that it interfered with our bathymetry data acquisition and caused poor quality
results. We decided to leave the site of Macdonald and go to work longer on the
Society hotspot.
In my opinion, the Polynaut cruise seems to be an example of a very well
prepared scientific expedition. Both the scientific and technical participants on the
cruise were well adapted to life on board and to the experience of obtaining data at
sea. They were respectful and cooperative with each other and the atmosphere on
board remained very pleasant during the entire cruise. Captain Tredunic was a
young officer who was eager to help and ready for any last minute changes in the
program. This often happens when exploring an unknown domain. He took particular care and paid tremendous attention to his task of lowering and recovering
the submersible safely on board. I also have to add that when a scientific vessel is
in the vicinity of Pitcairn, and despite any plans to the contrary, it is extremely
difficult to avoid making a stop on the island.
Pitcairn Island
Pitcairn Island is located at 25°05
0 S-130°05
0 W on the southeastern extension of the
Duke of Gloucester-Mururoa-Gambier-Pitcairn volcanic alignment, with a N110°
orientation (Duncan et al. 1974; Jarrard and Clague 1977).
The Island of Pitcairn was discovered July 2, 1767 by captain Carteret on board
the British vessel HMS Swallow. The name Pitcairn was given after the midshipman who first sighted the island from the Swallow. No landing party was sent
to shore. Because of an error in reporting the island’s exact position on the navigation charts at the time, Pitcairn remained unknown and unvisited for the first
18 years after its discovery. Even today, the island is isolated from the routes of
most normal sailing ships, which could be a blessing for the inhabitants. Only four
scheduled supply ships per year will transit to bring mail and other supplies from
the rest of the World.
When Pitcairn was first discovered in 1767, it was uninhabited, but the presence
of stone axes, the remains of carved stone pillars resembling those of Easter Island,
and skeletons wearing pearl mussel shells were found later on. The island is made
up of steep slopes of basaltic lava and dykes standing 430 m high above the sea’s
surface (Fig. 9.12). It is 3.5 km long and about 2.5 km large, located about
2,000 km from Tahiti, 3,000 km from Easter Island and 5,500 km from New
Zealand.
The island itself has a half moon shape that opens to the northeast with a
volcanic crater of 3 km in diameter. The filled crater has a plateau with luxuriant
tropical vegetation (Fig. 9.12). The apparent age of the surface lavas from Pitcairn
Island is between 0.45 to about 1 million years (Duncan et al. 1974; Woodhead
and McCulloch 1989; Devey et al. 2003). The last explosive eruption, which took
place about 600,000 years ago, covered the island with ash and basaltic lavas that
extended down to the ocean (Fig. 9.13). The base of the Island is at 3,800 m depth
324
9 Hotspots
results. We decided to leave the site of Macdonald and go to work longer on the
Society hotspot.
In my opinion, the Polynaut cruise seems to be an example of a very well
prepared scientific expedition. Both the scientific and technical participants on the
cruise were well adapted to life on board and to the experience of obtaining data at
sea. They were respectful and cooperative with each other and the atmosphere on
board remained very pleasant during the entire cruise. Captain Tredunic was a
young officer who was eager to help and ready for any last minute changes in the
program. This often happens when exploring an unknown domain. He took particular care and paid tremendous attention to his task of lowering and recovering
the submersible safely on board. I also have to add that when a scientific vessel is
in the vicinity of Pitcairn, and despite any plans to the contrary, it is extremely
difficult to avoid making a stop on the island.
Pitcairn Island
Pitcairn Island is located at 25°05
0 S-130°05
0 W on the southeastern extension of the
Duke of Gloucester-Mururoa-Gambier-Pitcairn volcanic alignment, with a N110°
orientation (Duncan et al. 1974; Jarrard and Clague 1977).
The Island of Pitcairn was discovered July 2, 1767 by captain Carteret on board
the British vessel HMS Swallow. The name Pitcairn was given after the midshipman who first sighted the island from the Swallow. No landing party was sent
to shore. Because of an error in reporting the island’s exact position on the navigation charts at the time, Pitcairn remained unknown and unvisited for the first
18 years after its discovery. Even today, the island is isolated from the routes of
most normal sailing ships, which could be a blessing for the inhabitants. Only four
scheduled supply ships per year will transit to bring mail and other supplies from
the rest of the World.
When Pitcairn was first discovered in 1767, it was uninhabited, but the presence
of stone axes, the remains of carved stone pillars resembling those of Easter Island,
and skeletons wearing pearl mussel shells were found later on. The island is made
up of steep slopes of basaltic lava and dykes standing 430 m high above the sea’s
surface (Fig. 9.12). It is 3.5 km long and about 2.5 km large, located about
2,000 km from Tahiti, 3,000 km from Easter Island and 5,500 km from New
Zealand.
The island itself has a half moon shape that opens to the northeast with a
volcanic crater of 3 km in diameter. The filled crater has a plateau with luxuriant
tropical vegetation (Fig. 9.12). The apparent age of the surface lavas from Pitcairn
Island is between 0.45 to about 1 million years (Duncan et al. 1974; Woodhead
and McCulloch 1989; Devey et al. 2003). The last explosive eruption, which took
place about 600,000 years ago, covered the island with ash and basaltic lavas that
extended down to the ocean (Fig. 9.13). The base of the Island is at 3,800 m depth
324
9 Hotspots