Caldera formation and varied eruption styles on North Pacific seamounts: the clastic lithofacies record

Portner, R. A.; Clague, D. A.; Paduan, J. B.

doi:10.1007/s00445-014-0845-3

Cited by 12 publications

(7 citation statements)

References 107 publications

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“…Significant lava stacking seems at odd with the characteristics and stratigraphic context of lava intervals and individual lava flows preserved in the studied drill sites, which are very thin and are interbedded within a predominantly volcaniclastic basement with local evidence for shallow-marine environments. A third hypothesis that could account for the formation of a summit platform is the collapse and infill of calderas on the volcanoes (e.g., Portner et al, 2014). However, the absence of hydrothermal alteration, hydrothermal deposits and polymictic breccia in the uppermost volcanic basement of Louisville seamounts (Koppers et al, 2012a; this study) are not consistent with this interpretation.…”

Section: Constructional Volcanic Summit Platformmentioning

confidence: 61%

Non-Hawaiian lithostratigraphy of Louisville seamounts and the formation of high-latitude oceanic islands and guyots

Buchs

Williams

Sano

et al. 2018

Journal of Volcanology and Geothermal Research

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Guyots are large seamounts with a flat summit that is generally believed to form due to constructional biogenic and/or erosional processes during the formation of volcanic islands. However, despite their large abundance in the oceans, there are still very few direct constraints on the nature and formation of guyots, in particular those formed at high latitude that lack a thick cap of shallow-marine carbonate rocks. It is largely accepted based on geophysical constraints and surficial observations/sampling that the summit platform of these guyots is shaped by wave abrasion during post-volcanic subsidence of volcanic islands. Here we provide novel constraints on this hypothesis and the summit geology of guyots with a lithostratigraphic analysis of cores from three Louisville seamounts (South Pacific) collected during Expedition 330 of the Integrated Ocean Drilling Program (IODP). Thirteen lithofacies of sedimentary and volcanic deposits are described, which include facies not previously recognized on the top of guyots, and offer a new insight into the formation of high-latitude oceanic islands on a fastmoving plate. Our results reveal that the lithostratigraphy of Louisville seamounts preserves a very consistent record of the formation and drowning of volcanic islands, with from bottom to top: (i) volcaniclastic sequences with abundant lava-fed delta deposits, (ii) submarine to subaerial shield lava flows, (iii) post-volcanic shallow to deeper marine sedimentary rocks lacking thick reef deposits, (iv) post-erosional rejuvenated volcanic rocks, and (v) pelagic sediments. Recognition of erosional boundaries between subaerial lava flows and shallow-marine sedimentary rocks provides novel support for post volcanic wave planation of guyots. However, the summit geology of Louisville seamounts is dissimilar to that of high-latitude Hawaiian-Emperor guyots that have emplaced in a similar tectonic and environmental setting and that include thicker lava stacks with apparently little lava-fed delta deposits. To explain observed lithostratigraphic discrepancy we propose that Louisville seamounts represent a distinct type of intraplate ocean volcano characterized by formation of a smaller island, with a central shield volcano surrounded by extended shallow-marine shelves formed by lava-fed deltas. In this interpretation the summit platform of Louisville-type guyots results from early (syn-volcanic) subaerial to shallow-marine constructional volcanic processes and marine erosion, enhanced by later (post-volcanic) wave planation. This contrasts with larger Hawaiian edifices that are capped by thicker shield volcanoes, and that develop an extended wave planation surface during postvolcanic subsidence (in the absence of efficient coral growth). The difference between Hawaiian-and Louisville-type volcanic islands and guyots can be explained by contrasted dynamic disequilibrium between magmatic growth, erosion, and subsidence during the island-building stage. Unlike Hawaiian-type volcanoes, Louisville seamounts are characterized by a...

