Topographic map of
Zealandia that includes the Tasmantid Seamount Chain (unlabelled, above the label Australia) off the east of
Australia extending from the
Coral Sea southwards into the
Tasman Sea.
The Tasmantid Seamount Chain (alternatively Tasmantid Seamounts, Tasman Seamounts, Tasman Seamount Chain,Tasmantide Volcanoes or the Tasmantids)[2] is a 2,000 km (1,200 mi) long chain of
seamounts in the
South Pacific Ocean. The chain consists of over 16
extinct volcanic peaks, many rising more than 4,000 m (13,000 ft) from the
seabed.[3][4][5]
It is one of the two parallel seamount chains alongside the
East Coast of Australia; the
Lord Howe and Tasmantid seamount chains both run north-south through parts of the
Coral Sea and
Tasman Sea. These chains have
longitudes of approximately
159°E and
156°E respectively.[6]
Like its neighbour, the Tasmantid Seamount Chain has resulted from the
Indo-Australian Plate moving northward over a stationary
hotspot.[7] It ranges in age from about 56 to 7 million years old.[3]
Features
The Tasmantid Seamount Chain includes the following named seamounts:
There is an unnamed seamount between Stradbroke Seamount and Derwent Hunter Guyot and 7 unnamed seamounts in the
Coral Sea near Mellish Reef that have been assigned to the chain.[1] Some of the later have age ranges between 37.0 to 50.5 Ma.[1] Also assigned to the chain are two sampled areas of the southern
Louisiade Plateau with ages of 56.40 ± 0.60 and 55.00 ± 0.40
Ma respectively that are believed to represent the most northern aspects of the chain.[1]
^Only limited sampling and age studies have been done. Ages are available on some of the eleven dredging samples analysed by Eggins et al.(1991) by
K/Ar absolute methodology and some of 32 later samples by the
40Ar39Ar relative methodology. While different specimens from Gascoyne Seamount matched on age, different specimens from Britannia Guyots mismatch by 5 million years odd by the two different methodologies. However adjacant volcanoes can have long eruptive histories. 40Ar39Ar age subsample data as presented in conference proceedings in 2015 is sourced from the appendix published by Douglas(2022).