# Tasmantid Seamount Chain

The Tasmantid Seamount Chain (alternatively Tasmantid Seamounts, Tasman Seamounts, Tasman Seamount Chain, Tasmantide Volcanoes or the Tasmantids) 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. 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.
Like its neighbour, the Tasmantid Seamount Chain has resulted from the Indo-Australian Plate moving northward over a stationary hotspot. It ranges in age from about 56 to 7 million years old.

## Features

The Tasmantid Seamount Chain includes the following named seamounts:
Tasmantid Seamounts :
| Seamount | Location | Age | Notes |
| Gascoyne Seamount | 36°41′00″S 156°07′00″E﻿ / ﻿36.68333°S 156.11667°E﻿ / -36.68333; 156.11667 | 7.13 ± 0.07 Ma | |
| Kimbla Seamount | 35°06′37″S 156°28′32″E﻿ / ﻿35.110323°S 156.475641°E﻿ / -35.110323; 156.475641 | | |
| Taupo Bank | 33°10′00″S 156°10′00″E﻿ / ﻿33.166667°S 156.166667°E﻿ / -33.166667; 156.166667 | 10.3 to 11.4 Ma | |
| Barcoo Bank | 32°35′00″S 156°15′00″E﻿ / ﻿32.58333°S 156.25°E﻿ / -32.58333; 156.25 | | |
| Derwent Hunter Guyot | 30°52′00″S 156°11′00″E﻿ / ﻿30.86667°S 156.18333°E﻿ / -30.86667; 156.18333 | 16.83 ± 0.1 Ma | |
| Stradbroke Seamount | 29°05′00″S 155°45′00″E﻿ / ﻿29.08333°S 155.75°E﻿ / -29.08333; 155.75 | | |
| Britannia Guyots | 28°17′00″S 155°38′00″E﻿ / ﻿28.28333°S 155.63333°E﻿ / -28.28333; 155.63333 | 17.6 to 23 Ma | North, Central and South Seamounts Central Britannia 23.0± 0.2 Ma, South Britannia age 21.68 ± 0.17 Ma |
| Queensland Guyot | 27°35′00″S 155°11′00″E﻿ / ﻿27.58333°S 155.18333°E﻿ / -27.58333; 155.18333 | 20.9 Ma | |
| Brisbane Guyots | 26°59′00″S 155°05′00″E﻿ / ﻿26.98333°S 155.08333°E﻿ / -26.98333; 155.08333 | 27.28 ± 0.15 | Age is North Brisbane North and South Brisbane Seamounts |
| Mooloolaba Seamount | 26°20′S 154°52′E﻿ / ﻿26.33°S 154.87°E﻿ / -26.33; 154.87 | | |
| Moreton Seamounts | 26°01′00″S 154°58′00″E﻿ / ﻿26.01667°S 154.96667°E﻿ / -26.01667; 154.96667 | | North and South Moreton |
| Recorder Guyots | 25°10′00″S 154°55′00″E﻿ / ﻿25.16667°S 154.91667°E﻿ / -25.16667; 154.91667 | 26.4 to 30.0 Ma | North Recorder is younger Named from the British cable ship "Recorder" North and South Recorder Seamounts |
| Fraser Seamounts | 24°26′00″S 155°17′00″E﻿ / ﻿24.43333°S 155.28333°E﻿ / -24.43333; 155.28333 | 26.4 ± 0.2 Ma | Age South Frazer North and South Fraser Not to be confused with Fraser Island. |
| Cato Reef | 23°13′S 155°34′E﻿ / ﻿23.217°S 155.567°E﻿ / -23.217; 155.567 | 31.25 ± 0.16 Ma | Coral reef |
| Wreck Reefs | 22°11′S 155°20′E﻿ / ﻿22.183°S 155.333°E﻿ / -22.183; 155.333 | 31.7 to 32.9 Ma | Coral reef |
| Kenn Reef | 21°12′S 155°43′E﻿ / ﻿21.200°S 155.717°E﻿ / -21.200; 155.717 | | Coral reef |
| Mellish Reef | 17°25′00″S 155°50′00″E﻿ / ﻿17.41667°S 155.83333°E﻿ / -17.41667; 155.83333 | | Most northern coral reef of seamount chain |
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. Some of the later have age ranges between 37.0 and 50.5 Ma. 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.

## Geology

The volcanics are saturated tholeiitic to transitional alkali-olivine basalt.

### Age note

* ↑ 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 $^{40}$Ar$^{39}$Ar 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 adjacent volcanoes can have long eruptive histories. $^{40}$Ar$^{39}$Ar age subsample data as presented in conference proceedings in 2015 is sourced from the appendix published by Douglas(2022).