Structural characteristics of the Bayonnaise Knoll caldera as revealed by a high-resolution seismic reflection survey

Yamashita, M; Kasaya, Takafumi; Takahashi, Narumi; Takizawa, Kaoru; Kodaira, Shuichi

doi:10.1186/s40623-015-0214-2

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…1a), rather than being formed by simple upwelling fluid flow like the TAG mound on the Mid-Atlantic Ridge (e.g., Hannington et al 1998). A seismic study of the Bayonnaise caldera revealed fractures pervasively distributed inside of the caldera rim (Yamashita et al 2015). Yamashita et al (2015) postulated that these fractures induce fluid flow outside of the caldera rim.…”

Section: Modelingmentioning

confidence: 99%

“…A seismic study of the Bayonnaise caldera revealed fractures pervasively distributed inside of the caldera rim (Yamashita et al 2015). Yamashita et al (2015) postulated that these fractures induce fluid flow outside of the caldera rim. Further studies might elucidate the hydrological structure including this type of caldera-scale fluid flow that forms the Sunrise deposit.…”

Section: Modelingmentioning

confidence: 99%

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Self-potential mapping using an autonomous underwater vehicle for the Sunrise deposit, Izu-Ogasawara arc, southern Japan

Kawada

Kasaya

2018

Earth Planets Space

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We performed a simultaneous survey of self-potential and plume turbidity using an autonomous underwater vehicle (AUV) above the Sunrise deposit in the Myojin Knoll caldera of the Izu-Ogasawara arc. A 10-m-long electrode rod, on which five electrodes referenced with a common electrode were mounted, was connected at the tail of an AUV. The survey was conducted at a typical speed of 2 knots, covering the 1500 m × 1500 m area with a typical spacing of survey lines of 100 m. With AUV altitude of 100 m above the seafloor, a negative self-potential anomaly of a few millivolts was observed. The self-potential anomaly was found to spread 300 m × 300 m. The self-potential is probably attributable to the geo-battery mechanism: electric current is generated by redox reactions occurring around an ore body crossing a redox contrast. Assuming that the source of the self-potential is an electric current dipole, we can image a southward-dipping dipole with the moment of approximately 10 3 A m, approx. 30 m below the southern part of the ore deposit. Anomalies of turbidity, which are correlated to ambient temperature and which are signatures of discharged hydrothermal fluids, were distributed more broadly than the self-potential. Some turbidity anomalies were found without self-potential anomalies. They were probably transported by the ocean current. Spatial decoupling between the self-potential and turbidity anomalies suggests that the direct contribution of hydrothermal fluids to the self-potential anomalies is probably a secondary effect. The survey altitude of 100 m and the survey speed of 2 knots in the present study represent practical limitations for the self-potential survey when active hydrothermal fields are targeted. We have observed that the self-potential method responds exclusively to the presence of hydrothermal ore deposits. This behavior differs from other methods for exploring seafloor hydrothermal ore deposits: The geomagnetic method responds not only to ore deposits but also to volcanic bodies. The plume method can detect remote hydrothermal activities, but the source locations are not necessarily specified. The self-potential method is useful as an excellent exploration tool, particularly for initial surveys.

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Section: Modelingmentioning

confidence: 99%

Section: Modelingmentioning

confidence: 99%

Self-potential mapping using an autonomous underwater vehicle for the Sunrise deposit, Izu-Ogasawara arc, southern Japan

Kawada

Kasaya

2018

Earth Planets Space

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Geological big data acquisition based on speech recognition

Zhang

Zhao

Xie

et al. 2020

Multimed Tools Appl

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Geology of a Large Intact Extensional Oceanic Arc Crustal Section with Superior Exposures: Cretaceous Alisitos Arc, Baja California (Mexico)

Busby

Morris

DeBari

et al. 2023

Geology of a Large Intact Extensional Oceanic Arc Crustal Section With Superior Exposures: Cretaceous Alisitos Arc, Baja Califo

