:Takuyo-Daisan
{{Short description|Guyot in the Western Pacific Ocean off Japan}}
{{Infobox seamount
| name = Takuyo-Daisan
| depth = {{convert|1409|m|ft|abbr=on}}
| height =
| map = {{Location map|Oceania
| label = Takuyo-Daisan
| mark = Red triangle with thick white border.svg
| coordinates = {{coord|34.2|N|144.3|E}}
}}
| map_caption = Location offshore Japan
| image =
| image_alt =
| image_caption =
| image_size =
| summit_area =
| translation =
| language =
| pronunciation =
| location = Western Pacific Ocean
| group = Japanese Seamounts
| coordinates = {{coord|34.2|N|144.3|E|display=inline,title}}
| country = Japan
| type = Guyot
| volcanic_group =
| range =
| age = Cretaceous
| last_activity = Aptian
| last_eruption =
| discovered =
}}
Takuyo-Daisan is a guyot in the Western Pacific Ocean off Japan. It is {{convert|1409|m}} deep and has a square-shaped flat top surrounded by a perimeter ridge. Several other seamounts lie nearby.
The seamount formed as a volcanic island during the Cretaceous in the area currently occupied by French Polynesia. Subsequently reefs developed around the volcanic island and generated a carbonate platform which drowned during the Albian along with several other such platforms in the world.
Name and research history
Takuyo-Daisan was formerly known as "Seiko guyot"; "Seiko guyot" was used even earlier for Takuyo-Daini while Takuyo-Daisan was named "Eiko".{{sfn|Vogt|Smoot|1984|p=11087}} This seamount was drilled by the Ocean Drilling Program, with Site 879 located on the seamount.{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=199}}
Geography and geology
Takuyo-Daisan lies southeast of the city of Yokohama, Japan.{{sfn|Haggerty|van Waasbergen|1995|p=842}} It is the easternmost seamount in the "Seiko" cluster{{sfn|Haggerty|van Waasbergen|1995|p=841}} of the Japanese Seamounts.{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=199}} The Boso triple junction lies only {{convert|200|km}} away from the seamount.{{sfn|Vogt|Smoot|1984|p=11087}}
= Local =
Takuyo-Daisan is a guyot{{sfn|Rack|Lawyer|Gee|1995|p=973}} that rises to a minimum depth of {{convert|1409|m}}{{sfn|Vogt|Smoot|1984|p=11088}} and is capped by an approximately square-shaped surface platform at about {{convert|1600|m}} depth{{sfn|Haggerty|van Waasbergen|1995|p=845}} which has a surface area of about {{convert|86|km2}}.{{sfn|Vogt|Smoot|1984|p=11088}} Depressions up to {{convert|75|m}} deep cover the flat top. The top is surrounded by a {{convert|0.6|-|1|km}} wide and up to {{convert|110|m}} high ridge, especially on the northeastern and southern sides.{{sfn|Haggerty|van Waasbergen|1995|p=843}} It may be either a bioherm or a karst landform. A {{convert|100|m}}{{sfn|Ogg|Camoin|Jansa|1995|p=361}}-{{convert|110|m}} high structure may be part of the old volcanic edifice;{{sfn|Rack|Lawyer|Gee|1995|p=973}} the interface between the carbonate platform and the volcanic basement has a sloping aspect.{{sfn|Haggerty|Premoli Silva|1995|p=943}}
Away from the platform, the seamount has steep slopes probably formed by short lava flows{{sfn|Rack|Lawyer|Gee|1995|p=973}} that rise {{convert|4.3|km}} above the seafloor.{{sfn|Larson|Erba|Nakanishi|Bergersen|1995|p=915}} Channels, debris flow fronts and levees decorate its slopes.{{sfn|Vogt|Smoot|1984|p=11093}} Noticeable ridges emanate from the east-southeastern, southwestern, west-northwestern and north-northeastern corners of the seamount;{{sfn|Haggerty|van Waasbergen|1995|p=845}} they appear to be rift zones, and flank cones are found on the eastern slopes. The southern slopes feature slump deposits, and the entire seamount is surrounded by a sediment fan.{{sfn|Vogt|Smoot|1984|p=11093}} The volume of the entire seamount is about {{convert|1300|km3}}.{{sfn|Vogt|Smoot|1984|p=11090}} Two large seamounts lie west and southwest of Takuyo-Daisan with a smaller seamount between the two; Takuyo-Daini is the western one and Jensen seamount the south-western one.{{sfn|Vogt|Smoot|1984|p=11093}} The seafloor underneath Takuyo-Daisan has an age of 143 million years.{{sfn|Larson|Erba|Nakanishi|Bergersen|1995|p=919}}
= Regional =
The Western Pacific Ocean features many seamounts with flat tops at depths of {{convert|1|-|2|km}} below sea level which are known as guyots. They were considered to be remnants of eroded islands before Cretaceous carbonate platforms were discovered on them{{sfn|Haggerty|van Waasbergen|1995|p=841}} which resemble present-day atolls although they do not have exactly the same properties.{{sfn|Larson|Erba|Nakanishi|Bergersen|1995|p=915}} Later similar submarine mountains were identified elsewhere in the Pacific Ocean as well. Menard 1958 suggested that the Western Pacific guyots once were part of an elevated region known as the Darwin Rise, later compared to present day French Polynesia.{{sfn|Haggerty|van Waasbergen|1995|p=842}}
