Active underwater volcano, a post-caldera lava dome on the northeastern rim of a 9 km wide underwater caldera, located 420 km south of Tokyo, 130 km south of Hachijo island.
Located north east of the Bayonnaise Rocks.
Composed principally of hypersthene-augite dacite. The summit is around 50 meters under the ocean surface, but has occasionally in the past appeared above the surface. An explosive eruption in 1952 killed 31 people on board a research vessel. There have also been eruptions of tens of millions of tons of pumice, which can be carried large distances across the Pacific by ocean currents.
The volcano barely rises above the surface of the sea. Most eruption have occurred at Myojin-sho in the NE of the caldera. The eruption of Myozin-syo was the most notable eruption in Japan during the years 1951-1954. First reported on 17th September 1952 by crew of the fishing boat. The eruption occurred at Myozin-syo dome, 30 km NNE of Bayonnaise Rocks. Eruptions from the volcano formed a temporary island 150 m long, 100 m wide and 30 m high. The island disappeared under the water on 23rd September. On 24th September a 2 m high tsunami was produced by eruptions.

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Standard Detailed Gallery Strunz Chemical Elements

Mineral List

Mineral list contains entries from the region specified including sub-localities

ⓘ 'Tennantite Subgroup'

7 valid minerals.

Detailed Mineral List:

ⓘ Baryte

Formula: BaSO₄

References:

Iizasa, K, Yuasa, M, Yokota, S (1992) Mineralogy and geochemistry of volcanogenic sulfides from the Myojinsho submarine caldera, the Shichito-Iwojima Ridge, Izu-Ogasawara Arc, northwestern Pacific. Marine Geology, 108 (1) 39-58 doi:10.1016/0025-3227(92)90212-z

ⓘ Galena

Formula: PbS

References:

ⓘ Greenockite

Formula: CdS

References:

ⓘ Pyrite

Formula: FeS₂

References:

ⓘ Quartz

Formula: SiO₂

References:

ⓘ Sphalerite

Formula: ZnS

References:

ⓘ Tellurobismuthite

Formula: Bi₂Te₃

References:

ⓘ 'Tennantite Subgroup'

Formula: Cu₆(Cu₄C²⁺₂)As₄S₁₂S

References:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘ	Sphalerite	2.CB.05a	ZnS
ⓘ	Greenockite	2.CB.45	CdS
ⓘ	Galena	2.CD.10	PbS
ⓘ	Tellurobismuthite	2.DC.05	Bi₂Te₃
ⓘ	Pyrite	2.EB.05a	FeS₂
ⓘ	'Tennantite Subgroup'	2.GB.05	Cu₆(Cu₄C²⁺₂)As₄S₁₂S
Group 4 - Oxides and Hydroxides
ⓘ	Quartz	4.DA.05	SiO₂
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
ⓘ	Baryte	7.AD.35	BaSO₄

List of minerals for each chemical element

O	Oxygen
O	ⓘ Baryte	BaSO₄
O	ⓘ Quartz	SiO₂
Si	Silicon
Si	ⓘ Quartz	SiO₂
S	Sulfur
S	ⓘ Baryte	BaSO₄
S	ⓘ Galena	PbS
S	ⓘ Greenockite	CdS
S	ⓘ Pyrite	FeS₂
S	ⓘ Sphalerite	ZnS
S	ⓘ Tennantite Subgroup	Cu₆(Cu₄C₂²⁺)As₄S₁₂S
Fe	Iron
Fe	ⓘ Pyrite	FeS₂
Cu	Copper
Cu	ⓘ Tennantite Subgroup	Cu₆(Cu₄C₂²⁺)As₄S₁₂S
Zn	Zinc
Zn	ⓘ Sphalerite	ZnS
As	Arsenic
As	ⓘ Tennantite Subgroup	Cu₆(Cu₄C₂²⁺)As₄S₁₂S
Cd	Cadmium
Cd	ⓘ Greenockite	CdS
Te	Tellurium
Te	ⓘ Tellurobismuthite	Bi₂Te₃
Ba	Barium
Ba	ⓘ Baryte	BaSO₄
Pb	Lead
Pb	ⓘ Galena	PbS
Bi	Bismuth
Bi	ⓘ Tellurobismuthite	Bi₂Te₃

Localities in this Region

Japan

Tokyo Metropolis
- Hachijō Subprefecture
  - Myojin Knoll Volcano
    - Sunrise deposit

Other Regions, Features and Areas containing this locality

Eurasian Plate

Izu Bonin ArcVolcanic Arc

Japan

Tokyo Metropolis
- Izu ArchipelagoArchipelago

Philippine Sea PlateTectonic Plate

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

Niino H., Tsuya H., Morimoto R., Ossaka G., Hamaguchi H., Tatsumoto M., Hamaguchi Y., Matsue Y., Komai Y., Arinara C., Ebina K. andTakagi K.:Report on the Submarine Eruption of Myozin-syo. Jour. Tokyo Univ. of Fisheries, Vol. 40, No. 2 (1953), 1–43 (in English).

Fiske, Richard S., Cashman, Katharine V., Shibata, Atsushi, Watanabe, Kazuki (1998) Tephra dispersal from Myojinsho, Japan, during its shallow submarine eruption of 1952-1953. Bulletin of Volcanology, 59 (4). 262-275 doi:10.1007/s004450050190

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