Geochemistry of lavas from the Caroline hotspot, Micronesia: Evidence for primitive and recycled components in the mantle sources of lavas with moderately elevated 3He/4He

Jackson, Matthew G.; Price, Allison; Blichert‐Toft, Janne; Kurz, Mark D.; Reinhard, Andrew A.

doi:10.1016/j.chemgeo.2016.10.038

Cited by 28 publications

(26 citation statements)

References 134 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: 81%

“…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]. 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].…”

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].…”

Section: Introductionmentioning

confidence: 99%

“…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. However, the effect of thick lithospheric mantle on the chemical composition of Caroline Island lavas has not yet been explored.…”

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: 81%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

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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“…Among the most important questions is whether the Yap Trench is active at present. The Caroline Ridge, a prominent, complex NW-SE striking structure in the Caroline Plate, might have formed via the Caroline hot spot on top of the Oligocene seafloor in the Caroline Basin, as it shows generally increasing ages on Eastern Caroline Islands Ridge (Clague & Jarrard, 1973;Hegarty & Weissel, 1988;Jackson et al, 2016;Keating et al, 1984;McCabe & Uyeda, 1983), constraining the nature of the oceanic plateau. The Sorol Trough was the spreading center of the Caroline Ridge during the period~17-7 Ma and is thought to be the northern boundary of the Caroline Plate (Altis, 1999) or a structure separating the Caroline Plate (Hegarty & Weissel, 1988).…”

Section: Geologic Settingmentioning

confidence: 99%

Subduction Erosion, Crustal Structure, and an Evolutionary Model of the Northern Yap Subduction Zone: New Observations From the Latest Geophysical Survey

Zhang

Dong

Sun

et al. 2019

Geochem Geophys Geosyst

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The Yap subduction zone is a distinctive erosive margin with an extremely slow convergence rate. The high relief of the subducting plate, generated by horst and graben structures and seamounts, leads to attenuation of the crust. In this study, we present the latest geophysical data, collected by the Chinese research vessel Kexue, to investigate subduction erosion at the Yap subduction zone and develop subduction models for Yap subduction zone structures. We show an anomalous distance between the Yap Trench and the adjacent volcanic arc, the steep slope of the trench arcward, a frontal prism, and rare sediment in the trench, all typical features of erosive margins. We propose that the high‐relief subducting plate has led to erosion of the overlying plate and that different subduction processes, controlled locally by the topography of the subducting plate, have modified the Yap subduction zone. Numerous normal faults increase the relief of the seafloor entering the trench, and an anomalously large slope angle along the trench reflects uplift of the fore‐arc high via seamount subduction. In addition, the thin crust of the subducted horst and graben structures, along with the normal faults, might have eroded the fore‐arc crust and subsequently eroded the Yap arc crust during subduction. These subduction erosional processes at the Yap Trench provide one of the best cases of an erosive margin in the world, particularly for a subduction zone with an extremely slow convergence rate.

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Tectonic Settings of Potassic Igneous Rocks

Müller¹,

Groves²

2018

Potassic Igneous Rocks and Associated Gold-Copper Mineralization

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Geochemistry of lavas from the Caroline hotspot, Micronesia: Evidence for primitive and recycled components in the mantle sources of lavas with moderately elevated 3He/4He

Cited by 28 publications

References 134 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

Subduction Erosion, Crustal Structure, and an Evolutionary Model of the Northern Yap Subduction Zone: New Observations From the Latest Geophysical Survey

Tectonic Settings of Potassic Igneous Rocks

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