Takuyo-Daini is a
seamount
A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...
in the
Pacific Ocean.
Takuyo-Daini is part of the so-called "Seiko" cluster or the "Geisha Guyots"
in the
Japanese Seamounts
Japanese may refer to:
* Something from or related to Japan, an island country in East Asia
* Japanese language, spoken mainly in Japan
* Japanese people, the ethnic group that identifies with Japan through ancestry or culture
** Japanese diaspor ...
;
it lies just west of
Takuyo-Daisan
Takuyo-Daisan is a guyot in the Western Pacific Ocean off Japan. It is 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 t ...
seamount with which it forms a pair.
Takuyo-Daini rises from a depth of to a minimum depth of and has a regular round shape with a small volume of .
Both seamounts are
guyots
and together with two other guyots known as
Winterer and
Isakov have been interpreted as being part of a
hotspot track
In geology, hotspots (or hot spots) are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii, Iceland, and Yellowstone hotspots. A hotspot's position on t ...
.
The
Western Pacific Ocean contains a large number of
seamount
A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...
s which often from clusters or groups. Many of them have flat tops below sea level. A number of these formed during a large-scale volcanic episode in the
Albian-
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...
era of the
Cretaceous; this includes Takuyo-Daini, where
radiometric dating has yielded ages of 118.6 million years ago. At the time of its formation this seamount was located in the central Pacific Ocean.
Fossils of
rudist bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
s have been found on Takuyo-Daini; the seamount once featured rudist
reefs that ceased growing during the
Albian.
The rudist genera ''
Magallanesia'' was discovered on Takuyo-Daini and on
Cebu in the
Philippines.
References
Sources
*
{{refend
Seamounts of the Pacific Ocean
Cretaceous volcanoes
Geography of Japan