Many of these seamounts originally formed in the South Pacific, such as in French Polynesia,{{sfn|Christie|Dieu|Gee|1995|p=495}}{{sfn|Pringle|Duncan|1995|p=553}} where a number of recent volcanoes and volcanic chains can be found.{{sfn|Christie|Dieu|Gee|1995|p=495}} The original location of Takuyo-Daisan closely matches the present-day location of the Society hotspot,{{sfn|Pringle|Duncan|1995|p=548}} and together with Takuyo-Daini, Winterer Guyot and Isakov Guyot appears to form a linear volcanic chain, the Geisha guyots.{{sfn|Vogt|Smoot|1984|p=11086}}
= Composition =
Takuyo-Daisan has erupted basalt{{sfn|Pringle|Duncan|1995|p=549}} containing olivine and plagioclase{{sfn|Christie|Dieu|Gee|1995|p=502}} and which define an intermediary to tholeiitic magma suite.{{sfn|Christie|Dieu|Gee|1995|p=505}} Weathering of volcanic rocks has given rise to calcite,{{sfn|Christie|Dieu|Gee|1995|p=502}} clay{{sfn|Ogg|Camoin|Jansa|1995|p=361}} which also contains coal,{{sfn|Ogg|Camoin|Jansa|1995|p=366}} iddingsite and zeolite.{{sfn|Christie|Dieu|Gee|1995|p=502}} Carbonates occur in the form of floatstone, grainstone, limestone, packstone, oncoids, peloids, rudstone and wackestone;{{sfn|Haggerty|van Waasbergen|1995|p=867}} the limestone is of reefal origin. Hypersthene andesite samples taken from Takuyo-Daisan were probably brought there by ice rafting{{sfn|Heezen|Matthews|Catalano|Natland|1973|p=693}} as no such rocks have ever been found on this kind of volcanic island.{{sfn|Heezen|Matthews|Catalano|Natland|1973|p=684}}
Geologic history
= Volcanism =
Obtaining reliable radiometric ages from Takuyo-Daisan has been difficult; the most reliable age has been obtained from nearby Takuyo-Daini, 118.4 ± 1.8 million years ago.{{sfn|Pringle|Duncan|1995|p=553}} From this date an age of 119.0 ± 1.8 million years ago has been inferred for Takuyo-Daisan.{{sfn|Larson|Erba|Nakanishi|Bergersen|1995|p=927}} A more recent date from Takuyo-Daisan is 117.5 ± 1.1 million years ago. The seamount formed at 9{{sfn|Haggerty|Premoli Silva|1995|p=942}}-7 degrees south from the equator.{{sfn|Haggerty|Premoli Silva|1995|p=941}}
Volcanic activity formed breccia, lava flows with thicknesses of about {{convert|1|m}}{{sfn|Ogg|Camoin|Jansa|1995|p=366}} and volcanic sediments. The volcanic rocks were subject to weathering, forming over {{convert|20|m}} thick soils.{{sfn|Ogg|Camoin|Jansa|1995|p=361}} Phreatomagmatic deposits{{sfn|Haggerty|Premoli Silva|1995|p=943}} and rocks interpreted as peperite have also been found,{{sfn|Pringle|Duncan|1995|p=549}} implying that some lava flows may have interacted with wet soils as they were emplaced. Takuyo-Daisan at this time might have been an{{sfn|Ogg|Camoin|Jansa|1995|p=366}} at least {{convert|138|m}}{{sfn|Larson|Erba|Nakanishi|Bergersen|1995|p=929}} and possibly as much as {{convert|900|m}} high{{sfn|Vogt|Smoot|1984|p=11088}} tropical volcanic island with marshes that were inhabited by bioturbatory organisms.{{sfn|Ogg|Camoin|Jansa|1995|p=366}}
= Carbonate sedimentation =
Carbonate sedimentation at Takyuo-Daisan lasted from the Aptian to the Albian (based on foraminiferal fossils{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=211}}) and led to the deposition of about {{convert|150|m}}-{{convert|200|m}} of carbonate sediment.{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=199}} Carbonate sedimentation took place while the initial volcanic edifice was still emergent, similar to present-day Truk, Micronesia;{{sfn|Ogg|Camoin|Jansa|1995|p=371}} this resulted in terrigenous sedimentation in the carbonates.{{sfn|Ogg|Camoin|Jansa|1995|p=366}} The total duration of carbonate sedimentation is about 15 million years,{{sfn|Haggerty|Premoli Silva|1995|p=946}} {{convert|3|m}} thick distinct sequences in the carbonate sediments may be correlated to Milankovich cycles.{{sfn|Ogg|Camoin|Jansa|1995|p=373}}
The carbonate platform at Takuyo-Daisan featured both barrier shoals and lagoonal environments.{{sfn|Ogg|Camoin|Jansa|1995|p=366}} Biogenic mounds grew at the margin of the platform. Redeposition of carbonate sediments led to the formation of sandy shoals{{sfn|Ogg|Camoin|Jansa|1995|p=370}} which formed the later perimeter ridge.{{sfn|Haggerty|Premoli Silva|1995|p=945}} Overall the environment of the platform was a warm Tethyan environment.
