Volcanism in Response to Plate Flexure

Hirano, Naoto; Takáhashi, Eiichi; Yamamoto, Junji; Abe, Natsue; Ingle, Stéphanie; Kaneoka, Ichiro; Hirata, Takafumi; Kimura, Jun–Ichi; Ishii, Teruaki; Ogawa, Yujiro; Machida, Shiki; Suyehiro, Kiyoshi

doi:10.1126/science.1128235

Cited by 284 publications

(308 citation statements)

References 24 publications

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“…The Pliocene volcanic rocks, which formed on 100 Myr old ocean crust, provide compelling evidence that EM1-type components are still located in the shallow mantle beneath the Indian Ocean, well away from hotspot tracks or MORs. This very low volume volcanism took place when Christmas Island was uplifted, as it moved onto the flexural bend outboard of the Java Trench, and thus formed in a similar tectonic setting to the Petit Spot seamounts, which formed outboard of the Japan Trench 24 . Bending and uplift of the subducting plate could generate low-degree decompression melts, whereas extension and bend-faulting could facilitate the rise of these melts to the surface.…”

Section: Information S1mentioning

confidence: 99%

Origin of Indian Ocean Seamount Province by shallow recycling of continental lithosphere

et al. 2011

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Ar age, Sr, Nd, Hf and high-precision Pb isotope analyses of volcanic rocks from the province with plate tectonic reconstructions. We find that the seamounts are 47-136 million years old, decrease in age from east to west and are consistently 0-25 million years younger than the underlying oceanic crust, consistent with formation near a mid-ocean ridge. The seamounts also exhibit an enriched geochemical signal, indicating that recycled continental lithosphere was present in their source. Plate tectonic reconstructions show that the seamount province formed at the position where West Burma began separating from Australia and India, forming a new mid-ocean ridge. We propose that the seamounts formed through shallow recycling of delaminated continental lithosphere entrained in mantle that was passively upwelling beneath the mid-ocean ridge. We conclude that shallow recycling of continental lithosphere at mid-ocean ridges could be an important mechanism for the formation of seamount provinces in young ocean basins.Volcanic seamounts are one of the most abundant features on the ocean floor (>20,000 at least 1 km high 4 ), yet the origin of most seamounts remains elusive. The diffuse Christmas Island Seamount Province (CHRISP) extends from the Argo Basin to the Wharton Basin, west of the Investigator Rise, covering ∼1,000,000 km 2 ( Fig. 1). In addition to Christmas Island and the Cocos/Keeling Islands, it consists of ∼50 large, up to 4,500 m high seamounts, and abundant smaller volcanic structures. During the RV Sonne SO199 CHRISP Expedition, 54 seamounts were partially mapped with the SIMRAD EM 120 multi-beam echo-sounding system and 38 were sampled by dredging. The recovered rocks indicate that all structures are volcanic in origin. Compositions range from tholeiitic to basanitic to trachytic, with alkali basalts being the main parental lava type. The abundant large guyots indicate that this was a former province of ocean island volcanoes, which were eroded to sea level and subsequently subsided (1,200-3,000 m). The goal of this study was to constrain the origin of the CHRISP and to determine if its source(s) could have affected the chemistry of the Indian upper mantle.Step-heating plateau ages on plagioclase, hornblende, Kfeldspar, glass and matrix separates were generated from 32 seamount and 10 Christmas Island samples (Supplementary Information S1). The ages of the seamounts and the underlying crust decrease from east to west: from Argo Basin Province (AP, 136 Myr; to Eastern Wharton Basin Province (EWP, Myr from SE to NW) to Vening-Meinesz Province (VMP, 95-64 Myr; crust ∼100-78 Myr from SE to NW) to Cocos-Keeling Province (CKP, refs 5,6; Fig. 1). A plot of longitude versus age forms a good linear correlation (r 2 = 0.87). The age difference between a seamount sample and the underlying crust is 0-25 Myr, indicating that the seamounts formed on or near the West Burma-Australian/Indian spreading ridge. Christmas Island and its submarine flanks record two younger, intraplate phases of volcanism: (1) the Eocene shi...

