesia

Zong

Dong

et al. 2020

Minerals

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The lithospheric mantle is of paramount importance in controlling the chemical composition of ocean island basalts (OIBs), influencing partial melting and magma evolution processes. To improve the understanding of these processes, the pressure–temperature conditions of mantle melting were investigated, and liquid lines of descent were modelled for OIBs on Pohnpei Island. The studied basaltic samples are alkalic, and can be classified as SiO2-undersaturated or SiO2-saturated series rocks, with the former having higher TiO2 and FeOT contents but with no distinct trace-element composition, suggesting melting of a compositionally homogenous mantle source at varying depths. Both series underwent sequential crystallization of olivine, clinopyroxene, Fe–Ti oxides, and minor plagioclase and alkali feldspar. Early magnetite crystallization resulted from initially high FeOT contents and oxygen fugacity, and late feldspar crystallization was due to initially low Al2O3 contents and alkali enrichment of the evolved magma. The Pohnpei lavas formed at estimated mantle-melting temperatures of 1486–1626 °C (average 1557 ± 43 °C, 1σ), and pressures of 2.9–5.1 GPa (average 3.8 ± 0.7 GPa), with the SiO2-undersaturated series forming at higher melting temperatures and pressures. Trace-element compositions further suggest that garnet rather than spinel was a residual phase in the mantle source during the melting process. Compared with the Hawaiian and Louisville seamount chains, Pohnpei Island underwent much lower degrees of mantle melting at greater depth, possibly due to a thicker lithosphere.

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Section: Geological Backgroundmentioning

confidence: 85%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geochemical Constraints on Mantle Melting and Magma Genesis at Pohnpei Island, Micronesia

Zong

Dong

et al. 2020

Minerals

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The effect of seamount chain subduction and accretion

Yang

Tong

et al. 2022

Geological Journal

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Seamount chains (oceanic plateaus, submarine ridges) are unique morphologic features on the seafloor, which resulted from the motion of the lithosphere over a convective plume. Seamount chains are being carried along by plate motions, which are eventually subducted beneath continental/oceanic plates or accreted in the accretionary complex, thus causing a series of effects in the convergent margin. In this paper, we briefly review the distribution and features of the typical modern seamount chains, including Hawaiian‐Emperor and Louisville seamount chains, Cocos, Ninetyeast and Caroline ridges, and Ogasawara Plateau, and mainly focus on the effects of seamount chains subduction and accretion. The geological effects mainly include the following: (1) deformation and tectonic erosion of the overriding plate; (2) flat‐slab subduction in the convergent margin; (3) growth of continental crust through time; (4) subduction initiation of plate tectonics; (5) generation of large earthquakes; (6) magmatism of the volcanic arc; and (7) formation of porphyry copper and gold deposits. The subduction of seamount chains resulted in similar effects in the Central Asian Orogenic Belt (CAOB) which is one of the largest and longest‐lived accretionary orogens on Earth. However, there are still many aspects that need further improvements, such as identification of the seamounts in the geological record, and geodynamic effects of subducted seamount chains. A detailed study on these sides of the seamount chains will enable us to further understand the tectonic evolution and metallogenesis of the CAOB, especially in accretionary orogenesis, continental crust growth, and subduction initiation dynamics.

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The dynamics of the Sorol Trough magmatic system: Insights from bulk‐rock chemistry and mineral geochemistry of basaltic rocks

Yan

Shi

et al. 2022

Geological Journal

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The Yap trench‐island arc system, where three tectonic plates (i.e., the Philippine Sea Plate, Pacific Plate, and Caroline Plate) interact, has undergone a relatively complicated geological evolution. East of the system, the Caroline Plateau are being subducted, and the plateau has been rifted into east and west Caroline ridges by the development of the Sorol Trough. However, until now, knowledge of the nature of the basement of the Sorol Trough is lacking, which limits our understanding of the complete tectonic evolution of the Yap island arc‐trench system and the Caroline Plateau. In this study, we performed petrological and mineral geochemical (in situ major element compositions and trace element compositions) analysis of newly acquired subducting basalt samples from the Sorol Trough segment, which is being subducted along the Yap Trench, and K‐Ar age of the Sorol basalts is 23.8 ± 0.7 Ma. The results show that phenocryst minerals of basalt from Sorol Trough are mainly olivine and plagioclase, with minor clinopyroxene microlites. The forsterite (Fo) values of the olivine phenocrysts in these rocks vary from 84.97 to 86.85, and plagioclase (Pl) phenocrysts are predominantly labradorite, with a few andesine plagioclase microlites. Bulk‐rock chemical compositions confirm that these rocks are intraplate alkaline basalts and show ocean island basalt (OIB)‐like geochemical characteristics. The mantle source of these basement basalts could be peridotite, and these Sorol Trough basalts may have been formed by 5–10% partial melting of mantle spinel lherzolite. The potential temperature of the mantle beneath the Sorol Trough was inferred to be 1,331–1,393°C, shows that there is no thermal anomaly in the mantle source. In addition, the crystallization temperatures of the clinopyroxenes (1,068–1,263°C) and plagioclase (702–1,216°C) and their compositional characteristics indicate that the magmatic processes have a conspicuously fast rate of magma upwelling. In conclusion, the basalts in the Sorol Trough were the products of low‐degree partial melting of a relatively enriched mantle source that passively upwelled as the Sorol Trough separated the Caroline Ridge into its western and eastern parts.

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Geochemical and chronological constraints on the mantle plume origin of the Caroline Plateau

Cited by 28 publications

References 63 publications

Geochemical Constraints on Mantle Melting and Magma Genesis at Pohnpei Island, Micronesia

Geochemical Constraints on Mantle Melting and Magma Genesis at Pohnpei Island, Micronesia

The effect of seamount chain subduction and accretion

The dynamics of the Sorol Trough magmatic system: Insights from bulk‐rock chemistry and mineral geochemistry of basaltic rocks

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