Algae{{efn|Such as Marinella, Neomeris, Pycnoporidium, Terquemella and Zittelina.}}{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=212}} including algal mats,{{sfn|Ogg|Camoin|Jansa|1995|p=365}} bivalves, corals,{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=212}} cyanobacteria,{{sfn|Ogg|Camoin|Jansa|1995|p=365}} echinoids, foraminifera,{{efn|Genera include Arenobulimina, Axiopolina, Bdelloidina, Cuneolina, Daxia, Debarina, Fischerina, Istriloculina, Lituola, Nezzazata, Novalesia, Orbitolina, Paracoskinolina, Trocholina, and Vercorsella.{{sfn|Arnaud Vanneau|Premoli Silva|1995|pp=202-210}}}}{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=212}} molluscs,{{sfn|Haggerty|van Waasbergen|1995|p=867}} nannofossil-forming species{{sfn|Erba|Premoli Silva|Watkins|1995|p=164}} and rudists inhabited the carbonate platform, and arthropods and woods have been found in the oldest carbonate deposits. The fauna of Takuyo-Daisan was not particularly diverse, probably because the seamount was located close to the paleoequator and away from the Tethyan margin that many species found at Takuyo-Daisan originate from.{{sfn|Arnaud Vanneau|Premoli Silva|1995|p=212}}
= Drowning and post-drowning evolution =
The drowning of the carbonate platform at Takuyo-Daisan has been attributed to different causes. A large transgression took place in the late Albian and may have caused the drowning. In other guyots nutrient excess has been implicated but there is no evidence of such at Takuyo-Daisan.{{sfn|Ogg|Camoin|Jansa|1995|p=374}} Other factors may include hostile conditions close to the equator and unfavourable changes of the geomorphology of the platform at the time of its drowning.{{sfn|Ogg|Camoin|Jansa|1995|p=375}} The drowning of the Takuyo-Daisan platform was simultaneous to the drowning of carbonate platforms elsewhere around the world and may have been caused by tectonically-induced sea level fluctuations.
After cessation of the platform activity, manganese crusts{{sfn|Haggerty|van Waasbergen|1995|p=867}} and chalks later modified by phosphate developed on exposed rocks. During the Neogene, oozes,{{sfn|Ogg|Camoin|Jansa|1995|p=361}} terrigenous sediments,{{sfn|Rack|Lawyer|Gee|1995|p=981}} wind-borne material such as pollen{{sfn|Fenner|1995|p=62}} and volcanic ash from the approaching Japanese volcanic arc accumulated on Takuyo-Daisan.{{sfn|Ogg|Camoin|Jansa|1995|p=361}}
Presently, Takuyo-Daisan lies in a region of high plankton productivity which has led to a high diatom{{efn|Diatom genera include Asterolampra, Asteromphalus, Chaetoceros, Cyclotella, Neodenticula, Nitzschia, Odontella, Paralia, Rhizosolenia, Stephanopyxis, Thalassionema, Thalassiosira, Thalassiothrix and Xanthiopyxis.{{sfn|Fenner|1995|pp=73-74}}}} deposition rate{{sfn|Fenner|1995|p=73}} as well as high sedimentation rates in general. Corals and sponges have been found on the seamount; crinoids may also occur there.{{sfn|Fenner|1995|p=76}}
Notes
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References
{{Reflist|refs=
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= Bibliography =
{{refbegin}}
- {{Citation|last1=Arnaud Vanneau|first1=A.|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_10.pdf|date=December 1995|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.002.1995|access-date=2018-08-06|last2=Premoli Silva|first2=I.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Biostratigraphy and Systematic Description of Benthic Foraminifers from Mid-Cretaceous Shallow-Water Carbonate Platform Sediments at Sites 878 and 879 (MIT and Takuyo-Daisan Guyots)|doi-access=free}}
- {{Citation|last1=Christie|first1=D.M.|date=December 1995|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_29.pdf|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.028.1995|access-date=2018-08-07|last2=Dieu|first2=J.J.|last3=Gee|first3=J.S.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Petrologic Studies of Basement Lavas from Northwest Pacific Guyots|doi-access=free}}