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Section: Information S1mentioning

confidence: 99%

Origin of Indian Ocean Seamount Province by shallow recycling of continental lithosphere

et al. 2011

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“…The widespread occurrence of this process is indicated by the discovery of small volcanoes petit-spots across broad regions of the NW Pacific plate and near the Tonga Trench, and is supported by a reinterpretation of the origin of alkaline basalts found within accretionary prisms. This paper provides new insights into the findings of Valentine andHirano, 2010 Baba et al, 2007b;Shito et al, 2008Obayashi et al, 2006Machida et al, 2009Hirano et al, 2006Abe et al, 2006, Grégoire et al, 2000Neumann et al, 2004 …”

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confidence: 69%

プチスポット火山から期待される海洋リソスフェアの包括的理解と地質学の新展開－超モホール計画の提案－

Hirano¹,

Abe²,

Machida³

et al. 2010

Jour. Geol. Soc. Japan

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“…Seamounts can also form along cracks resulting from stress in the oceanic lithosphere, e.g., as a result of plate cooling, plate bending outboard of subduction zones, collision of continental blocks, or abrupt changes in plate motions (Natland and Winterer, 2005;Valentine and Hirano, 2010). Petitspot volcanoes near Japan and Pliocene volcanism on Christmas Island near Indonesia, for example, formed outboard of subduction zones due to plate bending (Hirano et al, 2006;Hoernle et al, 2011). Plate cracking formed by extension can not only facilitate the rise of melts through the lithosphere but also can trigger asthenospheric upwelling causing decompression melting (O'Connor et al 2015).…”

Section: Charting Abundance and Distributionmentioning

confidence: 99%

“…Seamounts <1,000 m tall are sometimes referred to as "knolls" (e.g., Hirano et al, 2008). "Petit spots" are a newly discovered subset of sea knolls confined to the bulge of subducting oceanic plates of oceanic plates seaward of deep-sea trenches (Hirano et al, 2006). …”

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Seamounts

Buchs¹,

Hoernle²,

Grevemeyer³

2015

Encyclopedia of Marine Geosciences

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DefinitionSeamounts are literally mountains rising from the seafloor. More specifically, they are "any geographically isolated topographic feature on the seafloor taller than 100 m, including ones whose summit regions may temporarily emerge above sea level, but not including features that are located on continental shelves or that are part of other major landmasses" . The term "guyot" can be used for seamounts having a truncated cone shape with a flat summit produced by erosion at sea level (Hess, 1946), development of carbonate reefs (e.g., Flood, 1999), or partial collapse due to caldera formation (e.g., Batiza et al., 1984). Seamounts <1,000 m tall are sometimes referred to as "knolls" (e.g., Hirano et al., 2008). "Petit spots" are a newly discovered subset of sea knolls confined to the bulge of subducting oceanic plates of oceanic plates seaward of deep-sea trenches (Hirano et al., 2006). Charting, Abundance, and DistributionSeamounts form one of the most common bathymetric features on the seafloor. Two techniques, both with advantages and disadvantages, have been used to chart them. The first technique is satellite altimetry that measures the height between a satellite and the instantaneous sea surface. This distance can be used after correction for oceanographic effects on the sea surface to derive the geoid undulation, which (with assumptions) can be used to derive gravity anomalies. These are then converted (with assumptions) to seafloor bathymetry (Wessel, 2001). This technique permits full coverage of the ocean floor in the 72° latitude range. However, oceanographic noise at the sea surface limits the identification of seamounts smaller than ~1.5 km in most areas of the ocean (Wessel et al., 2010). The second type of technique uses ship SONAR (e.g., multibeam echo-sounding systems) or towed/autonomous underwater vehicles (AUVs), allowing topographic mapping at high resolution of the ocean floor. This technique permits recognition of seamounts of virtually any size provided that they are not entirely covered by sediment. However, the spatial coverage of the multibeam swath is restricted to a narrow stripe beneath the vehicle conducting the measurements, with the width of the stripe increasing with water depth between the vehicle and the seafloor. As a consequence, <10 % of the global seafloor has been charted using this method. Size-frequency relationship of seamounts based on satellite and ship track data can be combined to estimate the total number of seamounts (Hillier and Watts, 2007). It is therefore speculated that there are 3-80 million seamounts greater than 100 m in height on the seafloor. The total number and global distribution of smaller seamounts, however, remains poorly constrained due to relatively limited coverage of the seafloor by echo sounding. Around 90 % of the seamounts, a fraction primarily including the smallest, <100 m-tall edifices, remain to be charted (Wessel et al., 2010). Only a very limited number of seamounts are currently included in open-source databases like the Seamou...

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Volcanism in Response to Plate Flexure

Cited by 284 publications

References 24 publications

Origin of Indian Ocean Seamount Province by shallow recycling of continental lithosphere

Origin of Indian Ocean Seamount Province by shallow recycling of continental lithosphere

プチスポット火山から期待される海洋リソスフェアの包括的理解と地質学の新展開－超モホール計画の提案－

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