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The Rosario segment of the Early Cretaceous Alisitos oceanic arc exposes the transition from upper-crustal volcanic and hypabyssal rocks to middle-crustal plutons, which formed in an extensional environment. The Rosario segment forms a structurally intact, unmetamorphosed, spectacularly well-exposed, gently tilted section that is 50 km long and 7 km deep. The top of the exposed section is unconformably overlain by flat-lying Late Cretaceous sedimentary rocks (Rosario Group, described elsewhere), and the base of the section passes downward into ductilely deformed metamorphic rocks (not mapped herein). We divided the Rosario segment into three subsegments: a central subaerial edifice, underpinned by the La Burra pluton; a southern volcano-bounded basin (dominantly shallow marine), underpinned by the San Fernando pluton; and a northern fault-bounded basin (dominantly deep marine), underpinned by the Los Martires pluton. Using a combination of published and new geochronologic data, we infer that the time span represented by the arc crustal section could be as little as 1.7 m.y., dated at ca. 111–110 Ma. Volcanic and plutonic samples show a continuum from basalt/basaltic andesite to rhyolite, are low to medium K, and are transitional tholeiite to calc-alkaline in character. Hf isotopic data from zircons indicate primitive magma, consistent with previously published whole-rock isotopic data. The volcanic stratigraphy can be correlated across all three subsegments using the tuff of Aguajito (Ki-A), a distinctive rhyolite welded ignimbrite that fills the 15-km-wide, >3.6-km-deep La Burra caldera on the central subaerial edifice. Additionally, a second caldera is preserved below the tuff of Aguajito (Ki-A) in the northern fault-bounded basin, floored by a large rhyolite sill complex, up to 700 m thick with a lateral extent of >7 km. Up section from the tuff of Aguajito (Ki-A), there is an abrupt shift to dominantly mafic volcanism that we correlated across all three subsegments of the Rosario segment, dividing the section into two distinct parts (phase 1 and phase 2). The pluton beneath the central subaerial edifice (La Burra) is associated with the caldera that produced the tuff of Aguajito (Ki-A) during phase 1. Plutons beneath the northern fault-bounded basin (Los Martires) and the southern volcano-bounded basin (San Fernando) were emplaced during phase 2. However, we infer that the La Burra pluton, which is associated with the phase 1 La Burra caldera, continued to grow incrementally during phase 2 because it intruded and tilted both phase 1 and phase 2 strata. The Rosario segment escaped postmagmatic deformation, other than gentle tilting (25°–35°) to the west as a single rigid block. The Rosario segment of the Cretaceous Alisitos arc represents an extensional oceanic arc with abundant silicic pyroclastic rocks, culminating in arc rifting with outpouring of mafic magmas. The excellent exposure and preservation provide us with the opportunity to herein describe the following: (1) caldera collapse features and the products of varying explosive eruptive styles; (2) caldera plumbing systems, including silicic sill complexes; (3) the transition from plutons through hypabyssal intrusions to eruptive products; (4) incremental pluton growth and its effects on the structure of the roof rocks; (5) the products of deep-water mafic to silicic eruptions; and (6) flow transformations that occur when hot pyroclastic flows enter marine basins on gentle slopes versus steep slopes. We also used this data set to address questions highly complementary to the work being done on understanding the growth of continental crust at subduction zones. Finally, this volume serves as a model for detailed geologic study of paleo-arcs.

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Structural characteristics of the Bayonnaise Knoll caldera as revealed by a high-resolution seismic reflection survey

Cited by 4 publications

References 27 publications

Self-potential mapping using an autonomous underwater vehicle for the Sunrise deposit, Izu-Ogasawara arc, southern Japan

Self-potential mapping using an autonomous underwater vehicle for the Sunrise deposit, Izu-Ogasawara arc, southern Japan

Geological big data acquisition based on speech recognition

Geology of a Large Intact Extensional Oceanic Arc Crustal Section with Superior Exposures: Cretaceous Alisitos Arc, Baja California (Mexico)

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