- {{Citation|last1=Erba|first1=E.|date=December 1995|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_08.pdf|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.071.1995|access-date=2018-08-07|last2=Premoli Silva|first2=I.|last3=Watkins|first3=D.K.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Cretaceous Calcareous Plankton Biostratigraphy of Sites 872 through 879|doi-access=free}}
- {{Citation|last=Fenner|first=J.|date=December 1995|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_03.pdf|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.006.1995|access-date=2018-08-07|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Siliceous Microfossils in Upper Neogene Sediments from Five Guyots in the Western North Pacific, with Special Emphasis on Diatoms|doi-access=free}}
- {{Citation|last1=Haggerty|first1=J.A.|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_48.pdf|date=December 1995|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.075.1995|access-date=2018-08-06|last2=van Waasbergen|first2=R.J.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Geochemistry of MIT and Takuyo-Daisan Carbonate Platforms Compared with Other Northwest Pacific Guyots Drilled during Leg 144: Implications for Their Diagenetic History|doi-access=free}}
- {{Citation|last1=Haggerty|first1=J.A.|date=December 1995|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_53.pdf|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.074.1995|access-date=2018-08-07|last2=Premoli Silva|first2=I.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Comparison of the Origin and Evolution of Northwest Pacific Guyots Drilled during Leg 144|doi-access=free}}
- {{Citation|last1=Heezen|first1=B.C.|date=November 1973|chapter-url=http://deepseadrilling.org/20/volume/dsdp20_32.pdf|publisher=U.S. Government Printing Office|doi=10.2973/dsdp.proc.20.132.1973|access-date=2018-10-03|last2=Matthews|first2=J.L.|last3=Catalano|first3=R.|last4=Natland|first4=J.|last5=Coogan|first5=A.|last6=Tharp|first6=M.|last7=Rawson|first7=M.|title=Initial Reports of the Deep Sea Drilling Project, 20|volume=20|chapter=Western Pacific Guyots|doi-access=free}}
- {{Citation|last1=Larson|first1=R.L.|date=December 1995|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_52.pdf|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.063.1995|access-date=2018-08-07|last2=Erba|first2=E.|last3=Nakanishi|first3=M.|last4=Bergersen|first4=D.D.|last5=Lincoln|first5=J.M.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Stratigraphic, Vertical Subsidence, and Paleolatitude Histories of Leg 144 Guyots|doi-access=free}}
- {{Citation|last1=Ogg|first1=J.G.|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_18.pdf|date=December 1995|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.043.1995|access-date=2018-08-06|last2=Camoin|first2=G.F.|last3=Jansa|first3=L.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Takuyo-Daisan Guyot: Depositional History of the Carbonate Platform from Downhole Logs at Site 879 (Outer Rim)|doi-access=free}}
- {{Citation|last1=Pringle|first1=M.S.|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_32.pdf|date=December 1995|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.033.1995|access-date=2018-08-06|last2=Duncan|first2=R.A.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Radiometric Ages of Basement Lavas Recovered at Loen, Wodejebato, MIT, and Takuyo-Daisan Guyots, Northwestern Pacific Ocean|doi-access=free}}
- {{Citation|last1=Rack|first1=F.R.|chapter-url=http://www-odp.tamu.edu/publications/144_SR/VOLUME/CHAPTERS/sr144_55.pdf|date=December 1995|publisher=Ocean Drilling Program|doi=10.2973/odp.proc.sr.144.044.1995|access-date=2018-08-06|last2=Lawyer|first2=M.W.|last3=Gee|first3=J.S.|title=Proceedings of the Ocean Drilling Program, 144 Scientific Results|volume=144|chapter=Data Report: Bulk Sediment Composition and Magnetic Susceptibility Variations in Hole 880A, Takuyo-Daisan Guyot|doi-access=free}}
- {{cite journal |last1=Vogt |first1=Peter R. |last2=Smoot |first2=N. Christian |title=The Geisha Guyots: Multibeam bathymetry and morphometric interpretation |journal=Journal of Geophysical Research: Solid Earth |date=10 December 1984 |volume=89 |issue=B13 |pages=11085–11107 |doi=10.1029/jb089ib13p11085 |bibcode=1984JGR....8911085V |language=en |issn=0148-0227}}
{{refend}}