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Section: Constructional Volcanic Summit Platformmentioning

confidence: 61%

Non-Hawaiian lithostratigraphy of Louisville seamounts and the formation of high-latitude oceanic islands and guyots

Buchs

Williams

Sano

et al. 2018

Journal of Volcanology and Geothermal Research

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“…They found no foraminifera in sediment collected near hydrothermal vents, so we avoided those areas and collected cores between vent fields in the graben and on the east and west flanks. The recovered sediments are generally light brown tuffaceous ooze [ Portner et al ., ] that includes planktic (e.g., radiolaria, diatoms, and foraminifera tests) and benthic (e.g., foraminifera tests and sponge spicules) biological components, volcanic glass shards, hydrothermal minerals, and fine sediment derived from the North American continent.…”

Section: Geologic Settingmentioning

confidence: 99%

Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages

Clague

Dreyer

Paduan

et al. 2014

Geochem Geophys Geosyst

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High-resolution bathymetric surveys from autonomous underwater vehicles ABE and D. Allan B.were merged to create a coregistered map of 71.7 km 2 of the Endeavour Segment of the Juan de Fuca Ridge.Radiocarbon dating of foraminifera in cores from three dives of remotely operated vehicle Doc Ricketts provide minimum eruption ages for 40 lava flows that are combined with the bathymetric data to outline the eruptive and tectonic history. The ages range from Modern to 10,700 marine-calibrated years before present (yr BP). During a robust magmatic phase from >10,700 yr BP to 4300 yr BP, flows erupted from an axial high and many flowed >5 km down the flanks; some partly buried adjacent valleys. Axial magma chambers (AMCs) may have been wider than today to supply dike intrusions over a 2 km wide axial zone. Summit Seamount formed by 4770 yr BP and was subsequently dismembered during a period of extension with little volcanism starting 4300 yr BP. This tectonic phase with only rare volcanic eruptions lasted until 2300 yr BP and may have resulted in near-solidification of the AMCs. The axial graben formed by crustal extension during this period of low magmatic activity. Infrequent eruptions occurred on the flanks between 2620-1760 yr BP and within the axial graben since 1750 yr BP. This most recent phase of limited volcanic and intense hydrothermal activity that began 2300 yr BP defines a hydrothermal phase of ridge development that coincides with the present-day 1 km wide AMCs and overlying hydrothermal vent fields.

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“…Seamounts are much more abundant on the western flank of the ridge than on the eastern flank. In addition to the large Cobb‐Eickelberg chain, there are several chains of small seamounts that form close to the Juan de Fuca ridge on the western flank [ Clague et al , ; Portner et al , ]. Because the Juan de Fuca ridge is migrating westward in the absolute hot spot reference frame at ~20 mm/yr and the Juan de Fuca plate is nearly stationary, Davis and Karsten [] originally proposed that this westward migration provided the fundamental driver of the seamount asymmetry.…”

Section: Introductionmentioning

confidence: 99%

Ridge asymmetry and deep aqueous alteration at the trench observed from Rayleigh wave tomography of the Juan de Fuca plate

2016

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Using Rayleigh wave tomography of noise‐removed ocean bottom seismometer data from the Cascadia Initiative, we illuminate the structure of the upper mantle beneath the Juan de Fuca plate. Beneath the Juan de Fuca ridge, there is strong asymmetry, with a pronounced low‐velocity zone in the 25–65 km depth range. Extending to the west from the spreading axis, this anomaly has velocities low enough to indicate the presence of melt. The asymmetry in velocity structure and the much greater abundance of seamounts on the west flank of the ridge suggest that dynamic, buoyant upwelling is important, perhaps triggered by thermal or compositional anomalies beneath Axial Seamount. In contrast, there is no evidence for asymmetry in the axial zone or lower than expected velocities beneath the Gorda ridge. On the eastern flank of the Juan de Fuca ridge, the shear velocity in the 25–65 depth range is higher than expected; the lithosphere appears to be colder and thicker than predicted by standard plate cooling models, perhaps caused by the downwelling counterpart of the upwelling on the west side of the ridge. Close to the trench, there is a sharp decrease in shear velocity. We interpret this as aqueous alteration caused by hydrothermal circulation through deep normal faults associated with bending of the plate. Beneath the Astoria and Nitinat fans, where abyssal plain sediment is thickest, the velocity decrease is much smaller, which is consistent with a thick sediment cap that prevents hydrothermal alteration of the plate.

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Caldera formation and varied eruption styles on North Pacific seamounts: the clastic lithofacies record

Cited by 12 publications

References 107 publications

Non-Hawaiian lithostratigraphy of Louisville seamounts and the formation of high-latitude oceanic islands and guyots

Non-Hawaiian lithostratigraphy of Louisville seamounts and the formation of high-latitude oceanic islands and guyots

Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages

Ridge asymmetry and deep aqueous alteration at the trench observed from Rayleigh wave tomography of the Juan de Fuca plate

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